WO2008083786A1

WO2008083786A1 - Method and device for painting machined surfaces

Info

Publication number: WO2008083786A1
Application number: PCT/EP2007/009774
Authority: WO
Inventors: Thomas Turner; Hermann Schauer; Karl-Heinz Stellnberger; Christian Ivancsits
Original assignee: Vatron Gmbh
Priority date: 2006-12-22
Filing date: 2007-11-12
Publication date: 2008-07-17
Also published as: ATE524242T1; EP2091664B1; EP2091664A1

Abstract

The invention relates to a device (1) for applying a liquid to cut edges of metal sheet components (12), comprising at least one stamp device (14) having a stamp surface which corresponds to the contour of a workpiece edge to be wetted. The device is constructed in such a manner that the stamp edge or edges and the workpiece can move towards each other and are arranged in such a way that the stamp edges, wetted with the liquid, can be brought into contact with a workpiece edge. The invention also relates to a method for coating machined edges.

Description

Method and device for painting cut surfaces

The invention relates to a method and apparatus for painting cut surfaces.

It is known to punch from sheet steel, especially galvanized steel, components for the automotive industry but also for the household appliance industry and then to shape.

But also from other sheets, such as aluminum sheets such parts are produced.

In this case, it is disadvantageous that a corrosion protection, if appropriate affixed to a surface, for example a zinc coating in the region of the edges, is no longer present, so that edge corrosion can take place.

In addition, such edges are often sharp-edged, so that there is an accident risk during installation and operation.

From "Cut surface protection on galvanized sheet metal", Andreas Schütz, Institute for Corrosion Protection Dresden GmbH, the negative effects of the cutting edge and the possibility of improving the corrosion behavior of the so-called round section are discussed. From "Behavior of Surface Coatings on Steel Sheets during Forming and Cutting", 3rd Steel Symposium, Materials Application, Research, Dusseldorf, 12.03.2003 are also known corrosion problems, especially at cut edges. In order to provide cut edges with a corrosion protection layer, it is known from this publication to produce an edge protection in that either the complete body is immersed, a cut surface coating by laser and powder coating, a coating is carried out by means of zinc pin friction welding, an application radiation of a zinc coating Zinc coatings are made on the zinc edge or UV varnish coatings are carried out, for which purpose only preliminary investigations should be available. Such a method for applying a corrosion protection layer on edge surfaces of sheets is known, for example, from DE 101 06 474 A1, in which a laser zinc powder, which is mixed with flux, is applied to the edges. In such a method is disadvantageous that this is very complicated and expensive.

From DE 40 11 320 C2 a method for the treatment of the edges of stamped, pressed or cut metal parts is known in which the edges of the metal parts are coated with a powder coating in the electrostatic powder rinsing, wherein a plurality of metal parts are joined together to form a metal sub-packages.

Such a method is difficult to integrate into existing manufacturing processes, since the individual components must first be stacked.

DE 38 280 045 C1 makes it possible to produce corrosion-protected cut edges of corrosion-protected metal sheets by rubbing a corrosion inhibitor known, the anzureibende corrosion inhibitor can be made of metal or plastic. This should be ensured in particular by attachments to the cutting scissors. However, this has the disadvantage that such a device does not give a particularly good corrosion protection.

From DE 37 04 364 Cl a method for cutting edges of blanks made of coated material for sheet metal housing parts is known, in which at least the visible cut edges are coated with a curing by UV radiation paint by means of one or more spray nozzles, which are moved along the cutting edges and are positioned and aligned such that they are at a distance from the respective edge region at an angle from the viewing side of the opposite side of the blank, directed to this and that the applied paint is cured with UV radiation.

All of the aforementioned methods of the prior art have in common that they are quite slow as punctual methods, the apparatus complexity is very high but only a conditional three-dimensional capability is present or these methods are not suitable for complex geometries. In addition, the majority leak leaky, in terms of corrosion protection unsatisfactory coatings results and the visual appearance does not meet the requirements.

It is an object of the invention to provide a device for coating of cut edges, which is simple and reliable works even at high clock rates. The object is achieved with a device having the features of claim 1. Advantageous developments are characterized in the subclaims.

A further object of the invention is to provide a method for coating cut edges, which is simple, quick and safe to carry out, provides good corrosion protection and cut protection at the edge and with which even complex geometries with undercuts can be coated.

The object is achieved by a method having the features of claim 14. Advantageous developments are characterized by the claims dependent thereon.

Dipping methods have hitherto been known from the prior art (FIGS. 41 to 44) in which a component is immersed in a coating bath. In this case, a workpiece edge is immersed in the paint bath and then lifted from the paint bath. As can be seen in a highly schematic way, this leads to long process times, since in this case the immersion times must be taken into account. In addition, it must be noted that the bath level is constantly kept constant and the bath surface does not change the viscosity and that no skin forms on the bath level.

As can be seen in Figures 45 and 46, can be coated with the known dipping process workpieces then not satisfactory edges, if they have a three-dimensional edge profile, ie z. B. have projections or recesses with respect to a Badspiegelhöhe.

As shown in Figs. 49 to 50, hole edges can not satisfactorily be coated by such methods. The inventive method provides for applying a liquid to a well-defined area of a workpiece, in particular the cut edges, to use a stamp that is adapted to the particular shape of the workpiece or to the edge profile. The stamp is initially in a container and is completely covered by the liquid to be applied. In order to achieve a defined liquid layer on the intended for coating the workpiece contours of the punch, it is lifted from the liquid container and left for a certain period of time, so that excess liquid can run off. For application of a liquid film on the workpiece this is now brought into contact with the punch form-fitting or with a small distance and removed immediately or after a short residence time again.

This method is used e.g. for applying a corrosion protection varnish to the cut surfaces of coated steel strip workpieces. This is done in a further step, the curing of the paint.

Steel, stainless steel, aluminum, plastics and other materials, with or without additional coating in the form of galvanizing, chrome plating, nickel plating, plastic coating or powder coating or the like, may be used as the material for the construction of the stamp. be used.

