DE102007056112A1 - Method for processing workpiece by laser radiation, comprises subjecting a ridge present in the workpiece with the laser radiation and then partially melting, which causes chamfering, displacing, pressing and/or fixing - Google Patents

Abstract

The method for processing of workpiece (10) by laser radiation, comprises subjecting a ridge (G) present in the workpiece with the laser radiation and then partially melting, which causes chamfering, displacing, pressing and/or fixing. The laser radiation is directed on an area of an edge of the workpiece created through stamping in temporal and spatial predetermined manner in order to partially melt the ridge on the edge of the workpiece. The laser radiation is guided in a process gas stream so that the melted material of the ridge is shifted in the area of the stamp eruption surface. The method for processing of workpiece (10) by laser radiation, comprises subjecting a ridge (G) present in the workpiece with the laser radiation and then partially melting, which causes chamfering, displacing, pressing and/or fixing. The laser radiation is directed on an area of an edge of the workpiece created through stamping in temporal and spatial predetermined manner in order to partially melt the ridge on the edge of the workpiece. The laser radiation is guided in a process gas stream so that the melted material of the ridge is shifted in the area of the stamp eruption surface. The laser radiation is subjected selectively in the area of the edge of the workpiece to be processed along the edge of the workpiece to be processed. The edge of the workpiece to be processed has the form of a circle. The laser radiation is guided in temporal and spatial predetermined manner in such a way that the areas of the edge bordering to each other are subjected intermittently with the laser radiation so that an area is freed between two areas that are subjected successively with laser radiation and overlap.

Description

Field of the invention

The The present invention relates to a method for processing Workpieces by means of laser radiation.

at Workpieces and components arise due to the manufacturing process often burrs, for example when punching or molding. For example, with every stamped contour, this is due to the process a ridge burrs are disturbing or even dangerous Areas on a workpiece and therefore must be in usually be removed as far as possible. Especially with the use such produced workpieces in a fuel or Injection system or medical technology may not loose metallic particles are formed by a loosening burr. The burr height for punched parts is according to experience up to about 10% of the strength of the material making up the workpiece was punched.

at very small contours is the removal of each ridge for example by tumbling, belt grinding, brushing or vibratory finishing not possible, the burr is pressed into the contour and possibly even solved. The embossing the contours is only limited effective, as loose ridge also through Imprinting can no longer be reliably fixed can. Chemical deburring is very expensive and not included all parts geometries feasible (for example, susceptible boards to each other) and also not selective for subareas, but only applicable to the entire workpiece.

State of the art

From the DE 100 34 806 C1 is a method for deburring workpieces and generating a predetermined workpiece geometry using a laser known. In this case, a burr of a workpiece is first coarsely separated in a first step by a laser cutting process and further processed the residual burr in a subsequent step. One known method for processing stamped workpieces is the so-called Trowalisieren. In this case, abrasive bodies are used in a drum, with the help of which the edges are subjected to a smoothing treatment.

Summary of the invention

at However, very small punched structures is none of the above Method applicable, since on the one hand, the occurring relatively small Burrs of the order of a smallest possible Focus diameter currently known laser are and thus not can be separated and on the other the smallest possible still effective grinding wheel of the Trowalisierverfahrens are so big that they do not penetrate into the contours can or even damage the workpiece can cause.

The So problem is, the burr in a punched workpiece edit so that he can not solve and the predetermined workpiece contour is not affected becomes.

task Thus, the present invention is a method of processing to create a workpiece that allows for rapid processing permitted by burr-loaded workpieces.

The The object of the invention is achieved by a method solved according to claim 1. The dependent ones Claims define advantageous developments the invention.

The The invention thus provides a method for processing a stamped Workpiece by means of laser radiation ready, in which a through the punching burr on the workpiece at least partially melted becomes.

