Method of creating metal components using the deposition of material and apparatus to implement this method.
Technical field
The invention concerns a method of creating metal components using the deposition of material and apparatus to implement this method. This involves the industrial area of 3D printing of metal components, additive manufacturing, hybrid manufacturing, and specifically it deals with the area of procedures designed to create metal 3D components in the working zone of a manufacturing machine which uses metal powder or metal wire as an input material. State of the art
Metal components are made by the gradual deposition welding of individual weld deposits from which metal layers are created. These layers of metal form either directly the entire components, in case of simpler parts, or individual topological elements of which the component is composed. Different methods of deposition welding are applied. The most common methods include deposition welding of metal powder entrained in a gas stream using laser or an electron beam, deposition welding of metal powder in a thin layer by means of laser, deposition welding of metal wire using laser or an electron beam, deposition welding of wire using MIG-MAG welding techniques. Potential, but unused metal deposition welding techniques include, for example, depositing by electric arc using the TIG method, plasma welding, flame welding. The known methods for metal deposition welding use powder or wire as the input material to be deposited. Deposition welding by means of heat effects and forces ensures that that deposited material is placed in a new spot where a weld deposit is created.
This invention does not address the deposition welding process as such, but uses a known deposition welding method. The patent does not deal with the solution of a method/technology of deposition welding, i.e. a technology to transfer the molten metal onto the substrate. In this regard we refer to finished technology supplied by the manufacturer of the metal deposition equipment. The invention only uses these technologies, sets the process parameters and determines the beginning and the end. Layers are created using one or several successive metal deposits made of related materials. The weld deposit may have the basic topology of a spot or a weld bead. When a weld bead is
created, there is relative movement between the base surface onto which metal is deposited and the welding device. The movement takes place on a plane parallel to the area of the base surface onto which metal is deposited. The shape of the surface onto which metal is deposited can be a general 3D shape. When a spot weld deposit is created, there is no relative movement between the base surface onto which metal is deposited and the welding device.
When one weld is deposited and one layer is finished, welding continues with another weld deposit, another layer, which creates the entire new component or gradually individual topological elements of the component. In general, it is possible to weld deposit any metal materials for which deposition welding technology is available. During deposition welding, almost all metal materials require the presence of a protective shielding gas atmosphere to avoid degeneration of the deposited material. Some materials, such as titanium and its alloys, require the presence of a shielding gas not only during the welding process, but also during the cooling of the weld deposit to its limit temperature. The specific deposition welding process parameters and protective atmospheres are not subject to protection.
The existing commercially available machinery and technologies and the existing patents generally do not include cooling, cleaning, machining, surface checks prior to further deposition welding when individual weld deposits are created and before another weld deposit and layer is made. The cooling operation is usually passive, using the ambient air or shielding gas atmosphere. The cleaning operation is generally carried out after the completion of the component and outside the production machine. The machining operation usually stake place after the completion of the component or the topological element of the component outside the machine, using a different machine or, on machines combining deposition welding and machining (Hybrid Manufacturing machines) in a single working area, machining is carried out directly in the machine where deposition welding took place.
The invention does not address the specific process and technological parameters and the tools for individual operations of deposition welding, cooling, machining and cleaning. Furthermore, the patent does not deal with software tools or a description of the machine design and its details.
The existing known solutions of machinery and technology in the industry designed to create metal component from a base metal substrate in the form of a welding wire or metal powder are as follows:
Solution 1: Deposition welding from wire using an electron beam. This technology is offered by Sciaky (http://www.sciaky.com) in its machine EBAM 300 and many other machines.
Solution 2: Deposition welding from wire using electric arc by the Gas Tungsten Arc Welding (GT AW/TIG) method and by Plasma Arc Welding (PAW). This technology is offered by Sciaky (http://www.sciaky.com) in its machine AcuWeld 1000.
