EP1007241B1 - Method for producing exact cut edges - Google Patents

Abstract

In a process for producing precise cut surfaces on a workpiece by stamping or blanking, in particular by fine-edge blanking, a contour first is stamped or blanked out at a distance (a) from the actual contour of the workpiece, and the workpiece then is scraped down to its final contour. It is intended here, in a first step, for only up to part of the thickness (d) of the workpiece to be scraped and, in a following step, for the contour of the workpiece to be achieved by scraping in the opposite direction to the first step.

Description

The invention relates to a method for producing exact cutting surfaces on a workpiece by punching or cutting, especially by fine cutting, wherein first punching out or cutting out a contour in a distance from the actual contour of the workpiece and then a scraping up to the contour of the Workpiece takes place.

Although in the present case the description in is essentially related to the so-called fineblanking, should also be a normal punching process of the invention be included, in which the inventive method for Application can come.

In contrast to the Normal stamping parts with an almost 100% smooth cut surface produce. Due to the procedural also occurs Fineblanking an edge indentation on the insert facing part cut surface and the edge feed opposite ridge on. This edge indentation or ridge is mainly from the geometric part shape, but also dependent on material and part thickness. With a projecting corner, this is much larger than in a corner corner. The biggest advantage of the Part manufactured in the fineblanking process consists of the smooth cut surface in that the surface of the Part cutting surface is hardened.

Functional shapes on fineblanked parts are always the requirement for little or little edge indentation levied. Especially the protruding, acute-angled ones The shapes of the finely cut parts are large Moving in, e.g. Ratchet teeth or gears. The removal one on the cutting surface of a finely cut part resulting edge indentation and one of the edge indentation opposite ridge is cut through executed. This increases the proportion of the Functional surface; this includes making the component higher can be loaded or at the prescribed carrying height thinner sheet thicknesses can be transferred.

In CH 665 367 A2, for example, there is a re-cutting process described, in which the recutting in Cutting direction or opposite to the cutting direction the preliminary stage of the fineblanking process. That is, in several stages are approximated to the actual one desired contour of the workpiece to be manufactured. there has proven to be a major disadvantage that the re - cutting creates chips that in the Tool or remain in the press and in the course of Time can cause significant disruption.

The present invention is based on the object To develop processes of the type mentioned above, in which the No disadvantage of the chips remaining in the tool occurs.

The solution to this problem is that in at least one Level the scraping only to a part of the thickness of the Workpiece and in a final stage the contour of the workpiece by re-scraping in the opposite Direction for punching or cutting is reached.

The main advantage of this procedure is that the Chip certainly remains on the material strip and with this strip of material, i.e. punched grid, from which Tool or the press is discharged. It doesn't come to release the chip from the lead frame, which means that no loose chip remains in the tool.

Another major advantage is that for one of the indentations created by fineblanking again in the final stage of resharpening, the opposite the direction of fineblanking is carried out and at the same time compared to that of fineblanking indentation only a small indentation through the Resurfacing arises. The ridge also becomes complete away.

In contrast to fineblanking, which runs through the whole Punching is done when re-shaving, that only an existing area, a smaller one Power needed. Because of the smaller force it is too possible with the same material load as the Fineblanking to perform smaller corner rounding.

The first stage of re-scraping is preferably carried out up to half the thickness of the workpiece. This is done a favorable power distribution, because in the second stage of the Scraping already half of that to be scraped Material is converted into a chip.

Furthermore, the first stage of resharpening should also be around at least half the distance between one Tooth. In the second stage, the whole Distance away.

Within the scope of the invention it should also lie that Re-scraping in several stages in or opposite to the Cutting or punching direction takes place. This mainly depends depends on the material used for the workpiece.

Figur 1 eine perspektivische Ansicht einer fein- und nachgeschabten Klinke;

Figur 2 eine schematische Darstellung eines Feinschneidvorganges;

Figur 3 einen vergrösserten Ausschnitt aus Figur 2;

Figur 4 eine schematische Darstellung des Feinschneidvorganges in einem anderen Ausführungsbeispiel;

Figur 5 einen vergrösserten Ausschnitt aus Figur 4;

Figur 6 eine schematische Darstellung eines Nachschabevorganges am feingeschnittenen Zahn der Klinke gemäss Figur 1;

Figur 7 eine schematische Darstellung des erfindungsgemässen Nachschabvorganges.gemäss Figur 6 in Seitenansicht;

Figur 8 eine schematische Darstellung eines Nachschabevorgangs entsprechend Figur 6 in einem weiteren Ausführungsbeispiel;

Figur 9 eine schematische Darstellung des Nachschabevorgangs gemäss Figur 8 in Seitenansicht.

Further advantages, features and details of the invention result from the following description of preferred exemplary embodiments and from the drawing; this shows in

Figure 1 is a perspective view of a fine and scraped pawl;

Figure 2 is a schematic representation of a fineblanking process;

FIG. 3 shows an enlarged detail from FIG. 2;

Figure 4 is a schematic representation of the fineblanking process in another embodiment;

FIG. 5 shows an enlarged detail from FIG. 4;

FIG. 6 shows a schematic illustration of a resharpening process on the finely cut tooth of the pawl according to FIG. 1;

FIG. 7 shows a schematic illustration of the resharpening process according to the invention.

