Single Point Diamond Turning Service
Custom aspheric mirrors, IR lenses, freeform surfaces, and micro-lens arrays — machined to <5 nm RMS roughness with λ/20 form accuracy. Prototype to production, 5–14 day lead time.
- SPDT machines optical surfaces to <5 nm RMS roughness and λ/20 form accuracy — no grinding or polishing required.
- Compatible with metals (aluminum, copper, electroless nickel), optical plastics (PMMA, polycarbonate, Zeonex), and IR crystals (germanium, ZnSe, silicon).
- Prototype turnaround in 5–14 days with zero tooling cost — 3× faster than conventional optical grinding.
- Slow-slide servo and fast-tool servo modes enable freeform, non-rotationally symmetric geometries impossible with standard lathes.
- KUSLA delivers prototype-to-production continuity: the same material and surface spec from first article through 1,000+ piece runs.
What Is Single Point Diamond Turning?
Single point diamond turning (SPDT) is an ultra-precision CNC machining process where a single-crystal diamond cutting tool removes material from a rotating workpiece at the nanometer scale. The workpiece spins on an air-bearing spindle while the diamond tool follows a computer-controlled path, generating optical-quality surfaces directly from the machine — without grinding or polishing.
The diamond tool's cutting edge has a radius as small as 100 nm, with advanced tooling reaching 10–30 nm. This edge geometry, combined with hydrostatic or aerostatic bearing spindles and nanometer-resolution linear axes, produces surface roughness 100–1,000× finer than conventional CNC turning (which typically achieves 0.2–0.8 μm Ra).
How SPDT Differs from CNC Turning
Conventional CNC turning uses carbide or HSS inserts and achieves ~1 μm accuracy with Ra ~0.2 μm. Diamond turning uses a single-crystal diamond on air-bearing spindles with nanometer-resolution feedback, producing optical-quality surfaces (Ra <10 nm) directly — no post-polishing needed. The material removal mechanism is micro-shearing rather than bulk shearing.
Equipment: 2-Axis to 5-Axis Lathes
SPDT machines range from 2-axis (rotationally symmetric parts) to 5-axis configurations (complex freeform surfaces). Positioning accuracy reaches 100 nm. Machine precision depends on bed stability, spindle guide rail quality, control system resolution, and environmental isolation — KUSLA Prototype operates in a temperature-controlled cleanroom (±0.1 °C).
Why Engineers Choose KUSLA for Diamond Turning
Nanometer-Level Precision
Surface roughness down to 1 nm RMS and surface figure accuracy of λ/20. KUSLA Prototype produces optics meeting MIL-PRF-13830B requirements directly off the machine.
Zero Tooling Cost
The tool path is programmed directly from your CAD file — no molds, custom fixtures, or upfront tooling fees. Design changes cost only reprogramming time.
5–14 Day Lead Time
Prototypes ship in as few as 5 business days. Standard lead time is 7–14 days — 3× faster than the 4–8 weeks typical of conventional optical grinding and polishing.
Prototype-to-Production Material Match
Optical polymers (PMMA, polycarbonate, Zeonex) can be diamond-turned directly, letting you prototype in the same material used for injection-molded production optics.
Complex Geometry Capability
Slow-slide servo (SSS) and fast-tool servo (FTS) modes enable freeform surfaces, toroidal profiles, micro-lens arrays, and non-rotationally symmetric geometries.
Full Post-Processing In-House
Gold, silver, aluminum, UV, and AR coatings. Anodizing, electroless nickel plating, and diamond-like carbon (DLC) coatings — all under one roof, no outsourcing delays.
Types of Diamond Turning KUSLA Prototype Offers
Each method addresses different geometric requirements — selecting the right one at the design stage avoids unnecessary cost and lead time.
On-Axis Turning
Workpiece and optical axis are coaxial. Produces rotationally symmetric components: spherical lenses, aspheric lenses, plano-convex mirrors, and cylindrical optics.