Solution 3: Deposition welding of metal powder entrained in a gas stream or of a metal wire fed to the deposition welding site by a laser beam. This technology is usually referred to as "laser cladding". Laser heads are usually moved using a robot, but they can also be moved by other motion structures. This technology is offered for example by LaserTec (http ://lasertec .pl/?lang=en) .
The downside of the technology in solutions 1, 2 and 3 is their large thermal load on the produced component, large internal stresses and deformation of the components after production; the technology does not allow to treat the surface of the weld deposit for the next welding step after each deposition welding process; it does not contain machining and does not allow to cool the weld deposit before the next deposition welding step; in addition, the technology does not involve monitoring of the temperature of the welded-on component prior to the next welding step. The gradual application of weld deposits on a previous untreated weld deposit results in degeneration of the precision of geometry of every subsequent deposit, in an undefined thermal condition of the deposit - the deposition welding process uses substrates of various temperatures, which leads to an uncontrolled internal stress in the components and their material structure and homogeneity. The technology does not employ interstage surface cleaning before every deposition welding step and it is not possible to provide maximum homogeneity of the subsequent weld deposit and cleanliness of the created material. Its significant disadvantage is the high cost of the created component, between CZK 10,000 and 25,000 per kg, resulting mostly from the need to use laser technology and the electron beam technique. The process of manufacture of metal components under solutions 1 to 3 results in the manufacture of components with substandard material homogeneity, higher probability of occurrence of internal defects,
undefined thermal effects, uncontrolled distribution of internal stresses, high costs. Patents referring to this technology include for example US 7,020,539 B l.
Solution 4: Deposition welding of components from metal powder in a layer by means of a moving laser beam or a moving electron beam. This technology sinters together individual metal particles in the layer by means of a laser or electron beam. Only the defined area of the powder is bonded in each layer through laser/electron beam movement control. The technology is commonly called "Selective Laser Sintering (SLS)" and the leading manufacturer of machines for it is EOS (http://www.eos.info/), and the use of an electron beam is called "electron beam additive manufacturing" and the leading manufacturer of machines for it is Arcam AB (www.arcam.com). The basic patent describing the technology is WO 1988002677 A2, while many other patents are linked to it, e.g. JP, 2008- 106319,A; US 6,682,684 B l; US 2005/0112230 Al; US5904890.
The downside of the technology in solution 4 is its large thermal load on the produced component, large internal stresses and deformation of the components after production; the technology does not allow to treat the surface of the weld deposit for the next welding step after each deposition welding process; it does not contain machining and does not allow to cool the weld deposit before the next deposition welding step; in addition, the technology does not involve monitoring of the temperature of the welded-on component prior to the next welding step. Because the welded component is surrounded by metal powder, temperature accumulates without any control around the component. The temperature conditions are uncontrolled and the thermal load of the component is principally affected by its geometric orientation in the working area and the position and shape of other components manufactured simultaneously in the working area. The temperature condition of the weld deposit is undefined - the substrate has a different temperature every time, which results in uncontrolled internal stress in the components. A significant downside is the slow process with real productivity up to 250 g/h and the high cost of the created component, between CZK 10,000 and 25,000 per kg. The process of manufacture of metal components using solution 4 results in manufacture of components with undefined thermal effects, uncontrolled distribution of internal stresses, high cost and high demands on the manufacturing time. Solution 5: Technology combining deposition welding from powder or wire using laser (Solution 3 - Laser Cladding), integrated in a machine tool. This technology allows deposition welding generally in the machine's working area as well as to machine the
welded component. This technology is offered for example by DMG MORI (http://us.dmgmori.com) in its machine LASERTEC 65 3D, by MAZAK (https://www.mazakusa.com) in its machine INTEGREX Ϊ-400ΑΜ, by HAMUEL Maschinenbau GmbH in its machine HSTM 1500, or by WFL Millturn Technologies GmbH, IBARMIA INNOVATEK, S.L.U. and ELB-SCHLIFF Werkzeugmaschinen GmbH as machine accessories. All these machines make it possible to apply materials using the Laser Cladding technology and to machine in a single working area, and thus to use the Hybrid Manufacturing technology. Most manufacturers add the laser deposition technology to a modified machine tool. Currently known and presented technologies initially carry out gradual deposition welding of the component or its part, consisting of multiple weld deposits - deposited layers. This is followed by spontaneous cooling without temperature control and by rough machining of the entire component or its part. Patents linked to this technology include WO 90/15375; WO 02/073325 A2 and others.