The at least partial melting causes a rounding, shifting, Smoothing and / or fixing the ridge. The physical The basis for this is the surface tension the melt on the fused burr: the workpiece surface becomes locally melted, the ridge melts and rounds under Effect of surface tension. The ridge can be under the However, the effect of laser radiation also shift, smoothed be fixed or on the workpiece.

There the production of complex stamped and bent parts always in consecutive, follow-on or transfer tools and the superficial Melting of metallic materials with modern efficient Laser can be accomplished in very short periods of time, Thus, it is possible, the laser processing process in one or several further, the punching process downstream sequences of Perform tool without reducing the number of cycles is or even an additional downstream follow-up outside the tool is required.

The laser used is a laser suitable for material processing with suitable optics and a scanner device or a linear axis system for controlling the laser beam on or on the workpiece to be machined. The degree of focusing is adapted to the requirements of the material and the edge geometry. In this way, the laser beam along a Kan te a workpiece are performed, so as to couple the laser energy in the material of the workpiece in the region of the deburred edge. This creates heat in the irradiated material areas. For fusible materials, the introduced heat may result in localized melting of the material such that the molten material converges due to the surface tension of the resulting local melt zones, thus fusing a burr such that it either completely melts and melts on or on the workpiece runs. Or the burr shifts so that it melts over its entire extension or part of it on the workpiece. Smoothing may also occur such that the burr collapses due to the local melting process. Finally, the burr as a whole can be fixed to the workpiece snugly. In other words, the burr on the base material is melted and fixed by targeted local heating with a laser beam. The laser beam is adjusted via the laser parameters, such as beam energy, pulse duration, width, frequency and the like, specifically to the machining task and the currently available burr height, which depends on the state of wear of the punching tool.

each Die-cut surface consists of the areas of stamping (on the surface where the cutting punch enters), Slitting section (shear surface), punching outbreak (free cutting) Crack propagation between punch and die edge) and burr. Conditioned through the cutting gap, the punching excavation surface runs usually below 5-15 ° to the smooth cutting surface.

The inventive method has the effect that the molten burr material under the influence of the surface tension mostly pulled into the punching break area becomes. Since the volume of the ridge is usually smaller than the "missing" Volume of the punch breakout area, the burr material disappears in the punching breakout without exceeding the contour of the smooth cutting area and the inner contour is thus measurably reduced.

The Specification of a maximum ridge is usually done in the Form of a maximum projection over one Reference surface or in the form of a minimum radius between Reference surface perpendicular to the punching surface and punching surface.

at the process of the invention is substantially no material removed.

In a preferred embodiment of the invention The procedure is the laser radiation in temporal and spatial predetermined manner on areas of an edge of the workpiece is directed so as to create a burr on the edge of the workpiece at least partially melt. This beam guidance is achieved by a suitable scanner optics.

In a preferred embodiment of the invention Procedure is along the edge of the workpiece to be machined the laser radiation at points in the area of the edge to be processed applied to the workpiece. To complete the ridge and to work evenly, the laser points should preferably be placed overlapping along the contour.

In a further embodiment of the invention Method has the edge to be machined on the workpiece essentially the shape of a circle.

In a preferred embodiment of the invention The laser radiation is in a temporal and spatial predetermined manner such that adjacent to each other Areas of the edge to be deburred one after the other with the laser radiation be acted upon, preferably overlapping. This means, that the laser radiation is directed in such a time-dependent manner, that it follows the contour of the edge to be processed. In the case of a circular edge means for example, that the laser radiation, for example, in a clockwise direction or in a counterclockwise direction. This is for pulsed as well as for continuous laser radiation possible. So that is in the immediate vicinity of an already processed Area a next area of the edge edited. This Method is advantageous if overheating of the material is not to be feared. Some materials are against overheating sensitive, such as metals above certain temperatures Phase transformations suffer, which also usually with an altered Energy exchange go hand in hand.

alternative The laser radiation is in a temporal and spatial predetermined manner such that adjacent Regions of the edge to be processed so intermittently with the laser radiation be acted upon that between two areas, with laser radiation be applied, always at least one area is released. That is, for example, on a circular edge temporally directly successive laser points spatially be applied opposite each other. To this This way, overheating is avoided.