The workpieces to be machined are stamped or otherwise severed sheet metal parts that may be flat, bent or deep-drawn. The application of paint can be done on almost every possible cutting surface of a three-dimensional, deep-drawn molding. The sheets can be galvanized, galvanized and / or with an organic coating be provided. Depending on the complexity, the workpiece can be coated with one or more stamps in one or more steps.

According to the invention, anti-corrosion lacquers, lacquers with or without pigments, adhesives, liquid zinc or liquid materials which can be foamed in a further working step are used as liquids to be applied. Preferably, liquids are used which are cured by thermal energy input or by energy input in the form of UV radiation. In particular, UV lacquers are preferably used.

The viscosity of the liquids used may need to be adjusted to the process by solvents or other additions.

In a further advantageous embodiment, thermoplastics are used instead of paints.

Since the viscosity of the liquids used is an important process parameter, the paint container is provided with stirrers and / or devices for temperature control.

In a further advantageous embodiment, the liquid container, which also houses the die, is designed such that it has an inlet and a drain, so that the corresponding liquid is pumped in the circulation and is in each case refreshed in a separate mixing tank and, in particular, with new ones Solvents provided and / or heated. The inventive coating of cut surfaces in deep-drawn workpieces made of coated steel sheet with UV-curing protective coating, which is applied over the stamp, resulting in an extremely good corrosion protection behavior, both after salt spray fog test, VDA change test and electrochemical corrosion tests and gives the workpiece an attractive appearance , Preferably, the coating of the cut surface can be further painted together with the workpiece, for example by powder coating.

A further advantage of the invention is that the coating of the cut surfaces of the workpiece encloses the cut surfaces and covers the very sharp cutting edge to the outside and leaves a smooth, rounded contour on the workpiece, which virtually eliminates the risk of injury.

According to the invention it has been found that the special design of the stamp is crucial for a perfect result of the cut edge coating.

In the context of the invention, the classic stamping was first tried, being used as stamp material foam or rubber, such as sponge rubber. The stamp was immersed in a paint vessel, then the cut surface of a stamped part was stamped, but the result was not satisfactory because the paint distribution was uneven, have formed in the paint bubbles and a large wear on stamp material was present and the corrosion protection is not always sufficient was. In order to avoid air bubbles and high wear, according to the invention rubber or bare steel are used for stamping. By immersing the stamp in a paint container initially no uniform coating distribution on the stamp could be achieved, which is why the paint was applied with a compressed air dosing system on the stamp. Around To avoid air connections in the paint, the paint cartridges used were degassed by centrifuges. These changes eliminated the shortcomings of the classic stamp. A fully automated test station was set up, with which a certain part could be reproducibly coated and the corrosion-protective coating was also visually good. Due to the complex coating of the stamp, however, this method is slow, ie, this stamping method provides a satisfactory quality of the coating, but is associated with a long cycle time, which is not particularly advantageous in mass parts.

In addition, in the method according to the invention, openings within a sheet metal component can also be provided with an edge protection lacquer, wherein the coating of the edges delimiting an opening can take place simultaneously with the coating of the outer edges or sequentially. According to the invention mandrels are retracted in such openings, which are either conical and have a corresponding cross-section of the opening or which can enlarge and reduce its size and are optionally rotated to effect a uniform application of paint on the edges bounding an opening.

The invention will be explained by way of example with reference to a drawing. It shows:

Figure 1: a partially sectioned side view of a first embodiment of the device according to the invention;

FIG. 2 shows the device according to FIG. 1 in a perspective partially sectioned view; Figure 3: another embodiment of the invention

Device in a partially sectioned side view;

FIG. 4 shows the device according to FIG. 3 in a perspective partially sectioned view;

Figure 5: the device according to Figures 1 and 2 with marked liquid level and the directions of movement of the moving parts;

Figure 6: the device of Figures 3 and 4 with the directions of movement of the moving parts and a drawn liquid level.

FIG. 7 shows a further embodiment of the device according to the invention for flat stamped parts with circumferential edges;

Figures 8a - 8c: the device of Figure 7 in a first standby state in which a stamped part can be placed;

Figures 9a - 9c: the apparatus of Figure 7 in a second state in which a stamped part is placed and a first set of stamps in readiness;

FIGS. 10a-10c: the device according to FIG. 7 during stamping of opposite sides of the stamped part; FIGS. 11a-11c: the device according to FIG. 7 during the stamping of the further opposite sides of the stamped part, with the stamps in stand-by;

Figures 12a - 12c: the device of Figure 7 in the stamping of the other sides of the stamped part, wherein the stamp are formed adjacent;

FIGS. 13a, 13b show the device according to FIG. 7 with stamps that have emerged and with a stamped part lifted off and moved away after stamping has taken place;

FIG. 14: a further embodiment of the device according to the invention in a perspective top view;

Figure 15 is an exploded view of the device of Figure 14;

FIGS. 16a-16c:

The device according to the invention when coating the edges of a three-dimensionally curved component with an inner recess during the painting of a peripheral edge facing the vessel;

FIGS. 17a-17c: the device according to FIG. 14 of first opposing edge regions of a substantially oval opening; FIGS. 18a, 18b: the device according to FIG. 14, wherein the coating punches rest against the first peripheral edge regions;

Figures 19a-19c: the apparatus of Figure 14, wherein the punches are for painting the remaining cut edges of the opening in the stamping position;

Figures 20a-20c: the apparatus of Figure 14, wherein the remaining cut edges of the opening are stamped;

FIG. 21 shows a further embodiment of the device according to the invention for painting the cut edges of a hole or a punch-like cut with an outer guide of a coating mandrel;

FIG. 22 shows a further embodiment of the device according to FIG. 21 with an internally guided coating mandrel;

FIG. 23 shows another device for coating the cut edges of a hole, wherein the mandrel works according to the displacement principle;

FIG. 24 shows a further embodiment of a device for coating the cut surfaces of holes, wherein the coating mandrel is rotatably mounted;