A downside of this technology according to solution 5 is the large thermal load on the produced component, large internal stress and component deformation after manufacture; the technology does not allow to adjust the temperature of the component after each deposition, clean the weld deposit surface and its vicinity and machine the deposit surface accurately in preparation for the next deposition welding operation. The offered, known and presented technologies do not contain or offer cooling, temperature control, cleaning and machining after each deposition welding step and before every other deposit. The gradual application of weld deposits on previous untreated weld deposits results in degeneration of the precision of geometry of every subsequent deposit, in an undefined thermal condition of the deposit - the deposition welding process uses substrates of various temperatures, which leads to an uncontrolled internal stress in the components and their material structure and homogeneity. Surface cleanliness and its shape are also undefined. The technology does not employ interstage surface cleaning before every deposition welding step and it is not possible to provide maximum homogeneity of the subsequent weld deposit and cleanliness of the created material. Its significant disadvantage is the high cost of the created component, between CZK 8,000 and 25,000 per kg, resulting mostly from the use of laser deposition technology.
The process of manufacture of metal components under solution 5 results in the manufacture of components with substandard material homogeneity, higher probability of occurrence of
internal defects, undefined thermal effects, uncontrolled distribution of internal stresses, lower precision of the weld deposit position, high costs.
Solution 6: Deposition welding of components from metal powder in a layer using a moving laser beam, with the possibility of use of an additional milling spindle integrated in the machine tool. This technology enables deposition welding in the machine's working area as well as, to a limited extent, manufacture without using cooling by cutting fluid. This technology is offered, for example, by Matsuura
(http://www.matsuura.co.jp/english/index.html) in its machine LUMEX Avance-25, or by SODICK (http://www.sodick.com/)) in its machine OPM250L. Both these machines make it possible to apply materials using the Selective Laser Sintering (SLS) technology and, to a limited extent, to machine in a single working area, and thus to use the Hybrid Manufacturing technology. Both of these manufacturers add a milling spindle to the modified machine for the Selective Laser Sintering (SLS) technology. Currently known and presented technologies initially carry out gradual deposition welding of the component or its part, consisting of multiple weld deposits - deposited layers. This is followed by spontaneous cooling without temperature control and without the possibility of cooling, and by the machining of partial surfaces of the weld deposit to which access would not be possible in the following deposition welding technology steps, i.e. surfaces remaining in closed cavities or channels. Considering the seating of the component, embedded in metal dust, it is not possible to use fluid cooling and to machine with greater cutting forces. The basic patents linked to this technology include: US 6,657,155 B2; US 2006/0208396 Al; US 8,329,092 B2; US 7,323,132 B2; US 7,172,724 B2; US 2011/0123383 Al; US 8,828,116 B2; US 8,738,166 B2; US 2013/0065073 Al; US 2006/0208396 Al. Other close patents are EP 0596683 Al, which divides the technology into multiple working stations, and patents EP 0470705 A2; EP 2 581 154 Al; EP 2 581 155 Al; JP 2000 73108A; JP 3446618; US 2002/0147521 Al; WO 02/073324 A2 and others.
