LU100676B1 - Method and device for producing articles of metal - Google Patents

Abstract

A method or apparatus for producing a metal object wherein a metal wire progressively in layers by means of a wire-carrying primary electrode in the resistance welding method is welded spotwise or in sections, passing through the main body of the wire-guiding primary electrode, a channel through which the metal wire in the solid state passed and in or just below the mouth, this channel through which the metal wire is led out of the wire-carrying primary electrode is bent at a very small bend radius to apply it flat by sliding the lower contact surface of the wire-guiding primary electrode below the mouth of the channel the metal wire is placed on an adjacent metal surface and welded pointwise, wherein the metal surface is a support plate, or on a previously attached metal wire layer, the method fol (b) moving the wire-guiding primary electrodes relative to the metal surface and simultaneously laying out a metal wire length corresponding to the movement on the adjacent metal surface, (c) repeating steps (a) and (b) to form the metal article by successive welds and movements; and wherein, in addition to these steps, the method further optionally comprises the following step: (d) conducting a further electrical current from a secondary electrode by means of steps (a) and (b) already spotwise and partially welded metal wire around this at least partially additionally, preferably on the total in one or more of the steps (b) laid out length, heat up and stronger to connect with the adjacent metal surface even merge with this possibly completely melt.

Description

METHOD AND DEVICE FOR PRODUCING OBJECTS FROM METAL

Technical Field The present invention relates generally to a method and apparatus for making articles of metal.

Background Art [0002] In the world of additive manufacturing methods, there are different devices for making metal objects. The dominant methods are selective laser sintering and selective laser melting. For this purpose, there is the method of applying metal by resistance welding by means of a movable electrode to an object as described in the patent US 6443352. In this case, metal is connected to one another by the heat generated by the flow of current in the metal at the contact surface with the already applied metal. This method implements a wire electrode that applies metal wires to three-dimensional objects, and 3D printers that use this method are not available for the general household, unlike other plastic 3D printers that are available in abundance.

Today's metal 3D printers prove to be complex, expensive and cumbersome devices. In contrast to the plastic FDM 3D printers, which already have a large number of people at home, they are unsuitable for the masses of people. The available so-called desktop 3D printers can mainly produce only plastic objects with low strength and temperature resistance compared to metals. Printing a metal object for a wide variety of applications is too expensive and cumbersome for most people and therefore out of the question.

OBJECT OF THE INVENTION It is therefore an object of the present invention to provide a method and a corresponding device with an easy-to-handle technique which allow metal objects to be produced in good quality and strength and are also cost-effective. In addition, a corresponding device should be relatively small and light to space, building material and thus save costs.

General description of the invention This object is achieved according to the invention in a first aspect by a method for producing a metal object wherein a metal wire progressively in layers by means of a wire-guiding primary electrode in the resistance welding process stretched or spot welded, wherein by the main body of the wire-leading The primary electrode is a channel through which the metal wire is passed in the solid state and in or directly below the mouth of this channel through which the metal wire out of the wire-guiding primary electrode, laid out on an adjacent metal surface and welded pointwise or pointwise, wherein the Metal surface is a carrier plate, or a previously attached metal wire layer, the method comprising the steps of: (a) For distance or pointwise resistance welding, passing an electrical Stromsto from the wire-guiding primary electrode through the metal wire to the adjacent metal surface, (b) moving the wire-guiding primary electrodes relative to the metal surface and simultaneously laying out a length of metal wire corresponding to the movement on the adjacent metal surface, (c) repeating steps (a) and (b) to form, by subsequent line or spot welds and movements, the metal article layer by layer, and in addition to these documents, the process further comprises the following: (d) passing a further electrical current from a secondary electrode through Steps (a) and (b) metal wire already welded in sections or points in order to at least partially heat, in addition, preferably over the entire length laid out in one or more of the steps (b), and fuse with the adjacent metal surface, ie stronger to connect by resistance welding Or even to merge with this possibly completely melt.

Preferably, the metal wire is bent laterally during laying out at the mouth of the channel of the wire-guiding primary electrode during step (b). More preferably, the metal wire is bent at a very small centerline radius, e.g. 0.5 * q <centerline radius <3 * q, where q is the diameter of a round wire or the width / thickness of a different shaped wire to be applied flat by sliding the lower contact surface of the wire-guiding primary electrode below the mouth of the channel the metal wire to the adjacent metal surface, ie the support plate, or on a previously attached metal wire layer, placed.

The bending of the metal wire can be done on the one hand by guiding and friction along the mouth of the wire-guiding primary electrode. The mouth may comprise or consist of a different material from the body. Particularly preferably, the different material is a ceramic material or a different / different from the base metal.

On the other hand, the bending of the metal wire can also be done by heating the metal wire and moving the wire-carrying primary electrode.

The channel of the wire-guiding primary electrode can be closed laterally, i. be tubular. In other embodiments, however, the channel may also be open and correspond to a notch attached laterally to the body through which the metal wire is passed and which terminates in an orifice to the bottom surface of the wire-carrying primary electrode.

The mouth of the channel of the wire-guiding primary electrode preferably comprises an annular contact surface. Under such a contact surface of the metal wire during application can advantageously rotate around it in order to apply it in any direction of a plane can. The contact surface is preferably configured such that it can transmit at least a portion of the current from the wire-guiding primary electrode to the metal wire.

In a preferred embodiment, the channel of the wire-guiding primary electrode (in and short) above the mouth wider than the remaining part of the channel so as to facilitate or allow the bending of the metal wire and thereby to ensure that the wire-guiding primary Electrode with the lowest contact surface can rest on the wire. More preferably, the wider part extends for a length from the bottom of the mouth of the channel along the centerline of the channel, which may be between 0 and 4 * q, where q is the wire diameter of one round wire or the width / thickness of another shaped one Wire is.

Alternatively, the wire-carrying primary electrode may also apply the metal wire without resting on the bottom surface of the top of the metal wire.

Advantageously, the metal wire is preheated by means of a wire leading primary electrode upstream, second electrode by conducting a second current (shock). For this purpose, the second electrode is preferably arranged inside the main body of the wire-guiding primary electrode.

During the process, the guidance of the metal wire through the channel by a motorized feed, preferably by adhesion via rollers, are supported.

The cross section of the metal wire may be round or any other shape. An embodiment sees e.g. suggest that prior to the introduction of the metal wire in the wire-guiding primary electrode whose cross-section, preferably by rolling, is changed.

The movement of the wire-guiding primary electrode relative to the carrier plate is designed so that it can be performed in three dimensions, wherein in step (b) either only the wire-carrying primary electrode, or only the carrier plate, or both are moved. For example, For example, the primary electrode may be movable in only one (vertical, Z) direction, in which case the carrier plate is movable in the other two (X and Y) directions. In another variant, the carrier plate is firmly mounted and the primary electrode can be moved in all three directions.

Advantageously, in step (d), a pressure is exerted on the heated metal wire to press the underlying, in the case of at least partially melted metal wire, metal wire flat, for example.

The electrical opposite pole of the secondary electrode is usually the carrier plate. In an advantageous embodiment, the opposite pole can also be one or more further counter-pole secondary electrode (s) which can be placed on the metal object.

Preferably, the mouth of the wire-guiding primary electrode, if necessary, or the tip of the secondary electrode can be reground automatically if necessary, particularly preferably by means of a grinding surface adjacent (i.e., in the vicinity of the corresponding electrode and within the range of its movement unit).

The method may further comprise a step of additionally shaping the article from metal during and / or after its completion, e.g. by means of a movably arranged metal-removing tool, preferably a movably arranged grinding surface or a movably arranged milling cutter.

The metal wire is usually a wire made of a metal or a metal alloy. In some cases, it is advantageous that such a metal wire additionally comprises a sheath with fusible solder material, wherein the solder material has a melting temperature which is expediently below that of the metal wire.

The metal object is solved by the carrier plate after its completion and can then be removed.

In a second aspect, the invention relates to a device for producing articles of metal by progressively layered application and resistance welding of a metal wire. The device comprises means which are suitable for the execution of the method, or adapted / configured.

The device preferably comprises a power supply designed to generate electrical surges for resistance welding, a wire-guiding primary electrode for guiding and pointwise or in sections resistance welding of a metal wire, wherein the wire-carrying primary electrode is connected to the power supply, a support plate for receiving the metal object to be produced, the support plate being connected to the power supply, possibly a secondary electrode, wherein the secondary electrode is connected to the power supply, one or more movement arrangements is designed / are the wire-carrying primary, optional and / or secondary electrode and to move the support plate relative to each other in three dimensions, a control unit for controlling the movement assembly (s) and the power supply, wherein through the main body of the wire-guiding primary electrode, a channel passes through which the metal wire in fe most state can be performed up to an orifice of the channel and can be designed in point or in sections in or directly below this mouth on an adjacent metal surface, and wherein the metal surface is a support plate, or on a previously attached metal wire layer.

The mouth of the channel of the wire-guiding primary electrode preferably comprises a different material from the base body or consists of this, preferably a ceramic material or a different metal.

The mouth of the channel of the wire-guiding primary electrode may comprise an annular contact surface and be configured to transmit at least a portion of the current from the wire-guiding primary electrode to the metal wire.

The device further advantageously comprises a second electrode arranged upstream of the wire-guiding primary electrode and designed to preheat the metal wire by conducting a second current, wherein preferably the second electrode is arranged within the main body of the wire-guiding primary electrode. [0028] It may further be provided a motorized feed is designed to guide the metal wire through the channel, preferably by traction over roles to support.

The apparatus may further comprise rollers preceding the wire-guiding primary electrode which are adapted to change the cross-section of the metal wire prior to its insertion into the wire-carrying primary electrode.

The moving unit is preferably designed to move either only the wire-guiding primary electrode, or only the support plate, or both.

As already mentioned above, the opposite electric pole of the secondary electrode, the support plate or another on the object of metal can be placed opposite polarity secondary electrode.

In a further embodiment of the device, an adjacently mounted grinding surface is provided which is suitable to regrind the mouth of the wire-guiding primary electrode or possibly the tip of the secondary electrode.

Particularly preferably, a movably arranged metal-removing tool is further arranged in the device, advantageously a movably arranged grinding surface or a movably arranged milling cutter, which is suitable for additional shaping of the metal object during and / or after its completion and can be used if necessary ,

An apparatus according to the invention, referred to herein by analogy with the known plastic FDM 3D printers, also simply called a 3D printer, does not require an artificial protective atmosphere, ie no protective gas, for printing with steel. Different wires made of different metals or alloys can be used to "print" with a described 3D printer. The price and geometrical dimensions of a device according to the 3D printing method described herein is only a fraction of a common model available on the market. Relatively large objects in comparison to the size of the 3D printer can be produced with the so-called 3D printing process according to the invention from metal wire.

