How to Minimize Scrap and Downtime in Sheet Extrusion
If you manage or support a sheet extrusion line, you know how costly even short interruptions can be. Downtime and material scrap aren't just annoying—they directly impact throughput, profitability, and customer satisfaction.
For plants running materials like ABS, PET, HIPS, or PMMA, it’s common to face issues like:
One of the most overlooked—but highly effective—ways to reduce these issues is to optimize your purging strategy. In this post, we’ll explore how smart purging practices can help you minimize scrap, reduce downtime, and improve operational efficiency in your sheet extrusion process.
Why Changeovers Are So Painful in Sheet Extrusion
Sheet extrusion requires precision. Inconsistent layers, gels, or discoloration can turn entire rolls into scrap. Unfortunately, the way many processors handle color or material transitions makes things worse.
Common shortcuts include:
The result? Hidden contamination remains inside the screw and barrel, creating layering and thermal degradation that doesn’t show up until the next run—or later. This leads to:
Proactive Purging = Less Scrap, Faster Changeovers
Instead of waiting for contamination to appear, high-performing sheet extrusion plants are adopting proactive purging. This means incorporating purging into regular operating procedures to maintain cleaner machines and better throughput.
Key advantages of proactive purging include:
✅ Cleaner Startups: Fewer black specks, faster ramp-up
✅ Shorter Changeovers: Less time between jobs = more production
✅ Consistent Quality: Less off-spec sheet = fewer rejected rolls
✅ Extended Equipment Life: Less degradation and fewer screw pulls
✅ Lower Operating Costs: Less wasted resin and labor
Purging compounds designed for sheet extrusion temperatures and materials can quickly remove degraded resin, carbon, and color residue—unlike regrind or next-run resin, which may make the problem worse.
3 Ways to Cut Downtime and Scrap with Better Purging
A common source of contamination? Changeovers handled inconsistently from shift to shift. Train operators to follow a standardized purging process before changeovers, shutdowns, and startups. This ensures you’re not inheriting contamination from the previous run—and avoids surprises when new shifts start cold.
Cooling down with production resin in the barrel leads to oxidation and baked-on material that can flake off later. Instead, purge hot and seal with a thermal-stable purge compound. This keeps oxygen out and protects your equipment during off-shift or weekend downtime—making your next startup faster and cleaner.
Not all purging compounds are created equal. For sheet extrusion, look for purges that:
If you regularly run multiple materials, consider having different purge types on hand—such as a high-efficiency mechanical purge for everyday use and a chemical purge for deep cleaning during maintenance cycles.
Final Thoughts
Scrap and downtime will always be challenges in sheet extrusion—but they don’t have to be constants.
By implementing a more thoughtful purging process, you can:
For plants facing tighter margins, labor shortages, and higher resin costs, better purging isn’t just smart—it’s necessary.
Ready to see the difference Asaclean® can make in your production? Request a free sample today and experience how our purging compounds can enhance your color change efficiency, reduce waste, and improve your manufacturing process. Our team of experts is here to guide you through the process and help you achieve the best results. Contact us now to get started!