A downside of the technology under solution 6 is the large thermal load on the manufactured component, large internal stress and deformation of components during and after manufacture, and machining therefore takes place on a component deformed by temperature. The technology does not offer the possibility to adjust the temperature of the component accurately after each deposition step, to clean the weld deposit surface and its vicinity and to machine the deposit surface accurately in preparation for the following deposition operation as it would result in contamination of the last layer of metal dust by cutting chips and the
subsequent single layer of metal dust would not be able to cover the cutting chips reliably, thus threatening of the quality of the weld deposit in the following layer, The offered, known and presented technologies do not contain or offer cooling, temperature control, cleaning and machining after each deposition welding step and before every other deposit. The gradual application of weld deposits on previous untreated weld deposits results in degeneration of the precision of geometry of every subsequent deposit, in an undefined thermal condition of the deposit - the deposition welding process uses substrates of various temperatures, which leads to an uncontrolled internal stress in the components and their material structure and homogeneity. Surface cleanliness and its shape are also undefined. The technology does not employ interstage surface cleaning before every deposition welding step and it is not possible to provide maximum homogeneity of the subsequent weld deposit and cleanliness of the created material. Its significant disadvantage is the high cost of the created component, between CZK 10000 and 25,000 per kg, resulting mostly from the use of laser deposition technology. The metal component manufacturing processes using solution 6 result in the manufacture of parts with undefined temperature effects, uncontrolled distribution of internal stress, absence of the possibility to define the shape of the surface before every deposit, lower accuracy of the position of the weld deposit, and high costs.
Essence of invention The deficiencies mentioned above are, to a large extent, eliminated by the method of creating metal components using the deposition of material according to this invention. Its essence is that a weld deposit with the size of 2 to 200 mm3/s is created, and then cooled to a temperature of 20 to 90 °C and cleaned; after that the weld deposit is machined to the shape of the base with 1 to 3 defined contact surfaces for the next deposit and, after additional cleaning and drying, another weld deposit is created with the size of 2 to 200 mm3/s.
Cooling is preferably effected by flooding the component with coolant to a maximum level of 3 mm under the new weld deposit and/or by cooling the work table of the machine. Weld deposit is created by at least one procedure selected from a group of gas deposition welding using laser, deposition welding by an electron beam, deposition welding of metal powder in a thin layer using laser, deposition welding of metal wire using laser, deposition
welding using an electron beam, deposition welding of wire using MIG-MAG welding techniques, arc deposition welding by the TIG method, plasma welding, flame welding.
Cleaning can be carried out mechanically and/or by flowing fluid.
The subject of invention also includes an apparatus for implementing the method according to any of the preceding claims, comprising a support structure of the machine, which is composed of a bed, a stand and at least three motion axes X, Y, Z, connected to each other and/or to the stand and the bed by means of linear guides, and a work table with at least one welding head and at least one machining head. Its essence is that at least three motion axes, a head stock and a tool spindle are integrated in one closed, ventilated area in the apparatus, and other technology units are connected to the body of the head stock, selected from the group of welding head, continuous cooling unit, weld deposit cleaning unit, cleaning and drying unit and temperature control unit, and the table is equipped with internal cooling.
The apparatus can be complemented with additional rotary motion axes B and C. The motion axes are preferably provided with an electric actuator, which is connected to the machine's control system.
The apparatus is preferably provided with at least one temperature sensor. The invention concerns technology and manufacturing apparatus which is modularly composed of partial operations allowing cheaper and more accurate manufacture of components, compared to the existing technology, with a homogeneous structure and lower residual stress. The basis of the technology is a combination of standard deposition welding methods with intermediate operations of cooling, cleaning and machining, so that the newly applied layer is applied onto a geometrically defined surface, a clean and smooth surface. This solution with the given degree of complexity has not been presented and offered by anyone so far, even though many close technologies are presented and offered and many others are being developed.
The present invention provides a cost-efficient technology using electric arc deposition welding based on the consumption of standard welding wires, welding gases and machine tools. The price of 1 kg of the created component is 25 to 30% of the price of a component produced by 3D printers (SLM), or by Laser Cladding from powder.