FIG. 25 shows a further device for coating the cut edges of an opening or a hole in a component, the mandrel having a region with an enlargeable cross section for applying the lacquer; FIG. 26 shows a further embodiment of a device according to the invention for painting the cut edges of a hole, wherein the mandrel is moved linearly into the corresponding height and then horizontally into the hole;

FIG. 27 shows a rotatable, anchor-like coating mandrel, wherein several components can be coated successively;

Figures 28a-28d: a coating mandrel with internal supply

FIGS. 29a-29d show different mandrel geometries in a side view;

Figures 29e - 29h: the mandrel geometries of Figures 28a to 28d in a plan view;

Figures 29i - 291: the coating mandrels according to Figures 28a to 28d in a perspective view with matching hole geometries in components;

FIG. 30a shows a further device according to the invention for painting the cut surface of a hole or a recess in a component, in particular a component with a greater material thickness, wherein the mandrel has an enlargeable circumference via a segmentation; FIGS. 30b, 30c show a first embodiment of a segmented mandrel in the rest position and in the painting position;

FIGS. 3Od, 3Oe: another embodiment of a segmented mandrel, wherein the mandrel opens with a gap;

FIGS. 3Of, 30g: a segmented mandrel for coating an elliptical recess;

FIG. 31 shows a perspective, partially cutaway view of a further embodiment of a device for painting the cut surface of a recess or a hole in a component;

FIGS. 31a-31f:

Cross sections of the segments of the inventive device according to Figure 30 with different coating profiles;

Figures 32a-32e illustrate the operation of the apparatus of Figure 30 with a rotatable segmented mandrel for coating the cut edges of a hole or recess;

FIG. 33 shows the device according to FIGS. 1 and 2 in a further embodiment with a coating mandrel for coating the cut edges of an opening;

Figures 34a - 34d: another embodiment of a stamp according to the invention FIG. 35 is a schematic of the process sequence;

FIG. 36: a schematic description of the method;

FIG. 37: a process description of the pretreatment;

Figure 38: a process tree of the paint circuit according to the invention;

Figure 39: the handling sequence in a complex workpiece having a plurality of openings;

FIG. 40 shows the integration of the coating device according to the invention in a system with a deep-drawing device;

Figures 41 to 44: a dipping method according to the prior art;

Figures 45 and 46: schematically the disadvantages of a dipping method according to the prior art.

The device 1 according to the invention has a paint container 2, which has, for example, a square base surface or an oblong rectangular base surface in accordance with the workpiece to be processed.

The paint container 2 thus has a bottom wall 3 and a circumferential side wall 4. A coating stamp 5 is arranged in the paint container 2. The coating die 5 has a substantially U-shaped bracket 6 which, via a bottom wall 7, extends from this upwardly extending ironing Walls 8 and 8 of the Bügelwandungen laterally outgoing support walls 9 has. The support walls 9 extend beyond the walls 4 of the paint container to the outside and are arranged on a lifting mechanism 10, for example on a pneumatic or hydraulic piston 11 of the lifting mechanism 10. With the lifting device 10 and the pneumatic or hydraulic piston 11, on the support walls 9 act, thus the coating die 5 can be up and lifted within the paint container 2.

The coating die 5 additionally has a die wall 13 corresponding to the edge contour of a workpiece 12 to be coated, the die wall 13 being arranged on the bottom wall 7 and having an upwardly directed peripheral die edge 14.

The stamp edge 14 is both respect. their circumferential course as well as with respect to their height profile to the contour of a component 12 in the present images of a gas cap 12 adapted such that a gas cap 12, which is placed on the punch edge 14, rests with its peripheral edge on all sides the same.

The workpiece 12 is positioned with a gripper 15 above the coating die 5, wherein the gripper 15 is, for example, a suction gripper 15.

The stamp edge 14 may be flat, but the stamp edge 14 may also be formed as a groove with a u- or v-shaped groove, which collects in the groove, the liquid with which the edge of the workpiece to be coated. The bottom wall 7 preferably has apertures 16, so that in the area enclosed in front of the stamp wall 13 region of the paint can flow.

Preferably, one or more webs 17 are left to stand on which, for example, one or more centering mandrels 18 can be arranged, which engages in the following to be described laying the workpiece in a corresponding center hole 19 to center the workpiece.

In order to bring about the coating (FIG. 5), both the workpiece 12 can be moved toward the stamp edge 14 and the stamp can be lifted out of the liquid by means of the lifting mechanism, in such a way that at least the stamp edge 14 projects beyond the liquid level 20.

The placement of the cutting edge to be coated on the upper coating edge of the stamp can be such that the edge rests on the stamp or a certain distance of the edge to be coated edge to the die edge, the edge but already immersed in the coating liquid and the coating liquid due to capillary forces on the Edge of the workpiece and the adjacent areas flows or spreads.

After the coating of the edge, the workpiece and the punch edge 14 or the punch are again moved away from each other and then caused a drying or curing of the edge covering liquid, for example by a so-called UV drying in a corresponding facility (UV oven ).

In a further advantageous embodiment (Figures 3, 4 and 6), the outwardly or inwardly facing edges of a workpiece are coated. For this purpose, such a device 30 also has a paint container 31 with a bottom wall 32 and a peripheral container wall 33. The paint container preferably has a continuous bottom surface, wherein in the paint container, a coating device 34 is present. The coating device 34 consists, for example, of a base frame 35 and a hingedly hinged stamping device 36 arranged thereon. The stamping devices 36 are pivotable upwardly about an axis 37 and have a coating edge 38 extending substantially vertically in the coating state. The coating edge 38 may also be flat or formed with a groove.

In the present device 30, two mutually parallel edges 39 of a workpiece 40 are coated, wherein the workpiece 40 is moved with a gripper 41 in the region of the punch edge 38 and the punch edges 38, according to Figure 6 are moved out of the liquid level 42 out. Preferably, the workpiece is first placed in this device and then the coating movement 43 is performed.