The method, in principle, involves the process of making an object layer by layer of wire of metal in an automated process. In this case, the wire is passed through a primary electrode of a three-dimensional printer and placed on a platform (carrier plate) or an already created layer or part of an object and connected by electric current in the resistance welding process. The electrode that carries the wire, the wire and the carrier plate or build platform close a circuit when the wire makes contact between the electrode and the build platform. The electrode has a channel through which the wire is passed. At the lower end of the electrode, where the wire is led out, there is a contact area which, in principle, is mostly parallel to the layer to be created. In the region of the mouth of the channel of the wire-guiding primary electrode, the wire makes a bend at an angle which, ideally, e.g. about 90 °. The wire is then bent directly out of the mouth. The lower, preferably annular, contact surface of the primary wire-guiding electrode slides over the wire and releases surges, and preferably applies additional pressure to the wire. The electrode preferably does not rotate around itself in the manufacturing process, but moves e.g. only in the direction of the levels. The wire often forms the highest electrical resistance portion in the closed circuit during welding and is heated by the current flow therethrough and can thereby make a metal connection at the point of contact with the metal on which it is seated. By moving e.g. the electrode to the build platform (or vice versa), the wire is placed below the mouth of the wire-guiding primary electrode in the plane of the layer to be created. With a channel in the wire-guiding primary electrode, which is advantageously perpendicular to the plane of the layer to be created and thus the bending of the wire in the mouth of this electrode, e.g. is an angle of 90 °, the wire can be applied in all directions in the plane of a layer, as it were, without the need for a self-rotating electrode driving the wire. In addition, the wire with the primary electrode, which leads the wire out through a channel and directly bends it, can be easily applied in any way without the wire being pinned on top of other adjacent wire paths and blocking further application.

After applying a layer of cross-section in principle completely unchanged paths of wire with the primary electrode, preferably drive secondary electrodes so "printed" layer of adjacent wire paths in places and edit the wires in the resistance welding method further stronger if necessary Make connections between them to generate three-dimensional objects.

In the welding process with the secondary electrodes, the wire webs can be melted kompleit and fuse together to produce isotropic objects. Strong connections can thus be made everywhere between the wire paths applied with the primary electrode. The wire paths of, for example, standard round wires may be flattened by the secondary electrodes and flattened to a flat plane on which turn round wires with the primary electrode can be precisely applied. By such a fusion of the wire webs together disappears the pronounced groove pattern that would otherwise be present in cross-section almost unchanged stacked wires. The shape of the sheets of wire is thus changed by the welding process with the secondary electrodes. By printing with the fusion of the wire paths with the secondary electrodes, it is easy to make airtight objects unlike the wire application with only the primary wire leading electrode. By the thus achieved fusion of the layers with each other, can large

Tensile forces are transmitted between the layers and each applied part of a wire.

Preferably, the electrodes are attached to a printhead. At this cooling is preferably also attached, which consists for example of cooling fins to cool the electrodes. As a matter of principle, the secondary electrodes generally use up in the welding operations and their lower contact surface can therefore be advantageously ground down step by step by sliding over a grinding surface which is fastened to the printer. This ensures a clean electrode surface at all times. The electrodes are preferably interchangeable and advantageously there are various types of electrodes that can be used.

With the method according to the invention and with a device described here different metals and alloys can be "printed". For example, items made of steel, stainless steel or aluminum can be produced.

With the wire-guiding primary electrode, very thin wires with a diameter of e.g. 0.1 mm can be applied precisely. By simply changing the primary electrode, other wires can be printed quickly and easily and there is a large variation in the diameter of the wires that can be printed with a printer device. The primary electrode is particularly suitable for attaching the wire only slightly and applying it in a form-fitting manner.

By the optional flat melting of the wires with the secondary electrode (s), it is also possible to set the final height of a layer. The simultaneous coalescence by the secondary electrodes of the wires that will be made part of the article will result in more equality and uniformity in the structure of the articles, making them more stable and aesthetic. Welding with the secondary electrodes allows a solid connection between the material of the individual wires and between them. This is especially true for the connection between the inner material and the walls of the objects to be created.

The primary wire-guiding electrode may be stationary, that is to say rigidly connected to the frame of the 3D printer, or it may be movable. If the electrode is movably attached to the device, it is preferably driven by motors and places the paths back in order to be able to apply the wire on the required paths. When the electrode is rigidly mounted, the build platform / carrier plate moves to apply the wire to the desired locations. Both the electrode and the build platform can be made as self-moving parts.

As a material for the electrodes is a hard good electrically conductive material such as forged copper or a copper alloy or an electrode of a plurality of materials, which consists for example mainly of copper and the tip with the contact surface to the wire made of tungsten. Where the copper provides better electrical and thermal conductivity properties and the harder material such as tungsten at the contact surface for a hard lower wear surface. It is good if the electrode contact surface has a high melting point to better withstand high heat and of a material to which the wire is applied will not stick too much to the electrode in the transmission of current.

The controller (or control unit) of the 3D printer controls the so-called printing operation and gives the power supply the signals for current delivery. The power supply of the primary wire-guiding electrode can also be separated from the motion control and be operated independently, but this usually brings disadvantages. Also, the power supply of the primary lead-wire electrode may be controlled partly by the overall control unit of the printer via the software, and partly by hand-operated regulators on the printer with which one can simply change parameters such as the current during the printing process.

A round cross-section is suitable for the channel in the wire-carrying electrode through which the metal wire, the material is passed, so that a rotation of the wire in the channel of the electrode is possible. Other cross sections are also possible. The channel must be at least as wide as the wire being used and the channel should have a smooth surface and be as straight as possible so that the wire can be moved easily. The wire coming out of it directly outside the wire-guiding electrode has a small cross section in relation to the rest of the circuit and a very high electrical resistance. Therefore, when strong electric current is passed through the wire from the wire-carrying electrode, the wire directly under the primary electrode heats up strongly. Due to the resulting heat in the wire, the wire can melt locally or completely, or with the contact surface of the metal on which the wire rests a punctiform or partially metallic connection and thus connect with adjacent tracks of metal wire.

Particularly suitable is a round wire, because of its small point or linienweise Kontaktflche which facilitates resistance welding.

The wire can also melt when applied with the primary electrode in places over the entire cross section and fuse with the layer to make solid connections. The force pushing the wire through the wire-carrying electrode presses the wire against the surface on which it is applied.

Thus, the resting of the wire-guiding electrode on the wire is easily possible at the location of the lower mouth of the channel of the wire-guiding electrode should be enough space in which the bending of the wire, which is necessary to lay the wire flat in the plane , can be done. In order to have enough room for the bending of the wire, the channel in the wire-guiding electrode is preferably wider than the width of the wire and in principle wide enough to allow the bend or the area at and just above the mouth of the channel is wider than the rest of the channel and shaped so that the bending of the wire can take place. It is usually important to keep the lowest width in the area of the mouth small, while ensuring that the bending of the wire can be carried out properly and reliably by means of tensile or compressive forces in order to be able to apply the wire more precisely. Therefore, a push device which presses the wire through the wire-carrying electrode is also suitable. Such compressive force pushing the wire through the channel allows for smaller bending radii of the wire and thus more accurate application and less wear of the wire-carrying electrode because it does not have to exert lateral pressure on the wire around the wire

Movement relative to the electrode must pull out to the object to be created. In addition, the electrode does not have to rest with the lowest surface at the level of the layer to be created. In addition, there is the glow of the wire in or below the mouth of the electrode, through the heat conduction in the wire section is welded. This is usually important for applying thicker wires.

The invention thus also relates to a method which makes it possible to produce metal objects in an automated process by the layered application of a metal wire with a wire-carrying primary electrode through which a channel passes through which the wire is passed and in or directly below the mouth of this channel, where the wire is led out of the electrode, is bent over an angle which is ideally about 90 ° so that it can be made flat on a metal surface at which it by current transmitted from the primary electrode to him in the resistance welding process for the most part applied uncross-sectionally and is usually only slightly tacked. The wire is applied by the layer-wise printing with the primary wire-guiding electrode in the correct locations according to the pattern of the respective cross-section of the object to be created. Secondary electrodes continue to drive after a layer has been applied from adjacent mainly cross-sectionally unmodified wire webs, the layer automatically on, put on her in places and further weld the wire webs in the resistance welding process to make tighter connections. In this case, the secondary electrodes can melt the wire webs under their contact surface into a flat, flat section made of wires fused together and flattened. The contact surfaces of the secondary electrodes, after a number of welding operations, due to wear of the contact surface by pressure welding, can be automatically abraded or abraded by a tool so that the contact surface maintains a good quality for the welding operations that it must perform.

The invention also preferably relates to a device, namely a so-called 3D printer, for producing objects made of metal, wherein the device comprises at least one primary wire-carrying electrode through which a channel passes through which a metallic wire in the solid state are passed can emerge from the mouth of the channel and after a process of bending under the lowermost surface of the primary wire leading electrode is pressed against the surface on which it is applied and by current transfer from the wire carrying electrode to the wire in the resistance welding process with the metal surface which the wire is applied is connected. For this purpose, the device preferably also has at least one secondary electrode, which put on the applied with the primary wire leading electrode webs of wire and these together with each other stronger in the resistance welding process with each other. In this case, the mainly cross-sectionally changed already designed with the primary wire leading electrode on adjacent tracks wire in cross section can be changed by the plate melting with the secondary electrode, so that the wire loses height and with the surrounding tracks of wire and the existing metal material of the piece which the wire is piled up can be fused.

Preferably, the device may be operated with the following (replaceable) types of the electrode, or may include the following further features: - with a primary wire-guiding electrode in which the lowermost surface is an annular contact surface which is on the bent, from the Mouth of the channel of the electrode carried out, rests part of the wire and transfers most of the current from the wire-carrying electrode to the wire to weld it.

- With a wire-carrying primary electrode with a channel which is wider just above the mouth of the channel to space for the deflection of the wire in each direction in the plane as it allows to and so as to reliably apply the wire can. In this case, the electrode with the lower contact surface can be placed on an applied wire part at the level of the uppermost surface of the layer which is being applied, and slide over when the layers are applied flat and parallel to one another.

- With a wire-guiding primary electrode with lower area with annular contact area for welding, wherein the lower cross-section has an unchanged cross-section at a defined height and is removed by the wear of the contact surface of the electrode during wire application and welding.

- With a wire-guiding primary electrode with ceramic tip, the

Press wire against the surface can be applied to this.

- With a wire-carrying primary electrode with a tip of a different metal than that of the base.

- With a wire-carrying primary electrode which is not created during printing with its lowest surface on the surface of the layer is created and exerts no pressure from above the wire, but the power for welding by a free-standing piece of wire from the Channel comes out and is located between the primary electrode and the layer being created.

[0058] - with a wire-guiding primary electrode, the one inner second

Has electrode which can preheat the wire through the line of a second current flow therethrough.

- With motorized advancement of the wire over rollers which pushes the wire through the electrode and helps to bend the wire in or below the mouth of the channel.

- With an additional electrode which preheats the wire before it into the channel of the primary wire-carrying electrode by passing a current through the wire.

- With a device which rolls the wire in another form before it is introduced into the primary electrode.

[0062] with secondary electrodes of a defined height on which the

Electrode is present uncross-sectionally, so that by wear and grinding of the lowest contact area for welding, welding can be continued with the same conditions.

During the welding process with the secondary electrodes, the complete

Melting and dissolving the wires under the secondary electrode (s).

[0064] With secondary electrodes, any shape of the lower one

Have contact surface.

With secondary electrode with raster surface.

With rolling wheel electrode as a secondary electrode.

- With subsequent resistance welding with a plurality of mutually insulated gegenpoligen each other located secondary electrodes between which the welding current flows.

[0068] with two opposed rolling wheel electrodes as secondary electrodes for resistance welding.

With roller wheel electrode as a secondary electrode whose contact surface for

Welding is continuously or automatically reground step by step.

[0070] - With attached passive, rigidly mounted on the machine

Sanding surface consisting of sandpaper, a file or a grindstone or other rough material on which the electrode surface of the electrodes can be removed.

- With attached active, offset by a motor in motion

Grinding surface, Fraser, file or other metal-removing tool.

[0072] with a plurality of secondary electrodes connected by a common electrode

Stepper motor are individually linearly moved via a camshaft.

[0073] - with an attached milling head on the print head, which can run off and scrape off the contours of a printed layer.

