Mold processing deformation problem processing method

Mold processing refers to the processing of forming and blanking tools, in addition to shearing and die cutting dies. Usually, the mold has two parts, an upper mold and a lower mold. The steel plate is placed between the upper and lower molds, and the material is formed under the action of the press. When the press is opened, the workpiece determined by the shape of the mold is obtained or the corresponding waste is removed. Small to electronic connectors, up to the dashboard of the car can be molded with a mold. Progressive die refers to a set of molds that can automatically move a workpiece from one station to another and obtain a molded part at the last station.

Cutting process of cemented carbide tooth punch:

1, under normal circumstances

When the shape of the punch is regular, the wire cutting process will always reserve the connecting part (the pause point, that is, a small cutting trajectory reserved for the workpiece to be completely separated from the blank after the first rough cut) remains in the plane. In the position, after most of the finishing cuts, only one cut is made to the reserved joint portion, and then trimmed by the fitter, which can reduce the processing cost of the punch in the middle wire cutting. Due to the high hardness and long shape of the material, the cemented carbide punch has a slow processing speed and is easily deformed. Especially in the case of irregular shape, the grinding of the reserved joint portion brings great difficulty to the fitter. Therefore, in the middle wire cutting processing stage, the process can be appropriately adjusted to meet the requirements of the dimensional accuracy, and the grinding process of the pause point before the fitter assembly is eliminated. Due to the high hardness of the cemented carbide and the large cutting thickness, the processing speed is slow and the torsional deformation is severe. Most of the shape processing and the reserved joint part (pause point) are processed in 4 times and the cutting parameters and offset of the two parts are taken. The amounts are all consistent. The offset of the first cutting electrode wire (molybdenum wire) is increased to 0.15-0.18mm, so that the workpiece can fully release the internal stress and complete torsional deformation, and there can be sufficient margin for finishing cutting in the next three times. The final dimensions of the workpiece are guaranteed.

The specific process analysis is as follows:
(1) The Φ1.0-Φ1.5mm threading hole is processed in advance at the appropriate position of the blank by a punch or an EDM machine, and the length of the introduced cutting line between the center of the threading hole and the contour of the punch is 5-10 mm.
(2) The outline of the punch and the width of the edge of the blank shall be at least 1/5 of the thickness of the blank.
(3) The connection part (pause point) reserved for subsequent cutting should be selected close to the center of gravity of the workpiece blank, and the width should be 3-4 mm (depending on the size of the workpiece).
(4) In order to compensate for the torsional deformation, most of the residual deformation is left in the first rough cutting stage, and the offset is increased to 0.15 - 0.18 mm. The subsequent three times use the fine cutting method, and the deformation amount is also small because the cutting allowance is small.
(5) After the 4th cutting process is completed, the workpiece is blown dry with compressed air, then the end face of the blank is washed with alcohol solution, dried, and then used with adhesive or liquid quick-drying glue (usually 502 quick drying) Glue) The metal foil with a thickness of about 0.3 mm smoothed by the grinding machine is adhered to the blank, and the reserved portion of the workpiece is cut according to the original offset of 4 times (Note: Do not drop the glue to the workpiece. Connect the part so as not to cause non-conductivity and cannot be processed).

2. Deformation analysis in concave template processing

Before the online cutting process, the template has been cold-worked and hot-processed, and a large residual stress has been generated inside, and the residual stress is a relatively balanced stress system. When the wire is cut to remove a large amount of waste, the stress is destroyed with the balance. Released. Therefore, when the template is cut online, with the influence of the original internal stress and the processing thermal stress generated by the spark discharge, non-directional and irregular deformation will occur, so that the thickness of the cutting knife behind is uneven. Processing quality and processing accuracy. In this case, for a template with a relatively high precision, four cutting processes are usually used. In the first cutting, the waste of all the holes is cut off, and after the waste is taken out, the second, third, and fourth cuts are completed by the automatic shifting function of the machine tool. a cutting the first time, taking the waste → b cutting the first time, taking the waste → c cutting the first time, taking the waste → ... → n cutting the first time, taking the waste → a cutting the second time → b cutting the second time →...→n cutting the second time→a cutting the third time→...→n cutting the third time→a cutting the fourth time→...→n cutting the fourth time, the processing is completed. This cutting method can make enough time for each type of hole to release internal stress after processing, and can reduce the mutual influence and micro-deformation caused by different processing orders of each type of hole to a minimum, and better ensure the processing size of the template. Precision. However, such processing time is too long, the number of threading times is large, and the workload is large, which increases the manufacturing cost of the template. In addition, the machine itself will creep as the processing time increases and the temperature fluctuates. Therefore, according to the actual measurement and comparison, the template can be used for the first uniform processing to take the waste without the processing precision, and the second, third, and fourth times are combined for cutting (ie, a cutting second) After that, do not shift, do not remove the wire, then cut the 3rd, 4th → b→c...→n), or save the 4th cut and do 3 cuts. After the cutting is completed, the shape and size are basically in accordance with the requirements. This not only improves production efficiency but also reduces labor, thus also reducing the manufacturing cost of the template.

3. Processing technology of concave template hole small corner

Due to the larger diameter of the selected electrode wire (molybdenum wire), the radius of the corner of the cut hole is also larger. When the corner radius of the template hole is very small (such as R0.07-R0.10mm), you must use a filament (such as Φ0.10mm). However, in the case of thick yarns, the filaments are processed at a slower speed and are prone to breakage. If the entire hole is machined with filaments, the processing time is extended and waste is caused. After careful comparison and analysis, we first increase the corner radius appropriately, cut all the holes with thick wire to meet the size requirements, and then replace the filaments to uniformly cut the corners of all the holes to the specified size. However, if the filament of Φ0.10mm is replaced, the center should be re-aligned. The coordinate value of the re-centering center should be about 0.02mm from the original center coordinate value.

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