Of course, inner edges of a workpiece 40 can be coated in a comparable manner by corresponding pivoting punch devices 36 are folded into it. For example, in the case of a square opening, two opposite edges can first be coated and then the other, opposite edges can be coated. In the case of round or oval openings, one partial circle or one partial oval can first be coated and, with a further pivoting movement, the other partial oval or the other partial circle. The devices 1 and 30 can also be used together in a device in which both down and side edges are coated.

In a further advantageous embodiment (FIGS. 7 to 13b), a paint container is present which, in its interior, approximately centrally comprises a receiving column 52 which has upwardly directed receiving mandrels 53. The receiving mandrels 53 are formed so that they can engage in corresponding receiving holes 54 of a workpiece 55 in order to hold the workpiece immovably in the x and y direction and lead.

In addition, the coating device 50 has two pairs of workpieces 55 and Lackierstempeln 56th

This coating device 50 according to the exemplary embodiment is designed, for example, to paint an elongated oval workpiece 55, which is formed flat flat, at the edges. For this purpose, there are two opposing punches 56a and two opposing punches 56b offset by 90 °, wherein the punches of the four punches together correspond at least to the outer circumference of the workpiece.

In order to coat the workpiece, the workpiece 55 is first moved over the coating device 50 (FIGS. 8a to 8c), with the punches 56a and the punches 56b resting in the lacquer bath. The punches 56a, 56b are guided via lifting devices 57, which engage from outside on the punches 56a, 56b. After the workpiece 55 has been placed on the receiving mandrels 53, a first pair of opposing punches 56a are first moved out of the paint container 51 by the lifting devices 57 and positioned at the level of the circumferential edge 58 of the workpiece 55 (FIGS. 9a to 9c). Subsequently, the Workpieces 55 (Figures 10a to 10c) pressed against the corresponding edge 58 of the workpiece 55 and thereby applied the paint. Subsequently, the punches 56a are moved back into the paint bath and the punches 56b for the not yet coated circumferential edge parts are extended out of the paint bath (FIGS. 11a to 11c) and subsequently pressed against the corresponding edge 58 (FIGS. 12a to 12c), then back from the workpiece 55 weggefahren and the workpiece 55 with a nipple or gripper 59 gripped and removed from the device 50.

In a further advantageous embodiment (FIGS. 14 to 20c), a workpiece 60 is coated on the edges, which has a circumferential edge 63 pointing in the direction of the paint bath, for example by punching and deep drawing, and a central opening 61 which extends from an edge 62 is limited.

The corresponding coating device 50 in turn has a paint container 51, wherein in the paint bath a first, the course of the edge 63 corresponding liftable punch 66 has and in turn stamp 56a and 56b stamp. The punches 56a and punches 56b can in turn be raised and lowered by means of suitable lifting devices 57 from outside the lacquer bath and can also be moved horizontally outward and inward in this coating device 50. The guides are arranged in the paint bath, that in the paint bath a hollow, in this case slot-shaped, column 65 is present, which comprises an opening 64, which makes it possible to control the guides from below the paint container 51. In such a coating device 50, the workpiece 60 is first deposited on the stamp 66, which is moved up from the paint bath and applied paint on the peripheral edge 63 (Figures 16a to 16c). Due to an overlap of the stamp 56a and 56b, the punches 56a, 56b must first be moved inwards before they can be conveyed up to the workpiece 60 (FIGS. 17a to 17c). When the punches 56a, 56b are at the correct height, they are brought into contact with the peripheral edge 62 (Figures 18a, 18b) and then lowered again. Subsequently, the other two punches 56b are moved inward and brought to the correct height (Figures 19a to 19c) and then (Figures 20a to 20c) brought into contact with the inner edge 62, so that the inner circumferential edge 62 and the outer circumferential Edge 63 are completely coated. Subsequently, the component is moved, for example, to a UV dryer or UV oven.

In addition to such large internal openings of a component, of course, smaller holes, such as round holes, oval holes or slots, but also square openings to be coated.

In a further advantageous embodiment of the invention (FIGS. 21 to 27), at least one coating mandrel 72 is provided for coating a circumferential edge of a hole 71 in a corresponding workpiece 70. For reasons of clarity, only the coating of a hole or a circumferential edge of a hole 71 is shown in FIGS. 21 to 27. Of course, the methods described above for coating larger openings or circumferential edges of the workpiece can be carried out at the same time or before or after.

In a first embodiment (FIG. 21), a coating mandrel 72 is arranged on a coating mandrel bridge 73, wherein the coating mandrel bridge 73 is attached to a lifting device 57 as known from the preceding examples and is written, arranged. A workpiece 70 is placed in a positionally accurate manner above the coating mandrel 72 and then the coating mandrel 72 is raised. The mandrel has a conically encircling coating surface 74, which is extended from the paint bath 75 and enters the hole 71. The conical surface 74 of the coating mandrel 72 is smaller at its thinnest point in diameter than the hole 71 and in its thickest portion larger than the hole 71. As a result, the conical surface is in the hole 71 completely retracted state at the hole 71 delimiting edge on, whereby paint, in particular paint, which flows off the coating surface 74, wets the corresponding edge. Subsequently, the coating mandrel 72 is driven down again with the coating mandrel bridge 73 into the paint bath, the workpiece 70 is moved and further processed.

In a further advantageous embodiment (FIG. 22), a lifting mechanism 76 is present instead of a lifting device 57. The lifting mechanism 76 consists for example of a lifting cylinder 77 and a reciprocating rod 78, wherein the Hubkolbenstange 78 passes through the bottom of the paint container and acts directly on the coating mandrel 72.

In a further advantageous embodiment (FIG. 23), the coating mandrel 72 is formed with a radial groove 79 in the region in which it is located within the hole 71. The coating mandrel 72 is designed with respect to the radial groove 79 so that it narrows, for example, by a head portion 80, which is retractable into the coating mandrel 70, the groove 79. The operation of this mandrel is in this case such that accumulates in the groove 79 in the idle state in the paint bath of the paint. When the mandrel is moved into the opening 71 of the workpiece 70, the groove 79 is narrowed, so that the paint is pushed out of the groove 79 and to the circumferential edge of the hole 71 passes. As a result, the edge of the hole 71 can be coated without contact.

