**1. Introduction** Electrical Discharge Machining (EDM) is a critical process in mold manufacturing, particularly in the production of plastic molds. Most mold components are typically finished using EDM to achieve high precision and surface quality. The performance of the final product—such as its assembly accuracy or molding quality—is directly influenced by the machining quality. Any abnormalities during the EDM process can lead to unnecessary rework, potentially causing the entire workpiece to be scrapped, increasing production time, raising costs, and reducing overall mold quality. Therefore, preventing processing anomalies is essential for maintaining efficiency and quality in mold manufacturing. Processing anomalies can manifest as either issues during the machining process or defects that appear after the operation. **2. Common EDM Problems and Analysis** (1) **Unqualified Dimensions After Machining** The dimensional accuracy achieved through EDM is usually around 0.005 mm. However, depending on the part’s requirements, some areas may demand stricter tolerances. If the dimensions fall outside the acceptable range, it results in defective parts. This can happen due to several factors: a. **Electrode Scaling Effects** During EDM, spark gaps exist between the electrode and the workpiece. Proper scaling of the electrode is crucial to ensure accurate dimensions. If the actual spark gap differs from the electrode scale, it affects the final size. For example, if the spark gap is smaller than the electrode scale, the machined dimension will be too small. Conversely, if the electrode scale is too small, the result will be oversized. Correct electrode scaling depends on the type of component being machined—structural parts versus forming parts. Structural parts require precise dimensions but not necessarily high surface finish, while forming parts need both accurate dimensions and smooth surfaces. b. **Control of Electrode Translation** When electrode translation is used, the amount of movement directly impacts the final dimensions. Accurate control of the translation is necessary to maintain the desired size. c. **Electrode Calibration Accuracy** Poor calibration can cause misalignment, leading to larger-than-expected dimensions. Smaller electrodes are more prone to calibration errors, which can affect the final size. d. **Electrical Parameter Adjustments** Changes in current, pulse width, and other parameters influence the spark gap and, consequently, the final dimensions. Maintaining stable electrical conditions is key to achieving consistent results. e. **Electrode Wear During Machining** Electrodes naturally wear during the process, which can reduce the final size. Controlling this wear is essential for maintaining dimensional accuracy. f. **Depth Control Issues** The depth of the machined area is a critical dimension. Factors such as tool setting, debris, and thermal expansion can affect the accuracy of depth control. (2) **Surface Quality Issues** Surface quality problems in EDM include carbon deposition, insufficient roughness, and thick metamorphic layers. a. **Carbon Deposition** This occurs when the discharge is unstable, often during finishing. Improper electrical settings or oil flushing methods can lead to carbon buildup, damaging the mold surface. b. **Roughness Not Meeting Requirements** If the surface is too rough, additional polishing may be required, affecting both appearance and functionality. Electrode material, surface condition, and machining allowances all play a role in surface quality. c. **Thick Metamorphic Layer** High discharge energy can create a thick altered layer on the surface, reducing wear resistance and service life. Careful control of current and discharge energy is needed to prevent this. (3) **Position Deviation** Misalignment of the electrode or workpiece can occur due to improper clamping or positioning. Ensuring accurate reference points and proper setup is crucial to avoid this issue. (4) **Processing Abnormalities** Common issues include low processing efficiency, excessive electrode wear, unstable discharges, electrode deformation, and "powdering" in hole-making. These can be caused by incorrect electrical parameters, poor oil flushing, or improper tooling. (5) **Human Errors** Mistakes such as incorrect coordinates, wrong electrode selection, or program errors can also lead to quality issues. Training and attention to detail are vital to minimize these errors. **3. Conclusion** Preventing abnormal EDM processes is crucial for ensuring high-quality mold production. By understanding and controlling each factor that influences the outcome, manufacturers can improve efficiency, reduce waste, and enhance the overall performance of their molds. Attention to detail, proper parameter settings, and regular maintenance are key to achieving consistent and reliable results.

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