The single-electrode direct molding method refers to using the same electrode tool to complete rough, medium and fine machining of the mold cavity. For ordinary EDM machines, a non-loss or low-loss electrical gauge is first used for rough machining during the machining process, and then the electrode tool is moved in a circular motion using a linear head. The electrical gauge is gradually changed according to the order of rough, medium, and fine, and side trim machining is performed.
When using the single-electrode linear motion method on the EDM die sinker machine, the tool electrode only needs to be clamped and positioned once, avoiding positioning errors caused by repeated clamping. However, for cavity models with high angular requirements, it is difficult to guarantee machining accuracy. If a CNC machine tool is used, there is no need for linear motion, and the worktable can be used to make fine adjustments to the side surface according to a certain trajectory.
The multiple-electrode replacement method refers to using several different-sized electrode tools to complete rough, medium, and fine machining of a cavity model according to the different discharge gaps during the process. During the machining process, the roughing electrode is first used to remove a large amount of metal, and then the electrode is replaced for medium and fine machining. For cavity models with high machining accuracy requirements, more electrodes are often needed for precision trimming.
High similarity accuracy, suitable for cavity mold machining with sharp corners and narrow gaps.
Multiple electrodes need to be manufactured, and the precision requirements for repeated manufacturing of electrodes are high; during machining, the sequential replacement of electrodes requires a certain degree of repeated positioning accuracy.
The decomposed electrode machining method for EDM molding is to decompose the electrode into a main cavity electrode and a sub-cavity electrode according to the geometric shape of the model cavity, and then make them separately. The main cavity electrode is first used to machine the main cavity, and then the sub-cavity electrode is used to machine the sub-cavity parts such as sharp corners and narrow gaps.
Different machining standards can be selected according to the different machining conditions of the main and sub-cavities, which is beneficial to improve machining speed and improve machining surface quality. At the same time, electrode manufacturing can be simplified and electrode trimming is easier.
Precise positioning between the main and sub-cavities is difficult to solve.
This EDM molding method is mainly used for non-CNC EDM machines without linear motion. The specific method is to use the X and Y coordinates of the moving worktable, and switch between different machining standards to polish the side walls in each direction. For example, after rough machining a certain cavity model, the bottom surface is first polished using a medium machining standard. Then, the worktable is moved to the right by a size of d along the X coordinate, and the left side wall of the cavity is polished, and then other surfaces are polished one by one.