Process & Material
Titanium Grade 2 Small Hole EDM Drilling High Precision Tolerance + Fine Finish Review
This Titanium Grade 2 Small Hole EDM page combines a High-precision tolerance target with a Fine surface target. These requirements must be planned together because finishing passes improve texture while also changing profile offset, cavity size, hole size, or edge geometry.
Quick Answer
For Titanium Grade 2, ±0.005–0.010 mm and Ra 0.8–1.6 μm are achievable on selected Small Hole EDM features when electrode runout, flushing, breakthrough support, and the finishing sequence are planned together. Apply both targets from the same datum, and reserve the tightest values for the dimensions and faces that control function.
Key Quality Decisions
What These Targets Mean
On Titanium Grade 2, ±0.005–0.010 mm controls the named dimensions and Ra 0.8–1.6 μm controls the named functional faces. In Small Hole EDM, diameter, straightness, wall condition, and breakthrough respond differently to electrode wear and finishing energy. The supplied condition adds a separate risk: thin sections can move and corrosion or medical surfaces need selective recast removal and cleanliness.
Getting Both Targets Right
Use one machining and inspection datum. Apply ±0.005–0.010 mm only to dimensions that control fit, and Ra 0.8–1.6 μm only to functional faces. Plan electrode diameter, true path depth, aspect ratio, flushing, rotation, straightness, and breakthrough support. State the exact Titanium Grade 2 condition and the inspection method before releasing the result.
What Gets Missed
On a deep small hole specified at ±0.005–0.010 mm and Ra 0.8–1.6 μm, entry diameter can pass while exit diameter, straightness, or breakthrough position fails. The tolerance represents a small remaining offset allowance, while the finishing pass removes enough stock to change edge radius and local size; treating them as independent callouts can make the last finishing step destroy the dimension it is meant to improve. Inspect entry, exit, taper, straightness, and hole-wall condition after the final surface step. For Titanium Grade 2, also account for this material-specific risk: thin sections can move and corrosion or medical surfaces need selective recast removal and cleanliness.
How the Targets Interact
For Titanium Grade 2, ±0.005–0.010 mm and Ra 0.8–1.6 μm are linked through the Small Hole EDM finishing route. Diameter, straightness, wall condition, and breakthrough respond differently to electrode wear and finishing energy. The release plan must bind material condition, geometry, datum, finishing stage, and measurement to the same named features.
Small Hole EDM Capability Reference
| What you're asking | What you can expect |
|---|---|
| Feature types | small through holes, deep holes, angled holes, cooling holes, vent holes, and start holes in hard or heat-resistant alloys |
| Tolerance | ±0.010–0.050 mm |
| Surface finish | Hole-wall finish is feature-dependent |
| Typical diameter | About 0.3–3.0 mm for ordinary planning |
| Depth driver | Depth-to-diameter ratio, straightness, and breakthrough |
| Main limitation | Very small diameter combined with extreme depth may require specialized equipment, staged electrodes, and dedicated metrology. |
Quality Target Reference
| Requirement | Planning range | What it means in practice |
|---|---|---|
| High-precision tolerance | ±0.005–0.010 mm | Plan finishing passes, thermal stability and inspection from the same datum scheme. |
| Fine finish | Ra 0.8–1.6 μm | Usually needs a finishing pass or lower-energy discharge on the specified surface. |
Material Condition Reference
| Condition | What to expect | Watch out for | Surface notes |
|---|---|---|---|
| annealed | Use stable support and low-energy finishing. | Thermal surface effects can reduce fatigue resistance. | Specify recast and edge condition on fatigue and medical faces. |
| stress-relieved | Plan around stress relief and thin-wall movement. | Residual stress can distort delicate profiles. | Use trim passes and controlled post-processing on critical faces. |
Tolerance & Surface Requirements
For Small Hole EDM at ±0.005–0.010 mm and Ra 0.8–1.6 μm, apply the finish only to the faces named on the drawing. On Titanium Grade 2, use low-energy finishing and define whether recast removal, polishing or passivation is required. Roughness does not replace recast, edge, corrosion, crack, or post-process acceptance where those items affect function.
Titanium Grade 2 Small Hole EDM Quality Checkpoints
- Mark the dimensions that actually need ±0.005–0.010 mm and use the same datum for machining and inspection.
- Circle the faces that need Ra 0.8–1.6 μm; leave nonfunctional surfaces at a practical production finish.
- State the Titanium Grade 2 condition, Small Hole EDM finishing strategy, measurement method, and any recast or edge requirement.
Limits and Better Alternatives
Main Limit
±0.005–0.010 mm and Ra 0.8–1.6 μm are selected-feature planning references for Titanium Grade 2 in Small Hole EDM, not unconditional whole-part guarantees.
Consider Another Route When
Use mechanical drilling for accessible easy-cutting material, laser drilling for suitable thin high-volume parts, or Micro EDM for smaller precision features.
Practical Next Step
Send the Titanium Grade 2 drawing with the Small Hole EDM features that need ±0.005–0.010 mm, the faces that need Ra 0.8–1.6 μm, the supplied condition, quantity, datums, and inspection method.
Practical Takeaway
On Titanium Grade 2, plan ±0.005–0.010 mm and Ra 0.8–1.6 μm together for the selected Small Hole EDM features. Use one datum and one inspection plan, and apply the tightest values only where they control function.
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: Small Hole EDM
- Material: Titanium Grade 2
- 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 Small Hole EDM hold the selected tolerance on Titanium Grade 2?
Use ±0.005–0.010 mm as a selected-feature planning reference. The confirmed result depends on material condition and geometry. Process control covers electrode diameter, true hole depth, depth-to-diameter ratio, tubular-electrode wear, flushing pressure, breakthrough quality, and hole-wall inspection. Machining and inspection should use one consistent datum.
Should Ra 0.8–1.6 μm apply to every surface?
No. Apply the fine finish only to functional faces. Other areas can remain at a practical production finish, which reduces cycle time and avoids unnecessary processing.
How does the condition of Titanium Grade 2 affect both targets?
Titanium Grade 2 is a commercially pure titanium grade with lower strength and higher ductility than alpha-beta Grade 5. The condition changes support, stress response, finishing energy, dimensional stability, and surface-integrity planning.
What should the drawing identify?
Identify the dimensions that need ±0.005–0.010 mm, the faces that need Ra 0.8–1.6 μm, the datums, the exact Titanium Grade 2 condition, the Small Hole EDM feature, and the inspection method. Machining and inspection should use the same datum scheme.