Page 247 - Injection Molding Advanced Troubleshooting Guide

238 25 Delamination

finally found what they believed to be more concentrate on a storage rack.
They loaded up the “new concentrate” and started running parts. It was later
discovered that they had grabbed an alternate material in black, not a
concentrate, and were running contaminated parts. Close inspection of the
parts showed an increase in scrap from splay and delamination because the
materials were incompatible. All of the parts run during the shift were
scrapped out due to the contamination. If someone had not assumed that
the black material was OK to use, this problem would not have occurred.


25.3.4.2„ Material: Incompatible Color Concentrate
When a concentrate is used to color a natural base resin, be sure to use a concen-
trate that matches up with the base resin. Although there are concentrates that
can be used across different materials it is critical to make sure that the concen-
trate is intended for the desired material. Communication with the concentrate
supplier will help resolve potential issues with using the wrong color concentrate.
Also be sure to clearly document the bill of materials for a part so that everyone
can quickly see what the base material is as well as the specific color concentrate
to be used.
If the concentrate is suspected as the culprit, verify that someone did not grab a
similar concentrate by accident (again make sure to clearly label and document).
Also, a call to the concentrate supplier will verify that a particular concentrate
number is intended for the base material being molded.