In a further advantageous embodiment, instead of a groove 79, the coating mandrel 72 is formed with a cushion 81, for example made of a rubber-like plastic or foam, which can be bulged outward over the circumference of the coating mandrel 72 (here FIG. 24). For example, the pad 81 is arranged radially circumferentially in a groove 79 and is bulged by reducing the groove width of the groove 79, for example, by the interaction of a head portion 80 with the coating mandrel 72 to the outside. However, the protrusion can also be done by a pneumatic inflation or hydraulic filling of the pad 81. In this case, the cushion 81 may also be formed as a tube 81 which rests in a groove 79.

In a further advantageous embodiment (Figure 25), the mandrels are not moved with a lifting device 57 from the paint container 51, but are pivotally mounted on the paint container 51 via a pivot arm 85. By way of the swivel arm 85, the coating mandrels 72 can be pivoted, for example, in such a way that they engage in a hole with a vertical hole plane (FIG. 25 on the left) or in a hole with a horizontal hole plane.

In a further advantageous embodiment (FIG. 26), the coating mandrels 72 are arranged on a lifting device 86 which is provided separately for each mandrel and lift the coating mandrels 72 out of the paint bath or paint container 51 in the vertical direction (arrow 86a). In order to introduce the coating mandrels 72 into a hole with a vertical hole plane, the mandrels also have a device that allows a horizontal displacement (arrow 86b). The horizontal one Displacement is accomplished, for example, via a pneumatic or hydraulic piston-cylinder arrangement or a stepping motor or the like.

In a further advantageous embodiment (FIG. 27), the mandrel is arranged rotatably outside a lacquer container 51, wherein the mandrel is designed as anchor mandrel 89, the armature mandrel 89 having two identical armature leg mandrels 87 arranged on an armature shaft 88, the armature shaft 88 is rotatably mounted at its end outside of the paint container 51. By pivoting the armature pin in the pivot point, the armature leg 87 can emerge alternately from the coating bath and be introduced into a correspondingly extending with a horizontal hole plane hole, which allows relatively high clock rates.

In a further advantageous embodiment (FIGS. 28a-28d), there is a mandrel 100 which, in addition to other mandrels or other coating elements, may also be present alone, wherein this mandrel 100 does not have to be immersed in a varnish bath. This is particularly advantageous when several openings are arranged very close to each other, so that in such more complex forms, the coating of the holes can be done both from below from a paint container and from above. For this purpose, this mandrel is formed with a ring groove 101. The circumferential annular joint 101 has feeds 102, which lead paint from a central axial bore 103 in the mandrel 100 into the annular joint 101.

For the application of a lacquer, lacquer is first pressed through the central axial feed bore 103 in the punch 100 into the feed bores 102 and from these into the peripheral annular joint 101 (FIG. 28b). As a result, an outwardly projecting paint bead 104 forms on the annular joint. The Lackwulst 104 is stripped by the immersion of the mandrel 100 in an opening at the opening edges 105, preferably with tracking of paint, the mandrel and thus the annular joint is moved through the opening (Figures 28c, 28d) to pull out the mandrel 100 from the opening also at the bottom of the opening edge 105 during the upward movement strip paint and thus completely coat the edge circumferentially.

The mandrels can take on a variety of forms, which of course depends on the geometry of each hole. Four different geometries are shown in Figures 24a to 291, wherein the coating mandrels 72 are each formed with an inclined application surface 74 (Figures 30a to 301). The mandrels may be formed in cross-section or the application surfaces 74 in cross-section substantially round, oval, square or rectangular pyramidal or triangular pyramidal.

In a further advantageous embodiment, in particular for medium to large sheet thicknesses, a coating mandrel 72 is likewise arranged on a coating mandrel bridge 73 with a lifting device 57, wherein other lifting devices are also possible here. For coating the peripheral edge of a hole 71, in these embodiments (FIGS. 30a to 30g), radially extendable segments 90 are provided in the coating mandrel 72. In this device according to the invention, the coating mandrel 72 is brought into the correct height position with retracted segments 90. Then, the segments 90 are extended and the inner edge of the opening 71 is coated. The contact pressure of the segments 90 is advantageously chosen so that not too much paint is displaced. Prior to removing the mandrel, the segments must be partially retracted to shearing the lacquer off at the cutting edge. degree. Such a coating mandrel 72 with segments 90 can be seen in Figure 30b, 30c, wherein the movement of the segments 90 takes place radially. In this schematic illustration, the distance between the segments 90 to the peripheral edge of the opening 71 is drawn greatly enlarged. Advantageously, the distance between the retracted segments and the peripheral edge of the opening 71 is kept as small as possible. At a small distance and thus small path that must cover the segments 90, with a suitable adjustment of the viscosity of the paint still a nationwide coating of the peripheral edge can be achieved because the paint spreads on the edge and also flows between the segments. Such an embodiment is of course also conceivable for elliptical openings, as indicated in FIGS. 29f, 29g.

In a further advantageous embodiment (FIGS. 3Od, 3Oe), only one spring-ring or a spring-ring segment 90 is present, which is pressed against the peripheral edge of the opening 71 by bending. Again, the distance to the edge is as small as possible.

In a further advantageous embodiment (FIGS. 31, 32a to 32e), a segmented, rotatable mandrel 91 is provided on the device 50 on a lifting device 93. The segmented, rotatable mandrel 91 consists for example of two mandrel halves 92, which are each formed as a stamp. Here, the mandrel halves 92 and die halves 92 are immersed in a paint bath, wherein the paint bath or paint container 51 has a central opening with walls, so that the paint container 51 is formed as a circumferential round groove and the mandrel halves 92 and die halves 92 the paint container 51 in the middle. The punch halves 92 and thorn halves 92 are in this case on a lifting device 93 vertically displaceable and designed to be rotatable about the vertical axis and horizontally displaceable.

