JPH0221348B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a trimming die that uses a press to remove burrs and sprues attached to a workpiece.

[Conventional technology]

A trimming mold used for removing burrs and sprues from a workpiece has a lower mold whose inner shape is the same as the outer peripheral shape of the workpiece, and the burrs and sprue can be removed by one trim. If this type of trimming type is used to remove large width and thick sprues and attempts are made to completely remove them in one trim, deep bends will occur, resulting in defects, and the workpiece will become distorted, making it difficult to straighten. It will be necessary to do so. Particularly when a workpiece has a sprue in an arcuate portion, deep bending defects are more likely to occur.

Conventionally, as shown in Fig. 3a, the shape of the lower mold for trimming this type of workpiece is a stairway in which the width of the blade for removing the sprue is narrowed discontinuously toward the bottom in the width direction of the sprue. By making the blade shaped like
There is a method of reducing the contact area between the sprue and the blade of the lower die and removing the sprue in stages in one trim. According to this method, it is possible to perform trimming at a low speed, and it is possible to improve the finishing accuracy after removing the sprue portion of the workpiece, and to prevent deep bending defects.

Similarly, as shown in FIG.
By making the blade shaped like a letter, the contact area between the sprue and the blade can be reduced and trimming can be performed at low speed.

[Problem that the invention seeks to solve]

In the method described above, when trimming continuously, the cut pieces removed at the bottom of the V-shaped blade and the step-shaped blade become stuck between the grooves of the blade, and the shape of the blade is maintained due to the blockage of the cut pieces. This becomes difficult.
Therefore, the finish accuracy of the workpiece sprue part is reduced, and polishing is required to increase the cost, and deep bends are more likely to occur. In order to remove the cut pieces that are stuck in the blade, they must be removed mechanically, and since the part where the cut is clogged is inside the lower trimming mold, this imposes restrictions on the equipment and causes a decrease in efficiency. In addition, the protrusion 10 of the blade on the stairs is subject to severe wear, resulting in a reduction in the finishing accuracy of the sprue. Therefore, frequent replacement of the blades is required, leading to a decrease in efficiency.

[Means and actions for solving problems]

In view of these drawbacks of the trimming molds in the prior art, the present invention provides a method for reducing the contact area between the workpiece sprue and the lower mold in order to have a simple trimming blade shape that is less likely to wear out and to perform trimming at low speed. Two blades, one for preliminary trim and one for finishing trim, were combined in the lower trimming mold in the pressing direction of the workpiece. The first step is to remove part of the sprue using a pre-trim blade. The second step is to completely remove the sprue using a finishing trimming blade. This method improves the finishing accuracy of the workpiece sprue with one trim and eliminates deep bending defects.

In addition, as a method for discharging the sections remaining on the finishing trim blade, a section self-discharging groove connected to the outer periphery of the lower trimming die was provided between the preliminary trimming blade and the finishing trimming blade. The pieces left on the finishing trimming blade are mixed with the pieces generated during the next trimming process, are placed on the outer periphery of the mold, and are discharged.

〔Example〕

The configuration of the present invention will be explained below based on examples. FIG. 1 shows the shape of the lower die of the trimming mold, and FIG. 2 shows an enlarged view of the main part of FIG. 1. By being pushed in the Y direction by the press, the work 1
A part 3 of the sprue 2 is first removed by a blade 5 for preliminary trim, and by further pushing the workpiece 1 in the Y direction, a remaining part 4 of the sprue 2 is removed by a blade 6 for finishing trim. At this time, the section removed by the finishing trim blade 6 remains on the finishing trimming blade 6, and the section generated when the workpiece is trimmed next removes the remaining section in the Z direction. By repeating this process, the section passes through the section self-discharge groove 7 and is discharged from the discharge port 8. Width of this section self-ejection groove 7
l ₁ was set to be l ₁ >l 2 with respect to the width l ₂ at the maximum cross section of the workpiece sprue ₂ in order to avoid clogging of the section.

Further, in order to prevent the cutting edge for finishing trim from being worn easily and to facilitate the ejection of the cut pieces, the cut self-ejection groove 7 is formed at an angle of 80° to 88° with respect to the direction of gravity.

〔Effect of the invention〕

When trimming with a lower mold having two blades, one for preliminary trim and one for finishing trim, configured as described above, the finish of the workpiece sprue part can be finished accurately with one trim, and the trim can be performed at low speed. This is effective in preventing deep folds.

Furthermore, by providing a section self-discharging groove between each blade, the sections remaining between the blades are discharged without clogging, and the machine is not restricted by equipment, and it is possible to operate without extending the takt time.

[Brief explanation of drawings]

FIG. 1 shows a schematic diagram of an embodiment of the invention, and FIG.
The figure shows an enlarged view of the main part of FIG. FIG. 3 is a diagram for explaining the prior art. 1: Workpiece, 2: Sprue, 5: Preliminary trim blade,
6: Finish trim blade, 7: Section self-ejection groove, 8:
Discharge groove, 11: Trimming lower mold.

Claims (1)

[Claims] 1. In the sprue part of a trimming mold, which is composed of an upper mold that is movable in the vertical direction and a lower mold that supports a workpiece with burrs and a sprue attached, a preliminary trim for rough finishing and a finishing trim are provided. A trimming type that features two blades that perform trimming in one go. 2. The trimming mold according to claim 1, characterized in that two or more preliminary trimming blades are provided. 3. Claim 1 is characterized in that a section self-discharging groove connected to the outer periphery of the lower die is provided between each blade in order to automatically discharge the sections removed in the second and subsequent trim stages. Trimming type.