Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D31/00—Other methods for working sheet metal, metal tubes, metal profiles
  • B21D31/06—Deforming sheet metal, tubes or profiles by sequential impacts, e.g. hammering, beating, peen forming

Definitions

• the invention relates to a method of the type specified in the preamble of patent claim 1. Furthermore, the invention relates to a device for carrying out said method.
• a method of this type is known from DE-OS 29 06 509.
• This beam are edium, rules Ku ⁇ particular, accelerated in a pressure jet and directed at a rate of 10 to '90 m / s on the surface of workpieces to bring about a deformation of bending that is superior.
• the individual balls are classified within certain diameter ranges and, due to their conveyance in the material jet, hit the impact surface in a statistically distributed manner.
• the invention is based on the object of achieving a shaping which has been targeted from the outset, and in particular a specific curvature, “in the case of sheets and plates, without the possibility of shaping the To be able to use the material only to a limited extent due to the intended forming directions. Above all, this is intended to achieve an increased dimensional accuracy of the forming, and undesired workpiece stretching should also be largely avoided. The change in shape should be even more pronounced in one plane, whereby the conditions for avoiding or at least reducing a change in the thickness of the sheets or sheets should be met. Finally, the considerable mechanical outlay, as was necessary in the previous shaping by means of material radiation, is to be considerably reduced.
• OMPI only a precisely dimensioned curvature is achieved, but also an extension in the longitudinal direction, that is to say transversely to the direction of curvature, is practically excluded.
• the formation of a geometrically precisely predetermined curvature can be made considerably easier by first clamping the workpiece with two opposing edges and then elastically bending it to the extent of the intended change in shape or curvature while the clamping means are approaching, whereupon the dynamic loading of the workpiece surface e follows.
• the shape change achieved is practically free by
• the further improvement of the uniformity of the reshaping is achieved by guiding the punch over the workpiece surface in essentially parallel lines and covering the impact areas within the line-wise impact tracks in the longitudinal direction.
• the extent of the length can be determined by interpolation and extrapolation if one starts from two advantageous assignments, one of which provides a tool area of approximately 2 ⁇ 12 mm for workpiece thicknesses between 5 to 8 mm, whereas the other one Workpiece thickness of 8 to 20 mm provides a tool surface of 2 x 27 mm.
• the punch or tools or tools can be used directly for the impact loading of the workpiece surface, it is in the interest of improved control of the shape change process to guide the tools themselves lying on the workpiece surface and to dynamically load them by means of a percussion piston.
• the tools transmit the impulse of the percussion piston, whereby the relative position between the workpiece surface and the tool is particularly reliably ensured.
• the kinetic energy is thus applied via the piston. Its mass is less of an effect than the speed it has when it hits the punch. The latter in turn depends on the action of the piston as well as on the stroke when a pressurized fluid is applied to the piston. A satisfactory change in shape is achieved if the cross section and also the stroke of the piston are increased proportionally as the sheet thickness increases, a sheet thickness of 5 to 8% increasing
• the piston is useful within a compressed air
• OMPI Cylinder can be acted upon on both sides, specifically with compressed air which can be controlled in the range from 2 to 10 bar.
• the length of the stroke is between about 40 to 120 mm.
• the * inventive device has in particular a punch having a cylindrical shank, the ist.und out can be acted upon by a piston in a conventional manner.
• this shaft is designed as a tool surface.
• the latter is advantageously carried out on a widening base of the shaft and is rectangular with rounded corner shapes. Instead of the rounded corners, semicircular surfaces attached on the narrow side can also occur. It is particularly advantageous to surround the tool surface directly with a hem surface whose level in the direction of action is set back by approximately 0.05 to 0.5 mm with respect to the plane of the tool surface. If the tool surface should penetrate the material, this type of recessed hem surface leads to the hem surface contacting the workpiece surface at a penetration depth of more than 0.05 to 0.5 mm. This immediately reduces the specific surface load, so that another
• the hem surface is therefore expediently formed on each long side of the tool surface and has about the same width as the tool surface.
• the tool surface or the hem surface also expediently merges into the stamp or into its base via a rounded edge.
• the formation of sharp-edged surface defects can thus be avoided with certainty.
• the übergangsber I following the work of convincing area or the seam area widens in übri gen appropriate trapezoidal towards the wider So ⁇ ckel the stamp.
• FIG. 1 shows a workpiece with a change in shape according to the invention
• Figure 2 shows the line-wise application of a piece according to the invention
• Figure 1 shows a * sheet 1, which was dynamically loaded in its longitudinal direction with a stamp by guiding this stamp along the longitudinal direction 2. It continued to run in several ' parallel ' tracks.
• the individual loading surface has a width 6 and a length 7 extending in the longitudinal direction 2, the latter being preferably six times the width.
• the overlapping impact areas form impact tracks 8, 9, the spacing 10 of which, in the illustration in FIG. 2, is approximately the same width as the width 6 of the impact area or the impact track 8.
• the feed can be increased or the impact frequency reduced, so that the individual impact surfaces 4 finally no longer overlap one another.
• FIG. 3 A cylindrical shaft 11 whose lower end is designed as a tool surface 12 can first be seen, the latter being shown in plan view in the lower part of FIG. 3.
• the tool surface 12 is formed on the widening base 13 of the shaft 11 and has an essentially rectangular shape. Your - - 8th -
• Length 7 fulfills the condition of being about six times the width 5.
• Semicircular surfaces 14 are attached to the narrow sides of the tool surface 12.
• the tool surface 12 is directly surrounded by a hem surface 15, which is offset parallel to the plane of the tool surface 12 opposite to the direction of impact 16.
• the extent 17 of this dislocation is between 0.05 to 0.5 mm.
• the hem surface extends to both longitudinal sides of the tool surface 12 and there is of a width 18 which is approximately the same as the width 5 of the tool surface 12.
• a workpiece may well lie on a soft, yielding material, such as foam or the like, during the treatment according to the invention.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Shaping Metal By Deep-Drawing, Or The Like (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6127932

Family Applications (1)

Country Status (3)

Cited By (3)

Families Citing this family (4)

Citations (4)

Family Cites Families (4)

• 1981
  • 1981-03-21 DE DE19813111148 patent/DE3111148A1/de active Granted
• 1982
  • 1982-03-16 WO PCT/DE1982/000058 patent/WO1982003192A1/de not_active Ceased
  • 1982-03-16 EP EP19820900794 patent/EP0074967B1/de not_active Expired

Patent Citations (4)

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