Techniques for Multi-Step Wire EDM Cutting

Wire EDM Techniques in Multi-Stage Cutting Processes

When performing multiple cuts on the remaining portion of a wire‑cut workpiece, it is essential to first address the workpiece’s electrical conductivity. In high‑precision wire EDM, the wire electrode follows a reciprocating path along the machining contour to ensure superior surface finish. Below, we will outline the key techniques involved in multi‑pass wire cutting with medium‑speed wire EDM.

To ensure high machining accuracy of the workpiece, wire electrical discharge machining (WEDM) relies on the remaining material to maintain electrical conductivity and enable the process to proceed normally. However, during the cutting of this residual material, if it is removed in a single pass, the cut portion may separate from the parent workpiece, breaking the electrical circuit and halting further machining. Therefore, it is essential that the residual material remains electrically conductive to the parent workpiece throughout multiple cutting passes.

To achieve this goal, operators must artificially create the necessary environment and conditions to meet the conductive requirements. Methods such as bonding copper foils between the cut section and the parent material, or inserting copper shims into the cutting gaps, can be employed to establish both positioning and conductive conditions.

A copper connecting strip is bonded between the cut section and the parent material to ensure that, during cutting, the remaining workpiece remains securely attached to the parent material. This provides excellent positioning for wire EDM and helps maintain superior machining quality. The process can be carried out according to the following steps:

1. Cut the thin copper sheet into long strips according to the size of the workpiece, then fold it, ensuring that each folded section has one long side and one short side.

2. Flatten the bent portion of the copper sheet with a hand hammer and shape it into a wedge.

3. Next, insert the copper sheet—having undergone the two preceding steps—into the gap created by wire electrical discharge machining, and simultaneously apply an instant‑drying adhesive to the surface of that area on the workpiece.

During cutting, the wire EDM machine’s water‑cooling system subjects the workpiece to significant pressure. Relying solely on copper shims to ensure electrical conductivity and secure the workpiece can lead to problems: if the shims are too loose, the connection becomes unreliable and conductivity is unstable; if they are too tight, the shim may damage the workpiece surface and compromise geometric tolerances. Therefore, adhesive can be used to securely bond the cut portion to the parent material.

When using wire electrical discharge machining to process small workpieces with high hardness, high precision, and complex geometries, performing fine finishing on the residual areas of the workpiece according to the aforementioned method is a highly effective approach. Moreover, this technique is economical and straightforward, significantly improving and enhancing the quality of precision wire EDM operations.

Dongguan Fulin Machine Co., Ltd. specializes in wire EDM, high-precision grinding, slow-wire EDM, mechanical parts, multi-axis machining, CNC machining, five-axis machining, precision parts, non-standard parts, and general machining. The company boasts state-of-the-art production equipment and is equipped with advanced inspection instruments, such as coordinate measuring machines, microscopes, projectors, hardness testers, 3D measuring devices, and Swiss height gauges, ensuring the production and processing of high-precision products to meet customer requirements. To date, we have maintained successful long-term collaborations with numerous related enterprises, and our product quality has consistently earned widespread recognition and praise from customers. Our unwavering commitment is to put people first, excel through quality, foster unity and progress, and pursue continuous innovation—satisfying our customers by delivering superior quality, honoring precise delivery schedules, providing exceptional service, and ensuring customer satisfaction through systematic management.