Best for: standard IR lenses, collimating optics, spherical mirrors
Off-Axis Turning
Optical axis is offset from the spindle axis. Produces off-axis parabolic (OAP) mirrors, off-axis elliptical (OAE) mirrors, and toroidal reflectors for systems requiring unobstructed beam paths.
Best for: IR spectrometers, telescope fore-optics, laser beam delivery
Fly-Cutting
The diamond tool rotates on a spindle while the workpiece translates linearly beneath it. Generates high-quality flat surfaces on large substrates without the curvature artifacts of rotational methods.
Best for: flat mirrors, optical windows, reference flats, scanner polygons
Freeform / Servo Machining
Slow-slide servo (SSS) or fast-tool servo (FTS) dynamically adjusts tool position during each spindle revolution to create non-rotationally symmetric surfaces.
Best for: freeform mirrors, lenticular arrays, micro-lens arrays, Alvarez lenses
Diamond Turning Capabilities by Optic Type
| Optic Component | Typical Material | Surface Figure (RMS) | Scratch-Dig | Roughness (RMS) | Coatings |
|---|---|---|---|---|---|
| Off-Axis Parabolic Mirror (OAP) | 6061-T6 Aluminum | λ/20 | 60-40 | <5 nm | Gold, UV Enhanced Al |
| Flat Metal-Coated Mirror | Aluminum / Fused Quartz | λ/10 | 40-20 | <5 nm | Gold, Silver, Protected Al |
| Reflective Beam Expander | 6061-T6 Aluminum | λ/10 | 60-40 | <5 nm | Gold, Protected Al |
| Hollow Retroreflector | K9 Glass / Aluminum Alloy | λ/10 | 40-20 | <5 nm | Gold, Silver, Protected Al |
| Aspheric IR Lens | Germanium / ZnSe / Silicon | λ/10 | 40-20 | <5 nm | AR (3–5 μm or 8–12 μm) |
| Micro Lens / Lens Array | Acrylic (PMMA) | λ/4 | 60-40 | <20 nm | AR, Hard Coat |
| Freeform Metal Mirror | Electroless Nickel / Al | λ/8 | 60-40 | <10 nm | Gold, Enhanced Al |
| Diffractive Optical Element | Germanium / ZnSe / PMMA | λ/4 | 60-40 | <10 nm | AR Coating |
Diamond Turning vs. Conventional Optical Fabrication
SPDT and conventional grinding/polishing each serve distinct use cases. This comparison helps engineers decide which process fits their project requirements.
| Factor | Single Point Diamond Turning | Conventional Grinding & Polishing |
|---|---|---|
| Surface roughness | 1–10 nm RMS | 0.3–1 nm RMS (best case) |
| Form accuracy | λ/20 RMS achievable | λ/20 RMS achievable |
| Prototype lead time | 5–14 days | 4–8 weeks |
| Tooling cost | None — programmed tool path | Custom lap / polishing tools |
| Complex geometry | Aspheric, freeform, DOE — native | Limited; requires MRF or IBF |
| Material range | Metals, plastics, IR crystals | Glass, crystal, ceramic |
| Post-processing | Usually none | Polishing always required |
| Best for | Prototypes, short runs, IR optics, aspheres | High-volume glass optics, UV/DUV |
Not sure if your optic design is diamond-turnable? Send your CAD file or optical prescription for a free DFM review and material recommendation.
Submit Your DesignIndustries Served by KUSLA Prototype Diamond Turning
Aerospace & Defense
OAP mirrors and aspheric reflectors for missile guidance seekers, airborne FLIR pods, space telescope fore-optics, HUDs, and Schlieren imaging. Diamond-turned aluminum mirrors offer significant weight savings over glass equivalents.
OAP mirrors, HUD reflectors, seeker optics
Infrared & Thermal Imaging
Aspheric germanium, ZnSe, and silicon lenses for thermal cameras operating in the 3–5 μm (MWIR) and 8–12 μm (LWIR) atmospheric windows. SPDT is the standard production method for IR optics due to the brittleness and expense of these materials.