FIG. 8 shows a schematic illustration of a re-shaving process corresponding to FIG. 6 in a further exemplary embodiment;

Figure 9 is a schematic representation of the re-shuffling process according to Figure 8 in side view.

1 shows a finely cut pawl 1, whose tooth 2 additionally cut or scraped has been. The scraping of an already cut shape also refers to the inner and outer forms of an in cut line contour closed and limited not only on tooth areas as shown in Figure 1.

The tooth contours are provided with sharp edges 3, whereby Tooth cut surfaces 4.1 and 4.2 right-angled, free of edges and are low in burrs.

The fineblanking process is shown schematically in FIGS 5 shown. Before the actual fineblanking process into a strip of material 5 outside a cutting line 6 a notch 8 is pressed in by means of a ring spike 7. The Ring-shaped tooth 7 can either be a guide plate 9 or one Cutting plate 10 or both a guide plate 9 as also a cutting plate 10 (not shown) of the Fineblanking be molded.

As can be seen from FIGS. 3 and 5, the Attach the ring prong 7.1 or 7.2 to the edge feed the cut surface of the finely cut part 1 reduced. In particular, the edge indentation is caused by the the latter measure, i.e. the attachment of the ring spike 7.1 and 7.2 both on the guide plate 9 and on the Insert 10 significantly reduced; this measure is but expensive for manufacturing and maintenance reasons. The in Figures 3 and 5 removable feed width is c and the feed depth of the edge feed 11.1 with d designated.

In Figures 6 and 7 is the schematic Resharpening process on the cut surface 4.1 or 4.2 of the finely cut ratchet tooth 2 shown. This will in a first step in the material strip 5 a ratchet tooth hole 12 is formed, which of a dash-dotted outline 13 of the ratchet tooth 2 maintains a distance a. The figure in FIG Edge feeder 11 and edge feeder 11 opposite ridge 14 can be seen. Cutting out the Pawl tooth hole 12 takes place in the cutting direction x.

In the next stage, a re-scraping takes place in the Area of the distance a between the contour 13 of the Pawl tooth 2 and the first inner contour 15 of Pawl tooth hole 12. Here, a scraping takes place around half of the distance a and about half of the Thickness d of tooth 2. This creates a chip 16 which but remains on tooth 2.

In a last step, a re-scraping takes place against the cutting direction x by the entire dimension of the Distance a, so that now both the edge feed 11 and also the ridge 14 is removed and an exact Cut surface 4 on the tooth 2 is formed. The Span 16.1 remains on the tool strip 5 and is with this Material strips 5 from the corresponding tool discharged.

Another exemplary embodiment is shown in FIGS of a replenishment process according to the invention. in the The first part of the figures is a tooth 2.1 from a Material strips 5.1 punched out, the first Inner contour 15.1 the distance a from a desired maintains the final contour 13.1. The punching direction is indicated by the arrow in Figure 9.

In a second stage, a first scraping and contrary to the punching direction, so that the Edge feed 11 is balanced and there accumulated scrap material as Span 16.2

In a second resharpening operation, there is again a resharpening opposite to the punching direction by a further part of the distance a and in a last step, another resharpening takes place opposite to the punching direction, the finished tooth 2.2 being simultaneously ejected downwards. The chip 16.3 sticks to the material strip 5.1 or the lead frame. Position Number List 1 pawl 34 67 2 tooth 35 68 3 edge 36 69 4 section 37 70 5 Material strip 38 71 6 intersection 39 72 7 V-shaped projection 40 73 8th score 41 74 9 guide plate 42 75 10 Schmid plate 43 76 11 edge rollover 44 77 12 Ratchet tooth hole 45 78 13 contour 46 79 14 Degree 47 15 inner contour 48 16 chip 49 a distance 17 50 d thickness 18 51 x cutting direction 19 52 20 53 21 54 22 55 23 56 24 57 25 58 26 59 27 60 28 61 29 62 30 63 31 64 32 65 33 66

Claims (4)

1. Method of producing exact cut edges (4.1, 4.2) on a workpiece (2, 2.2) by stamping or respectively cutting, more especially by fine cutting, a contour (15, 15.1) firstly being stamped-out or respectively cut-out at a spacing (a) from the actual contour (13, 13.1) of the workpiece (2, 2.2) and said contour (15, 15.1) subsequently being shaved to form the contour (13, 13.1) of the workpiece (2, 2.2), characterised in that, in at least one step, the subsequent shaving is only carried out over a part of the thickness (d) of the workpiece and, in a last step, the contour (13, 13.1) of the workpiece (2, 2.2) is achieved by a subsequent shaving in the opposite direction to the stamping or respectively the cutting.
2. Method according to claim 1, characterised in that the first step of the subsequent shaving is carried out up to more than half of the thickness (d) of the workpiece (2, 2.2).
3. Method according to claim 1 or 2, characterised in that the first step of the subsequent shaving is carried out over at least half of the spacing (a), and the second step of the subsequent shaving is carried out over the entire spacing (a).
4. Method according to one of claims 1 to 3, characterised in that subsequent shaving is carried out repeatedly in one and/or in the other direction in or in opposition to the stamping direction or respectively the cutting direction.

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