Not every piece of germanium needs to be a flat wafer. In the world of infrared optics, shaped elements—like arcs, domes, and asymmetrical blocks—are becoming increasingly common. These parts usually feed into custom lenses, beam splitters, or specialized window assemblies.
The challenge?
Cutting brittle, expensive Ge material into precise, non-flat geometries without introducing stress or fracture.
That’s where CNC diamond wire saws like the SGI20 step in. Unlike fixed-blade machines or ID saws, a programmable multi-axis wire saw can follow a defined curved path without contact pressure, and do it repeatably.
Why Arc-Shaped Germanium Is Difficult to Process
When cutting curved or angled Ge parts, you’re working against three things at once:
- The material’s low fracture toughness (it’s easy to chip)
- The need for dimensional precision at odd angles
- The desire to maximize usable yield from each ingot
Conventional saws typically rely on linear movement and fixed jigs, which don’t adapt well to multi-angle or non-planar shapes. Worse, trying to force a straight cut through a curved profile often leads to edge cracking or material waste.
CNC Diamond Wire Saws: A Better Approach for Complex Ge Geometry
Multi-axis diamond wire saws solve the problem in a few smart ways:
- Follow programmable paths (including arcs and compound angles)
- Keep the wire in constant tension and low-vibration motion
- Avoid localized heat or pressure that could stress the Ge crystal
- Produce thin kerfs (~0.35 mm) to minimize material loss
The result? Clean profiles, consistent radii, and surfaces that require minimal post-processing.
Real-World Case: SGI20 Cutting Arc-Shaped Germanium Blocks
One of our clients needed to slice a germanium crystal into a precisely curved shape for a custom thermal imaging application. Initial tests with conventional tools caused chipping along the arc and inconsistent edge smoothness.
After switching to the SGI20, and tuning the program for a controlled multi-angle cut:
- The arc-shaped Ge pieces came out clean and accurate
- No visible chipping at the start or end of the curve
- Machining accuracy exceeded ±0.03 mm across the full profile
Over time, the customer scaled production and placed three separate orders for SGI20 machines to support different shape and size requirements.
Video: SGI20 Cutting Curved Germanium Piece
Key Setup Tips for Shaped Ge Cutting
- Utilisation fine wire (0.3 mm) for narrow kerfs and lower stress
- Pre-program contour paths into CNC system with smooth transitions
- Adjust feed rate between 2-3 mm/min depending on arc radius
- Mount the Ge piece securely with flexible damping to avoid chatter
- Always use filtered water-based coolant to maintain edge clarity
Best Equipment Choice
- SGI20: Purpose-built for complex slicing, with gantry motion and CNC programmable pathing
- SGR15 (alternative): Also supports compound cuts but better for polyhedral shapes
- SG20 (for simpler arc cuts): A great option when rotation is not required but steady multi-slice precision is
Cutting arc-shaped germanium parts is not just possible—it’s practical with the right tools. CNC diamond wire saws like the SGI20 are making it easier than ever to machine complex Ge geometries while preserving material integrity and optical performance.
If you’re tired of cracking expensive Ge blanks on irregular cuts, it may be time to look at smarter slicing options. Reach out to Vimfun to see the SGI20 in action or request a sample cut for your next custom-shaped project.