FLIR lenses, thermal camera optics, spectroscopy windows
Medical Devices
Precision polymer lenses for endoscope illumination, ophthalmic diagnostic instruments, surgical microscopes, and OCT systems. Prototyping in the final production material (PMMA, Zeonex) accelerates design iteration.
Endoscope lenses, OCT optics, diagnostic housings
Laser Systems
Reflective beam expanders, focusing mirrors, and cavity optics for CO₂ lasers, quantum cascade lasers (QCLs), and high-power fiber laser delivery. Metal mirrors withstand higher power densities than coated glass optics.
Beam expanders, cavity mirrors, focusing reflectors
Telecom & LiDAR Sensors
Micro-lens arrays for fiber coupling, LiDAR sensor optics, collimating elements for laser diodes, and freeform optics for compact sensor modules in autonomous vehicles.
Fiber couplers, LiDAR lenses, sensor modules
Automotive Lighting
Freeform reflectors and light-guide lens arrays for LED headlamp modules, DRL optics, and interior ambient lighting. Diamond-turned mold inserts enable mass-production injection molding of complex automotive lighting optics.
Headlamp reflectors, DRL optics, mold inserts
Materials for Single Point Diamond Turning
Metals
- Aluminum 6061-T6
- OFHC Copper (Cu)
- Electroless Nickel (NiP)
- Brass
- Stainless Steel (limited)
- Titanium (Ti)
Optical Plastics
- Acrylic (PMMA)
- Polycarbonate (PC)
- Polystyrene (PS)
- Zeonex / Zeonor (COP)
- TOPAS (COC)
- Ultem (PEI)
IR Crystals
- Germanium (Ge)
- Silicon (Si)
- Zinc Selenide (ZnSe)
- Zinc Sulfide (ZnS / Cleartran)
- Calcium Fluoride (CaF₂)
- Indium Antimonide (InSb)
Chalcogenide Glasses
- AMTIR-1 / AMTIR-2 / AMTIR-4
- GASIR-1 / GASIR-5
- IRG-22 / IRG-24 / IRG-26
- IG-6 (Schott)
- BD-2 / 1173
From CAD File to Finished Optic: KUSLA Prototype SPDT Workflow
Every diamond turning project follows a structured workflow to deliver on-spec optics on the first iteration.
Design Review & DFM
Optical engineers review your CAD model or optical prescription. Manufacturability issues (aspect ratio limits, minimum tool radius) are flagged with DFM optimizations.
Material Sourcing
Certified optical-grade blanks procured from qualified suppliers. For IR crystals, material certificates with transmission data are provided.
Tool Path Programming
Proprietary compensation algorithms generate the diamond tool path accounting for tool geometry, thermal drift, and material spring-back.
Rough & Fine Turning
Rough turning shapes the blank to within 0.5 mm of final dimensions. The diamond-tipped tool then performs fine turning to reach nanometer-level finish in a temperature-controlled cleanroom (±0.1 °C).
Metrology & Inspection
Every part is measured: Zygo interferometer (surface figure), white-light profilometer (roughness), CMM (dimensions). Full test reports ship with your parts.
Coating & Delivery
Optional thin-film coating (AR, gold, silver, DLC) and mechanical assembly performed in-house. Cleanroom-packaged shipment worldwide.
Diamond Turning DFM Tips & Process Challenges
Practical guidance from KUSLA Prototype's SPDT production floor — these factors directly affect surface quality, cycle time, and cost.
Process Tips from Our Shop Floor
Metal cutting uses liquid coolant at the contact point to manage thermal expansion. Plastic cutting uses compressed air only — liquid coolant damages polymer surfaces and causes haze.
Room temperature is held at 20 °C ± 0.5 °C. Part temperature is controlled to 20 °C ± 0.05 °C via constant-temperature liquid spray — thermal drift is the leading source of form error.
