Germanium Lens Blank Cutting Machine
One machine that slices round blanks et prism-cuts polygons from germanium ingots — at a closed-loop wire kerf near 0.5 mm, so you keep the expensive material instead of grinding it into slurry.
A fully enclosed upright wire saw
Steel frame, observation window, side touchscreen — built to keep coolant mist and swarf contained on a working shop floor.
The SGR40 germanium lens blank cutting machine ships as a fully enclosed upright unit. The cabinet keeps coolant mist and swarf contained, and the observation window lets the operator watch the diamond wire and rotary fixture during a cut — useful when you're proving out a new prism angle.
- Empreinte ~1044 × 943 mm · height ~1970 mm
- Weight ~680 kg — rigid frame for low vibration
- Interface side touchscreen + handheld controller
- Cooling recirculating coolant with mist recovery
- Power 220 V three-phase · 1.5 kW
What the SGR40 germanium lens blank cutting machine does
Two motions — a servo YZ slicing stage and a programmable rotary table — give you round blanks and multi-faceted prism blanks from a single setup.
Multi-angle prism & polygon cutting
The rotary worktable indexes to any angle and produces triangles, squares, pentagons, octagons or nonagons — multi-faceted germanium blanks without re-clamping.
Automatic round-blank slicing
Set thickness and quantity on the touchscreen; the machine slices a Ge cylinder into discs unattended, and supports different thicknesses inside one job.
~0.5 mm closed-loop kerf
The endless diamond wire keeps the kerf near wire diameter — roughly $200–$600 of germanium saved per ingot versus a core drill.
Servo YZ motion, ±0.01 mm
Linear guides and ball screws on both axes give 0.01 mm feed resolution and ±0.01 mm repeatability for consistent blank thickness.
Enclosed frame + PLC touchscreen
Steel frame with an observation window, English-language PLC, and a handheld controller for manual alignment and override.
Water cooling + auto lubrication
Recirculating coolant with mist recovery and an automatic oiling system keep the cut clean and maintenance low.
See the SGR40 rotary wire saw in action
This walkthrough shows how the germanium lens blank cutting machine pairs an endless diamond wire with the programmable rotary worktable. Watch the servo-driven YZ axes, automatic tension control, and the rotating fixture index a workpiece between cuts to build a clean polygon in one program.
▸ Working principle — rotary prism & polygon cutting
▸ Slicing function — automatic round Ge blanks
Material in the working-principle clip is optical glass; germanium runs at a lower wire speed (30–45 m/s), but the motion sequence is identical. Request a germanium sample cut →
Why germanium kerf loss is the real number
A 200 mm germanium ingot is worth $6,000 to $10,000 at today's $1,800–$2,400/kg spot price. Run that ingot through a core drill and you lose 30–40% of it to kerf and edge chipping before a single surface is ground. The SGR40 germanium lens blank cutting machine goes straight at that loss with a closed-loop kerf near 0.5 mm.
The math we run for customers is simple. A core drill removes an entire cylindrical shell on every cut — typical bit kerf is 5 to 10 mm. Push that through a $2,200/kg ingot and you waste $11–$15 of germanium per cut. An ID saw does better on kerf (0.3–0.5 mm) but leaves a 30–80 µm subsurface damage layer the polisher grinds away later, plus concentric blade marks as the blade wears.
A closed-loop diamond wire runs unidirectionally, so there's no reversing pattern, the abrasive face refreshes as the loop circulates, and the kerf stays near the wire diameter. For germanium we run 0.35–0.5 mm wire, landing the kerf around 0.5 mm — $200–$600 of germanium kept per ingot. The process detail is on our découpe de flans de lentilles en germanium page.
Round blanks and prism blanks
Round lens blanks (puck slicing)
Program slice thickness and quantity, and the machine slices a germanium cylinder into discs automatically — mixing, say, 8 mm lens blanks and 3 mm window blanks in one run off the same rod. Cut surfaces come off the wire at Ra 0.6–1.2 µm with TTV around 8–15 µm over a 50 mm disc, flat enough that the grinder can usually skip a rough pass.
Square, polygonal and prism blanks
Enter a prism angle and the rotary table indexes the workpiece between cuts — triangle, square, pentagon, octagon or nonagon, in one setup. For beam-folding prisms, square window blanks, or polygonal blanks ground into non-circular optics, this avoids the wasteful "cut an oversized square, then grind it round" route that throws away germanium and chips at the corners.