- With the application of solder material sheathed wires with the primary wire-guiding electrode to produce three-dimensional objects with wire with different possible cross-sections.

- Sections of the round wires are melted kompleit and pressed flat.

[0076] With a milling head attached to the printer, the contours of the

Can cut off layers.

In summary, depending on the embodiment, the invention has one or more of the following advantages: no expensive dangerous laser necessary [0079] no inert gas or artificial atmosphere for various metals and

Alloys Required - Wires may be applied adjacent to each other, which means that less support material is needed.

[0081] It is easy to place a plurality of wire-guiding electrodes next to each other on the

Printhead to be attached - no rotation of the electrode is needed [0083] - easy change from the printing material [0084] - several metals printable - low weight and small dimensions of the 3D printer when large

Construction Space - Fabrication of Composites Possible - It is easy to apply a Fraser to further process the contours of the layers. Particularly in the case of the layers fused together by the secondary electrodes, the contours of the layers can be smoothed by milling only a very small amount of material and brought into a considerably more detailed form.

- no metal powder needed - no flash arc with a bath of liquid metal in the

Wire is introduced and melted.

- Adjustable layer height with a wire with the secondary

Electrodes - Fusion of laterally juxtaposed wires to each other by melting, flattening and flattening of the wires by resistance welding method - favorable operation - large difference in the possible printable layer heights and thus the printing speed and detail accuracy, with round wires which have, for example, between 0.1 mm to 1 mm in diameter, with only one change of the wire-carrying and -priming primary electrode - printing with standardized round wires which are flattened and thus give a smooth surface - heat to each other Melt that first to the

Contact points happens, accumulates particularly quickly in the material on the contact surfaces, so that they can merge together. Thus, several layers can be applied one above the other with the wire-guiding electrode and be fused in a welding process with the secondary electrodes.

- The disappearance of the graded lines on the surfaces by the fusion of the wire webs together - it is easy to make a strong connection between the inner padding material and the outer walls of the printed objects.

Creation of a flat flat surface of the lower layer by flattening and fusing the round previously applied wires so that the next layer of round wire webs with their center lines can always be applied to it at the same height.

- Smooth surface possible by merging with the secondary electrodes - by grinding the electrodes gives a long operating time - in contrast to the rolling wheel electrode which applies the wire can, with the wire-guiding primary electrode with channel of Wire is applied in any desired way in a layer that is created without the wire being applied to and welded to other laterally adjacent wires centered over the laterally adjacent wires, which hampers the wire application process and is likely to fail blocking the rotation of the rolling wheel electrode so caused would break because the spot weld is not directly below the axis of the rolling wheel electrode and therefore the unwanted weld on a laterally adjacent wire path would have to be ruptured to drive the rolling wheel electrode to continue to apply the wire in another direction.

- Isotropic material properties of the printed objects by the complete merge by means of secondary electrodes. Thus, internal forces in printed objects are transmitted uniformly over large areas.

It is easy to produce hermetically sealed objects - disappearance of the graded lines at the edges and surfaces of the layers, by the coalescence of the layers through the secondary electrodes, at which stress concentrations under mechanical stress can occur, which reduce the stability , And so even smoothed surfaces of the printed objects are the result.

- precise design of thin wires possible - the outer dimensions of the wire-carrying electrodes with channel do not differ for wires of different thicknesses, so that they can be easily replaced - the wire is not led into a molten bath where It is then melted or layered juxtaposed or layered to create the geometry of an object in layers and is joined by resistance welding at the contact surface to the surrounding wires, either with or without handling the liquid phase of the wire.

Brief Description of the Drawings Embodiments of the invention will now be described with reference to the accompanying drawings.

Fig. 1 shows an embodiment of a 3D printer having a primary wire-guiding electrode, with three secondary electrodes, with a build platform on which an object is stacked and with a mounted on the printer housing grinding surface on which the contact surface of the secondary electrodes can be ground ,

Fig. 2 shows an embodiment of a printhead in the application of wire to the primary wire-carrying electrode.

Fig. 3 shows an embodiment of a primary vertical channel lead-wire electrode to the surface to which it applies a metal wire.

Fig. 4 shows an enlargement of the mouth of the channel of a primary wire-guiding electrode when wire is applied. Fig. 5 shows a general embodiment of a primary wire-guiding electrode.

Fig. 6 shows an embodiment of a primary wire-guiding electrode having a lower portion with a contact surface for welding the wire, which is intended to be worn and worn during the printing process.

Fig. 7 shows an embodiment of a primary wire-guiding electrode with inner second electrode for preheating the wire in the channel of the electrode.

Fig. 8 shows an embodiment of a primary wire-guiding electrode which, when a wire is applied, does not rest on the wire with the lowest surface and does not exert downward pressure on the wire.

Fig. 9 shows an embodiment of a primary lead-wire electrode with a ceramic tip.

Fig. 10 shows an embodiment of a block in which secondary electrodes are mounted.

Fig. 11 shows an embodiment of a secondary electrode with exchangeable tip.

Fig. 12 shows another embodiment of a secondary electrode.

Fig. 13 shows an embodiment of a secondary electrode having a different contact material as the main part of the electrode.

Fig. 14 shows by way of example the operation of fitting and welding with a secondary electrode.

Fig. 15 exemplifies the process of welding with a secondary electrode in cross section.

Fig. 16 shows an example of a structure created from round in cross-section unchanged metal wires which were applied with a primary wire-guiding electrode.

Fig. 17 shows an example of a structure of metal wires fused together by the combination of the printing operation with the application of wire webs with a primary wire-guiding electrode and subsequent flat-melting with a secondary electrode.

FIG. 18 shows an embodiment of four secondary electrodes bonded to one another for resistance welding with more focused heat development in the metal to be welded. FIG.

Fig. 19 shows two opposed interconnected and electrically isolated electrodes for resistance welding with more focused heat development in the metal to be welded.

Fig. 20 shows a secondary electrode with a raster-shaped contact surface.

Further details and advantages of the invention can be taken from the following detailed description of possible embodiments of the invention with reference to the accompanying figures.

DESCRIPTION OF MORE EMBODIMENTS OF THE INVENTION FIG. 1 shows an embodiment of an automated device, also referred to herein as a 3D printer, with the implementation of the following main components: the printhead 105 to which the primary wire-guiding and wire-applying electrode 103 is attached, and the like Power cable 106 of the electrodes, the block 130 with the secondary electrodes 132, 133 and 109, the grinding surface 114, the build platform 101 with the attached power cable 107, and the housing 117 with built-in control unit and with integrated movement mechanism.

Referring to Fig. 1, an article 102, an art object, is manufactured on the build platform 101 by the layer-wise application of the metal wire 104, which is thus the fabrication material. The wire 104, for example a round cross-section stainless steel wire, is unwound from a roller and moved by a stepper motor whose axis 112 drives a roller 110 mounted thereon between which and an opposing roller 111 the wire 104 is driven and through which 3, channel 302 of the primary wire-carrying and -towing electrode 103 is conveyed. The wire-carrying electrode 103 is screwed into the printhead 105 moving in a plane parallel to the build platform 101 and is perpendicular to the channel 302 to the build platform 101. The wire 104 will be partially within the channel or entirely outward below the mouth of the wirewound electrode channel 302 103 bent at a substantially right angle, in a very small bending radius, so that it is pressed flat against the surface of the previous layer and by means of electricity between the primary electrode 103 and the building platform 101 and the object 102, through the part of the wire 104 flows below the electrode 103, applied by resistance welding and welded. In this case, webs of wire, according to the pattern of the respective layer of the cross section of the object 102, are juxtaposed side by side for the most part with short current impulses only slightly attached. In this case, the metal wire 104 is connected point-wise or in sections only in the fixed, mostly uninterrupted, state with the metal surface adjacent to it. The wire webs applied with the primary wire-guiding electrode 103 are thus usually weak with each other and with the

Surface on which they are applied and can be easily torn from this surface, without tearing. On the other hand, the wire can be patterned as quickly, accurately and with great certainty and with little wear on the electrode 103. Metal articles of only successive layers of coated round wire webs have lower strength and inferior mechanical properties in most directions, as compared to articles of isotropic and homogeneous structure, for example cast articles. Therefore, after a new layer has been applied to the primary electrode 103, the secondary electrodes 132, 133, and 109 housed in the metal block 130 connected to the printhead 105 can locally approach the new layer of wire paths make contact with their surface and transfer pressure and current to the layer in order to process the layer stepwise in the resistance welding process, thereby substantially improving the properties of the object 102. The secondary electrodes can melt the wire webs of a layer, which are applied with the primary wire-applying electrode 103, in cross-section completely unchanged, flatten them and allow them to be melted together into a unitary part of the article 102 in which the secondary electrodes carry a strong current flow guide them through. The secondary electrodes wear out during the printing process. Their contact surface is increasingly contaminated and worn with increasing number of welds and is therefore preferably automatically removed in stages by sliding over the grinding surface 114 so that the contact surface is as clean as possible so as not to affect the welding result and to allow a much longer life of the secondary electrodes, the It makes it possible to produce larger objects without interruption. The next layer is applied again in the same procedure.

The mostly existing standardized wires have a round cross section, this cross section is particularly suitable for printing by means of the primary and secondary electrodes, because the wire through the circular shape of the cross section has an increased electrical resistance in the direction perpendicular to the plane on which the wire is applied flat. For this purpose, the round wire is located only with a very small area, so that the resistance welding process, the current flow and the heat generation is concentrated at the point where the wire rests, which allows the creation of a compound with relatively low current flow. In addition, the round wires already applied can easily be melted and deformed under the secondary electrodes because of their usually higher electrical resistance compared to the rest of the circuit and much less heat transfer from the wire to the electrode and the surface on which it is made rests, because of the very small contact surface. This, in turn, causes a lot of heat to quickly build up in the wire instead of being quickly drained, in which case the necessary melting temperature would not be achieved.

By providing pauses during the printing process, the wire can be changed and, if necessary, the support material can be removed, in addition, parts can be introduced to the objects created at locations which are no longer accessible after the printing operation. In addition, it can be determined via a sensor whether there is still wire on the coil.

The build platform 101 is linearly mounted on the rails 124 and is moved up and down by the stepper motor 128 which drives a spindle.

Power to the build platform 101 could also be transferred via contact on an electrically conductive rail. Via a display 119 and a knob 118 on the printer housing, the device can be operated. The printer is connected to a power outlet.

2 shows the part of the print head 105 of FIG. 1 with the electrode 103 applying the wire 104 during the printing process of an object 205, a screw-on angle, and with. FIG the wire-applying electrode 103, which moves relative to the build platform 206 and thereby applies the wire 104. The print head 105 in FIG. 1 is mounted linearly on the guide rails 122. It is driven by stepper motors 127 via pulleys 126 moving belts 125, so that the position of the print head 105 can be adjusted to the build platform 101. In Fig. 2, the roller 111 is pressed against the wire 104 by a spring 204, which transmits a force to the jack 203, which in turn transmits a force to the roller 111. As a result, the wire 104 is also pressed against the roller 110. By operating the hoist 203, the wire 104 can be inserted from the electrode 103 and carried out. The force of the spring 204 on the Hebei 203 could be adjustable with a set screw. The channel 302 of FIG. 3 inside the electrode 103, through which the wire 104 is passed, is substantially perpendicular to the building platform 206 and so also the wire-carrying electrode 103 in order to apply the wire 104 in all directions as it can. At the mouth of the channel 302, or shortly below, under the electrode 103, the wire 104 is bent over, as here by the angle of usually 90 ° so that it can be applied parallel to a layer and parallel to the surface of the build platform 206. The construction platform is connected to the power cable 207 opposite to the wire-guiding electrode 103.

