Plastics Processing Purging Tips On The ASACLEAN Blog

How to Prevent Downtime in Profile Extrusion with Smart Purging

Written by Tom Hanvey | Apr 8, 2025 12:45:00 PM

If you're running a profile extrusion line, chances are you've dealt with carbon buildup, color streaking, or slow changeovers. These issues don't just hurt quality—they cost you time, scrap, and labor.

Whether you’re extruding UV-resistant vinyl siding or medical-grade clear profiles, contamination and unplanned downtime are two of your biggest enemies. The good news? You can significantly reduce both with a strategic approach to purging.

Let’s take a look at how you can minimize production headaches, avoid costly teardowns, and improve the efficiency of your extrusion line.

Why Contamination Is So Common in Profile Extrusion

Unlike batch processes, profile extrusion is continuous. That means when something goes wrong—like a color change that doesn’t fully clear out or carbonized material in the screw—it can linger in the system and affect your output for hours or even days.

Some of the most common issues include:

  • Black specks and color contamination in finished parts
  • Streaking during clear profile runs
  • Clogged dies and inconsistent flow
  • Manual screw pushes that take up valuable maintenance hours

If you're changing materials frequently or working with complex additives, these problems tend to multiply.

The Hidden Cost of Using Production Resin to Purge

Many plants still rely on running virgin resin or regrind during changeovers. While that may seem like a cost-saving move, it’s often counterproductive.

Here’s why:

  • Resins aren’t designed to clean. They don’t remove residue or contamination effectively.
  • They cause layering. Different materials stack up in the barrel and screw over time.
  • That buildup will break free eventually. And when it does, it can ruin your product run.

If you’re seeing output drops, contamination, or unexplained quality issues, your purge process might be to blame.

A Smarter Solution: Preventive Purging

A growing number of extrusion processors are shifting toward preventive purging—a proactive approach that minimizes downtime and avoids the need for screw pulls.

Rather than waiting for contamination to appear, preventive purging involves:

  • Cleaning before and after color or material changes
  • Purging before scheduled shutdowns
  • Incorporating it into routine maintenance cycles

The benefits include:

  • Reduced scrap and faster changeovers
  • Fewer customer rejects
  • Less frequent teardowns and screw cleaning
  • Improved line output and consistency

💡 TIP: Preventive purging typically uses just 1–2 barrel capacities of purge material and can save hours in lost production time.

What to Look for in a Purging Solution

Not every purging compound works well for profile extrusion. Look for solutions that are:

✅ Safe for tight die clearances
✅ Compatible with your resins and processing temperatures
✅ Effective at removing both color and carbon buildup
✅ Low in residue (especially for clear or medical applications)
✅ Easily displaced by your next production resin

Pro tip: It’s not just the purge material—it’s how your team uses it. A brief training session on purge procedures can dramatically improve your results and reduce waste.

3 Practical Purging Tips for Profile Extrusion

  1. Stop Using Production Resin for Changeovers

Production resins are too expensive and inefficient to use as cleaning agents. They don’t remove contamination and often create hidden problems that resurface later. Use material engineered for cleaning instead.

  1. Be Proactive, Not Reactive

Don’t wait until color streaks or carbon show up in your product. By then, the problem is already affecting your bottom line. Regular purging reduces downtime and helps your line run clean longer.

  1. Make Screw Pushes Less Painful

If a screw push is unavoidable, use a purge beforehand to loosen and flush contaminants. This can cut cleaning time dramatically and reduce the labor needed to get back up and running.

Ready to trial a new purge compound and experience the benefits for yourself? Get a free sample and schedule a meeting with an Asaclean purging expert to set up your onsite trial today. Our team is dedicated to helping you find the perfect purging solution for your needs, providing expert guidance and support every step of the way. Don't let another day go by without maximizing your efficiency and profitability – contact us now to get started on your journey to plastics processing excellence.