Why Colour Consistency in Injection Eyewear Is So Difficult | Pinnacle Eyewear

The Technical Difficulty of Colour Consistency in Injection Eyewear

Colour matching in injection-molded eyewear is a frequent source of quality issues. The technical complexity explains why.

Melt temperature sensitivity: The plastic must be melted before injection. Temperature variations of just a few degrees change the final colour. Too high and the colour shifts; too low and the flow is compromised.

Material batch variation: Raw material batches have slight colour variations, even from the same supplier. This is particularly significant for recycled materials, where the base colour varies batch to batch.

Mould pressure dependence: Higher pressure changes how colours appear. Lower pressure gives different results. The pressure must be precisely controlled for consistent colour.

Cooling rate impact: Faster cooling produces lighter colours. Slower cooling produces richer colours. The cooling process must be precisely timed.

The compounding challenge: Unlike acetate, where colour is inherent in the sheet material, injection colour is created by mixing pigments into molten plastic. Any variation in the mix ratio changes the final colour.

Injection colour consistency requires exact control of five variables. A factory without rigorous process control cannot achieve batch-to-batch consistency.

At Pinnacle Eyewear, our injection molding line maintains strict process control across all five variables. Our colour matching team monitors every batch, and we use spectrophotometers for precise colour measurement. We offer TR90, PC, PCTG, and recycled materials with consistent colour reproduction. Based in Wenzhou, we produce 100,000 injection frames per month. Email [email protected] to discuss your injection project.