For example, to form a circular hole 71 with a coated circumferential edge, the mandrel or the mandrel halves 92 is driven out of the annular paint container 51 in the appropriate height position. The punch segments 92 are extended outward in accordance with the direction of the arrow 94 until they rest against the edge delimiting the opening 71 (FIGS. 32a, 32b) and then retracted in accordance with the arrows 95. Subsequently, the mandrel or the mandrel halves are rotated according to the arrow 96 and immersed before or after in the paint container to apply paint again on the application surfaces. Subsequently, according to FIGS. 32d, 32e, the punch segments 92 are extended to the hitherto uncoated regions of the peripheral edge of the opening 71 in accordance with the direction of the arrow 94 and then retracted in accordance with the arrow directions 95. As a result, a slightly less complex construction is achieved than with a segmented mandrel.

Both the above-described dies and mandrels, segment mandrels or rotatable mandrels described above may have edge surfaces 97 that are smooth. In addition, these application surfaces 97 can be contoured in accordance with the application. Various groove shapes of the application surfaces 97 are shown in FIGS. 31a to 31d, wherein the groove is chosen such that it is slightly wider than the workpiece thickness. In the grooves accumulates due to adhesion but also through the groove-shaped undercut lacquer, during coating, the cut surface to be coated dips into the groove, whereby a particularly good Kantenumgriff is achieved. In a circumferential, in cross-section V-shaped groove (Figure 31b) can be an automatic centering of the segment, stamp or mandrel on the workpiece. By the embodiment of Figure 31c, the unbalanced cross-sectional image, which arises when punching thick sheets, can be compensated. For thin sheet thicknesses, an easy-to-manufacture groove according to FIG. 31d can be used. For particularly thick sheet edges to be coated, the surface of the punch or the segment with a contour, a structuring or with a corrugation or grooving that is sharp (Figure 3Ie) or gentler (Figure 3If) is formed to be uniform to the paint distribution ,

Of course, further groove shapes are possible both for the punches and for segments, ie generally for all application surfaces according to the invention.

In FIG. 33, in contrast to FIGS. 1 and 2, a comparable device is shown in which, in addition to the stamp edge 14 for coating the circumferential edge of the workpiece, a mandrel 108 is present to provide a hole 109 with a vertical hole plane with a varnish application. so that both a circumferential edge coating and a hole coating can take place with such a device. The mandrel 108 can be arranged displaceably in the horizontal direction for this purpose.

In a further embodiment according to the invention of the device according to the invention (shown in highly schematic form in FIGS. 34a-34d), the stamp is designed such that the stamp edge is supplied with lacquer from the stamp interior. Such an embodiment can be used alone or in conjunction with punches that emerge from a varnish bath. Such a punch (FIGS. 34a-34d) is designed as a substantially hollow punch 110 which has a cavity 111 which is surrounded by walls 112 and is supplied with paint via a feed line 113. The coating die has a stamping surface 116 towards a workpiece edge 114 of a workpiece 115 to be stamped. The stamping surface 116 is pierced by bores or slots 117, through which paint can be pressed from the cavity 111 to the surface 116. Preferably, the surface 116 is bounded on both sides of an edge 114 to be stamped by short wall sections 118, so that a coating groove 119 is formed. Preferably, the paint, which is pressed by the paint channels 117 into the groove 119, is pressed to a Badspiegel- or paint level height 119 a, so that a certain paint reservoir is present in the groove.

In order to be able to control the paint flow through the channels 117, if necessary, means for controlling the inflow 121 may be present in the channels 117, for example valves. The stamp can be from the shown, a straight line vaulted edge to coat and of course also three-dimensional d. H. also z. B. coat box-shaped edge courses, as shown for example in Figures 1 and 2. When viewing by means of a stamp with paint reservoir 111 or a paint cavity 111 and channels 117 of the punch direction of the coating workpiece edge 114 is moved (Figures 34a, 34b), the paint before or thereby through the paint channels 117 to the paint level boundary 120 into the groove 119 is filled.

Subsequently, the stamp is completely placed on the workpiece edge 114 or slightly spaced from it, so that the paint can spread to the workpiece edge 114. At- closing the punch 110 is raised again (Figure 34d), wherein a lacquer layer 122 remains on the edge.

Below will be discussed on the inventive method for performing a coating with the device according to the invention.

A decisive factor for the success of the process is the lacquer viscosity. The viscosity of the paint is an important process parameter. It depends on the behavior of the paint on the stamp and the behavior during transfer to the workpiece. Thus, there is a lower and upper limit for the viscosity, with too low a viscosity of the paint after coating withdraws again from the sharp cutting degree and too high viscosity of the paint does not flow around the cut surface around. In both cases, a corrosion resistance but also an effective protection of the edge or a user from cuts is not given. The stamp must be adapted to the selected viscosity, in particular by the shape of a possibly existing groove. In the process, the limit values for these parameters must be adhered to accordingly.

The embodiment of the stamp depends greatly on the viscosity of the paint. After the stamp has been lifted out of the paint bath, stamping must be carried out until excess paint has expired from the transfer surface 97 and a resting coating layer has formed on the corresponding transfer surface or in a corresponding groove or on a corresponding web. The resulting waiting time can be greatly reduced if the chipping of the paint is not hindered. For this purpose, z. B. the stamp web are made very high and the lower part of the stamp be provided with a large opening. The opti- Malfall is a stamp that consists only of a bridge. The width of the web determines the thickness of the lacquer layer on the workpiece. Here, a compromise between the corrosion resistance and a very thin coating must be considered. Basically, the viscosity is low or vice versa for a wide punch or a wide application area.

In the case of a thixotropic behavior of the paint, liquefaction can also be produced by the movement of the stamp, in particular at fast cycle rates, and reinforced by agitators. It should be noted that the reduction in viscosity only lasts as long as the paint is stirred. With little effort, the viscosity of the paint can be varied over the temperature in many areas, which makes a device for controlling the temperature of the paint an important component.

