Optical Mounting Plate CNC Machining Case Study: Brief, Process and Result

A CNC machining case study covering a black anodised plate for a laboratory optical bench: the customer brief, the machining challenge, the process route we used and the result delivered on the production order.

The brief

A customer asked us to produce a black anodised plate for a laboratory optical bench, specified as flatness of 0.02 mm across the working surface.

The order covered a first article for approval, followed by a production batch, with the drawing, material certificate and inspection report all part of the deliverable.

The challenge

The difficulty in this job was holding the specified geometry while keeping the part stable through cutting, handling and finishing.

The specification required flatness of 0.02 mm across the working surface, which ruled out a loose process and made fixture design the first task rather than an afterthought.

The process

We programmed the part with stock-aware roughing, a semi-finishing pass to even out the remaining stock, and a finishing pass with a fresh tool.

Workholding located on the datum features named on the drawing, so measurement and machining used the same reference throughout.

The result

The first article was approved without rework, and the production batch was completed to the agreed schedule.

Dimensional results on flatness of 0.02 mm across the working surface were recorded for every part in the sample inspection plan and supplied with the shipment.

What we would repeat

The decision to design the fixture before finalising the toolpath saved a round of rework and shortened the approval cycle.

We now apply the same sequence to similar parts, because the risk in jobs like this sits in the setup rather than the cutting.

Summary

The programme continues to run against the agreed control plan, and the approved first article remains the reference for every reorder.