It is important that the method according to the invention no longer takes time to machine the punched workpiece by means of laser radiation calls as the transformation in the other episodes and thus a manufacturing process as a whole is not delayed. The laser process preferably occurs during the time the tape is at rest. However, it is also possible for the contour to vectorially superimpose the movement of the conveyor belt by suitable programming and thus to carry out processing "on-the-fly" even during the drawing in and lowering of the belt.

Summarized Thus, the invention provides a method with which contours rapidly of workpieces, in particular stamped, are smoothed can.

Brief description of the figures

1a shows a section of the contour of a punched surface with a smooth cut portion, punching breakout and burr.

1b shows the burr side of a stamped sheet.

2a and 2 B show in plan view and a side view of a workpiece into which a circular opening has been punched.

3a and 3b each show in plan view a workpiece which has been processed according to the method according to the invention.

4a and 4b serve to illustrate with alternative control of the laser.

5 shows in high magnification a detailed view of a smooth cut portion of an edge, which was formed by punching a workpiece, wherein the workpiece has been processed according to the inventive method.

Detailed description the invention

in the Below is a preferred embodiment of the invention Method for processing a workpiece by means of laser radiation by way of example described.

1a shows in high magnification a measured contour of an edge by punching a metallic workpiece 10 was formed. 1b shows a photograph of a ridge on the punching out side of a punched hole. The workpiece 10 in this case has a surface O. The edge shows a contour that is divided into the punched main area (smooth cut surface) W, a transition area B (punching breaking area) and an unavoidable ridge G. A burr G typically has a longitudinal extent (burr height S) of approximately up to 10% of the material thickness. Shown here is so part of the smooth section portion, the punching outbreak, which is inclined at an angle α of about 15 ° to the smooth-cut surface, as well as the burr. An opposite punch insertion surface is not shown.

2a shows as an exemplary example the round workpiece 10 into which a circular opening Kr has been punched, as a whole. The dimensions given below are only an example. The circularly closed edge K of the opening Kr has a diameter d of approximately 0.8 mm (eg with the usual stamping part tolerance of +/- 0.05 mm) and the workpiece has a diameter of approximately 10 mm. Taken along the line AA is a cross section AA of the workpiece 10 in 2 B shown. Accordingly, the workpiece has 10 a height (thickness) t of about one mm.

The inventive method for processing a punched workpiece by means of laser radiation is applied to the present workpiece 10 applied, wherein the laser radiation in temporally and spatially predetermined manner on areas of the edge K of the workpiece 10 is directed to the so in 1 enlarged ridge G shown at the edge K of the workpiece 10 at least partially rounding off, fixing, relocating or smoothing into the punching outbreak. In this case, the laser radiation is punctually successively applied to areas of the edge K along the circle Kr. It is particularly advantageous in the method according to the invention that no further processing step for deburring is required. Furthermore, depending on the material and other requirements, it is possible to dispense with the use of a process gas. By varying the process gas pressure and the direction of the gas flow, the melt can also be pressed selectively into the punching outbreak region.

With In other words, the ridge on the base material is targeted through local Heating with a laser beam melted and fixed. The laser beam can be transmitted via a scanner system of the contour Follow and on the laser parameters targeted to the machining task and the currently available rathory, the connexion with the state of wear of the punching tool is adjusted become.

The result of the method according to the invention is exemplary in 3a and 3b shown. 3a shows in plan view a circular region Kr a by punching out of a band 10 generated edge area, which was smoothed by applying eight laser points L1 to L8 during 3b a circular area Kr ei In a top view, the edge region produced by punching out has been smoothed by applying twelve laser spots L10 to L21. With a suitable parameter selection, the remelted burr material lies completely in the punching break-out region and is thus no longer detectable optically (eg via projection) or even tactilely on the smooth-cut surface.

