Published sapphire window sizes held in inventory for quick-turn protection, sensing, inspection, and optical development requirements.
Every stock part number publishes its own diameter, thickness, crystal plane, scratch-dig, clear aperture, parallelism, and flatness. Use the stock line when the housing can accept one of them. If the drawing controls custom geometry, edge work, coating, or documentation, move directly to Custom Sapphire Components.
Stock windows exist for the case where the housing can accept a published size — and hand off cleanly to custom when it cannot.
What the stock program is for, what it is not for, and where the route to a fully custom sapphire component picks up.
Diameter, thickness, crystal plane, scratch-dig, clear aperture, parallelism, and flatness are listed against every part number, so the comparison happens before the RFQ.
Clear aperture is published at 90% on every stock size
Sapphire resists scratching, wear, heat, and chemical attack while transmitting from the ultraviolet into the mid-infrared — the reason it replaces glass in abrasive and high-temperature apertures.
Start optical, sensor, or environmental testing without waiting for custom tooling, then hold the design decision until the test data is in.
When the design freezes and the print starts controlling geometry, finish, coating, or documentation, the same team carries it into custom sapphire fabrication.
Custom windows run up to 8″ diameterThe published table is the specification. These are the four things worth reading off it before a stock window gets designed into an assembly.
The published options run from 80/50 through 40/20 to 20/10 across the same three diameters. If the aperture sits in an imaging or laser path, the scratch-dig grade matters more than the diameter, and the price difference between grades is published alongside it.
The stock table lists c-axis material on the 25.4 mm and 38 mm windows and randomly oriented material on the 31.75 mm windows. Orientation is part of the specification, not an interchangeable detail.
The published figures span 8 λ per inch down to 1/4 λ per inch. A window that is adequate as a protective cover may be nowhere near adequate in a transmitted wavefront, and the table is explicit about which is which.
IRD created its sapphire stock window program to make sapphire a practical alternative to fused silica where debris shields and cover lenses are replaced often. Sapphire costs more up front and lasts materially longer, which is a total-cost argument rather than a unit-price one.
These are the published stock ranges. Read the part number for the exact combination — the grades are not interchangeable across diameters.
| Attribute | Typical | Best case | Application note |
|---|---|---|---|
| Diameter | 25.4 mm | 38 mm | 25.4 mm, 31.75 mm, and 38 mm are stocked |
| Thickness | 1.0 mm | 3.0 mm | Both thicknesses appear across the size range |
| Scratch / dig | 80/50 | 20/10 | 80/50, 40/20, and 20/10 are published |
| Parallelism | 3 arc min | 3 arc sec | 3 arc min on the 25.4 mm × 1.0 mm windows only |
| Flatness at 633 nm | 1 λ per inch | 1/4 λ per inch | 8 λ, 2 λ, 1 λ, 1/2 λ, and 1/4 λ per inch by part number |
| Clear aperture | 90% | 90% | Published on every stock part number |
These figures are read from IRD's published stock window table, which also lists unit pricing in quantities of 1–20. Inventory and pricing change, so confirm the current part number, quantity, and lead time with the applications team before designing around availability. Anything outside the table — a different diameter, a coating, an edge treatment, or a documentation requirement — moves the part to the custom sapphire route.
The two sapphire lines are intentionally separate. Stock windows serve availability-led requirements; custom components serve geometry- and performance-led programs. Both are manufactured and stocked at IRD Ceramics in Alexandria, Minnesota.
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 national sales manager on synthetic sapphire's properties, where it earns its cost against glass, and how to select a grade and orientation for the application.
RecordingTechnical articleThe total-cost case behind the stock program: where BOROFLOAT® and sapphire replace fused silica debris shields, and why sapphire's higher initial price can still come out ahead on replacement frequency.
ArticleTechnical articleHow synthetic sapphire is grown, cut, ground, and polished into windows, and what its strength means against quartz and conventional glass at a fraction of the thickness.
ArticleThe finished component often crosses product categories. These pages cover the nearest materials, processes, and program contexts.
Quote from the table: give the part number, or the diameter, thickness, crystal plane, scratch-dig, flatness, and quantity you need. If nothing on the table fits, send the aperture, environment, and transmission requirement instead and the team will scope the custom route. For a new custom design, the Design for Manufacturability review is free of charge.
Or call 320.693.7217 to confirm current stock, pricing, and lead time before you design around a part number.