# Optics Shop Scheduling: Polishing, Coating and Metrology Capacity

> Source: https://netray.co/resources/optics-shop-scheduling-polishing-coating-metrology-capacity
> Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems.
> Section: Knowledge Base

## Short answer

How to schedule an optics shop: polishing machines, coating chamber batches, interferometer bottlenecks, rework loops and blank lead times in one plan.

## Category

erp-general

## Content

**Intro:** Scheduling an optics shop is hard because capacity is spread across very different resources: polishing machines with long and variable cycles, a coating chamber that runs in batches, and metrology stations such as interferometers that quietly become the bottleneck. Rework loops mean a job can return to polish several times, so fixed lead times fail. A workable schedule plans around the constraint, groups jobs for coating, reserves metrology time and treats blank arrival as a real gating item. This guide shows how to structure it.

**Sections:**

#### Find the Real Constraint

**Body:** In many shops the constraint is not the polishing machines but the coating chamber or the one interferometer and the person qualified to use it. A part may wait days for a measurement slot between polish cycles, and each wait multiplies when a part needs several cycles. Measure queue time before each resource for a few weeks. If most delay is waiting for the chamber or for test, adding polishing capacity will not shorten lead time. Schedule the constraint first and let other operations feed it.

#### Plan Coating as Batches

**Body:** Coating cannot run one job at a time without wasting the chamber. Group jobs by compatible coating process, substrate and fixture size, and set a cut-off for each run. The tradeoff is clear: waiting to fill a run improves cost but delays shipping, while running half-full costs margin. Many shops set a weekly or twice-weekly coating calendar and tell the planner which jobs must be polished and inspected by the cut-off. Late arrivals miss the run and wait for the next.

**Bullets:**

- Fixed coating calendar with cut-off times
- Compatible-process grouping rules
- Expedite rules and who approves a partial run

#### Account for Rework and Variable Cycles

**Body:** Polish time is not a constant. A tight figure may need three test-and-correct cycles, while another part finishes in one. Use historical distributions by material and spec class instead of a single standard time, and plan with a buffer on the constrained operations. When a job loops back, the schedule should show it as consumed capacity, not a surprise. If your ERP only supports linear routings, track rework as additional operations or in a simple board that planners trust.

#### Blanks, Outside Processing and Tooling

**Body:** Lead time on substrate blanks, especially crystals and infrared materials, can exceed the shop's own processing time. Treat blank due date as a start constraint, and flag long-lead materials at quote time. Outside processes such as specialty coating, edging or dicing need transit and queue time in the plan. Tooling such as lap tools, test plates and fixtures should be checked for availability before releasing a job, because a missing test plate can stall a whole route.

#### Where AI Fits and Where a Whiteboard Is Fine

**Body:** AI can help by learning realistic cycle and queue times from history, predicting which jobs will miss a coating cut-off, and answering what-if questions over live ERP data. Final sequencing and customer commitments should stay with the planner. If you run fewer than a few dozen open jobs and one chamber, a well-kept board and a weekly planning meeting may be all you need.

**Cta:** Netray can read your routings, cycle history and open orders so planners can ask which jobs will miss the next coating run, privately and on-prem.

**Faq:**

#### What is the bottleneck in an optics shop?

**Answer:** Often it is the coating chamber or the metrology station rather than polishing. Because parts return for rework after measurement, a single interferometer can hold up many jobs. Measure queue time before each resource to see where jobs actually wait, then schedule the constraint first.

#### How do you schedule a coating chamber?

**Answer:** Treat it as a batch resource. Group jobs by compatible process, substrate and fixture, set a regular run calendar with cut-off times and decide how to handle partial loads and rush jobs. Align upstream polishing and inspection to the cut-off so finished parts are ready when the run starts.

#### Can ERP finite scheduling work for optics?

**Answer:** It can help, but only if it handles shared batch resources and rework loops. Many ERPs assume linear routings and fixed run times. If yours does not, use it for orders and materials and supplement with a constraint-based board or a purpose-built planning layer.

## Related Slugs

- finite-capacity-scheduling-guide
- ai-production-scheduling-optimization
- plating-line-scheduling-rack-and-tank-capacity
- scheduling-aerospace-machine-shop-with-outside-processing

## Search terms

optics shop scheduling, coating chamber scheduling, optical manufacturing capacity planning, interferometer bottleneck, photonics production scheduling, polishing lead time planning

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