I. The Working Principle and Technical Advantages of EDM
The core principle of EDM is the energy conversion of "electrical energy → thermal energy → material removal". The specific process can be disassembled into the following four steps:
Discharge Preparation: A small gap (about 0.02 - 0.3mm) is maintained between the electrode and the workpiece, and they are immersed in an insulating dielectric fluid (such as kerosene or deionized water).
Pulse Discharge: When the voltage between the electrode and the workpiece breaks down the dielectric fluid, a plasma channel with a temperature as high as 10,000 - 15,000°C is generated instantaneously, causing the material at the contact point to melt and vaporize rapidly.
Material Removal: The high - temperature molten metal is washed away by the dielectric fluid, forming micron - level pits; the electrode feeds continuously, gradually "sculpting" the desired shape.
Circulation Cooling: The dielectric fluid circulates continuously, taking away heat and preventing the electrode from adhering to the workpiece, ensuring processing accuracy.
This process does not require physical contact, completely avoiding the tool wear and material deformation problems of traditional machining. It is especially suitable for difficult - to - machine materials such as hardened steel, titanium, and carbide. Its technical advantages include:
Ultra - precision Machining: The accuracy can reach ±0.005mm, meeting the strict requirements for components such as catheters and syringes in medical device plastic molding.
Complex Structure Processing: Through wire EDM (wire cutting), extremely fine slits of 0.05mm can be processed, realizing the manufacture of micro - fluidic channels in medical injection molding molds.
Material Compatibility: Secondary processing can be directly carried out on heat - treated metals without changing their properties, such as the stress - free processing of stainless steel parts.
II. How EDM Empowers Stainless Steel Parts and the Medical Field
1. The "Stress - Free" Machining Revolution of Stainless Steel Parts
Stainless steel parts are widely used in food machinery, medical devices, and other fields due to their corrosion resistance. However, traditional cutting is prone to cause material hardening and deformation. Through small hole EDM (small - hole machining) technology, EDM can drill holes with a diameter of 0.1mm in stainless steel without burrs and heat - affected zones, perfectly adapting to the precision requirements in component test fixtures for semiconductor industry. For example:
Semiconductor Test Fixtures: The porous structure processed by EDM can improve heat dissipation efficiency while maintaining the corrosion resistance of the material.
Aerospace Fasteners: The complex internal cavities manufactured by sinker EDM (electrical discharge sinking) can reduce weight and enhance structural strength.
2. The "Micron - Level" Breakthrough in the Medical Industry
Implant Manufacturing: Mechanical turned parts for the medical sector, such as artificial joints and dental implants, require EDM to process surface porous structures to promote bone tissue growth. For example, experiments on the electrical discharge machining of porous 316L stainless steel show that the porosity can be accurately controlled between 30% - 60% without destroying the original structure.
Surgical Instruments: Medical injection molding companies use molds manufactured by EDM to produce precision catheters with a diameter of 0.3mm, ensuring the safety of minimally invasive surgeries. Wire - cutting technology can also engrave nanoscale textures on titanium alloy, improving the biocompatibility of the instruments.
III. The Core Applications of EDM in Injection Molds and CNC Machining
1. The Precision Revolution in Medical Injection Molds
In the field of medical injection molding, EDM technology solves two major pain points:
High - Hardness Mold Processing: Traditional milling is difficult to process quenched steel molds, while EDM directly ablates complex cavities through sinker EDM, ensuring the dimensional accuracy and surface finish of components such as catheters and syringes in medical plastic molding.
Fine Structure Realization: Wire EDM can cut extremely fine slits of 0.05mm, meeting the manufacturing requirements of micro - fluidic channels in medical device plastic molding. For example, a medical device company controlled the wall thickness tolerance of catheters within ±0.01mm through EDM - processed molds, increasing the yield rate to 99%.
2. The Complementary Partner of CNC Machining
EDM and CNC machining form a golden combination:
Rapid Prototype Verification: In the metal rapid prototyping stage, EDM can quickly cut stainless steel parts samples, and cooperate with CNC turning services to complete the fine processing of complex surfaces.
Mold Post - processing: After the molds processed by automotive cnc machine are polished by EDM, the surface roughness is reduced by more than 50%, significantly improving the yield rate of plastic parts manufacturing. For example, an automotive parts manufacturer used EDM to mirror - treat die - casting molds, increasing the surface gloss of injection - molded parts by 30% and reducing the cost of subsequent polishing processes.
IV. The Industry Trends of EDM and Selection Suggestions
With the integration of intelligent and automated technologies, EDM equipment is moving towards unmanned machining and multi - axis linkage directions. For example, industrial molding corporation has realized the combination of EDM and AI. By real - time monitoring of the discharge state and automatically optimizing processing parameters, the efficiency has been increased by more than 30%.
For enterprises, when choosing an EDM service provider, three points need to be noted:
Equipment Accuracy: Confirm whether it has the ±0.001mm - level processing ability of wire EDM.