The rollers are arranged so that the wire driven between them is led directly into the channel 302 of the wire-guiding electrode 103. Therefore, the obéré part 303 of Fig. 3, the wire-guiding electrode 103 is advantageously tapered and conically shaped. By changing the electrode 103 to print with another wire, the distance between the channel and the rollers is also properly adjusted. The wire could also be passed into a thin channel and tapered tip portion which would be mounted between the wire-guiding electrode and the rollers, with any shape of the upper portion of the electrode 103.

The electrode 202 connected to the power cable 131 is an optional complement to the printhead 105 for preheating or preheating the wire 104 by passing an accurately adjustable current commanded by the system controller through the wire 104. The electrical opposite pole to the electrode 202 may be, for example, the build platform 206, the rollers 110 and 111 or the wire-carrying electrode 103. By preheating the wire 104, it becomes more ductile, less rigid and can be softened, thereby making the wire more easily bendable and the mechanical stress on the surface of the wire-applying electrode 103 is lower. In addition, the electrical resistance of the metal wire 104 is higher with higher temperature, which has a positive effect on the welding process. Similarly, the wire could be rolled between the rollers 110 and 111 to achieve a different cross section of the wire. In addition, additional rollers can be attached, with which the wire 104, can be pulled apart or rolled so that it thunder. The pressure on the wire 104 between the rollers could also be controlled by an attached motor to cause the wire to change its cross-section during the printing process with the wire-guiding electrode 103, for example, to change the layer height, or layers of the wire 104 in places adapted to produce a rectangular cross-section which is not melted with the secondary electrodes in order to make the surface of the first layers freestanding, supported by support material sections cleaner and more easily separable from the lower support layer. By using the electrode 202, a wire-carrying electrode 103 whose channel is coated with a current and heat-insulating ceramic or glass layer can be used. By annealing the wire tensions can be solved because of the winding of the wire on the coil, so the wire can be applied more easily.

Due to the small size and complexity of the wire-carrying electrode 103, it is very easy to grow a plurality of such electrodes on a print head with wire feeding mechanism, for example, to print with several different wires in one printing operation, for example, to print faster at the locations where the precision is not so important and can instead be filled with a thicker wire.

Fig. 2 Description of the printhead parts The wire-carrying electrode 103 is screwed into the metal block of the printhead 105, which is made of aluminum, for example, and the heat in the electrode 103, which is formed at the welds, from the electrode 103 can dissipate well and conducts the current for welding of the attached to the print head 105 power cable 106 in the wire-carrying electrode 103 well. The metal block of the printhead 105 which conducts current to the electrode 103 should be electrically isolated from the guide rails, for example by a layer of plastic between the linear bearings mounted on the printhead 105 in the holes 201 and supporting it on the guide rails 122. The power cable 106 is bolted to the movable printhead 105. The insulated power cable 106 is advantageously made of many individual thin wires so that it has a great flexibility and extends in a long arc coming from the power supply unit, which is installed in the printer housing 117, to the print head 105 so that it slightly in the direction of the plane in dererfährt out and can move here. The guide tube 120 through which the metal wire 104 is guided from a spool to the printhead 105 is made of flexible plastic, for example, and extends in an arc from the printhead 105 to an attachment to the printer housing 117. The guide tube 120 fulfills the function of especially with thin wires of, for example, 0.2 mm, that the wire can not get tangled and is not kinked by the movements of the printhead 105 or is exposed and dragged behind the printhead, thus hindering the printing process. In addition, the wire is so isolated. The printhead 105 preferably also cooling fins 113 are attached which ensure that heat absorbed by the printhead 105 can be released quickly to the ambient air and the printhead and thus also screwed to it the wire-carrying electrode 103 is cooled. The cooling of the wire-guiding electrode 103 increases its life. For improved cooling, a fan 121 allows the air to flow to the cooling fins. The stepper motor which drives roller 110 is preferably bolted to printhead 105 and moves with it.

The tip of the primary wire applying electrode 103, with which the electrode 103 makes the lowest contact with the wire 104 and with which it transfers the welding current to it, may be made of a different metal, for example tungsten or stainless steel for printing with a wire of aluminum. In addition, between the tip of the other material and the overlying main material may be a heat-insulating layer with small current-carrying contacts that conduct the current from the upper main material in the tip, so that the tip of the wire-carrying electrode 103 is very hot and when resting on the fresh During the welding process with the contact surface, heat is transferred to the wire during the bent-over process and does not dissipate much less, which promotes the welding process.

[00144] Use of Wire As the material for the electrodes, copper alloys that have the conductive properties of copper with a promoted hardness and strength, for example, copper alloy with zirconium, beryllium, or tungsten are suitable.

When applying the wire, which here has a round cross-section, but could also have a different shaped cross-section, the wire-carrying electrode 103 transmits current through the part of the wire 104 which emerges from the channel of the electrode 103 and usually the greatest electrical resistance in the circuit. Thus, the wire 104 is resistance welded together with the surface of the previous layer of the object 205 to which the wire is applied and fixed by fusing in spots or in sections because of the strong heat generated by the flow of current in the wire 104 Metallic connection is received at the point where the surface of the wire 104 touches the metal surface on which the wire 104 rests or bears laterally and which dissipates the current. This may be the surface of the already created object 205, the build platform 206 or a metal surface on which a structure of wire should be applied. When welding, the wire can melt in places over the entire cross section and fuse with the surrounding wires. In general, the cross-section of the wire 104 is not substantially changed and the wire 104 is only tacked when laying out and adhering to the primary wire-carrying electrode 103, so that the electrode 103 is less stressed and stronger connections thereafter, if necessary, be made with secondary electrodes. The wire is bent during application in the shape of the wire paths, which then pretend side by side the shape of the layer. The wire 104 can be applied by the wire-carrying electrode 103 over a large area without interruption. In this case, the resulting applied wire sections can abut directly against each other and they can be applied adjacent to each other regardless of the direction in which a wire section points to the wire section to which it is applied and partially welded, without the wire applied to the above directly adjacent wire part above rests and without cutting through the wire with subsequent re-placement during the printing process with the primary electrode 103. This is a great advantage over the methods that apply the wire directly by means of a rolling wheel electrode.

The current comes from the welding power supply accommodated in the housing 117 and is transmitted through the thick power cable 106 into the block of the print head 105, which passes the current to the wire-applying electrode 103 screwed into it then further passes through the portion of the wire 104 which has immediately left the mouth of the channel of the electrode. This part of the wire which is thereby strongly heated can thereby make the connections to the metal surface which is produced by the object 205 of FIG the build platform 206 on which the wire 104 is applied. The current then flows through the wire 104 through the already created portion of the object 205 on which it is being applied and through the build platform 206 on which the object 205 rests and is adhered. Then, the current flows into the power cable 107 attached to the build platform 206, which in turn returns to the welding power supply and thus closes the circuit. The wire-carrying electrode 103 forms the electrical opposite pole to the building platform 206 and the part of the object 205 applied thereon with the support material. The current flow may be bidirectional and may be DC or AC. The electrical voltage between the wire-guiding electrode 103 and the building platform 206 is very small and harmless to humans.

The welding power supply may consist of a simple transformer with electronic control, of low voltage capacitors or of high voltage capacitors with electronic control, which conduct electricity through a transformer to reach very high currents of several thousand amperes in the output. This is useful for producing extremely high, short power to create pulsed, stronger, and faster welds. Pulse-type welding is important for lower resistivity metal wires and results in shorter secondary electrode settling times with less heat transfer, which causes the secondary electrodes to overheat less quickly.

At the beginning of the printing operation of an object on the build platform 206, the first layer of the object is applied directly to the surface of the build platform 206. In order to be able to easily detach the object 205 from the building platform, the wire webs of the first layer are only tacked with little intense current impulses and are not fused by the secondary electrodes to the surface of the build platform 206. Thus, during the printing process, the object is fixed stably enough so that it does not become loose, and thus the lower layer does not bend or bulge due to tensions in the part of the object created thereupon, which may arise as the metal cools after the welding operations. Between the build platform 206 and the first layer of the object 205, a contact layer of adjacent wire paths can be created which has a larger area than the first layer of the object 205 or the first layer of the object 205 can be applied directly to the build platform 206 with additional Wire webs abutting the edges of the contours of the first layer. This establishes a stronger connection to the build platform 206. The object 205 is thus only weakly connected to the build platform 206, so that it can be removed easily without damaging it, for example, by pushing a thin spatula under the first layer and trying to lift the object from the build platform 206.

The build platform 206 may consist of a thick reinforced aluminum sheet, can be placed on the thinner removable panels 129 and clamped or screwed, on which then the objects to be printed are printed.

In general, the wire 104 is connected by means of current pulses from the electrode 103 to the metal surface on which it is applied. These current pulses, with a duration of usually a few milliseconds and up to several hundred amperes, are controlled by the system controller, which accesses a stored machine code, which specifies the printing operation of one or more objects. Multiple objects can be created side by side in one printing process. The machine code is e.g. a file created by layering software that uses as input a three-dimensional CAD file of the three-dimensional object to be printed and determines therefrom the required movements of the parts in conjunction of the printhead 105 and the build platform 206 with the timed stream impulses A sequence of respective layers corresponding to the cross-section of an object, which are possible or necessary by the application and welding of wire to print a three-dimensional object.

FIG. 2: Printhead, printing process The wire-carrying electrode 103 is exchangeable, and there are various types of the wire-guiding electrodes 103 that are suitable for printing differently and with different materials. Fig. 2 shows the operation of the print head 105, in which the wire 104 in layers according to the pattern suitable for the cross section of an object 205, a screw-on angle, is applied. In order for the wire not to be pulled through the wire-carrying electrode 103 by movement of the printhead 105 relative to the build platform 206, the wire 110 and 111 push the wire through the electrode 103 at the appropriate speed at which the wire 104 is applied. The rollers 110 and 111 may be made of steel, have a smooth surface and move the wire through the traction between them. This has the advantage that the engine speed can be set slightly higher than it actually has to be to apply the wire on a web. Thus, the rollers slip slightly over the smooth surface of the wire 104, thereby ensuring that the wire is always pushed through the electrode 103. For this, the motor force on the wire 104 must be sufficient to overcome the static friction between the rollers 110 and the wire 104, so that the motor 208, which drives the roller 110, not blocked. Likewise, the spring force on the roller 111 will be advantageously chosen so that the static friction between roller 110 and wire 104 is neither too large nor too small. If it is too small, sufficient force can not be transferred from the rollers to the wire 104 so that it receives the necessary power from the stepper motor 208 on the roller 110 around the wire 104 in or below the mouth of the roller

Channel of the electrode 103 to bend the wire 104 parallel to the layer is created to lay.

Electrode - Force - Pull - Pressure By forcing the wire 104 through the electrode 103, the wear of the wire-carrying electrode 103 is reduced because the wire would otherwise be pulled through the electrode 103, causing more pressure the inside of the channel in the mouth of the channel of the wire-carrying electrode 103 and thus could cut into the material of the electrode 103, if it is made of a material such as low-hardness copper. In addition, it allows firmer welds through the wire-bonding electrode 103, because there are no or less tensile forces in the wire part between the wire-applying electrode 103 and the object 205, which can tear the wire 104 at stronger surges, which are necessary to make tighter connections to the Where the wire heats up strongly and thus weakens during welding. However, it may also be printed with a non-advancing lead wire electrode 103, which wire is pulled toward the build platform 206 by the relative movement of the wire leading electrode 103, but which makes printing more difficult to control to successfully produce objects and requires more power Printhead 105 to move. In addition, pressing the wire 104 through the wire-carrying electrode 103 can more easily achieve greater precision. Stronger connections, for example, by spot-welding the applied wires, can also be performed with the wire-guiding electrode 103 when printing without pushing the wire, with the lower surface of the wire-guiding electrode 103 resting on the upper surface of the wire paths created in the layer will interfere with the interruption of the relative movement of the wire applying electrode 103 to the build platform 206 during the process of resistance welding.