If the starting machine for the technology is a CNC machine tool and if electric arc is used for deposition welding of the material, the lower price of the equipment is an advantage, reaching about 50% of the price of a machine using laser for welding.
The production process can be fully automated without any need for supervision and participation of human operators and there is therefore minimal risk of damage to the operators' health.
When using electric arc welding, the technology guarantees higher occupational safety for the operator because it does not use carcinogenic metal powder as the base substance to create the weld deposit. Also, there is no explosion risk with respect to the powder. Applying the entire procedure of individual operations to create multiple connected layers results in the formation of up to 100% homogeneous welded material without pores and slag.
If the starting machine for the technology and for ensuring the kinematic guidance of the weld torch is a CNC machine tool, it is possible to achieve extremely precise placement of the weld deposit thanks to the machine accuracy, programming and control. When electric arc welding is used, the position of arcing and the shape of the deposit can be controlled using an appropriately machined surface designed for deposition welding. It is possible to guide the electric arc specifically.
The technology allows to create machine components with a minimal amount of applied structural materials - optimum shape, open and closed cavities, and thus to save material resources and the environment. If such an optimum component is part of means of transport, there are also secondary savings on energy costs generated.
The technology enables rapid manufacture of complex semi-finished products and finished components, with welding wire being the base stock material for electric arc deposition welding. In case of electric arc welding, the technology allows to create components or support structures by means of colder continuous weld deposit, a technology known as CMT (Cold Metal Transfer), followed by cooling and machining of the applied partial layer in a single working area, with an automated cycle and rapid interval repetition.
In case electric arc welding, the technology allows to create components or support structures using a spot strategy with precise drop flashing-off, when a single spot is created with the desired size of 0.5 to 10 mm depending on the number of drops. This makes it possible to maintain the generated stress in the product at an acceptable limit and, at the same time, the component can be layered using the same defined drop volume, independent of the time of welding.
Integrated solution in a single working area for all operations, i.e. for the entire cycle, which reduces working time compared to a solution where individual operations are carried out at separate workstations. The time savings are fivefold. This integrated solution in a single working area for all operations also reduces the built-up area for the application of the technology. The savings on production areas are also fivefold.
Using electric arc welding, it is possible to create the surface of the component in the space, i.e. start the component and the surface in the air, by means of welded-on support structures. When using electric arc welding, support structures can be created at an angle of 0° to 90°. The enclosed working area allows to maintain stable working conditions for all operations.
During deposition welding, the system allows to diagnose any deposit defects and subsequently to remove any defective weld deposit automatically and apply it again, correctly. The technology allows to record all process parameters and to keep a report on the full production cycle for each produced component. If the starting machine for the technology and for ensuring the kinematic guidance of the weld torch is a CNC machine tool, it is possible to achieve extremely precise placement of the weld deposit, up to 0.05 mm accuracy of its position in the space, thanks to the machine accuracy, programming and control.
In case electric arc welding, the technology allows to create components or support structures using a spot strategy with precise drop flashing-off in the range of 1 to 100 drops, with the desired spot size of 0.5 to 10 mm created depending on the number of drops. This makes it possible to maintain the generated stress in the product at an acceptable limit and, at the same time, the component can be layered using the same defined volume of material in a single spot, independent of the time of welding.
The enclosed working area allows to maintain stable working conditions for all operations. During deposition welding, the system allows to diagnose any deposit defects and subsequently to remove any defective weld deposit automatically and apply it again, correctly. The technology allows to create machine components with a minimal amount of applied structural materials - optimum shape, open and closed cavities, and thus to save material resources and the environment. If such an optimum component is part of means of transport, there are also secondary savings on energy costs generated. The technology enables rapid manufacture of complex semi-finished products and finished components, with welding wire being the base stock material for electric arc deposition welding.
Clarification of drawings.