By the application of the method according to the invention the burr is securely fixed and the eruption rounded.

In the experiment, the thickness was t of the workpiece 10 about 0.8 mm. However, the application of the method according to the invention is also considered, for example, for thicknesses t to 3.5 mm and more. Thickness is relevant to the process only insofar as thicker materials tend to have a higher burr and larger cutting contour lengths. Since basically only the surface is melted, it does not matter how thick the material is.

In the experiment, in the method according to the invention, along the edge K of the circle Kr to be deburred, the laser radiation was applied selectively in the region of the edge K to be deburred, with eight or twelve laser spots on the workpiece at the circumference of the circle Kr 10 were charged. For the application in a production process, however, the number is insignificant, as long as the time requirement is not too high and the points overlap.

4a and 4b illustrate corresponding results in alternative activations of the laser, which can be selected depending on the material of the workpiece and the design of the laser. For simplicity, only the result of an embodiment of the method according to the invention with eight laser points is shown here. It will be apparent to those skilled in the art that alternative laser driving also works for different numbers of laser spots. In an in 4a As shown in the first variation, the laser radiation is guided in a temporally and spatially predetermined manner in such a way that adjacent areas of the edge to be deburred are successively subjected to the laser radiation in succession. The laser points are here designated # 1 for the first time set and # 8 for the time last set laser point, the laser points were thus set here in a clockwise direction. In 4b For example, the laser spots are alternately set in time or intermittently on an opposite side of the circular edge, respectively. This may be advantageous in certain combinations of material of the workpiece and laser parameters, such as power, pulse duration, mode, etc., to avoid overheating of the material. It should be noted, however, that if the distances between the laser spots are long, the traversing speed of the scanner system may limit the number of cycles, and the laser itself may be limited at neighboring points.

5 shows how 1 , A measured contour of a stamped workpiece, but after the inventive method has been applied. It can clearly be seen that a burr G produced before machining according to the invention is now located on the surface O of the workpiece 10 partially melted and only shows itself as a small elevation G '. The ridge height S 'of the fused ridge G' is significantly smaller than a typically occurring ridge height. The straight cut portion W has not been impaired in any way. This shows that the method according to the invention advantageously makes it possible to machine punched workpieces.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10034806 C1 [0004]

Claims (11)

Method for processing a workpiece by means of laser radiation, characterized in that a workpiece ( 10 ) existing burr (G) is acted upon by the laser radiation and at least partially melted. Method according to claim 1, characterized in that that the at least partial melting on a rounding, shifting, Smoothing and / or fixing the ridge causes. Method according to one of claims 1 or 2, characterized in that substantially no material removed becomes. Method according to one of claims 1 to 3, characterized in that the laser radiation in temporally and spatially predetermined manner on areas of a punched edge (K) of the workpiece ( 10 ) is directed to a ridge (G) on the edge (K) of the workpiece ( 10 ) at least partially melt. Method according to claim 4, characterized in that that the laser radiation is guided so that the melted Material of the burr essentially in the area of the punching break-out surface (B) is relocated. Method according to claim 5, that the laser radiation is guided in a process gas stream. Method according to one of the preceding claims, wherein along the edge (K) of the workpiece to be machined ( 10 ) the laser radiation punctually in the region of the edge (K) of the workpiece to be machined ( 10 ) is applied. Method according to one of claims 1 to 7, wherein the edge (K) to be machined on the workpiece ( 10 ) has substantially the shape of a circle (Kr). Method according to one of the preceding claims, where the laser radiation in a temporal and spatial predetermined manner is performed such that to each other adjacent areas of the edge to be processed consecutively be acted upon in succession with the laser radiation. Method according to one of claims 1 to 8, wherein the laser radiation in a temporal and spatial predetermined manner is performed such that the processed Edge so intermittently applied to the laser radiation That is, between two areas that are consecutive with laser radiation be applied, always at least one area is released. A method according to claim 9 or 10, wherein the overlap the laser radiation machined areas.