Crystal Nucleation of POM / Acetal
Problem
A global company reported polyacetal pigment warpage problems. Polyacetal is also known as acetal, POM or by the DuPont tradename Delrin. They experienced large differences in shrinkage and mechanical properties depending on the color of pigment added to the plastic. This made it impossible to make close-tolerance parts that fit together properly. Phantom had helped this company before, so they naturally came to us for help.
Action
It was quickly apparent that the differences in shrinkage were attributed to variable crystallization behaviour. Phantom searched the scientific literature and found peer-reviewed studies indicating that addition of pigments to polyacetal does indeed affect crystallization rate, final crystallinity level and therefore part shrinkage. The reason being that crystalline regions have higher density than amorphous, non-crystalline regions. Having confirmed the cause, the next step was solving the issue.
Solution
In just 1-2 days from the first inquiry the company asked for a meeting so that they could give some more specifics in order that Phantom could get started. When the meeting came, Phantom had already confirmed the cause of the problem, reviewed extensive scientific data and identified a solution. The customer was surprised that we had the solution when they were still at the stage of talking about the problem. Many consultants charge by the hour and are motivated to make each task last as long as possible. In contrast, Phantom works on a fixed monthly retainer contract and solves each problem as quickly as possible.
By finding very effective nucleating agents for POM / Acetal, we could ensure that every part had the same degree of crystallinity, no matter what pigment was added meaning that the nucleating agent overpowered the nucleating effect of all pigments used. An added benefit was lower cycle time meaning higher productivity and profits. This polyacetal pigment warpage problem is only one of many problems solved – read more in the case studies in the drop-down menu as well as the New Products Created page.