An exemplary solution will be described in greater detail on a specific embodiment using the attached drawings, wherein Fig. 1 provides a schematic view of the method of creating metal components using the deposition of material. Fig. 2 shows exemplary shapes of the weld deposit and Fig. 3 shows a front view of an exemplary embodiment, while Fig. 4 shows a side view.
Embodiments of the technical solution
In the exemplary method of creating metal components by means of deposition of material, a weld deposit with the size of 100 mm3/s is created, and then cooled to a temperature of 30°C and cleaned; after that the weld deposit is machined to the shape of the base with a contact surface for the next deposit and, after additional cleaning and drying, another weld deposit is created with the size of 100 mm3/s. This procedure is repeated until the desired size of the weld deposit is created.
The welding operation uses a less known method for the deposition welding of metals and commercially available metal welding equipment. Technologies with minimum heat transfer to the base material on which deposition welding is carried out are particularly suitable.
In particular, this involves electric arc welding - welding using a continuously supplied electrode, but generally there are more technologies using electric arc welding, laser welding with wire, laser welding with powder. Marginally, it can also involve plasma welding - from
powder, filler wire, flame welding - from powder, wire, and other deposition welding technologies.
The subject of the invention is a procedure of deposition welding of components where cooling of the created weld deposit, i.e. the weld bead, spot weld deposit, layer or part of a bead or a layer, is carried out between individual welding operations. The temperature of the metal material is at least at the melting point or higher. The base material has an ambient temperature, or workshop temperature, at which it will also be operated or at which its manufacturing dimensions and their tolerances are at least measured. The deposited material is the source of heat. The heat causes the base material to warm up and change its dimensions. When the weld deposit solidifies, which occurs immediately after deposition welding, the component has an increased temperature and, as a consequence, different dimensions and geometrical shape than after full cool-down to the ambient temperature. If the following weld deposit is applied without cooling the component, then it is applied on a heated and deformed component and, after component cooling, the material has a large residual internal stress and its dimensions and geometry are inaccurate. The present technology contains a cooling operation, carried out at least between individual layers or more often, between parts of layers, between beads, bead parts or groups of spot welds produced. The basis is that each new layer is welded on the previous layer - created element, which is cooled to ambient temperature - about 40°C, i.e. each additional layer is applied on a cold component. The goal of intermittent cooling is intense heat removal, transfer of heat generated during the deposition welding to the cooling fluid and its transport in the cooling fluid outside the working area and the created component.
The cooling method is generally implemented using fluid media - liquids and gases, mainly by using cutting emulsions and cutting oils used on machine tools, with the use of air, or other gases and liquids. These liquids or gases are cooled to ambient temperature or to a lower temperature and, using a hydraulic or pneumatic circuit - a pump, a compressor, distribution pipes, tubes, hoses, fittings - are supplied to the nozzle or multiple nozzles which direct, generally or in a controlled movement, the cooling liquid or gas to the weld deposits and the created component. The controlled movement of cooling can be performed using a separate handling apparatus which moves the nozzle or multiple nozzles or using the movement of the machine and its motion axes, which provide for movement during deposition welding, machining and cleaning.
Likewise, cooling can also be provided for spot welds constituting a weld bead or a deposit layer, cooling of a single layer comprising connected beads or connected spot welds, cooling of a single layer comprising beads welded in steps or spot welds and cooled in steps. Continuous cooling provides for the removal of heat created in the component either by deposition welding or by machining and cleaning. Continuous cooling removes heat from the clamping base - pallet, or from the machine's work table, or directly from the component which is flooded by the coolant.
The cooling method is performed generally using fluids. These liquids or gases are cooled to a temperature close to the ambient temperature or lower and are fed in an open or closed circuit to be in contact with the component or remove heat from the clamping base. Standard machine cooling systems are used - a pump, distribution pipes, tubes, hoses, fittings, which use water-based coolants in closed circuits. The method of cooling with an open circuit works with a cutting liquid which the machine employs for machining and for intermittent cooling - one type of liquid in the working area.
