Custom windows
Protective and transmitting windows built around the housing, pressure, abrasion, and wavelength requirements.
Up to 8″ in diameterProductsSapphire Components
Custom Sapphire Components.
IRD manufactures to your print. Send the drawing with the environment, the clear aperture, the chip and finish specifications you can accept, and how each one is measured, and the technical team reviews it for manufacturability before quoting. For a new design that review is free of charge.
What we manufacture
Hardness is only the starting property. Geometry, edge condition, polish, and coating determine whether the part integrates cleanly.
Lenses and optics
Optical sapphire surfaces processed for sensors, radiometry, laser, and imaging applications, with coatings from UV through IR.
Tubes and shapes
Machined sapphire geometry for mechanical, wear, and precision-engineering functions where the part is structural as well as transmitting.
Double-side processing
Double-side lapping and polishing for efficient yield, exemplary parallelism, and controlled flatness across both faces at once.
Process capability
Manufacturing limits by process
These are IRD's published capability limits across materials and geometries, not a grade every part ships to. Open the process that controls your critical surface and quote against that one.
Sapphire programs combine hard-material machining with optical finishing. These ranges frame the first manufacturability conversation.
| Attribute | Typical | Best case |
|---|---|---|
| Window diameterCustom sapphire windows | Print-defined | Up to 8″ |
| FlatnessSingle- or double-side polished faces | 1/4 wave | 1/10 wave |
| MachiningMounting features, profiles, and custom geometry | ±.005″ dimension | ±.0001″ |
| PolishingOptical faces and performance-critical surfaces | Ra < 1 µin | Ra < 2 Å |
| LappingSeals, spacers, and precision interfaces | ±.000050″ flatness | ±.000010″ |
Specifying sapphire
Sapphire is second only to diamond in hardness, and brittle with it. IRD's published super-hard design guidance names the specification habits that raise cost or make a part unbuildable, and what to write instead.
A chip specification is a number, not the word none
Sapphire is brittle, and any chip can be found by raising the inspection microscope's magnification far enough, so a drawing that says no chips cannot be satisfied. IRD works with customers to agree a maximum chip size and the method it will be measured by.
On one photonics window program the agreed figure was 125 µm, 0.005 inchSurface finish is priced by the Angstrom
IRD reports that a 10 Å finish can be consistently achieved on polished surfaces and that specifying better than that significantly increases cost. On ground surfaces the most commonly specified finish is 32 microinches or greater; 10 or 20 microinches is achievable but costs more depending on material and dimensions.
Tight tolerances belong only on the surfaces that need them
Tight tolerances require fine grinding or other low-removal-rate finishing to stay repeatable in production. IRD's guidance is to hold large surfaces to ±0.1 mm (±0.004 inch) and smaller dimensions to ±0.05 mm (±0.002 inch), and to reserve anything tighter for a surface that can be ground flat.
Sharp edges are where hard material fails
Despite the hardness, sharp edges are brittle and will fracture or chip against tight mating surfaces in downstream assembly. IRD's guidance is to specify a chamfer of 0.38 mm (0.015 inch) or greater where one helps; calling for 0.13 mm (0.005 inch) or less raises the manufacturing cost.
Case study: flat polished sapphire window for photonics
The drawing said no chips. The design review replaced it with a number.
Optical-grade sapphire windows under 10 mm in diameter and 0.5 to 2 mm thick are common in photonics, but this customer's print specified no chips, unreachable for a brittle material at up to 10,000 units a month, since any chip can be found by raising the microscope's magnification. The two technical teams met over the window's real quality requirement and agreed a chip specification of less than 125 µm (0.005 inch), a surface finish of 10 Å (0.039 µin), and the measurement method for each. IRD then developed the lapping and polishing processes using Design of Experiment methods to find the optimum finish at every step, and defined measurement using high-magnification microscopy for chip size plus profilometers and white-light interferometers for in-process surface control.
Talk to an applications expert- 125 µm
- Agreed maximum chip specification, 0.005 inch, replacing the word none
- 10 Å
- Surface finish specification, controlled in process rather than caught at final inspection
- 100 → 10,000
- First-article windows to windows per month, inside the customer's original schedule
Capabilities
Materials, coatings, and metrology
IRD's published materials, coating, and inspection equipment lists.
