DITAIImproving the fit of a thermoformed lighting cover.
A photographic lighting manufacturer in Dubai needed a thin diffuser with a defined centre bend. During development, the cover showed an edge gap and distortion when fitted to its support. We worked through the material and hole-clearance changes before an initial 1,500-piece trial run.
- Application
- Photographic lighting
- Development focus
- Material selection and assembly fit
- Project stage
- Initial 1,500-piece trial run
In this project
Material trials before the production tool
The customer’s initial brief specified a 0.8 mm diffusion-sheet reference. We used the supplied sample to compare candidates from several sheet suppliers.
Some candidates were unsuitable for thermoforming. Others softened and stretched during heating in ways that made the shape difficult to control. We compared processing approaches and checked light transmission as the samples developed.
Forming behaviour alone did not settle the choice. Assembly videos, bonding adjustments and repeated sample shipments let us review how the material worked in the cover. This development stage took more than a month.
Once the material and forming route were agreed, we made a dedicated, highly polished forming tool and produced another sample for an assembly check.
The assembled sample still showed an edge gap
The next sample revealed a gap along the assembly edge. The side edge also failed to remain straight. We checked the cover with its injection-molded support to understand what changed during fitting.
Two locating features on the support pointed in different directions. Our assembly review indicated that engaging these features pulled the thin sheet out of shape. We therefore looked at the clearance around the locating features and how the cover settled onto the support.
Two enlarged holes left the rear holes misaligned
We first increased clearance at two holes. With the cover fitted, the rear holes still did not line up. The first adjustment had not resolved the assembly problem.
We then proposed clearance changes at all six rear holes, using elongated openings. To check the proposal with the customer, we modified a sample by hand and demonstrated how it fitted.
The customer responded that the revised sample looked much better. We carried the six-hole revision into preparation for the trial run.
“It looks much better.”
A locating fixture for the first run
The formed cover needed support and a defined position during CNC machining. We made a locating fixture to hold the three-dimensional part while its assembly features were cut.
The project then entered an initial 1,500-piece trial-production run with the dedicated forming tool, revised hole-clearance approach and CNC fixture.
Send the drawing and the part it needs to fit.
Include the mating-part model and any trial samples. We can review the forming and machining requirements alongside the assembly.
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