Continuous cooling of the component and its base is also possible. Cooling is carried out in the form of controlled flooding of the component, maintaining the level of the cooling liquid just below the newly created weld deposit - the liquid is about 5 mm below the new deposit. It is an open cooling circuit with common coolant both for the cutting process and intermittent cooling.
Alternatively, it is possible to use cooling of the clamping base - pallet, work table of the machine. Cooling of the clamping base using an integrated labyrinth through which the coolant flows and removes heat from the pallet. It is a closed circuit using the same coolant and, if applicable, the same cooling unit as the one used for cooling the spindle or other closed cooling circuits of the machine.
Cleaning is followed by machining of the surface of the previous weld deposit - bead or layer - which allows to create the defined geometry of the surface for the deposition welding of a new weld deposit. The operation allows to define the geometric conditions for welding each new layer. This makes sure that a new weld deposit is not applied onto an undefined shape of the previous weld deposit. The homogeneity of the welded material is greater than
when deposited without machining between individual deposits. The clearly defined geometry of the machined surface for the new weld deposit allows to ensure stable weld conditions. The machining of side surfaces allows a better binding of the weld deposits on the edges of the component, to produce a smoother surface of the component than after welding without side surface machining and to minimize additions of material on the sides of the component for any possible finishing, if planned.
Machining is carried out using standard cutting tools for machine tools - cutters, turning tools, grinding wheels, etc., using standard procedures and tool movements with respect to the component - workpiece, with the use of standard cutting fluids or without them. Surface cleaning and drying before another weld deposit is made removes residual particles and liquids on the surface onto which the new weld deposit is applied. The cleaning method is carried out using a stream of compressed air. This employs a pneumatic circuit - a compressor, distribution pipes, tubes, hoses, fittings; compressed air is fed to the nozzle or multiple nozzles which direct air to the places of the future weld deposit generally or in a controlled movement. The controlled movement of cleaning and drying can be performed using a separate handling apparatus which moves the nozzle or multiple nozzles or using the movement of the machine and its motion axes, which provide for movement during deposition welding, machining and cooling.
With this method of creating metal components, the surface temperature is monitored using contactless measurement. Measurements can be performed using a thermal imaging camera which can capture, at least to some extent, the surface of the last weld deposit and layer. The view field of the thermal imaging camera shall be evaluated so as to perform automatic measurement and evaluation either of local maximum values in the place of the weld deposit, or of average values for the entire layer. Embodiment 1
Deposition welding is carried out using electric arc, with continuously fed electrode. It is followed by intermittent cooling of one weld bead and cleaning of the weld deposit using mechanical brushes. The front surface - a surface perpendicular to the direction of deposit growth or a surface whose normal is at an angle of no more than 45° to the direction of weld growth - is also machined. It is generally a shaped surface. It is carried out using standard cutting tools for machine tools - cutters, turning tools, grinding wheels, etc., using standard
procedures and tool movements with respect to the component - workpiece. It is followed by surface cleaning and drying before a new weld deposit is applied - contour controlled, performed by means of a standard pneumatic system and general or controlled direction of the air stream to the surface on which the new weld deposit is to be applied. Temperature monitoring on the surface for the future weld deposit is carried out using a thermal imaging camera Flir with cleaned porthole into the working area, with an evaluation, or output of data on maximum temperature in the field of vision.
Embodiment 2
Deposition welding is performed by laser welding of wire or powder. It is followed by the drying of one weld bead made in steps and cooled in steps, i.e. intercooling and cleaning of the weld deposit with a stream of liquid. Apart from the front surface, side surfaces are also machined - surfaces parallel to the direction of weld growth or surfaces whose normal is at an angle of 45° or greater with the direction of weld growth. Once again, it is carried out using standard cutting tools for machine tools - cutters, turning tools, grinding wheels, etc., using standard procedures and tool movements with respect to the component - workpiece. It is followed by surface cleaning and drying before a new weld deposit is applied - general, performed using special air nozzles with an air outlet in the form of a stream aperture which reaches the entire component during the cleaning sequence while only one motion axis moves. Temperature monitoring of the entire component is carried out using a thermal imaging camera Flir with cleaned porthole into the working area, with an evaluation, or output of data on average temperature in the field of vision.
