About This Part
EDM electrodes are the tools that sink or burn geometry into hardened mold steel, carbide and other difficult-to-machine workpieces. The electrode itself does not make the final part — but every micron of error, every tool mark and every corner radius on the electrode is replicated into the workpiece by the spark erosion process. In cnc machined electrode work for semiconductor and die-sinking applications, electrode quality is the ceiling on finished-part quality. Copper tungsten machining in particular is a demanding subset of edm electrode cnc milling because the material is exceptionally abrasive and unforgiving of process shortcuts. This electrode component is machined from **Copper Tungsten (CuW)**, a metal-matrix composite that combines the arc resistance and high melting point of tungsten with the electrical and thermal conductivity of copper. CuW electrodes hold their shape under high spark energy and produce fine detail without excessive wear — but the same hardness and abrasiveness that make them excellent electrodes make them punishing on cutting tools. The part is produced by **5-axis CNC milling + turning**, with all forming surfaces, reference datums and mounting shanks held to **±0.005 mm on critical dimensions**.
**Part:** Electrode Component
**Process:** 5-axis CNC milling + turning
**Material:** Copper Tungsten
**Tolerance:** ±0.005 mm on critical dimensions
**Inspection:** 100% CMM verification, full report with shipment
Challenges of This Part & How We Machined It
Severe tool wear on an abrasive composite
Copper tungsten is not a homogeneous metal; it is tungsten particles held in a copper matrix. The tungsten fraction is extremely hard and abrasive, and it wears carbide end mills at a rate that can be 5–10 times faster than tool steel. A tool that wears 0.02 mm mid-part produces an electrode that is undersized and out of tolerance — and since the electrode is the master for the EDM burn, that error transfers directly into the finished cavity. We account for tool wear by programming conservative tool-life limits based on measured wear rates in CuW, using wear-compensated finish passes, and verifying electrode dimensions on the CMM after every tool change. No electrode ships without dimensional verification after the finishing tool has completed its cut.
Fine ribs and thin-wall electrode features
EDM electrodes often carry fine ribs, deep narrow slots, or thin-wall projections that correspond to mold features. These small features deflect easily if cutting forces are too high, and a rib that is 0.01 mm off position at the tip will burn a mold feature that is 0.01 mm off at the cavity wall — an error that is invisible on the electrode until the mold is sampled. We use short, rigid micro-tools for rib machining, run at feed rates that keep chip load consistent, and take very light finishing passes to avoid deflecting thin projections. Electrode detail is verified under magnification and on the CMM.
Surface finish that replicates into the workpiece
EDM does not average out tool marks the way some machining processes do. A visible stepover line or a chatter mark on the electrode face is a negative of what appears on the burned cavity — and if the electrode has a rough finish, the EDM part must be polished longer, adding bench time and the risk of losing sharp corners. We finish electrode forming surfaces with tight stepovers and fine-pitch ball-end passes, avoiding tool changes on critical faces where possible. For high-gloss or optically critical burns, we can take additional finish passes or polish the electrode surface to a controlled Ra before shipment.
Machining Sequence
1. **CAM programming with tool-wear strategy** — toolpaths are programmed with CuW-specific wear rates in mind, and multiple semi-finish/finish passes are planned so that worn tools never take the last pass on a forming surface.
2. **CNC turning of electrode shank and datums** — the mounting shank, reference faces and any turned features are cut first, establishing the datums that the 5-axis mill references for the forming geometry.
3. **5-axis milling of electrode geometry** — roughing removes bulk stock with wear-resistant tooling; finish passes on forming surfaces are taken with fresh or compensated tools at minimal stepover.
4. **Deburring and edge prep** — sharp edges on non-working surfaces are broken; working edges are left intact per the drawing specification to preserve EDM detail.
5. **CMM inspection** — all forming geometry, feature positions and shank datums are verified on the CMM; electrode offsets (for EDM spark gap compensation) are noted on the inspection report where requested.
What You Get With Every Order
- **Free DFM review before quoting** — we flag manufacturability risk early, not after parts are made - **First Article Inspection report** with the first batch - **CMM dimensional report** on critical features - **Material certificates** for aerospace and medical grades - **Direct communication with the shop** — no trading company in between, we make the parts ourselves
Have a Drawing?
Send us your drawing or STEP file and we will come back with pricing within 48 hours. Prototype quantities and production runs both welcome — no minimum order quantity.
**TruPart Precision** trupartprecision.com | sales@trupartprecision.com WhatsApp: +86 137 1278 3205 No.114 Xinhua Road, Xinhe Dev Zone, Wanjiang, Dongguan, China