EDM electric discharge machining

author: Universe plastic

2024-08-23

What is EDM

EDM is a processing method that uses pulse current to generate high temperature through gas discharge, causing thermal corrosion between the tool electrode and the workpiece, thereby removing material.

EDM is widely used in metal parts manufacturing. It can process fine and complex metal shapes, especially those parts that are difficult to process through traditional machining methods, such as small holes, narrow slots, and various complex-shaped holes. and cavity.

Advantages of EDM processing

1. Processing complex shapes

EDM can process very complex geometries, including deep cavities, sharp corners, thin walls, small holes, etc. Shapes that are difficult to achieve with traditional machining can be easily processed by EDM.

2. Processing of high hardness materials

EDM is not limited by material hardness and can easily process various materials with high hardness, such as hardened steel, titanium alloys, carbide, etc. This makes EDM important applications in fields such as mold manufacturing, aerospace and tool manufacturing.

3. No cutting force

EDM machining corrodes materials through electric discharge and does not involve mechanical cutting forces. Therefore, it is particularly suitable for processing thin-walled or fine parts and avoids workpiece deformation caused by cutting forces in traditional machining.

4. High processing precision

EDM processing can achieve micron-level processing accuracy and is suitable for mold and parts manufacturing that require high precision. This gives EDM significant advantages in micromachining and high-precision manufacturing.

5. Excellent surface quality

EDM can produce very smooth surfaces, often without the need for additional post-processing. With appropriate adjustment of process parameters, almost mirror-level surface quality can be achieved.

6. Strong adaptability

EDM can process almost any conductive material, whether the material is soft or hard, thick or thin. Therefore, EDM is suitable for the processing needs of a variety of different materials and structures.

7. Ability to process inaccessible areas

EDM is particularly suitable for processing areas that are difficult to reach with traditional machine tools, such as deep grooves, narrow slits and small holes. In these locations, traditional cutting tools may be limited by space and tool size, but EDM does not have these limitations.

8. Good repeatability

Because EDM is machined through a precisely controlled electrical discharge process, part consistency and repeatability are extremely high in mass production. This is especially important for scenarios that require high-volume production and high precision for each part.

9. Suitable for mold and tool manufacturing

EDM is particularly important in mold manufacturing, especially for the processing of complex molds such as injection molds and stamping molds. EDM can achieve high-precision machining of mold cavities while reducing wear and machining errors.

10. High degree of automation in the processing process

Modern EDM machine tools are often equipped with CNC systems that enable highly automated machining processes. Through programming control, multi-step processing of complex parts can be completed at one time, greatly improving production efficiency.

11. Flexible processing capabilities

EDM can flexibly process workpieces of different shapes, materials and sizes, and is especially suitable for the manufacturing of customized products.

EDM processing difficulty and challenges

1. Slow processing speed

Compared with traditional machining, EDM can process at a slower speed, especially when machining large volumes or deep parts. Material is removed layer by layer, which takes a long time.

2. Electrode material selection

Electrodes are one of the keys to EDM processing. The choice of electrode material affects machining accuracy, speed and surface quality. Commonly used electrode materials include copper, graphite and copper-tungsten alloys. Different materials have different wear characteristics and conductive properties. It is crucial to select the appropriate electrode material and rationally design the electrode shape.

3. Electrode loss

Electrodes will wear during processing, especially when processing parts with high hardness or complex shapes. Electrode loss may be large, and electrodes need to be replaced or trimmed frequently to ensure processing accuracy and surface quality. This increases processing complexity and cost.

4. Heat affected zone

During EDM processing, high temperatures will be generated on the material surface, which may lead to heat-affected zones in the processing area, resulting in material surface hardening, micro-cracks or residual stress. These effects may need to be eliminated by subsequent processing such as polishing or heat treatment.

5. Optimization of process parameters

EDM processing involves the setting of multiple process parameters, such as discharge current, pulse duration, gap voltage, and machining fluid selection. The combination of different parameters affects processing efficiency, surface quality and electrode loss. Finding the optimal combination of process parameters requires extensive experience and experimental data.

6. Chip removal and machining fluid management

In EDM processing, metal particles generated by electrical corrosion need to be removed from the processing area in time to prevent short circuits and reduce processing efficiency. The flow and cleaning of machining fluids is also a challenge, ensuring proper circulation and purification of the fluids.

7. Complex-shaped electrode design

For complex-shaped metal parts, the design and manufacturing of electrodes can themselves be very complex, especially when multiple processes are required or multiple electrodes need to be manufactured to complete different processing steps. The manufacturing accuracy of electrodes directly affects the processing quality of the final product.

8. Processing environment requirements

EDM processing needs to be carried out in a specific medium, which requires a specific processing environment and equipment maintenance, including the purification of the medium and the cooling system of the equipment.

EDM processing precautions

1. In actual operation, EDM needs to follow certain process specifications. For example, the electrodes split by the design department should meet the requirements of precision machining, paying special attention to the treatment of thin and delicate parts.

2. Relevant processing drawings should be produced for the processing content, accurate positioning methods should be used, and accurate processing data should be given. Because many parts have tiny processing parts, it is difficult to grasp the shape to be processed before processing. Detailed 3D data should be provided to the processing personnel.

Summarize

EDM processing has significant advantages in precision machining and complex-shaped metal parts manufacturing, but it has significant advantages in processing speed, electrode design and loss, and process parameters. It needs to be overcome through experience, technology and process control.

Universe Plastic Factory has 15 years of experience in manufacturing injection molds. High-precision injection mold parts are processed through advanced EDM equipment to create high-quality and cost-effective injection molds for customers.

If you are looking for an EDM machining center, please contact us to get the latest service quotation.

Injection mold structure: exhaust hole

Injection Molded Manufacturing Products: Plastic Toys