Center the rotary table on the workpiece OD with a dial indicator before the first cut, or the polygon comes out asymmetric. Basic — but skip it and you'll scrap the first blank.
How does the 0.5 mm kerf compare to core drilling and ID saws?
Short version: the wire wins on material yield and surface quality; it loses on raw parts-per-hour against a multi-wire saw. Here's the honest comparison for germanium.
| Method | Kerf | Edge chipping | Subsurface | Pcs/cut |
|---|---|---|---|---|
| Core drill | 5–10 mm | 0,3–0,8 mm | high | 1 |
| ID saw | 0.3–0.5 mm | moderate | 30–80 µm | 1 |
| SGR40 closed-loop wire | ~0.5 mm | < 0,1 mm | low | 1 |
A 0.1 mm edge chip on the cut blank means the centering machine takes a 0.1 mm stock allowance instead of 0.5 mm — less germanium ground off, fewer passes. In our experience that downstream effect is bigger than the cutting-stage saving people focus on first.
The spec lists max wire speed at 59 m/s, but we run germanium at 30–45 m/s, feed 10–20 mm/min for slicing (4–8 mm/min on prism paths). Germanium cleaves on the {111} plane — it punishes aggressive feeds. Full material data is in Crystran's germanium datasheet.
Built for high-value brittle optics
The features that matter when the material on the table costs more than the cut.
SGR40 technical specifications
Standard-configuration numbers for the SGR40 germanium lens blank cutting machine. Worktable and travel can be customized for larger ingots.
| Worktable size | Ø 380 mm |
| Hauteur maximale de la pièce | 280 mm |
| Y / Z axis travel | 380 mm / 380 mm |
| Diamond wire diameter | 0.35–1.0 mm |
| Max wire linear speed | 59 m/s |
| Y / Z minimum feed | 0.01 mm |
| Y / Z repeatability | ±0,01 mm |
| Cutting / manual speed | 0–1000 mm/min (adjustable) |
| Rotary table | Yes — prism / polygon, any angle |
| Drive motor power | 1.5 kW |
| Power supply | 220 V, three-phase |
| Dimensions (L×W×H) | ~1044 × 943 × 1970 mm |
| Weight | ~680 kg |
| Cooling | Tank + recirculation + mist recovery |
Read cut-blank tolerances against your finished-lens drawing per normes de dessin optique ISO 10110 — the centering and grinding stages inherit whatever the cut leaves them.
Which brittle IR materials can it cut?
The wire cuts anything softer than diamond, so the SGR40 isn't germanium-only. We've run the following on the same platform, each with its own parameter set:
- Germanium (Ge) — 0.35–0.5 mm wire, 100–140 N tension, white mineral oil
- Silicon (Si) — mature, 0.42–0.5 mm wire
- Zinc selenide (ZnSe) & zinc sulfide (ZnS) — CO₂ laser and multispectral optics
- Saphir — 0.5–0.65 mm wire
- Optical glass (BK7 / K9) & fused quartz
Cutting something not on the list — chalcogenide glass, a specialty ceramic? Send a sample and we'll test-cut it before quoting parameters. We don't guess on materials we haven't run.
Where it fits in a germanium lens line
The SGR40 germanium lens blank cutting machine is the front end. It turns ingots into blanks; everything after — edge centering, spherical grinding, polishing, AR coating — works from the blank it produces. Because the wire leaves a consistent TTV and a low-damage surface, the downstream fixtures set up against known inputs instead of re-tuning every batch.
Building the whole chain rather than just the cutting station? The germanium lens manufacturing solution page lays out the five-stage workflow and how the tolerance budget flows station to station. For the full equipment range, start at the équipement de fabrication d'optique infrarouge hub.
The SGR40 does straight slices and rotary-indexed prisms — not free-form CAD contours (crescents, arbitrary curves); that's the SGI contour series. And if you only ever need round slices, the slicing-only germanium wafer slicing machine (SG40) is the cheaper choice. The rotary axis earns its keep only if you cut prisms or polygons.
Get a sample cut on your own germanium
Pick the SGR40 germanium lens blank cutting machine if your work mixes round blanks with prism or polygonal blanks and you want to stop losing material to wide kerf. Send your ingot diameter and length, target geometry, and monthly volume — we'll run a free test cut before you commit.
Vimfun · ISO 9001 · CE compliant · shipped to 20+ countries
Optics customers include Edmund Optics and Coherent.
Tel +1 (408) 571-8651 · daria@endlesswiresaw.com