Process & Material
Kovar Micro EDM Feasibility Review
Kovar can be machined with Micro EDM when the geometry matches micro holes, micro slots, miniature cavities, fine pins, and sub-millimeter precision details. Kovar is a controlled-expansion iron-nickel-cobalt alloy used where metal-to-glass or ceramic expansion matching matters; the supplied condition affects support, discharge energy, finishing, and inspection.
Quick Answer
Micro EDM is suitable for Kovar when the feature is a micro hole, micro slot, miniature cavity, fine pin, or other sub-millimeter detail. The supplied condition must be stated before tolerance and surface requirements are confirmed.
Key Material Decisions
How This Material Behaves
A controlled-expansion iron-nickel-cobalt alloy used where metal-to-glass or ceramic expansion matching matters. In Micro EDM, the supplied condition directly changes discharge stability, electrode wear, edge quality, and the finishing plan—especially at micro scale.
Choosing the Right Condition
Choose Micro EDM for micro holes, micro slots, miniature cavities, fine pins, and sub-millimeter precision details. State the exact Kovar condition, then set tolerance, finish, support, and inspection from the controlled feature rather than the whole part.
Risks to Manage
For Micro EDM, Thermal history, sealing faces and contamination control must be preserved because they affect glass-to-metal or ceramic-to-metal sealing performance. When the electrode, spark gap and material structure approach the feature scale, micro-flushing instability can alter both local surface condition and the effective feature boundary; the interaction is most important at temperature-sensitive datums and low-expansion geometry. For Kovar, this can produce apparent feature error produced by temperature drift, electrode wear and limited measurement resolution. For Kovar, stabilize workpiece and inspection temperature, finish from controlled datums, and measure only after the part has thermally settled. Use calibrated electrodes and metrology that resolves the actual remaining tolerance; document stabilized geometry, datum relationship and inspection temperature for Kovar.
How Micro EDM Works on Kovar
Micro EDM uses a very small electrode and low discharge energy to machine miniature features in Kovar. Electrode wear, spark-gap stability, micro-flushing, temperature control and measurement resolution consume a significant share of the available tolerance. The local feature size and aspect ratio—not the overall workpiece size—must define the route.
Micro EDM Capability Reference
| What you're asking | What you can expect |
|---|---|
| Feature types | micro holes, micro slots, miniature cavities, fine pins, and sub-millimeter precision details |
| Tolerance | ±0.002–0.010 mm |
| Surface finish | Ra 0.1–1.6 μm |
| Feature scale | Sub-millimeter holes, slots, and cavities |
| Primary micro limit | Electrode wear and measurement resolution |
| Main limitation | Loose-tolerance or easily accessible features are rarely economical with Micro EDM. |
Material Condition Reference
| Condition | What to expect | Watch out for | Surface notes |
|---|---|---|---|
| solution annealed | Use stable support and conservative energy. | High-temperature alloys can retain a hard recast layer. | Identify fatigue and hot-section faces before finishing. |
| cold-worked or stabilized | Account for cold-work and service stress. | Thin features can move and electrode wear can grow corners. | Use low-energy finishing and selective metallurgical inspection. |
How This Material Behaves
Kovar is an iron-nickel-cobalt alloy chosen for controlled thermal expansion in glass or ceramic seals. In EDM, this means sealing edges can be dimensionally correct yet unusable if recast, contamination, or residual stress disrupts the later joining process. Use clean finishing passes, protect seal surfaces from handling damage, and define post-EDM cleaning and inspection before brazing or sealing. For Micro EDM, Thermal history, sealing faces and contamination control must be preserved because they affect glass-to-metal or ceramic-to-metal sealing performance. At micro scale, phase condition, recast and tool wear can be comparable with the remaining dimensional and surface-integrity allowance.
Surface Integrity and Post-Process
For Micro EDM on Kovar, use lower-energy finishing and inspect critical surfaces when fatigue, sealing or corrosion performance is specified. Use low-energy finishing and account for electrode replacement or calibration before final sizing. Specify edge, recast and post-process requirements only on functional microfeatures, and use metrology that can distinguish true size from edge rounding and surface residue.
Kovar Micro EDM Checkpoints
- Confirm that the feature matches micro holes, micro slots, miniature cavities, fine pins, and sub-millimeter precision details.
- State the supplied condition: solution annealed and cold-worked or stabilized.
- Mark the controlled dimensions, functional surfaces, datum scheme, and inspection method.
Typical Parts and Features
- turbine and energy features
- corrosion-resistant inserts
- precision seals
- micro holes
- micro slots
- miniature cavities
Limits and Better Alternatives
Main Limit
Loose-tolerance or easily accessible features are rarely economical with Micro EDM. On Kovar, thermal history, sealing faces and contamination control are more important than generic alloy-steel wording; the supplied condition still controls support, finishing, and surface-integrity review.
Consider Another Route When
Use conventional EDM for larger features, precision laser processing for suitable thin geometry, or mechanical micro-drilling where a tool can reach.
Practical Next Step
Send the Kovar drawing with condition, controlled geometry, tolerance, functional surface callouts, quantity, and inspection requirements. If the route is unclear, we will compare Micro EDM with the adjacent EDM or conventional process.
Practical Takeaway
Kovar is compatible with Micro EDM when the feature matches the process access. The supplied condition determines support, finishing, surface control, and inspection.
Additional Project Information
Include application, destination and end-use notes together with the material, quantity and drawing requirements.
Project Details for Technical Review
Include application and end-use notes when they affect material, inspection, documentation, or export review.
- Process: Micro EDM
- Material: Kovar
- Drawing or part sketch
- Material grade
- Thickness / part size
- Quantity
- Tolerance and critical dimensions
- Surface finish or inspection requirement
STEP/STP, DXF, DWG, PDF, IGS/IGES or ZIP.
Confidential drawing review. NDA support available on request.
Frequently Asked Questions
Can Kovar be machined with Micro EDM?
Yes, when the feature is a micro hole, micro slot, miniature cavity, fine pin, or other sub-millimeter detail. Kovar is electrically conductive and the final route follows the feature geometry and supplied condition.
What controls Micro EDM on Kovar?
The main process controls are electrode wear, feature-to-electrode ratio, micro-flushing, aspect ratio, edge radius, thermal stability, and measurement resolution. The Kovar condition adds dimensional-stability and surface-integrity requirements.
What is the main risk?
For Micro EDM, Thermal history, sealing faces and contamination control must be preserved because they affect glass-to-metal or ceramic-to-metal sealing performance. When the electrode, spark gap and material structure approach the feature scale, micro-flushing instability can alter both local surface condition and the effective feature boundary; the interaction is most important at temperature-sensitive datums and low-expansion geometry. For Kovar, this can produce apparent feature error produced by temperature drift, electrode wear and limited measurement resolution. For Kovar, stabilize workpiece and inspection temperature, finish from controlled datums, and measure only after the part has thermally settled. Use calibrated electrodes and metrology that resolves the actual remaining tolerance; document stabilized geometry, datum relationship and inspection temperature for Kovar.
What should I send for review?
Send the drawing, exact Kovar condition, controlled geometry, tolerance, functional surface requirements, quantity, and inspection expectations. If any item is undecided, send what you have and we will help complete the review.