Forms
- Windows
- Lenses
- Tubes
- Wear surfaces
- Custom profiles
Environments
- Abrasion
- Heat
- Chemical exposure
- High pressure
- UV to mid-IR transmission
Markets
- Industrial
- Medical
- Security
- Sensors
- Precision engineering
Measured on
- Zygo GPI interferometer
- Zygo NewView
- Zygo Verifire XPZ
- Nikon 6D interferometer
- Micro-Vu automated vision system
- TriOptics Triangle
- TriOptics PrismMaster
- Starrett MVR300
- Zeiss Spectrum
- Zeiss O-Inspect
- Tagarno digital microscope
FAQ
Frequently asked questions
The answers an applications engineer would give you on the first call.
Start a quoteHow large a sapphire window can you make?
Up to 8″ diameter on IRD's precision sapphire machining equipment. That is the published limit; larger apertures need review before they can be quoted.
Is 1/10 wave flatness a standard grade on sapphire?
No. Typical flatness is 1/4 wave, achieved through double-side lapping and polishing, which is also what delivers the parallelism and yield that single-side processing on a material this hard cannot. Better than 1/10 wave is an advanced capability on the right geometry; thickness, diameter, and clear aperture all move what is achievable.
What do you need in order to quote?
IRD's quoting checklist: application, product type, volume potential and schedule, material, dimensions, surface quality, coatings, assembly, cleaning, and packaging. Attach the drawing. For a new design the technical team runs a no-cost Design for Manufacturability review before quoting, then estimates prototype and production volumes separately.
Does IRD design the part?
No. IRD manufactures to your print or performance requirement and contributes material, process, and manufacturability input, the design stays with your team. When a print calls for tighter tolerances than the application requires, IRD will flag the potential over-specification, since it can add unnecessary cost. Final optical design decisions remain yours.
How large a part can you make?
Machining runs to 30″ × 16″ × 16″, polishing to 36″ diameter, grinding to 24″ diameter at 6″ height, lapping to 13.3″ diameter, waterjet to 40″ × 24″ × 2″, and dicing to 8″ diameter at .300″ thick. Larger geometry is quoted against whichever process controls the critical surface.
Which coatings are applied in-house?
IRD applies basic anti-reflective and metallic coatings in-house for quick turnaround. Other coating requirements are handled through select, vetted coating partners. Name the coating target in the RFQ and the team will confirm the route before quoting.
Can you take ITAR-controlled work?
IRD is registered with the Directorate of Defense Trade Controls, and controlled programs are manufactured and stored domestically across the Litchfield and Alexandria, Minnesota facilities. Both plants operate under quality systems certified to ISO 9001:2015 and ISO 13485:2016 for ultra-high-precision glass, optical, and ceramic components.
How is the finished part protected in transit?
Packaging is tailored to the part and can include multi-layer foam, custom corrugated packaging, gel packs for sensitive optics, and military-grade cases. Components are supported on edges or non-critical surfaces outside the clear aperture and held against shifting in transit.
Technical documents
Use these IRD references when reviewing custom sapphire components requirements.
White paper
5 Most Common Mistakes in Designing Precision Super Hard Components
Legacy technical paper. Company-profile details may be outdated; use current site pages for IRD facts. IRD's design guidance for sapphire and technical ceramics, unnecessary complexity, over-specified finish, over-specified precision, missing clearance features, and the wrong material call, plus the photonics sapphire window case study in full.
PDFWebinarSynthetic Sapphire: Properties, Use and Selection
IRD's national sales manager on where synthetic sapphire earns its cost against glass and other hard materials, and how to select a grade and orientation for the application.
RecordingTechnical articlePrecision Sapphire Windows: The Choice When Performance Matters
The material case for sapphire, highest strength and melting point of any optical window material besides diamond, and transmission further into the UV and IR than most glasses.
Article
Start with the print
Send us your custom sapphire components requirement.
Send the drawing with the operating environment, the clear aperture, thickness, parallelism and flatness requirements, the chip specification you can accept and how it is measured, the surface finish per face, coating target, annual volume, and schedule. For a new design, the technical team runs a no-cost Design for Manufacturability review before quoting.
Or call 320.693.7217. If the drawing currently says no chips or no defects, bring it anyway, agreeing a measurable limit is the first thing the review does.