JPH035889B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold manufacturing method that allows various molds such as press molds to be manufactured accurately with fewer steps.

The upper mold (e.g. punch) and lower mold (e.g. die) for press working plate materials are made by machining the surface of the mold material cast into a predetermined shape by cutting or electrical discharge machining, etc. Manufactured. However, in order to manufacture molds such as upper and lower molds for pressing panel products with complex and delicately curved surfaces, such as automobile body components such as trunk lid outer panels and door outer panels, it is necessary to Because it is difficult to accurately calculate the amount of springback or sinkage in panel products, it is usually necessary to manufacture the mold several times and then modify it through trial and error to achieve the desired shape. Trying to get the mold. Since it takes a huge amount of man-hours to manufacture molds many times, it is possible to make prototypes of the upper and lower press molds (simple press molds) using resin and use these to press the plate material. Then, we measured the difference between the shape of the pressed panel prototype and the final required panel product, and successively made modifications to the shape of the simple press mold to obtain a mold with the desired shape. Sometimes it is. However, remaking the simple press mold many times using resin requires a huge amount of man-hours.

Therefore, a mold manufacturing method has been developed in which the amount of modification to be added to the surface of the basic mold, that is, the shape that takes into account the overcrown, is calculated using a computer, and the mold is processed. 1st
The figure is a drawing showing this manufacturing method. Based on the processing model 1, such as a clay model, which is molded to the same external shape as the actual vehicle, the shape data is transferred to the measuring device 2.
This is recorded on the NC tape 3 as numerical information.
This is input into the computer 4, and the computer 4 performs calculations using FEM (finite element method) to determine the expected amount of overcrown. After storing this shape data on the tape 5, it is used for machining. Recorded on tape 6. Using this processing tape 6, a mold 7 is processed using an NC machine tool.

However, with this method, the mold 7
Even if the mold 7 is used to manufacture the trial panel T, there may be errors in sink marks, and the amount of overcrown cannot be accurately estimated, and it is necessary to rely on experience and intuition. , the estimated amount may be off. And in that case,
Although the mold 7 must be reworked, finishing work to give the surface of the mold 7 an extra shape is not easy. Another problem was that the estimation method itself required a lot of man-hours.

The present invention has been made in view of the problems of the prior art, and aims to quickly manufacture a mold of a desired shape. a step of forming a processed surface of a mold into a basic shape corresponding to the surface shape of the mold, a step of pressing a panel material using a mold having a processed surface of the basic shape, and pressing the panel material. A step of comparing the shape of the prototype panel obtained with the shape of the final panel product to measure the amount of sink marks in the prototype panel, and forming a plating layer on the surface of the mold to a thickness corresponding to the amount of sink marks. This is a mold manufacturing method that includes a forming process and a finishing process.

Next, a description will be given with reference to drawings showing a case in which the present invention is implemented in order to manufacture a punch for press working. FIG. 2A is a diagram showing a punch 10 which is an example of a mold, and this punch 10 is for drawing a trunk lid outer panel. The processing surface 11 at the tip of the punch 10 corresponds to the surface shape of the final panel product to be pressed,
A processed surface 11 is formed in the same shape.

A panel material W is press-worked using such a punch (male die) 10 and a die (female die), not shown, which has a processing surface with a concavity and convexity relationship reversed to that of the punch (male die).
In FIG. 2, B is a diagram showing a prototype panel T obtained by pressing the panel material W using the punch 10. The part a indicated by the two-dot chain line in Fig. 2B is
The shape of the panel product to be finally processed, that is, the regular shape, is shown, and the portion b shown by the solid line shows the shape of the trial panel T as a result of shrinkage caused by the spring back of the panel material W. Note that V indicates the entire portion where the sink mark occurred. This sink mark V varies depending on the final shape of the panel product to be processed, the forming conditions, and the type of steel plate used, but sink marks generally occur in depressions rather than in regular shapes.

After molding the trial panel T as described above, as shown in FIG. Measure v. In FIG. 3A, a shows the shape of the minimum panel product, that is, the normal shape, b shows the shape of the trial panel T, and sink marks are indicated by hatching in the figure. Next, as shown in FIG. 3B, a plating layer P is formed on the surface of the punch 10 to a thickness corresponding to the amount of the sink mark v, and an overcrown is attached to the surface of the punch 10.

