A custom injection molding plant with more than 25 years of experience providing complete plastic manufacturing, reported earlier this year they were experiencing start-up contamination on a new Polypropylene (PP) tool, equipped with hot runner manifold.
It was taking 30 minutes in total every start-up for the contamination to clear out of the hot runner manifold.
Being fully aware this was a new tool with expected growth, they knew their current start-up method was not cutting it. They needed a better, faster solution to accommodate even more machine capacity.
I examined what their processing conditions were in order to help them troubleshoot what was causing their prolonged start-up contamination. I looked at factors such as then PP melt index, processing temperatures of their production materials for both barrel/screw and manifold, how many gates and cavities this tool had, gate tolerances, and if it was valve-gated or non-valve gated.
To help this this company achieve faster start-ups, I had them implement these easy and quick, yet extremely effective, steps:
- Use a mechanical PP-based purge compound suitable for this hot runner manifold application.
- Increase the manifold temperatures up by 20F in all gates to get a better viscosity match and achieve the proper flow.
- Purge the multi-cavity; non-valve gated Hot Runner Channels with Mold Plates Open.
They recently reported the purge evaluation was successful.
The contamination cleared out after a quick 10 minutes and saved 320 parts by implementing these simple steps.
They improved their process, achieved faster start-up, and are now in a better position to accommodate even more machine capacity.
Learn about the importance of implementing proper purging procedures by downloading this free industry guide.
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