[00159] Electrode - Force - Space - Centerline Radius Scheme [00160] In FIG. 5, the wire-carrying electrode 103 is shown individually. Fig. 3 shows a section along the channel 302 of the wire-guiding electrode 103 at

Applying a wire. Through the channel 302, which passes through the electrode 103, the wire 301 is passed until it comes out in the funnel portion 401 of the channel 302 shown in FIG. 5 - the part of the mouth of the channel 302. Fig. 4 shows an enlarged view of the area of the section of the wire-carrying electrode 103 with the bent in the mouth of the channel portion of the wire with its radius of the center line R. The center line radius R is always greater than the radius of the wire, for a wire with round circular cross section. The smaller the centerline radius, the easier it is to apply the wire precisely, because the bent portion of the wire 301 between the wire-guiding electrode 103 and the metal surface 403 at a smaller centerline radius is closer to the central axis of the electrode 103, the axis of the channel, than the reference applies to the application of the wire when traveling the predetermined paths on which the wire 301 is to be applied. This is especially true when re-attaching the wire-carrying electrode 103 to begin with the application of a new web from the wire. But the smaller the center line radius R, the larger must be the force F acting on top of the wire 301, which moves the wire through the electrode 103 and ensures the bending of the wire 301, this being true to the smallest possible center line radius to be printed can.

The path traveled by the wire-carrying electrode 103 should be programmed so that the design of the wire under the annular surface of the electrode 103 is on the correct tracks to make the layer more faithful. If the electrode 103 moves only with the main axis, that of the channel 302, the tracks on which the wire should be located afterwards, then the wire from the wire-guiding electrode 103 is not always applied to the correct tracks, because the mouth of the channel In which the wire can be reversed when applying is wider than the wire, then the wire is applied to more rounded corners and shorter curves than the descends the main axis.

FIG. 4: The channel 302 has a circular cross-section and the diameter d which is slightly larger than the diameter q of the wire, for a wire of circular circular cross-section and which is slightly larger than the widest part of the cross section of a wire of the other one

Cross-section, for example a flattened wire, which had a round cross-section before a rolling and subsequently has a rectangular-like shaped cross section [00163] Electrode - force - rounding - space - scheme Much heat is passed from the weld through the wire the, because of the small center line radius R and because of the small distance D, located very close to the weld part of the wire is bent in the mouth of the channel of the wire-guiding and wire-applying electrode 103. This can significantly reduce the rigidity of the wire and so ensure that a wire-carrying electrode 103 can be tuned to a very small bend radius and centerline radius R to lightly and precisely apply the wire 301.

FIG. 5: the contact surface 402 with which the wire-guiding electrode 103 rests on the upper surface of the wire webs of the layer that is being created is located in a continuous annular manner around the mouth of the channel 302 and is in parallel printing position over the build platform 206, FIG. so that the wire can be applied in all directions of the plane, as it were, without rotation of the electrode 103 around itself. When the electrode 103 rests on the build platform 206, it contacts it on an annular surface. The wire-carrying electrode 103 exerts a pressure on the bent wire on which it rests and presses the wire 104 against the surface on which the wire is applied, so that the welded connections are made as directly as possible on the newly bent part. The bending of the wire 104, as in this case, the perpendicular electrode 103 to the surface of the layer is created with a perpendicular to this channel 302 of the wire-carrying electrode 103 to the angle e. of 90 ° takes place in the end of the channel 302, which is wider in the final area to the mouth of the channel through the rounding 401. This funnel-shaped fillet 401 provides enough space in the interior of the electrode 103 for the wire to be bent directly at an angle, e.g. can be bent by 90 ° and the contact surface for welding 402 of the electrode 103 can rest on the bent wire. The annular contact surface 402 resting on the bent portion of the wire 301 and applying pressure to the wire generally conducts most of the current through the wire 301 so that it can be welded well in the portion below the point where the contact surface rests and has, for example, a width corresponding to the diameter of the wire 301 and an inner diameter D which is between twice and four times the diameter of the round wire 301. The contact surface 402 slides over the surface of the applied wires and is applied with very little, minimal pressure on the wire in the general printing process, so that it is less stressed and does not wear too quickly. In addition, a width b of the ring of the annular contact surface lying 402, which is preferably not greater than the width of the wire and an inner diameter D which is preferably not greater than twice the diameter of the wire, for a wire with a round cross section so that the Electrode rests on as few adjacent wire paths as possible and unnecessarily transfers power to them. In addition, when the width b is set too large, it is not ensured that enough current for welding is passed through the part of the wire currently being conveyed out of the channel 302 of the electrode 103.

However, the wire-carrying electrode 103 may also apply wire without resting on the wire with the surface 402, in which less severe surges are conducted through the free-standing portion of the wire between electrode 103 and the surface on which the wire is applied.

To make stronger connections in a continuous moving printing operation of the wire-carrying electrode 103, the positive force F acting on the wire 301 from above, the wire 301 passing through the channel 302 of the electrode 103 should be large enough for the wire 301 to move Wire on a smooth flat metal surface with no connections to this, with the positive force S in another, rotated in this case an angle of 90 ° direction, can be pushed with the low pressure electrode, with the contact surface 402 on the bent wire section. Where the wire is nothing in the way. The circular outer edge of the current transmitting annular bottom contact surface 402 is configured by the fillet 404 to allow the electrode 103 to more easily slide over bumps, such as small pieces of wire protruding out of the layer which have not been cleanly applied, rather than tangling or applied structures to damage. For this purpose, a slightly spring-acting suspension of the wire-guiding electrode 103 or the building platform 206 is also suitable.

Fig. 5 shows the thread 502 and the nut-shaped portion 501 with the wire-carrying electrode 103 is screwed into the print head 105. However, a wire-carrying electrode 103 can also be attached differently to the print head, for example by a plug connection.

By way of rollers 110 and 111, the wire may also be fed backwards through the wire-carrying electrode to assist, for example, the severing of the wire. To separate the wire below the wire-carrying electrode 103, the electrode 103 can be a stronger current pulse on the coming out of the electrode 103 and directly bent below the contact surface of the electrode 103 located piece of wire with simultaneous backward thrust of the motor 208 with the roller 110 to be transferred. Or the wire is cut with a current pulse with the simultaneous or shortly following movement of the electrode 103 from the point on which this touches on the piece of wire, for example, by a small movement of the electrode 103 upwards, away from the layer between the channel of the electrode 103 and the flat part of the wire already adhered in the layer by a short pulse of current heated so far that it melts or gets very hot and is torn by tensile forces exerted on the wire. This process should be set so that no or as little as possible sparks or flashes of light, otherwise contamination by oxidation or air bubbles can occur on the wire. Due to the possibility of sparks, flashes of light or metal spatter, the space should be sealed from the environment, however, it does not have to be airtight for the use of metals that do not ignite in the air during printing and release any pollutants. Through a door one then gains access to the interior of the printer. On the housing 117 windows can be mounted through which one can observe the printing process.

Objects with free-standing sections can be created in the support material is applied below them layer by layer. The support material is applied to the lower surfaces of an object and consists of a metal wire which has been applied to the primary electrode and which has also been post-processed with the secondary electrodes. Thus, on the current-carrying support material, wire may be pinned to the object to be created. The first layers of freestanding parts of an article to be created, which are applied to layers of support material, are subjected to less intensive welding operations, but the farther they are from the layers of support material, the harder the welding operations are performed to allow the support material to pass easily through remove subsequent tearing off. The support material usually consists of the same wire as the object being created. However, it can also be in the printing process with another variant of the 3D printer from FIG. 1 made of a different material which is applied with a second printhead electrode attached to the print head 105. For example, the aluminum wire support material may be for a steel article, or vice versa, so that the first layer wire paths on the support material may be fused together by the secondary electrodes without the support material forming too strong a connection. The support material can then also be made of two different wires. With a 3D printer from FIG. 1 with two wire-applying electrodes composites can also be created by the alternation of the material of the adjacent wire paths of a layer. The support material made of metal is also necessary for power conduction.

The use of different electrodes is generally dependent on the geometry and the material of the wire, as well as the printing process with the final result to be achieved.

The channel of a wire-carrying and -auftragendem electrode must be large enough in principle, so that the wire can rotate once within the channel around its own axis, so that the wire when applied in a plane in all directions without cutting the wire are designed can. In addition, the channel of the electrode should not be so wide that the wire through the

Push promotion forms a spiral-like shape in the channel or kinked and could block the printing process.

The wire-carrying electrode 103 may be mounted in a resilient suspension and / or the build platform 101 may be resiliently mounted, so that the pressure with which the wire-carrying electrode 103 rests when applying the wire, by the positioning of the electrode 103 to the build platform 101, can be easily controlled, so that the pressure is not too large in small position deviations and the wire-applying electrode is not damaged.

Fig. 6 shows the wire-carrying electrode 601 when wire 606 is applied to a metal piece 607 having a section near the mouth of the channel 605. It has a nut-shaped portion 602 for insertion into the print head 105 can be screwed. Below this subregion, it passes into the intermediate part 603, which tapers in the end region 604 of the electrode 601. The channel 605, which preferably passes right through the electrode 601, is wider than the wire 606 which is passed through this channel. The channel 605 provides sufficient space for the deflection of the wire 606 in the lowermost part, just above the mouth, of the channel 605. This allows the electrode 601 to rest directly on the bent portion of the wire lying flat on the layer to which it is applied. The lower part 604 of the electrode 601 is an area intended to be worn during the printing operation. Therefore, when the electrode 601 is new, the region 604 has a certain height T in which the cross section of the electrode remains unchanged, so that the lower annular contact surface 608 worn down by the wire welding may be degraded during printing by the electrode 601 resting on the wire without impairing the function and the effect of the electrode. By applying wire in all different directions in a plane, the contact surface of the electrode 601 is uniformly worn. The lower part of the electrode may also be automatically reground by the printer by moving the electrode 601 on the contact surface on the grinding surface 114 back and forth. Also conceivable is a printer in which the electrode is a Fraser or grindstone anfährt to be worked up so that the quality of the welds does not deteriorate. This primary electrode 601 is particularly suitable for applying wires which are intended to be directly fixed together, for example for printing without the use of secondary electrodes. In addition, it is suitable for applying wires of a rectangle-like cross-section, which require stronger current or stronger, longer-lasting current pulses to make a connection, because the wire-carrying electrode 601 is much more stressed and the lower contact area wears out quickly. The electrode 601 can be much more heavily loaded. By the pressure exerted by the wire 606 on the electrode 601 in the lowermost region of the channel 605, the lowermost edge of the channel 605 receives the rounding 609 which results when the wire 606 is imprinted.