FIGS. 4A to 4D are diagrams showing the details of the process of forming the plating layer P. First, areas other than the portions with the largest amount of plating are masked with a masking material M, and a partial plating tool (for example, Aiko KK's Daric A first plating layer PI is formed on the surface of the punch 10 by plating) R. The best type of plating is one with wear resistance, such as Ni plating, Cr plating, or Ni-W plating. The thickness of the plating layer can be controlled by the current value and time of energization, and the plating layer PI can be plated to a substantially uniform thickness.

Next, the area of the masking portion is expanded and the same operation is performed to plate the second layer P ₂ as shown in FIG. 4B and the third layer P ₃ as shown in FIG. 4C. Procure the masking area and plating time according to the area and height of the sink area and perform plating. Once the plating layer P has been formed into a substantially predetermined shape, back polishing is performed using a buff B as shown in FIG. 4, so that the surface of the plating layer P is smoothed. In particular, the boundary between the plating layer part and the masking part is carefully polished so that there are no steps. The expected amount is usually 1 to 2 mm at the maximum thickness for a mold for forming a panel product as shown in the figure.
The maximum length is 3mm, and it is possible to make plating. When a thick plating layer is required, the first and second layers are preferably Cu plating or Ni plating.

In this way, when the panel material W is pressed using the punch 10 with the plating layer P formed on the processing surface 11 of the punch 10 and an overcrown attached, sinkage occurs by the amount of the overcrown, resulting in a panel with an almost regular shape. The product is subjected to plastic processing. However, if the expected amount is too small, the machined surface 11 of the punch 10 is corrected by further plating, but since the already made corrections bring it closer to the normal shape, the correction can be easily performed.

Even in the unlikely event that the embedding comes off, use hydrochloric acid,
The plating layer P can be easily peeled off using a stripping solution such as chloric acid, and the basic shape of the surface of the punch 10 is preserved as it is, allowing the next countermeasure to be taken. Incidentally, FIG. 5 is a diagram showing the shape of the final panel product _W0 , and when the panel material W is pressed using a punch 10 having a shape 9 shown by a two-dot chain line C,
It is molded into a shape almost similar to the final panel product W ₀ .

FIG. 6 is a diagram showing a plating process according to another embodiment of the present invention, and in contrast to the case shown in FIG. The plating layer P is formed while gradually narrowing the area.

As described above, the present invention includes a process of forming a processed surface of a mold into a basic shape corresponding to the surface shape of a panel product to be pressed, and a process of forming a panel material using a mold having a processed surface of the basic shape. a step of pressing the panel material; a step of comparing the shape of the prototype panel obtained by pressing the panel material with the shape of the final panel product to measure the amount of sink marks in the prototype panel; and the amount of sink marks. Since the process includes a step of forming a plating layer on the surface of the mold to a thickness corresponding to , and a finishing step, a predetermined basic shape is sufficient for machining molds such as punches, and the estimated amount can also be modified. It was easy to carry out, and the effect of significantly shortening the molding time and process of the final shape of the mold was obtained.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing a conventional mold manufacturing method;
Figure 2A is a perspective view of a punch with a basic shape processing surface, Figure 2B is a perspective view of a prototype panel pressed using the punch in Figure A, and Figure 3A is a perspective view of the sink mark of the trial panel. 3B is a sectional view of the punch showing the state in which a plating layer is formed on the surface, FIGS. 4A to D are enlarged sectional views of the main parts of the punch showing the plating process, and FIG. 5 is a sectional view of the punch showing the plating process. 6A to 6D are cross-sectional views showing a final panel product, and FIGS. 6A to 6D are cross-sectional views showing a plating process according to another embodiment of the present invention. 10... Punch, 11... Processed surface, W... Panel material, W ₀ ... Final panel product, T... Prototype panel, P... Plating layer, V... Sink portion.

Claims (1)

[Claims] 1. A step of forming a processed surface of a mold into a basic shape corresponding to the surface shape of a panel product to be pressed; a step of press-working a panel material using a mold having a processed surface of the basic shape; A process of comparing the shape of a prototype panel obtained by pressing panel material with the shape of a final panel product to measure the amount of sink marks in the prototype panel, and adding the metal to a thickness corresponding to the amount of sink marks. A mold manufacturing method comprising a step of forming a plating layer on the surface of the mold and a finishing step.