Diamond turning machines must be isolated from all mechanical vibration and acoustic noise. Any external vibration source directly translates to surface roughness degradation.
The machining room must meet at least ISO Class 7 (10,000 level) cleanliness. Dust particles on the workpiece during cutting create surface defects visible under interferometric inspection.
Known Challenges & Limitations
SPDT works best with non-ferrous metals and optical plastics. Ferrous materials (steel, cast iron) cause rapid diamond tool wear through chemical affinity — carbon in the diamond reacts with iron at cutting temperatures. Electroless nickel plating is the standard workaround for steel substrates.
Despite being the hardest material, diamond edges degrade when cutting tough or chemically reactive substrates. KUSLA Prototype inspects tool condition at set intervals and replaces tools proactively — a worn tool produces mid-spatial-frequency (MSF) errors that compound across the surface.
Polycarbonate (PC) tends to produce burrs during diamond turning due to its high ductility. These typically require a secondary polishing step, adding cost and lead time. PMMA and Zeonex cut cleaner and are preferred for diamond-turned plastic optics.
The precision environmental controls (temperature, vibration, cleanliness) and specialized equipment make SPDT setup costs higher than conventional CNC. For parts that do not require optical-grade surfaces, standard CNC turning is more cost-effective.
Diamond-Turned Optics by KUSLA Prototype
Representative examples from production — OAP mirrors, flat mirrors, freeform reflectors, aspheric IR lenses, and micro-lens arrays. Prototype and production batches of 1,000+ pieces.
Frequently Asked Questions
Single point diamond turning is an ultra-precision CNC machining process that uses a single-crystal diamond tool to cut optical surfaces on a rotating workpiece. It achieves nanometer-level surface roughness (typically <10 nm RMS) and sub-micrometer form accuracy, making it the preferred method for producing aspheric lenses, off-axis parabolic mirrors, freeform optics, and infrared optical components.
Surface roughness of 1–10 nm RMS, surface figure accuracy of λ/20 RMS (at 632.8 nm), and dimensional tolerances within ±1 μm. Surface quality typically reaches 40-20 or 60-40 scratch-dig per MIL-PRF-13830B.
A single diamond-turned optic prototype typically costs $800–$5,000 depending on material, diameter (up to 300 mm), geometry complexity, and surface finish requirements. No tooling charge is required, which makes SPDT more cost-effective than glass grinding and polishing for prototypes and short runs.
Standard prototypes ship in 7–14 business days. Simple rotationally symmetric parts may ship in as few as 5 days. Production runs of 50+ pieces are quoted individually based on geometry and material.
Metals (aluminum 6061-T6, copper, electroless nickel, brass), plastics (PMMA, polycarbonate, polystyrene, Zeonex, TOPAS), and infrared crystals (germanium, silicon, zinc selenide, zinc sulfide, calcium fluoride, chalcogenide glasses). Glass cannot be diamond turned directly but can be processed via diamond-turned mold inserts for glass press molding.
Yes — SPDT is the industry-standard method for manufacturing IR optics. KUSLA Prototype diamond turns germanium, silicon, ZnSe, ZnS, CaF₂, and chalcogenide glasses to produce IR lenses, windows, and mirrors for thermal imaging, FLIR, spectroscopy, and laser systems operating across 1–14 μm wavelengths.
In most cases, no. Diamond turning produces mirror-like surface finishes with roughness below 10 nm RMS directly from the machine. Secondary polishing is only required for specific materials like polycarbonate (which tends to burr) or when sub-nanometer roughness is needed for UV/DUV applications.
Conventional CNC achieves ~1 μm accuracy and Ra ~0.2 μm surface roughness. Diamond turning achieves 100–1,000× finer results: sub-nanometer roughness and sub-micrometer form accuracy. SPDT uses a single-crystal diamond tool on aerostatic bearing spindles with nanometer-resolution feedback, producing optical-quality surfaces with no post-polishing required.
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