Custom sapphire windows, lenses, tubes, and shaped components for abrasive, high-temperature, chemical, sensor, medical, and security environments.
IRD manufactures to your print. Send the drawing with the environment, the clear aperture, the chip and finish specifications you can actually 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.
Hardness is only the starting property. Geometry, edge condition, polish, and coating determine whether the part integrates cleanly.
IRD Ceramics runs sapphire as its own discipline — machining, lapping, polishing, and coating the material rather than adapting a glass route to it.
Protective and transmitting windows built around the housing, pressure, abrasion, and wavelength requirements.
Up to 8″ in diameter
Optical sapphire surfaces processed for sensors, radiometry, laser, and imaging applications, with coatings from UV through IR.
Machined sapphire geometry for mechanical, wear, and precision-engineering functions where the part is structural as well as transmitting.
Double-side lapping and polishing for efficient yield, exemplary parallelism, and controlled flatness across both faces at once.
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.
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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.
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 inchIRD 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 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.
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.
Sapphire programs combine hard-material machining with optical finishing. These ranges frame the first manufacturability conversation.
| Attribute | Typical | Best case | Application note |
|---|---|---|---|
| Window diameter | Print-defined | Up to 8″ | Custom sapphire windows |
| Flatness | 1/4 wave | 1/10 wave | Single- or double-side polished faces |
| Machining | ±.005″ dimension | ±.0001″ | Mounting features, profiles, and custom geometry |
| Polishing | Ra < 1 µin | Ra < 5 Å | Optical faces and performance-critical surfaces |
| Lapping | ±.000050″ flatness | ±.000010″ | Seals, spacers, and precision interfaces |
These are IRD's published process capability figures across materials and geometries, not a guarantee for a given print. Grade, crystal orientation, thickness, clear aperture, and inspection method all move them. Sapphire is available in several grades and orientations that change both cost and manufacturability, so the material call belongs in the design review rather than after it.
Choose this page when geometry, thickness, finish, coating, or inspection is custom. For a standard diameter and a faster starting point, use the Stock Sapphire Windows line. Either way the work runs at IRD Ceramics in Alexandria, on equipment built for super-hard materials.
The IRD AdvantageUse these lists to frame the first review. The drawing, environment, performance requirement, inspection method, and volume determine the final route.
A web page is hard to attach to a review packet. These are IRD's own published technical documents on the questions this page raises.
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.
PDFWebinarIRD'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 articleThe 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.
ArticleThe finished component often crosses product categories. These pages cover the nearest materials, processes, and program contexts.
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.