Pros and cons
The ECM process offers numerous advantages and disadvantages as opposed to conventional machining techniques. The advantages can be categorized by product, material and machine advantages. The disadvantages of the ECM process are in general.
Product advantages:
- The product after processing is free of burrs
- No-contact process principle
- The process does not cause thermal or physical strain in the product
- Unlike other machining techniques, no upper-layer deformation occurs
- 3-Dimensional products can be processed in one single step
- High surface quality level attainable (Ra < 0,02 µm) depending on material
- High dimensional accuracy attainable
- Material strain which loosens during the process will be compensated where possible
- Stainless steels are affected by various conventional machining techniques in the upper-layer, as a result of which local rust formation can occur. This is not the case with ECM
- Using the ECM technique generates more freedom of design for a product
- ECM is a technique with high machining speed and relatively low costs.
Material advantages:
- The hardness, toughness and thermal resistance do not influence the material removal rate (MRR). Neither is it relevant for the machining of a product if it is processed before or after a hardening step.
- MRR is high, approximately 1,5 cm3/min at 1000A DC.
- MRR is almost independent on the type of material
- Hard and tough alloys are machined at the same speed as for instance aluminium
Machine advantages:
- Low running and tooling costs
- Initial investment of process design and electrode construction are high, however the recurring costs are low
- “No†electrode wear
Besides numerous advantages, ECM has a few disadvantages.
General disadvantages:
- ECM was previously known as a process that harmed the environment. Through developments in the treatment of electrolytes, the process has become less harmful to the environment. By using a closed electrolyte system dumping to the sewer is ruled out. Produced sludge can nowadays be used as raw material with or without follow-up treatment, depending on the machined material.
- Each product and material require new research
- Higher production numbers are essential, as a special electrode must be developed for each product. The optimum number of products depends on complexity and material.
- Power consumption is high but much lower than other non-conventional machining techniques. ECM processes operate at high current but relatively low voltage (5-15V).
- Design of electrode is complex and initially expensive, it can however be used “indefinitelyâ€.
- ECM requires a relatively high standard of knowledge from their staff.