What are the steps of edm ?

1. Analysis and review of the drawings
The analysis of the pattern is a decisive first step in ensuring the quality of the workpiece and the comprehensive technical specifications of the workpiece. Taking the blanking die as an example, when digesting the pattern, it is first necessary to pick out the workpiece drawings that cannot or are not easily processed by wire electric discharge, which are roughly as follows:
1. The surface roughness and dimensional accuracy are very high, and the workpiece that cannot be manually ground after cutting;
2. The workpiece with a narrow slit smaller than the wire diameter plus the discharge gap, or a workpiece with rounded corners formed by the discharge gap of the electrode rigid derrick is not allowed at the corner of the pattern;
3. Non-conductive materials;
4. Parts with a thickness exceeding the span of the wire frame;
5. The workpiece with a processing length exceeding the effective stroke length of the xy pallet and high precision requirements.
6. Under the conditions of the wire cutting process, careful consideration should be given to surface roughness, dimensional accuracy, workpiece thickness, workpiece material, size, fit clearance and thickness of stamping.
Second, programming considerations
1. Determination of die gap and transition circle radius
2. Reasonably determine the die clearance. The reasonable selection of die gap is one of the key factors related to the life of the die and the size of the punch. Die gaps for different materials are generally selected in the following ranges:
3, soft blanking materials, such as copper, soft aluminum, semi-hard aluminum, rubber wood, cardboard, mica, etc., the convex and concave mold gap can be selected as the thickness of the punched material 10% – 15% hard blanking material, such as For sheet metal, steel sheet, silicon steel sheet, etc., the gap between the convex and concave molds can be 15%-20% of the thickness of the punching.
This is the actual empirical data of some wire-cutting blanking dies, which is smaller than the internationally popular large-gap die. Because the workpiece surface of the wire cutting process has a layer of brittle melting layer, the larger the processing electrical parameters, the worse the surface roughness of the workpiece and the thicker the molten layer. As the mold punches up, the layer of crispy surface will gradually wear away, and the gap between the molds will gradually increase. Reasonably determine the radius of the transition circle. In order to improve the service life of the general cold stamping die, a transition circle should be added to the line, the line circle, the far intersection, especially the corner of the small angle. The size of the transition circle can be considered according to the thickness of the blanking material, the shape of the mold and the required service life, and the technical conditions of the punched part. As the punched part is thick, the transition circle can be correspondingly increased. Generally, it can be selected in the range of 0.1-0.5mm. In the three-dimensional network technology forum, for the thinner material of the punching material, the gap between the molds is small, and the punching piece is not allowed to increase the transition circle. In order to obtain a good convex-concave mold matching gap, a transition circle is generally added at the corner of the figure. Because the wire processing trajectory naturally produces a transition circle having a radius equal to the wire radius plus a single-sided discharge gap at the inner corner.
4. Calculate and write machining programs
When programming, choose a reasonable clamping position according to the condition of the ingredients, and at the same time determine a reasonable cutting point and cutting route. The cutting point should be taken at the corner of the figure or at the point where the cusp is easy to repair. The cutting route is mainly to prevent or reduce the deformation of the mold. Generally, it should be considered that the pattern near the side of the clamping is finally cut.
5. Program paper tape and proofing tape for threading and processing
After the paper tape is finished according to the program, the program sheet and the prepared paper tape must be proofed one by one. After the program is input into the controller with the proofreading paper tape, the sample can be tested and the workpiece can be processed directly. . For molds with high dimensional accuracy and small concave and convex molds with small gaps, it is necessary to use thin materials for trial cutting. The precision and fit clearance can be checked on the cutting parts. If it is found that it does not meet the requirements, it should be analyzed in time to find out the problem and modify the procedure until it is qualified before the mold can be formally processed. This step is an important part of avoiding scrapping of the workpiece.