Read the Print Like a Cost Driver Checklist
An optical drawing is a list of cost multipliers. Before pricing anything, extract the substrate (N-BK7, fused silica, CaF2, ZnSe, germanium, sapphire), the clear aperture and diameter, thickness and thickness tolerance, radius of curvature and its tolerance, surface figure in waves at 633 nm, scratch-dig per MIL-PRF-13830B, centration or wedge, edge treatment, and the coating call-out with its spec. Each one maps to a process step and a yield assumption.
A flat window at lambda/4 and 60-40 is a different business than a lambda/20 asphere at 10-5. Estimators who skip this step quote by part family and discover the difference on the shop floor.
- Substrate and blank form: boule cut, pressed blank, or finished stock window
- Surface count and type: flat, sphere, cylinder, asphere, off-axis
- Figure, irregularity and power tolerance, scratch-dig, and edge chip allowance
- Centration, wedge, parallelism and thickness tolerance
- Coating and environmental durability requirement
Fabrication Hours and Process Route
Convert the print into a routing: generate, rough and fine grind, lap, polish, core or edge, bevel, clean, inspect, coat, final inspect. Hours depend on the process, not just the size. Pitch polishing, pad polishing on CNC machines, magnetorheological finishing and single-point diamond turning for metal or infrared optics each have different setup and cycle behavior.
Batch processes such as block polishing of many pieces on one tool spread setup across the lot, while one-off prototypes carry the full tooling cost alone. Be explicit about which test plates, lap tools and blocking fixtures already exist, because new tooling is a real line on the quote, not overhead.
Price Yield Loss Explicitly
Yield is the margin killer in optics. A scratch-dig of 20-10 on a soft crystal can scrap many pieces at final inspection, and a tight figure spec may need repeated polish and test cycles that eat spindle time without producing a finished part. Use your own history by process route, material and spec grade, not an industry average.
For small lots, quote on a start quantity that covers expected loss and state that quantity in the terms. For prototypes, consider a not-to-exceed or time-and-material structure, and say so in the quote.
- Track scrap by operation and reason code so the yield assumption is real
- Quote start quantity, not just delivered quantity
- Separate first-article or development lots from production pricing
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Quote Margin Analyzer
Pressure-test a quote by amortizing setup across the order quantity, adding commission, and showing the price required to hit a 30% target margin.
Add Coating, Metrology and Outside Processing
Coating is often the largest single line on a short run, whether done in-house or at a coating partner. Add chamber time or vendor charges, fixturing, witness samples, spectrophotometer verification and any durability tests required by the spec. Metrology is the next hidden cost: interferometer time, profilometry, centration measurement and documentation for each piece or each sample.
Include shipping with insurance for fragile parts and a realistic lead time that includes blank procurement, since crystal and infrared blanks can take longer to source than the whole polishing cycle.
Where AI Helps and Where It Does Not
AI is useful at the front and back of the process. It can read a drawing package, extract the callouts above, pull comparable past jobs with actual hours, yield and coating cost from your ERP, and draft a quote for an estimator to approve. It should not set final price or promise a tolerance the process cannot hold.
If you quote a handful of repeat catalog-style parts a month, a well-built spreadsheet or your ERP's standard costs may be enough, and a custom quoting layer will not pay back.
Frequently asked questions
How do you estimate the cost of a custom lens?
Add the substrate blank, fabrication hours by operation, expected yield loss, coating cost, metrology time and tooling or setup, then divide across the lot. The two inputs that move the answer most are surface figure and scratch-dig grade, because they drive polish cycles and scrap. Use actual history from similar parts rather than a generic hourly rate.
Why are optics quotes so hard to get right?
Because cost depends on tolerances that are invisible in the geometry. Two lenses of the same size can differ several times in cost based on figure, scratch-dig, centration and material. Yield is also non-linear: tightening a spec one grade can cause a disproportionate rise in scrap, which only shows up in actual job history.
Should prototype optics be quoted differently from production?
Yes. Prototype lots carry the full cost of tooling, test plates, process development and learning, and yield is less predictable. Many shops quote prototypes on a start quantity, a not-to-exceed price or time and material, and then reprice production once the process is proven and yield data exists.
If your estimator spends hours rereading prints and hunting for similar past jobs, ask Netray to demo a private, on-prem draft quote built from your own routings, yields and coating history.