The parameters to be observed and the average times for this are shown in FIG. 35.

The basic sequence of the coating results from FIG. 35. The parts to be coated are removed from a charging system, provided that the workpieces have been preprocessed and stacked. Here, the items must be separated. If the coating system is mounted directly on an existing system or integrated into an existing system, the workpieces are already available individually. Existing plants can z. B. stamping, thermoforming or facilities for pre-assembly of the workpiece. After a separation of the workpieces, a pretreatment is carried out, in which case in particular the cut surfaces must be pretreated for coating. This refers in particular to the elimination of small amounts of oil, the elimination of paint crumbs at or- ganisch coated sheets, for example by brushing or blowing off with compressed air and optionally the roughening of the cut surface. Optionally, a chemical bond between the UV coating and an organic precoating of the sheet can be achieved by a chemical treatment of the cut surfaces or cut edges, which usually does not take place.

Subsequently, the coating takes place according to the possibilities already described, followed by curing. The curing preferably takes place via UV radiation or thermally in known aggregates, it being possible to work with intermediate curing in the case of a coating which takes place in several steps.

Preferably, according to the invention, a so-called paint circuit (FIG. 38) is used, in which fresh paint from a paint reservoir 120 is fed via an adjusting valve 121 and a pump 122 and optionally a filter 123 to an inner paint circuit. At 124, the viscosity may be adjusted via the addition of solvents or thixotropic agents, with a temperature control device 125 which regulates the temperature of the paint. The working container 126 is supplied with paint and the level of the paint level 129 and the bathroom mirror 129 is regulated and kept as constant as possible. The paint container may also be provided with a stirring device 128. The discharged paint is pumped through a filter and can also be a degassing 127 are supplied. In this case, air which has mixed into the lacquer during stamping can be removed by centrifuging or stirring with simultaneous ultrasound treatment. Finally, the processed paint can be returned to the circuit via a pump. Departures from paint through the coating are correspondingly replenished from the paint reservoir 120.

The entire handling sequence during the coating process is described in FIGS. 39, 40, wherein, for example, a component to be coated with a complex geometry is provided with holes, protrusions, etc. The component has a circumferential cut surface, cut surfaces on the end face of a flange and holes. The workpiece 70 is singulated, held with a gripper, coated at a first coating station 130 with a punch along one side edge, then rotated and coated at a second coating station 131 at the opposite edge. Subsequently, the component is picked up and tilted again, after which, at a further coating station 132, both the holes and a bent-out collar or flange are coated. This is followed by UV curing in the case of light at a curing station 133 and then stacking at a station 134.

The device according to the invention and the method according to the invention can also be integrated into a conventional stamping or deep-drawing system, as shown in FIG. 40, wherein the components are punched or deep-drawn in a first section 135 from flat blanks. The corresponding components are then hardened coated and deposited in a process sequence 136 at the edges.

embodiment

The exemplary embodiment is a complex component with a three-dimensional edge and a hole opening in a tab with a vertical orientation. The component is moved by a magnetic gripper, the pneumatic cylinder of the Lifting device are synchronized via throttle valves. The paint container is located in a temperature-controlled water bath, the stamp is made of hard chrome-plated steel and inside has a large recess, so as not to hinder the drainage of the paint. The ridge has a width of three millimeters, with the mandrel for coating the inner surface of the hole being mounted on the ram.

The UV varnish used is a formulation specially optimized for corrosion resistance, the varnish being thixotropic, translucent and hard, viscoplastic in the cured state. The density is 1.2 g / ml in the liquid and 1.3 g / ml in the cured state. The paint is solvent-free and the volume shrinkage stems from the crosslinking of the paint during curing. The viscosity of the paint is 6,000 mPa * s at room temperature and must be reduced for the coating process. Due to the thixotropic nature of the paint, the viscosity drops noticeably when the amount of paint is stirred. In this case, the thixotropic property already sinks by the entry and exit of the stamp. A further reduction of the viscosity is achieved by heating the paint, wherein the paint bath is heated to 35 to 40 ⁰ C and held there, whereby in the current process, together with the stamp movement, a viscosity of 3,200 to 4,200 mPa * s.

FIG. 35 shows the course of the coating with the time duration for each step. The component is located at the beginning next to the paint container. It is picked up by the gripper and placed above the punch. At the same time, the stamp is lifted out of the paint bath. In order to let excess paint run off, a sufficient waiting time is maintained and then the cut edge is pressed onto the face of the stamp and held. During this time, the paint spreads evenly over the cut surface. After this residence time, the component is moved 20 mm vertically over the punch to bring small paint threads to tear. The circumferential cut surface is now completely covered with a layer of varnish.

To coat the existing hole, the component is moved backwards, so that the tab of the component is located in front of the mandrel. Subsequently, the component is moved down until the bore is coaxially oriented with the mandrel (aligned) and the mandrel can penetrate into the bore. The component is moved horizontally backwards until the conical surface of the mandrel and the inside of the bore touch. Due to the small size no waiting time is required here and the component is removed after touching horizontally from the mandrel. The hole is now completely coated. It can happen that a paint pellet spans over the circular area of the bore after coating.

To bring this cuticle to burst, the component can be moved to the mandrel again, until the skin and the tip of the brush touch, resulting in the desired effect. The component is then brought to cure, at the same time for further transport of the component, the stamp is recessed in the paint bath and held there. The duration for a complete cycle is z. B. 10 seconds, after coating on the cut surface, a lacquer layer with 0.47 g / m ² based on the length of the cut surface is formed. The thinnest layer thickness is about 100 microns, with the curing in the UV oven is in about one second.

Advantageously, in the method according to the invention the viscosity is adjusted such that for the duration of the ap- plication, in particular in a device 30 sufficient liquid for coating the edge is available.

In the invention it is advantageous that stamped or cut sheet metal components can be formed easily, quickly and safely with an edge coating, wherein the inventive devices allow a fully automated fast operation with high cycle times.

