Processing super‑engineering resins like PEEK, ULTEM, or PEI presents serious challenges. These high‑temperature materials require extreme heat, and their residue can be stubborn. When transitioning from super‑engineering resins to normal engineering resins, cleanup must be meticulous to avoid contamination and downtime. A well‑designed two‑step purging strategy using Asaclean® grades brings consistency, cost savings, and operational confidence.
Why Super-Engineering Resins Require Special Purging
Super‑engineering resins often are molded at temperatures ranging between 280 °C (535 °F) and 420 °C (790 °F). Standard purge compounds fail quickly in this environment and may leave behind char or cause equipment damage. Asaclean® offers PX2 Grade and PF Grade precisely for that need. They are engineered to withstand extreme temperatures without degrading, ensuring the screw and barrel are clean and ready for the next process. One processor shared that using PX2 for a high‑cost resin saved them hands down. The purge paid for itself in just one cycle and delivered good parts in about 15 minutes.
The Risk of Skipping the Two-Step on Material Changeovers
Directly switching from a super‑engineering resin to a lower temperature material like ABS can cause serious issues. The residue from the high‑temp polymer may not melt properly at lower temps, leading to carbon spots, contamination, and scrapped parts. In the worst case, such layering forces a full screw pull and a machine teardown.
What Does the Two-Step Purge Look Like?
First, while the system is still hot, process the super‑engineering resin with PX2 or PF. This cleans aggressively at high temperature, removes residue, and keeps the system stable. Once the system is clean, reduce the temperature gradually to the overlap range where both high‑temp and normal resins can run. PX2 or PF ensures that no ghosting or layering remains.
Next, introduce a general‑purpose purge like U Grade or a strong scrubber such as EX Grade. This second stage brings the machine safely down in temperature, removing any residual PX2 or PF material and preparing the system for the target engineering resin. This method avoids black specks, maintains part quality, and minimizes wasted material and time.
Benefits You Can Count On
Adopting this two‑step approach yields clear performance gains. First, you reduce contamination and scrap, which translates into lower operating costs and fewer customer complaints. You also avoid the time and labor involved in screw pulls and teardowns. Estimates suggest savings of 3 to 16 hours per event, depending on machine size and complexity.
Maintenance and engineering teams see consistent startup cycles and higher uptime as a result. Finally, preventive purging before shutdowns and using thermally stable compounds seals out oxygen and avoids degradation during idle periods. That makes restart cleaner and faster.
When to Implement Two-Step Purging
This strategy works best during high‑risk transitions. Use it during tooling introductions, hot‑to‑cold material changes, shift handoffs, or extended off‑hours. Always purge while the machine is still hot so residue remains molten and easier to flush out. Avoid trying to clean when the system is cold unless you have ample time for a full teardown.
Final Thoughts
Handling super-engineering resins does not have to slow your operation down or jeopardize quality. By choosing PX2 or PF for initial high-temp cleaning and following with U Grade or EX as the system cools, you gain the flexibility to switch smoothly to normal engineering resins. That two-step process saves time, cuts scrap, and gives you peace of mind.
If your team is dealing with tough resin transitions or temperature swings, we can support you with a customized purge protocol. Request a free sample or schedule a consultation with one of our purging experts today.