Double Electrode Fig. 7 shows a section of a wire-carrying electrode 703 which consists of two electrodes electrically insulated from each other, another variant of the wire-carrying electrode 103. The wire 701 is led through the inner tubular electrode 702. Between the upper, inner electrode 702 and the wire-applying electrode 703 is an electrically insulating layer 704, which is heat-resistant, for example made of a ceramic material or of a heat-resistant plastic such as Teflon. The electrode 703 terminates above the lower contact surface of the electrode 703 with which the welds are made. Inner electrode 702 serves to preheat the wire by passing current through the wire in electrode 705. The electrical opposite pole of the electrode 703 may be either the lower wire layer 706, the build platform on which the wire 701 is applied, or the lower electrode 705. By preheating or preheating the wire 701, it becomes more ductile, loses rigidity and is more easily bent, and the electrical resistance of the metal wire increases with increasing temperature, which in turn aids in the process of welding to the contact electrode 705. In addition, the entire electrode 703 may be designed so as to be able to make tighter connections in the continuous printing process without pushing the wire through the electrode 703 and by designing the wire 701 from the electrode 703 by pulling the wire through which the electrode 703 passes Wire 701 adheres only with weaker current pulses and the electrode 705 then the stronger

Welding can be performed without the wire is cut through, because between the part of the wire to which the weld is created and the wire-applying electrode 703, a piece of wire is present, which is attached to the layer 706 and this forward the tensile forces to the layer 706 can, without thereby the wire 701 coming from the electrode 702 is severed. In this embodiment, the electrode 705 has a lower partial section which can wear without the contour shape of the contact surface changing, that is to say the cross section of the lowermost partial section remains unchanged over a certain height. This shape is particularly suitable for thicker wires (0.4-1 mm) that can be bent to smaller bending radii by reducing the stiffness due to the higher temperature with less force. The electrode 703, after mounting on the printhead of the printer, makes electrical contact with an extra power cable, thinner than the cable 106, which carries current from the welding power supply and is driven by the controller.

Fig. 8 shows a wire-carrying electrode 801 which does not rest with the lowest surface on the surface of the layer created during the printing process. The channel inside the electrode 801, through which the wire 802 is routed, need only be shaped so wide that the wire can be easily passed. The wire is bent underneath the bottom surface of the electrode 801 so that it can be laid flat in the plane of the layer to be created. By current pulses which are passed through the wire, the wire on the lower structure 803 is pressed on this and rests attached. These current pulses heat the wire 802 in the freestanding portion between the end of the channel of the electrode 801 and the surface of the structure 803 on which the wire 802 is applied and make it very ductile so that it can be easily shaped. The printing with the electrode 801 which does not rest on the layer being made is very gentle to the wire-applying electrode 801. Suitable for thicker wires and wires coated with solder material where the inner main wire does not melt and during printing for accurate shaping of the wires structure to be created, while the solder material around the wire 802 melts, due to the heat generated by the current in the portion of the wire between the electrode and the surface on which the wire 802 is applied, and at the small contact point to the below or next to it already applied wire web can melt with the existing solder material there and so fills gaps between the wire webs, when the structures on which the wire is applied are thin enough so that they are hot enough. Wires may be clad with brazing to make air- and waterproof surfaces, as well as stronger wire-to-wire connections easier, using only the wire-carrying electrode and avoiding excessive wear on this electrode. When melting the solder around the wire, a large part of the solder material always sticks to the wire so that it is applied with the wire. An advantage of the wire application process with this non-overlying electrode 801 is that it ensures that the current is transmitted integrally through the portion of the wire 802 leaving the channel of the electrode 801, and thus the welds are made thereto only. It allows the application of wire with little or no wear of the wire-carrying electrode.

Disadvantage over the other wire-guiding and applying electrodes is that when separating the wire, a small piece of wire can protrude from the layer, which can interfere with the subsequent printing process. In addition, there may be problems with separation, as well as more oxidation on the wire and less pressure on the lower resting part of the wire, which in turn is e.g. when starting the application of a new wire section to detach the tip of the wire, can lead by a caused by the different rapid page-dependent cooling and thus by contraction of the wire curling of the wire.

[00182] Ceramic Electrode FIG. 9 shows the electrode 902 which applies the wire 901 to a metal part 904. The electrode 902 differs substantially from the electrode 103 of FIGS. 5 and 3 in that the lower part, the tip with which it rests at the level of the upper surface of the layer to be applied, consists of a non-electrically conductive, hard and nonconductive material 903, preferably a ceramic. It is basically suitable for thicker wires depending on the material.

In addition, a contact of sheet metal, or brushes, for example, small wires of copper, may be mounted inside the channel of the electrode 902 and press against the wire 901, especially at the end of the channel to ensure that the current passes over a larger, better defined surface is transferred to the wire 901 and thus can provide more constant conditions and welds. In general, since there must be a tolerance between the channel of the wire-carrying electrode 902 and the wire 901 to allow the wire to move, this generally causes the wire 901 to make electrical contact on a very small area alternating during the printing process Electrode 902 has. This may cause the welds to be less constant due to the fact that the alternating length of the wire member through which the current flows and the variable resistance of the wire member.

The electrode 902 ensures that the current is transmitted entirely through the wire and thus the welds are performed only on this wire 901.

The electrode 902 receives the lateral pressure exerted by the wire 901 at the end of the channel and, when separated, may lay flat protruding pieces of wire against the lower layer when slipping over.

The ceramic tip 903 may be attached, glued or screwed to the electrode 902 with a press fit.

[00188] Abrasive Surface FIG. 1: A strip 116 is mounted on the printer housing 117 on which a abrading surface 114 is mounted parallel to the building platform by means of a clamp 115. The abrading surface 114 may be, for example, a piece of sandpaper that can be easily replaced or be a grindstone or a file. The lower surface of the secondary electrodes wears off during the printing process. Because of this, after a certain degree of wear, it can advantageously be abraded on the grinding surface 114, so that the lowest contact surface is again suitable for carrying out welds. Several attached grinding surfaces of different roughness are also possible. A brush may be mounted on the printhead 105, sweeping away the particles removed from the electrode on the abrasive surface 114, or a fan doing so with an air jet. A motor driven, moving abrasive surface on which the electrodes can be approached, for example a rotating abrasive surface, is also feasible to machine the electrode surface.

[00190] Secondary Electrode Block The block 130 includes the secondary electrodes. It is attached to the movable printhead 105 in FIG. 1 and is shown in more detail in FIG. Secondary electrodes 132, 133 and 109 are linearly movably mounted in block 130. As a material for the electrode block 130, a good current and heat conductive material such as copper or aluminum, in the interior of the block 130 is suitable, for. a camshaft 1003 is driven which is driven by a stepper motor 1001 which is connected to the block 130 by an insulating connector 1010. As the camshaft 1003 rotates, depending on the position of the shaft, the secondary electrodes 132, 133 and 109 move up and down. The cams of the camshaft 1003 are here offset by an angle of 120 ° about the axis of the shaft. Thus, with just one stepper motor, several secondary, here three, electrodes can be customized! control so they can individually put on and perform a resistance welding process. The secondary electrode welding current is conducted from the welding power supply via the power cable 106 of FIG. 1 via a connecting portion 123 to the metal block 130 and via contact to the secondary electrodes. The electrical opposite pole to the secondary electrodes is the build platform 101, from which the current through the power cable 107 leads back into the welding power supply, where then closes the circuit for welding. In this implementation, three secondary electrodes are used to print faster and to extend the life of the printer without replacing the secondary electrodes. At the secondary electrodes 132, 133 and 109 are compression springs 1005 with a locking ring 1004 attached. The compression springs 1005 push the electrodes into the block 130 and against the surface of the cams of the

Camshaft 1003. With the cam 1002 of the camshaft 1003, for example, the electrode 132 can be moved deeper than the other electrodes so that they can be individually ground by slipping on the grinding surface 114 and can individually put on a layer of applied with a primary electrode 103 wire webs order to melt and weld them. The stepper motor 1001 could drive the camshaft via a transmission, for example, via a self-locking worm gear to boost the force of the cams on the electrodes. A pressure sensor may be attached to the printhead 105 to measure the force with which the electrodes are placed to be considered as a size in the printing process. For this, the machine can determine whether the electrode touches down by the electrical contact of the secondary electrodes with a layer of an object or the build platform. This also applies to the primary electrode 103. Due to the rectangular shape of the electrodes, they can be placed several times on a layer and cover all areas without having to put them in the same place several times. The secondary electrodes heat up strongly during the welding process and therefore have to be cooled. Therefore, a large radiator 1008 with cooling fins is preferably attached to block 130 which is cooled by fan 1009.

Smaller electrode pads are suitable for thin areas where not too much heat should be created or the already laid with the primary electrode wire paths are close together. The larger ones are intended to weld places where little material has been applied, for example, the inner space of objects that are printed with little fill, that is, filling the interior of the items with a lattice-like structure with a lot of void space.

Further Types of Secondary Electrode Fig. 12 shows a secondary electrode 1201 having a lower portion in which the cross section is the same everywhere as the lower contact surface machined out of the base of the electrode during abrading on the abrasive surface has a much larger cross-section and is above the area of the same cross-section as the contact surface. As a result, the electrode 1201 may have a higher wear-out portion with which the welds can be made without the electrode overheating during welding operations. Due to the larger cross-section, the heat is better dissipated, as well as the electrical resistance is smaller, so less heat in the electrode caused by the current flow. Fig. 11 shows a secondary electrode 1101 with exchangeable lower tip 1102 of the contact material. The replaceable tip 1102 is pyramid-shaped so that it has less heat. In principle, it requires different grinding surfaces, which are parallel to respective surfaces of the electrode tip 1102 at which they can be reground.

Fig. 13 shows a lower-part electrode 1301, the tip of the electrode, the contact material 1302 made of metal other than the base. The adaptation of the contact material 1302 to the material, metal or alloy from which the wire is made, allows for better welding operations and may provide less adhesion of the electrode 1301 to the wire material during welding. For example, a tip made of tungsten or stainless steel, for the welds of aluminum wire. Some types of stainless steel are particularly suitable for aluminum, because they heat up strongly due to the high resistivity due to the strong current flow during resistance welding and thereby direct the resulting heat further into the aluminum, which makes it much easier and faster to melt. Added to this is the low adhesion to the aluminum during the resistance welding process, whereby, of course, the composition of the stainless steel also matters. In addition, the heat generated in the wire during a welding process is dissipated much less rapidly into the electrode material, because the tip, for example of stainless steel, has lower thermal conductivity than the main material of the electrode 1301, for which copper is particularly suitable. The tip 1302 can also be made of a plurality of materials, for example, the lowermost part, with the contact material of tungsten, and between the main material and the tungsten, a layer of stainless steel, with a particularly high electrical resistance, which heats up strongly during welding and the heat on which transmits tungsten, which, although very hot, has even more hardness than the stainless steel above would have at the temperature setting. The tip 1302 can also be ground on the grinding surfaces, lm

Main material of the electrode 1301, above the tip 1302, holes are formed through which air can circulate and increase the surface so that the main material of the electrode 1301 is better cooled and the thermal conductivity between the hot tip 1302 and the main material is lower Electrode block receives less heat. The junction between the tip 1302 and the main material of the electrode 1301 is realized in a small area so that the heat flux between both materials is less.

Secondary Electrode Printing Process The principle of the welding process with the secondary electrodes of the printer of FIG. 1 is shown in FIG. After a new layer, after the printing process with the wire-guiding electrode 103 on the metal part 1404, is connected to wire webs which are only weakly connected to the lower resting surface, the secondary electrodes set individually on the surface of this layer of wire webs in which the wire web 1403 lies on, exert a pressure on it and, depending on location and settings, conduct a strong current through the wire paths for a certain time. They heat up so much because they represent a section in the circuit with relatively high electrical resistance, allowing them to melt, melt and melt together and with the surrounding applied material. For this purpose, a wire 104 with a round cross-section, which is applied when applied with a wire-guiding electrode 103 only by small point connections on the surface on which it is applied with a non-changing cross-section, is particularly suitable as the input material. As a result, the wire webs thus applied have a high electrical resistance in the direction of current flow perpendicular to the plane in which the wire webs lie compared to the rest of the circuit. Thus, the newly applied layer can be selectively heated at the point at which the secondary electrode 132 rests in this case. A wire with a rectangular or rectangular cross-section is also suitable for printing with primary and later with secondary electrodes that fuse the wire. The welding current can be AC or DC. The structure of the wire webs applied with the primary electrode 103 changes with the secondary electrodes during melting. The goal is to create an object with non-directional, isotropic material properties to produce stable objects. The secondary electrode 132 has a flat surface 1402 which, when housed in the block, rests in parallel against a flat surface in the block 130 so that it is not twisted in the block 130. The obéré part 1401 may be narrower because it does not have to carry heat and electricity and around it a spring 1005 may also be mounted.