Fig. 2 shows, from the left, a weld deposit without machining, a weld deposit with the machined base with one defined contact surface for the subsequent weld, a weld deposit with the machined base and two defined contact surfaces for the subsequent weld, a weld deposit with the machined base and three defined contact surfaces for the subsequent weld.
The embodiment of the machine is based on a milling machine with three orthogonal motion axes X, Y, Z. The machine can be supplemented to include additional axes of motion, e.g. rotational axes B and C, so the machine would have a total of five controlled axes. The support structure of the machine comprises a bed (12), a frame (13) and motion axes (10), (11) and (14). The motion axes are connected to each other or to the stand and the bed via linear guides (15), (16) and (17). Movement of the motion axes is provided by an electric
actuator (not shown) and the movement is controlled by the machine control system (not shown), which processes the programme of movements and functions. The machine has a head stock and a spindle (OP 11 and OP 12), which can provide machining and shape modification of the weld deposit (4) on the surface of the component (2) using the tool (18). Other technological units are attached to the body of the head stock, in particular a welding head (OP01), an intermittent cooling unit (OP02, OP03, OP04, OP05, OP06), a weld cleaning unit (OP09 and OP10), a cleaning and drying unit (OP13 and OP14) and a temperature control unit (OP89 and OP99). All these units can move with respect to the component (2) located on the stand (10) using the motion axes X, Y, Z. The table and the motion axis X (10) are equipped with internal cooling OP08.
The apparatus includes the following features with the respective operations: welding head (OP01), intermittent cooling / cooling unit (OP02, OP03, OP04, OP05, OP06), weld cleaning (OP09 and OP1) weld machining - shape modification (OP 11 and OP 12), cleaning and drying (OP13 and OP14), temperature control (OP89 and OP99), continuous component cooling (OP07), continuous table / pallet / base cooling (OP08).
1 - table
2 - manufactured component
3 - coordinate system for the relative movement of the component with respect to the machine and individual technology units
4 - last created layer of the component
5 - support structure
10 - table and motion axis X
11 - cross slide and motion axis Y
12 - machine bed
13 - machine stand
14 - head stock and motion axis Z
15 - linear guide of motion axis X
16 - linear guide of motion axis Y
17 - linear guide of motion axis Z
18 - cutting tool
19 - sensor holder
In the embodiment of the technological process of component manufacture, the following technological steps are applied: a) to create layers with a core-less topology - closed contour / open contour start OP10 - OP13-OP01-OP02-OP11-OP02-OP13 end and repetition b) to create layers with a core topology start OP10 - OP13-OP01-OP02-OP11-OP02-OP11-OP12-OP99 end and repetition
Using electric arc welding, it is possible to create the surface of the component in the space, i.e. start the component and the surface in the air, by means of welded-on support structures. When using electric arc welding, support structures can be created at an angle of 0° to 90°. During deposition welding, the system allows to diagnose any deposit defects and subsequently to remove any defective weld deposit automatically and apply it again, correctly. The technology allows to record all process parameters and to keep a report on the full production cycle for each produced component.
Industrial use The method of creating metal components using the deposition of material and apparatus to implement this method can be used in particular for parts of machines and equipment, for the manufacture of rotary, box and prismatic parts from steel, stainless steel, aluminium alloys, titanium alloys, nickel alloys and other metallic materials, which are weldable and workable by deposition welding. Sectors that can use the parts made by means of this technology are in particular: aerospace, automotive, means of transport, energy, machine structures, instruments, manufacturing machinery, agricultural machinery, processing equipment, consumer products, artwork, and general engineering.