As a result, a perfect edge coating is achieved, which serves both the corrosion protection and the edge protection.

List of reference numbers:

1 device according to the invention

2 paint containers

3 bottom wall

4 circumferential side wall

5 coating stamps

6 U-shaped bracket

7 bottom wall

8 ironing wall

9 support wall

10 lifting mechanism or lifting device

11 pneumatic or hydraulic pistons

12 workpiece or component

13 Stem wall

14 circumferential punch edge

15 grippers

16 openings

17 bridges

18 centering pin

19 center hole

20 liquid level

30 device

31 paint container

32 bottom wall

33 surrounding container wall

34 coating device

35 base frame

36 punch device

37 axis

38 stamping or coating edge

39 edges

40 workpiece grab

liquid level

coating movement

coater

paint container

Aufnähmesäule

arbors

Aufnähmelocher

workpiece

LackierStempel a LackierStempel b LackierStempel

Lifting device circumferential edge

Sucker or gripper

Workpiece central opening inner circumferential edge outer circumferential edge

opening

pillar

stamp

workpiece

Hole or opening

coating Dorn

Coating thorn bridge

Coating surface or application surface

paint bath

lifting mechanism

lifting cylinder

lifting piston rod

radial groove

headboard

pillow 85 swivel arm

86 lifting device

86a vertical direction (arrow)

86b horizontal direction (arrow)

87 anchor legs or anchor legs

88 anchorage

89 Anchor pin

90 segments or ring segment

91 thorn

92 punch halves or stamp segment

93 lifting device

94 arrow direction

95 arrow direction

96 arrow direction

97 application areas

100 thorns

101 ring joint

102 feeder

103 bore

104 paint bead

105 opening edges

108 thorn

109 holes

110 hollow stamp

111 cavity

112 walls

113 supply lines

114 workpiece edge

115 workpiece

116 stamp surface

117 holes or slots

118 wall sections

119 Coating groove

119a paint mirror 120 paint memory

121 control valve

122 paint layer

123 filters

125 temperature control device

126 work containers

127 degassing device

128 stirring device

129 paint mirror or bathroom mirror

130 first coating station

131 second coating station

132 more coating station

133 curing station

134 stacking station

135 first section

136 Procedure

Claims

claims

1. A device for applying a liquid on cutting edges of sheet metal components, wherein at least one stamping device is present, which has a punch surface corresponding to the contour of a workpiece edge to be wetted, wherein the device is formed so that the punch edge or the punch edges and the workpiece to each other are movably arranged such that the stamp edges wetted with the liquid can be brought to a workpiece edge.

2. Device according to claim 1, characterized in that the punch edge (14) is adapted both with respect to its circumferential course and with respect to its height profile to the contour of a component (12) such that a component (12) that on the stamp edge ( 14) rests with its edge to be coated, rests with this peripheral edge on all sides.

3. Device according to claim 1 or 2, characterized in that the punch edge (14) is designed to coat the sensor-reflecting workpiece edge in one or more parts.

4. Device according to one of the preceding claims, characterized in that the punch edge (14) or the punch edges (14) flat, profiled, contoured, or formed with a groove or a groove or groove.

5. Device according to one of the preceding claims, characterized in that a paint container (2) is present is, and in addition a lifting device for the punch (66) is present, wherein the lifting device is formed so that the punch (66) with the die edge (14) in the paint container (2) submersible and heraushebbar is such that Collects liquid on the stamp edge (14) and is transferable from this on a workpiece edge.

6. Device according to one of claims 1 to 5, characterized in that the punch edge (4) via liquid feeds (102) in the punch (66) has, so that liquid from the punch (66) forth on the punch edge (14) can be brought ,

7. Device according to one of the preceding claims, characterized in that the punch (66) for coating a circumferential edge (58) of a hole (71) is formed as a coating mandrel (72).

8. The device according to claim 7, characterized in that the coating mandrel (72) has a coating surface (74).

9. Apparatus according to claim 8, characterized in that the coating mandrel (72) is formed as a truncated cone with a conical coating surface (74).

10. Device according to one of the preceding claims, characterized in that the coating mandrel (72) has a ring groove (101), wherein the annular joint (101) is formed circumferentially and serves to accommodate the liquid.

11. The device according to any one of the preceding claims, characterized in that the circumferential annular groove (101) feeds (102) which lead from a feed bore (103) in the mandrel (91, 100, 108) coating liquid in the annular joint (101) ,

12. Device according to one of the preceding claims, characterized in that the mandrel has an outer contour corresponding to the inner contour of a hole to be coated (54, 71, 109) or to be coated hole edge.

13. Device according to one of the preceding claims, characterized in that the coating mandrel (72) has radially extendable segments (90).

14. A method for coating cut edges of a component, in particular using a device according to one of the preceding claims, characterized in that a punch surface (116) of a punch (66) is provided with a liquid which is to be applied to a cutting surface and then the die surface (116) or the liquid located on the die surface (116) is brought into contact with a cutting edge such that the liquid to be applied is applied to the edge.

15. The method according to claim 14, characterized in that the stamp (66) is dipped for coating a cut edge with its stamping or coating surface in a liquid bath, while the liquid to be applied to the stamp surface (116) passes and then the punch (66 ) is led out of the liquid bath onto an edge to be coated, so that the bringing liquid to an edge to be coated (39) passes.

16. The method according to claim 14 or 15, characterized in that the liquid is brought by appropriate supply holes from the punch (66) out on the stamp surface (116) and distributed there and is then guided to an edge to be coated.

17. The method according to any one of claims 14 to 16, characterized in that on the stamp surface (116) a liquid bead or a liquid amount is formed, which is applied by stripping on an edge to be coated.

18. The method according to any one of claims 14 to 17, characterized in that the liquid is applied to the edge, that the liquid-carrying punch edge (14) is positively applied to the edge to be coated or slightly spaced from the edge to be coated edge in the liquid located on the stamp edge (14) immersed so far that the liquid spreads on the edge.