It is also possible to apply several layers in succession and on top of each other with the primary electrode 103, for example two or three, after which the secondary electrodes may be placed on the uppermost layer and the plurality of layers applied only to the primary electrode 103 may be applied to each other and weld the surface on which they rest. Due to the multiple stacked layers of wires, which are unchanged in cross-section and only very slightly welded, the electrical resistance of the point to be welded is higher, which favors the resistance welding process. To do so, the layers are heated less often, resulting in less oxidation, less wear on the secondary electrodes, and less power consumption. Likewise, this can be faster.

In this case, the electrode 132 with the contact surface of the tip 1007 which is intended for the resistance welding process on a plurality of wire webs, such as the wire web 1403, set up at the same time. The cross-section of a coated and adhered sheet of wire 1403, seen in FIG. 15, may change entirely during welding with the secondary electrode 132 as the wires thereby reflow and become an isotropic, homogeneous portion of the article 1404 upon cooling. By thus attaining stronger bonds between the layers, the finished articles have a large tensile strength corresponding to the metal in the direction perpendicular to the layers. In this case, the voids and gaps between the overlying webs of wire in the fusion of the adjacent wires can be closed when the wires are close enough to each other. By melting and flattening the

Wires with the width h of the cross section, the final height of the layer thickness H can be set, unlike the layer thickness of a layer consisting of webs of wire which are only pinned and unchanged in cross section. This makes it possible to achieve smaller layer thicknesses than the thickness of the wires. Also, different layer thicknesses can be made using the same wire, as well as within the print of an article. Thin layers are possible, for example, with a 0.2 mm diameter round wire which is flattened to a height of 0.1 mm or 0.05 mm. In Fig. 15, the height A of the lower welding intended part of the secondary electrode 132 is shown. This part is equal over the height A in cross section and thus ensures after the removal of the lowest contact layer for a constant welding result, until the height A is completely removed.

The flat surface created with the secondary electrodes allows the wire webs of the next layer to be easily applied thereon.

In addition, when printing objects that consist only of round wires that are unchanged in cross-section, using a wire-guiding and wire-applying electrode 103 results in many gaps in one plane, for example between parallel wire paths. If the wire webs are pressed firmly against the surface of the underlying layer when new wire paths are applied to these gaps of lower layers, this results for the new layer, measured from the uppermost surfaces of the layer of round wire webs underneath, in which the respective ones are new On the gaps applied wire paths are, a lower layer thickness than the thickness of the wire at the locations above the gaps of the lower layer. These differences in height in the layers to the surface of the build platform 101 may add up over the layers until further printing is no longer possible and the print becomes a failure. It is important to be able to simply apply the wires so that the area of the bottom layer on which a round wire is applied without cross section is flat. The creation of a flat surface is achieved by the welding operations of the secondary electrodes.

In order to produce areas which must have an exact height with a tolerance being maintained. When the wire is melted and flattened after being applied to the primary electrode with the secondary electrodes, the layer height for each layer can be varied, unlike the layered application of wires which remain unchanged in cross section, where the height of the sections is always a plurality is the constant height of a layer. Thus, with an average much higher layer thickness, areas of an article to be printed can be created faster, which have to comply with a certain tolerance of the height.

When printing the interior of the objects, the wire webs applied to the primary wire-guiding electrode 103 may overlap in a layer or be applied in places twice, for example, to quickly create an internal lattice structure from a continuous wire section. After the primary printing of a layer with a primary electrode, the secondary electrodes compress and fuse the applied wire paths into a uniform flat surface. In the process, the points where wire paths overlap and abut one another become fixed fused nodes. The juxtaposed wire webs are strongly interconnected by the Zusammeneinanderverschmelzen. It is therefore usually not as important as precisely the wire paths are applied next to each other, as this way any space can be filled inside.

For a defined layer thickness, the volume of wire material can be more rapidly applied by the wire-carrying electrode 103 using a thicker round wire which is thereafter melted and flattened than with a thinner round wire having the diameter of the thickness of the layer.

The electrodes could also be water cooled and have channels in the interior through which cooled water is circulated. The support material applied to the wire-carrying electrode 103 can also be reworked with the secondary electrodes.

[00207] The machine can automatically take breaks when overheating. A moving air exchange between interior and ambient air ensures cooling.

The parts are ready after printing immediately.

[00209] Abrading [00210] On the contact surface for welding, an oxide layer can form, which conducts the current very poorly. The surface may become rougher, rougher and degrade due to the welds, which leads to ever worse conditions for the quality of the welds. Therefore, and so as not to be adhered after contamination of the contact surface by welding, the contact surface for welding the secondary electrodes can be ground off automatically. A printer similar to that in Fig. 1 with an advanced mechanism for displacing the secondary electrodes in vibration and / or rotation is conceivable so that the electrodes do not adhere during welding. By grinding, the contact surface is smoothed and remains flat and even.

By the wear-away area with the lower contact surface with which the secondary electrodes transmit the current to perform the welds and the grinding of the contact surface, the life of the electrodes is considerably extended. For example, if the lower contact surface is suitable for an average of 1000 welds, the height of the lower abrasion foreseen region is 15 mm, and the electrode can be worn 25 times per millimeter to be suitable for welding, then the electrode is sufficient for 375,000 welds before it needs to be replaced. The wear of the electrode may be predicted by the number of welds, the amount of wire under the electrode at the welds, the flow of current through them, the temperature of the electrode or the time interval between welds, and the pressure with which it is applied during welding become. As an example, a stainless steel cube with an edge length of 100 mm, with an electrode with a square contact surface for welding with 5 mm width and with a layer height of 0.2 mm, by flattening and melting a round wire of 0.4 mm is created to print, it needs at least 100 * 10 * 10 * 5 * 4 = 200000 individual welds.

[00212] Pattern [00213] FIG. 16 shows a structure 1601 made of round wires which were not changed in cross-section during and after the layered application. Therefore, the surface of the structure viewed from the side of the layers has a pronounced groove pattern. For example, the structure of Fig. 16 is printed using only the wire-carrying electrode 103 with weak current pulses and welds. The wires stacked on each other only touch one another linewise or pointwise. In contrast, the structure 1702 in FIG. 17 is the result of the respective wire-applied electrode deposition 103 and fusion with the secondary electrode 132 of the respective wires of the structure 1601 with the wires surrounding the respective wires. A large part of the undesirable and disturbing step pattern or groove pattern disappears due to the process of surface minimization of the molten metal resulting from the fusion of the wires, which is caused by the surface tension of the liquid metal during the welding process. This makes the layers less visible. Due to the more uniform structure of structure 1702 thus achieved, the material properties are much less directional than those in structure 1601. Structure 1601 is much less mechanically resilient along most directions than structure 1702. In addition, the walls of structure 1702 are large in size Safety are hermetically sealed. The resulting surface of the printed articles by fusing by the secondary electrodes can be very smooth, which plays a very important role in engineering. Moreover, with the disappearance of the groove pattern, the stress concentrations that may otherwise result in the grooves on the surface of a printed object under mechanical stress disappear. In addition, with less layer resolution, a better, more precise surface closer to the original of the model can be created and printed faster.

[00214] The connection between the walls of an object and the inner material through which is so easy to create is also particularly important

Fusion of the adjacent wire paths to a continuous area. The connection region 1701 from the externally rounded welded joints is shown in FIG. 17. These soft transitions make the objects much more stable, because the internal forces are transmitted more uniformly over wider areas or areas, in contrast to the connection between round wires, which are unchanged in cross-section, as shown in FIG. 16.

The contours or edges of a layer, which later become the surfaces of the objects to be created, can be applied with the wire-guiding electrode from longer, continuous pieces of wire, which are directly thereafter connected to a secondary electrode with a larger contact surface, for example the electrode 109, fused with the lower layer, so that the surface of the objects to be created smoother and level.

The layers fused together by means of the secondary electrodes give objects whose properties are very close to those of cast parts and require little post-processing.

[00217] Secondary Electrode Block and General Operation Between torsion motor 1001 and camshaft 1003, a torsion spring 1006 is attached which allows a secondary electrode to be placed on a non-decreasing pressure layer when the electrode is melted beneath it , with a movement of the stepper motor 1001, which does not have to be adjusted exactly drops. The torsion spring 1006 can also be replaced by a flexible intermediate piece. The torsion spring 1006 is not mandatory. The secondary electrode 132 is the one with the smallest bottom contact area. It is suitable for fusing areas which thereafter have a continuous area equal to the area of the surface of the contact area 1007 of the electrode 132. The contact surface of the secondary electrodes is preferably rectangular so that the electrodes can cover the entire surface of a layer by multiples and placing the electrodes on individual partial surfaces of the layer, without causing overlapping areas exist on which the electrode with a portion of the contact surface several times.

[00219] One or more wheeled electrodes may also be attached as secondary electrodes to the printhead. On each of these a grindstone can be mounted which is pressed with a spring against the contact surface of the electrode and slowly abrades the uppermost contact surface as soon as the rolling wheel electrode rotates. In this case, the Rollradelektrode can put on a layer with applied wire paths, roll over them, transfer electricity to them and they weld so strong and possibly melt them and flattening. A rolling wheel electrode can also be moved over the camshaft. In addition, a grinding surface can also be approached at which their welding contact point is removed in order to achieve significantly longer operating times can.

The welding current and its flow time is set to the secondary electrodes, the respective amount, thickness, shape and composition of the wire webs as well as the required final height of the layer. If a secondary electrode does not drop enough during a welding operation, then this can be sensed, for example, by a pressure sensor, and it will transfer more current to the location it wants to weld.

The 3D printing apparatus may also be constructed such that one or more cutters may be mounted on the print head 105 which, after printing with the primary electrode (s), or with the primary electrodes and the secondary electrodes, form the contours of the new milled layer to achieve improved precision and surface finish. For example, an attached router on the printhead, which is driven by a motor, may be oriented perpendicular to the build platform 101 and thus can travel accurate paths from the printhead through the motion mechanism. When milling the router then only needs to mill a very small amount of material so that he can stop long, quickly leave the contours and with a thicker wire with the printed better precision can be achieved. The mounted on the print head 105 milling head could also be made multi-axis.

Fig. 19 shows a part consisting of two opposite-pole electrodes 1901 and 1903 which are very close to each other and are electrically insulated from each other. Between the electrodes 1901 and 1903 is an insulating layer 1902 which separates the two electrodes from each other. The layer 1902 may be, for example, Teflon or a ceramic material. The two electrodes have a rectangular contact area for welding, when placed on a metal layer, current flows between the electrodes during welding through the underlying metal that closes the circuit, causing the metal to heat up directly below the electrodes. The advantage here is that only the area of the metal to be welded located directly under and between the electrodes is heated so that more heat can accumulate more quickly and precisely so that the welding is improved. The lower contact area of the electrodes can wear down over a certain height and be ground, so that the electrodes last long. One of the electrodes 1901 and 1903 could also be mounted on the opposite electrode so that it can move towards it and be pressed by a spring in the resistance welding process against the surface at which the welds are made so that both electrodes are always in contact with that surface to have. In order for both electrodes 1901 and 1903 to always be in contact with the material to be welded during resistance welding, the electrodes can be moved back and forth over the surface on which the welds are made until both electrodes make electrical contact, say, for example to ascertain that the determined electrical resistance between the electrodes approaches zero.

