Process & Material
Pure Tungsten Sinker EDM Feasibility Review
Pure Tungsten can be machined with Sinker EDM when the geometry matches blind cavities, ribs, shaped pockets, mold details, deep forms, and internal geometry that a traveling wire cannot reach. Pure Tungsten is a very high-melting refractory metal with high stiffness and brittle edge behavior at room temperature; the supplied condition affects support, discharge energy, finishing, and inspection.
Quick Answer
Sinker EDM is suitable for Pure Tungsten when the feature is a blind cavity, rib, pocket, or internal form that a shaped electrode can reach from one side. The supplied condition must be stated before tolerance and surface requirements are confirmed.
Key Material Decisions
How This Material Behaves
A very high-melting refractory metal with high stiffness and brittle edge behavior at room temperature. In Sinker EDM, the supplied condition changes electrode wear, cavity-floor consistency, corner growth, and the finishing strategy—especially on deep ribs and textured surfaces.
Choosing the Right Condition
Choose Sinker EDM for blind cavities, ribs, shaped pockets, mold details, deep forms, and internal geometry that a traveling wire cannot reach. State the exact Pure Tungsten condition, then set tolerance, finish, support, and inspection from the controlled feature rather than the whole part.
Risks to Manage
For Sinker EDM, sharp cavity corners and floors are the main concern because repeated thermal cycling can create subsurface cracking even without cutting force. Where debris collects at a cavity root or sharp internal corner, orbit, local heating and electrode wear can shift wall size while dishing the floor, with the highest consequence at grain boundaries, brittle rims and subsurface damage zones. The Pure Tungsten feature may therefore show floor or corner cracking, grain pullout or phase-selective erosion in the cavity. For Pure Tungsten, use conservative discharge energy, strong local support and microscopic inspection of edges and subsurface damage. Compare the roughing electrode, finish electrode and final cavity rather than relying on nominal electrode size; document geometry, chipping, grain pullout and subsurface cracking for Pure Tungsten.
How Sinker EDM Works on Pure Tungsten
Sinker EDM reproduces a shaped electrode as a blind cavity in Pure Tungsten. Electrode material, wear, orbit, pulse energy and debris evacuation control wall size, floor depth, corner definition and surface condition. Where final size or texture is critical, roughing and finishing electrodes should be planned as separate operations.
Sinker EDM Capability Reference
| What you're asking | What you can expect |
|---|---|
| Feature types | blind cavities, ribs, shaped pockets, mold details, deep forms, and internal geometry that a traveling wire cannot reach |
| Tolerance | ±0.008–0.030 mm |
| Surface finish | Ra 0.2–6.3 μm |
| Electrode choice | Graphite or copper selected from cavity, finish, and wear needs |
| Primary cavity limit | Depth, rib width, access, and debris evacuation |
| Main limitation | Electrode access and debris evacuation limit deep, narrow blind geometry. |
Material Condition Reference
| Condition | What to expect | Watch out for | Surface notes |
|---|---|---|---|
| as-sintered or supplied condition | Use low-force fixturing and conservative discharge energy. | Brittle edges can chip or binder-rich zones can erode unevenly. | Inspect edge breakout and surface integrity rather than Ra alone. |
| stress-relieved or recrystallized | Use stable support and reduced energy on finished stock. | Grinding stress or porosity can cause local cracking. | Apply selective polishing or lapping where practical. |
How This Material Behaves
Pure tungsten is extremely refractory, stiff, and brittle. In EDM, this means sharp edges and thin sections can chip or microcrack under thermal shock even though no cutting force is applied. Use conservative pulse energy, avoid abrupt section changes where possible, and inspect critical edges by microscopy after final finishing. For Sinker EDM, sharp cavity corners and floors are the main concern because repeated thermal cycling can create subsurface cracking even without cutting force.
Surface Integrity and Post-Process
For Sinker EDM on Pure Tungsten, use conservative energy, strong support and inspection focused on edge chipping and subsurface damage. Use roughing and finishing electrodes separately where cavity size or texture is controlled. Apply polishing, lapping or recast removal only to named functional faces, and inspect wall, floor and corner condition after the final surface operation.
Pure Tungsten Sinker EDM Checkpoints
- Confirm that the feature matches blind cavities, ribs, shaped pockets, mold details, deep forms, and internal geometry that a traveling wire cannot reach.
- State the supplied condition: as-sintered or supplied condition and stress-relieved or recrystallized.
- Mark the controlled dimensions, functional surfaces, datum scheme, and inspection method.
Typical Parts and Features
- wear inserts
- high-temperature contacts
- hard-metal nozzles
- mold cavities
- blind pockets
- deep ribs
Limits and Better Alternatives
Main Limit
Electrode access and debris evacuation limit deep, narrow blind geometry. On Pure Tungsten, edge chipping and subsurface damage require strong support and low-energy finishing; the supplied condition still controls support, finishing, and surface-integrity review.
Consider Another Route When
Use Wire EDM for through profiles, CNC machining for open cavities with tool access, or grinding for simple flat precision surfaces.
Practical Next Step
Send the Pure Tungsten drawing with condition, controlled geometry, tolerance, functional surface callouts, quantity, and inspection requirements. If the route is unclear, we will compare Sinker EDM with the adjacent EDM or conventional process.
Practical Takeaway
Pure Tungsten is compatible with Sinker EDM when the feature matches the process access. The supplied condition determines support, finishing, surface control, and inspection.
Technical Reference
Use the values as planning references and define the functional requirement on the controlled drawing.
Use This Guide to Prepare Your RFQ
Contact us when your drawing and requirements are ready for review.
- Process: Sinker EDM
- Material: Pure Tungsten
- Drawing or part sketch
- Material grade
- Thickness / part size
- Quantity
STEP/STP, DXF, DWG, PDF, IGS/IGES or ZIP.
Confidential drawing review. NDA support available on request.