From visible polishing marks to a cleaner, more consistent finish.
The Challenge
During final inspection, we found fine surface marks on some acetate frames. These marks were small, but became clearly visible under direct light and affected the overall appearance of the finished product.
For eyewear brands, details like these matter. A frame may meet its dimensional and functional requirements, but inconsistent surface finishing can still make the product feel below the expected quality level. receive the same level of finishing quality regardless of which frame they pick from the batch.
Fine surface marks identified during inspection.
Finding the Cause
Rather than simply polishing the affected area again, we reviewed the finishing process to understand where the surface quality could be improved.
Acetate frames go through several finishing stages. Each stage affects the final surface, and relying too heavily on one polishing process can leave fine marks or inconsistencies in difficult areas.
The solution was to improve the sequence and control of the finishing process.
Step 1 — Tumble Polishing
The frames first go through tumble polishing with polishing media.
This process helps smooth the overall surface, soften machining marks and prepare the frame for the following finishing stages.
The polishing time and condition need to be controlled carefully to achieve a consistent base finish without affecting the frame shape or details.
Acetate frames during the tumble polishing process.
Step 2 — Manual Polishing
After tumble polishing, areas requiring a higher level of surface finishing are polished manually.
Manual polishing allows our technicians to work more precisely on frame fronts, edges, end pieces and other areas where surface marks are more visible.
Instead of simply increasing polishing time, the operator adjusts the polishing according to the condition and geometry of each area.
Manual polishing for more precise surface finishing.
Step 3 — Final Surface Inspection
After polishing, the frames are inspected again under direct light.
This makes fine scratches, polishing marks and uneven gloss easier to identify before the product moves to final assembly and shipment.
Frames that do not meet the approved finishing standard are returned for further adjustment.
The Result
After refining the polishing process, the frame surface became noticeably cleaner and more consistent.
Fine polishing marks were reduced, the surface gloss became more uniform, and the frame maintained cleaner transitions around the edges and end pieces.
Cleaner and more consistent surface after finishing improvement.
Small Details. Visible Difference.
Finishing quality is not determined by one polishing step.
It comes from controlling each stage — from tumble polishing and manual finishing to final inspection.
At Timing Optical, when we identify a finishing issue during production, our goal is not simply to correct the individual frame. We review the process behind it so the improvement can be applied consistently across the production batch.
Because good eyewear manufacturing is often defined by the details customers notice — even when they don’t know exactly why.