How Much Do You Know About Hexagonal EDM Machining?

How Much Do You Know About Hexagonal EDM Machining?

In precision machining, it's common to see “hexagonal holes” or “hex-shaped countersinks” on customer drawings. These internal features are not only geometrically complex but also often require high accuracy in terms of dimensions and positioning. So, how do we process these features effectively? One reliable answer is EDM (Electrical Discharge Machining). Today, let's dive into what hexagonal EDM machining is, when to use it, and what to pay attention to during the process.

What Is Hexagonal EDM Machining?

EDM is a non-traditional machining method that removes material using electrical discharges between an electrode and the workpiece. “Hexagonal EDM” refers to using a copper or graphite electrode shaped like a hexagon to erode a matching hexagonal profile into the part.

This method is especially useful when cutting internal hexagons, particularly deep holes or small sizes, where milling tools can't reach. EDM's non-contact nature makes it ideal for such cases.

When Is Hexagonal EDM Recommended?

Here are some typical scenarios where EDM is ideal for hexagonal features:

1. Deep or small hexagonal holes that milling cutters can't reach;

2. Hard materials such as hardened steel or titanium alloys;

3. High-precision demands, like ±0.01mm tolerance;

4. Complex part geometry, where tool access is limited;

5. Prototype or small batch production, saving the cost of custom tools.

General Process Overview

The typical steps for hexagonal EDM machining include:

1. Electrode Design: A copper/graphite electrode is created based on the drawing, with a clearance allowance;

2. Setup and Alignment: Workpiece is clamped on the EDM machine and aligned precisely;

3. EDM Process: Parameters like current, pulse duration, and gap are fine-tuned to start erosion;

4. Inspection: Dimensions and tolerances are verified using CMM or plug gauges;

5. Post-processing: Cleaning debris, deburring, and ensuring good surface quality.

Common lssues & Solutions

Pro Tips

• Copper offers high precision; graphite is more durable;

• For batch work, consider custom jigs to improve repeatability;

• EDM is slower than CNC but achieves shapes and tolerances CNC can’t;

• Label and store used hex electrodes for future reuse;

Conclusion

Hexagonal EDM machining is an efficient solution for challenging hex-shaped features. Whether it’s deep holes, hard materials, or tight tolerances, EDM offers unmatched accuracy and flexibility. If your design includes such hex features, consider EDM as a viable solution. With extensive experience in hex EDM processing, we’re here to help—reach out to us for professional advice!