FIG. 18 shows a part consisting of a plurality of electrodes 1801, 1802, 1805 and 1806. The electrodes 1802 and 1805 are separated from each other and insulated from the electrodes 1801 and 1806 by the insulating layer 1803. The principle is the same as in the part of Fig. 19. However, in the part having the two rectangular electrodes of Fig. 19, two parts are generally required to be seen as shown in Fig. 19, preferably rotated by 90 ° from each other mounted on the printer to weld any underlying structures equally. The electrodes 1801, 1802, 1805 and 1806 together form a part which can be moved in a block and via which the welding current is transmitted to the respective electrodes via mutually insulated contacts. The electrodes 1801 and 1806 are externally surrounded by insulation 1804 to be electrically isolated therefrom in the block 130. Power cables could also be connected directly to the electrodes. The electrodes of FIG. 18 can approach and weld virtually any location of a layer of wire webs coated with a wire-guiding electrode 103. It is also conceivable a double Rollradelektrode as a secondary electrode consisting of two opposite each other mutually separated and insulated Rollradelektroden for resistance welding according to the principle of the electrodes of FIG. 19.

Fig. 20 shows a secondary electrode having a contact surface with a raster pattern. It is suitable for performing spotwise merging on superimposed wires that are still cross-sectionally different, thereby reliably producing small areas that are fused together. The position with which the electrode 2001 touches should alternate for each successive layer, so that directly on areas of pointwise two fused wires of an overlying layer of the wire applied thereto at this point in this layer is not merged with the underlying layer and body, but only in the following layer above this point. Although this results in printed objects with less tensile strength against the layers and which are not airtight, but for the welds are easy to create and there is less heat and less oxidation of the material.

Explanation of symbols: 201 Hole 101 Carrier plate, building platform 202 Electrode 102 Object, object 2Q3 Lifting 103 Wire-guiding electrode, 2Q4 F. Wiring electrode, primary electrode 205 Object, object 104 Wire 206 Construction platform 105 Printhead 207 Power cable 106 Power cable, power cable 208 Motor, stepper motor 107 Power cable, power cable 301 Wire 109 Secondary electrode 302 Channel 110 Roller 303 Obéré Part 111 Roller 401 Funnel section, rounding 112 Motor axis, Motor 402 Contact surface, surface 113 Cooling fins 403 Surface 114 Abrasive surface 404 Rounding 115 Clamp 501 Nut-shaped portion 116 Bar 502 Thread 117 Housing of 3D printer 601 Wire-carrying electrode, primary electrode 118 Knob ", 602 Mother-shaped portion 119 Display, 603 Intermediate portion 120 Guide tube, Λ 604 End area 121 Fan γ-l. u- 605 Channel 122 Guide rail »,. ♦ I 606 wire 123 connector ",. 607 metal piece 124 rail 608 contact surface 125 belt, u u u u 609 rounding 126 toothed belt pulley o. .... 701 Wire 127 Stepper motor 702 Electrode 128 Stepper motor 703 Wire-carrying electrode, 129 Sheet-metal electrode 130 Secondary-electrode block 704 Insolating layer 131 Power cable 705 Electrode, contact electrode 132 Secondary electrode 706 Wire layer 133 Secondary electrode 801 Wire-carrying electrode, 1805 Electrode Wire-applying electrode 1806 E Electrode 802 Wire 1901 Electrode 803 Structure 1902 Black 901 Wire 1903 Electrode 902 Wire-carrying electrode 2Q01 Electrode 903 Non-conductive material, c "F force

Ceramic tip d Channel 904 diameter Metal part. R centerline radius of wire 1001 stepper motor ... S force 1002 cam q width of the wire

1003 Camshaft M «χ. D Inner diameter 1004 Locking ring b Width 1005 Compression spring T- t T Height 1006 Torsion spring A Height 1007 Contact surface,

Contact Area H Final Layer Thickness 1008 Radiator h Width of Wire 1009 Fan 1010 Connector 1101 Secondary Electrode 1102 Tip, Electrode Tip 1201 Secondary Electrode 1301 Electrode 1302 Contact Material, Tip 1401 Obéré Part 1402 Surface Area 1403 Wire Path, Wire 1404 Metal Part, Item 1601 Structure 1701 Junction Area 1702 Structure 1801 Electrode 1802 Electrode 1803 Insulating layer 1804 Insulation

Claims (30)

1. A method for producing an article of metal wherein a metal wire progressively in layers by means of a wire-guiding primary electrode in the resistance welding process is welded pointwise or, wherein the main body of the wire-guiding primary electrode, a channel passes through which the metal wire is guided in the solid state and in or directly below the mouth of this channel through which the metal wire is led out of the wire-guiding primary electrode, laid on an adjacent metal surface and welded spotwise or point-wise, the metal surface being a support plate, or a previously attached metal wire layer Method comprising the steps of: (a) for spot or pointwise resistance welding, passing an electric shock from the wire-guiding primary electrode through the metal wire to the adjacent metal surface, (b) moving (c) repeating steps (a) and (b) by successive dot or line welds and movements in layers from the article In addition to these documents, the method further optionally comprises the following document: (d) conducting a further electric current from a secondary electrode by means of steps (a) and (b) already stretched or spot welded metal wire thereat at least partially in addition, preferably over the entire length designed in one or more of the steps (b), and to fuse with the adjacent metal surface. 2. The method of claim 1, wherein during step (b) the metal wire is laterally bent at the mouth of the channel of the wire-guiding primary electrode. 3. The method of claim 2, wherein the bending of the metal wire by guiding and friction along the mouth of the wire-guiding primary electrode, wherein the mouth preferably comprises a material different from the body or consists of this, more preferably a ceramic material or a different metal. 4. The method of claim 2, wherein the bending of the metal wire is performed by heating the metal wire and moving the wire-guiding primary electrode. 5. The method of claim 1, wherein the channel of the wire-guiding primary electrode is open and corresponds to a laterally attached to the base notch through which the metal wire is guided and ends in an orifice to the lower surface of the wire-guiding primary electrode. A method according to any one of the preceding claims, wherein the mouth of the channel of the primary wire-guiding electrode comprises an annular contact surface below which the metal wire can rotate about when applied to apply the metal wire in any direction of a plane and is designed to be at least transferring a portion of the current from the wire-carrying primary electrode to the metal wire. A method according to any one of the preceding claims, wherein the channel of the wire-guiding primary electrode above the mouth is wider than the remaining part of the channel to facilitate the bending of the metal wire. 8. The method according to any one of the preceding claims, wherein the wire-guiding primary electrode does not lie with the mouth on the metal wire during application of the metal wire. 9. The method according to any one of the preceding claims, wherein the metal wire is preheated by means of a wire leading primary electrode upstream, second electrode by conducting a second current flow, wherein preferably the second electrode is disposed within the main body of the wire-guiding primary electrode. 10. The method according to any one of the preceding claims, wherein the guide of the metal wire through the channel by a motorized feed, preferably by adhesion via rollers, is supported. 11. The method according to any one of the preceding claims, wherein the cross section of the metal wire before its introduction into the wire-guiding primary electrode, preferably by rolling, is changed. 12. The method according to any one of the preceding claims, wherein in step (b) either the wire-carrying primary electrode, or the support plate, or both are moved. 13. The method of any one of the preceding claims, wherein step (d) further comprises applying a pressure to the heated metal wire. 14. The method according to any one of the preceding claims, wherein the electrical opposite pole of the secondary electrode, the support plate or another on the object of metal can be placed opposite polarity secondary electrode. 15. The method according to any one of the preceding claims, wherein the mouth of the wire-guiding primary electrode or the tip of the secondary electrode, if necessary, automated, preferably by means of an adjacently mounted grinding surface or a metal-removing tool, reground or post-processed. 16. The method according to any one of the preceding claims, comprising a step of additional shaping of the article of metal during and / or after its completion by means of a movably arranged metal-removing tool, preferably a movably arranged grinding surface or a movably arranged cutter. 17. The method according to any one of the preceding claims, wherein the metal wire additionally comprises a sheath with fusible solder material, wherein the solder material has a melting temperature which is below that of the metal wire. 18. The method according to any one of the preceding claims, wherein the metal object is dissolved after the completion of the carrier plate. 19. Apparatus for the manufacture of articles of metal by progressively layered application and resistance welding of a metal wire, comprising means for carrying out the method according to one of claims 1 to 16. 20. Apparatus according to claim 19 comprising a power supply adapted to generate electrical surges for resistance welding, a wire-guiding primary electrode for guiding and pointwise or pointwise resistance welding a metal wire, wherein the wire-carrying primary electrode is connected to the power supply, a support plate for receiving the metal object to be produced, the support plate being connected to the power supply, possibly a secondary electrode, wherein the secondary electrode is connected to the power supply, one or more movement arrangements is designed / are the wire-carrying primary, optional and / or secondary electrode and to move the support plate relative to each other in three dimensions, a control unit for controlling the movement arrangement (s) and the power supply, wherein a channel passes through the main body of the wire-guiding primary electrode through which the metal wire in solid state can be passed to an orifice of the channel and can be designed in line or point-wise welded in or directly below this mouth to an adjacent metal surface, wherein the metal surface is a carrier plate, or on a previously attached metal wire layer. 21. Apparatus according to claim 19 or 20, wherein the mouth of the channel of the wire-guiding primary electrode comprises or consists of a different material from the base body, preferably a ceramic material or a different metal. The apparatus of any one of claims 19 to 21, wherein the mouth of the channel of the wire-guiding primary electrode comprises an annular contact surface and is configured to transmit at least a portion of the current from the wire-guiding primary electrode to the metal wire. The apparatus of any one of claims 19 to 22, wherein the channel above the mouth of the wire-guiding primary electrode is wider than the remainder of the channel to facilitate the bending of the metal wire. 24. Apparatus according to any one of claims 19 to 23, further comprising one of the wire-guiding primary electrode upstream, the second electrode is designed to preheat the metal wire by conducting a second current flow, wherein preferably the second electrode is disposed within the main body of the wire-guiding primary electrode. 25. Apparatus according to any one of claims 19 to 24, further comprising a motorized feed is designed to guide the metal wire through the channel, preferably by adhesion via rollers to support. The apparatus of any of claims 19 to 25, further comprising rollers preceding the wire-guiding primary electrode and configured to change the cross-section of the metal wire prior to its insertion into the wire-carrying primary electrode. A device according to any one of claims 20 to 26, wherein the moving unit is adapted to move either the wire-carrying primary electrode, or the carrier plate, or both. 28. Apparatus according to any one of claims 19 to 27, wherein the electrical opposite pole of the secondary electrode is the support plate or another on the object of metal attachable opposite pole secondary electrode. 29. Apparatus according to any one of claims 19 to 28, further comprising an adjacently mounted grinding surface or a metal-removing tool which / is suitable for re-grinding or reworking the mouth of the wire-guiding primary electrode or possibly the tip of the secondary electrode. 30. Device according to one of claims 19 to 29, further comprising a movably arranged metal-removing tool, preferably a movably arranged grinding surface or a movably arranged milling cutter, which is suitable for additional shaping of the article of metal during and / or after its completion.