PEKUTHERM® as a Changeover Tool: Material & Color Changeovers in Injection Molding and Extrusion
Updated: Aug 30
Every material or color changeover has the same objective:
Get the outgoing material out, get the incoming material running clean, and return the machine to production.
The question is how much time, resin and scrap it takes to get there.
Processors can push the outgoing material through with incoming production resin. They can use a resin flush, carrier-resin purge, chemical purge or mechanical purging compound.
But simply moving material through a machine and cleaning the machine for the next production run are not necessarily the same thing.
That distinction is where PEKUTHERM® becomes more than a purge.
It becomes a changeover tool.
Learn about the five types of purging methods:
The Hidden Cost Between Two Production Runs
A changeover isn’t complete simply because the new material has entered the machine.
Previous color, degraded polymer and carbon can remain on metal surfaces inside the processing equipment. As the next resin moves through the system, those remnants can break loose and contaminate the new production run.
The result can be familiar:
Color streaking
Black specks
Residual material contamination
Additional flushing
Startup scrap
Longer downtime
And every pound of good incoming resin used to finish cleaning the machine is a pound that isn’t becoming saleable product.
That’s why changeover efficiency shouldn’t be measured only by how quickly the old material disappears.
The better question is:
How quickly can the machine transition from the outgoing material to clean, saleable production?
Tool 1: Material and Color Changeovers
PEKUTHERM® approaches the changeover mechanically.
Rather than relying on carrier resin dilution, chemical reactions, detergents or solvents, PEKUTHERM® uses a physical thermoelastic cleaning action.
During processing, PEKUTHERM® softens to a pencil-eraser-like consistency. It self-adheres and forms a custom soft-scouring plug that mechanically works against contaminated metal surfaces as it travels through the machine.
That action is designed to remove:
Outgoing material. Previous color. Degraded polymer. Carbon buildup.
And because PEKUTHERM® does not depend on a chemical reaction, no premixing, soaking or reaction time is required.
Material Displacement vs. Mechanical Cleaning
This is an important distinction!
A resin traveling through a barrel can displace the material ahead of it.
But material can also remain on machine surfaces.
If incoming production resin is used to continue flushing those surfaces, the processor is effectively using production material as a cleaning material.
PEKUTHERM® is designed specifically for the cleaning step.
Its self-adhering thermoelastic action soft-scours degraded material from metal surfaces and carries contamination out of the system without relying on carrier resin dilution or chemical reactions.
The objective is straightforward:
Use the purging compound to clean the machine. Use the production resin to make product.
Color Changeovers Make the Difference Easy to See
Color changes provide one of the clearest demonstrations of the difference between displacement and cleaning.
Moving from one color to another can leave traces of the previous color inside the machine. Even relatively small amounts can produce streaking or discoloration in subsequent production.
That becomes particularly noticeable during challenging transitions, such as moving from a dark color to a light color.
Continuing to run the incoming resin may eventually dilute and carry away the remaining color. But everything produced before acceptable color purity is reached represents time and material spent on the changeover.
PEKUTHERM® provides a mechanical cleaning step between those production materials.
Outgoing material → PEKUTHERM® → Incoming material
The new material can be run directly behind the outgoing material as part of the changeover procedure, with very short purge times possible depending on the application.
Don’t Use Your Next Resin to Ask, “Are We Clean Yet?”
There is another cost that is easy to overlook.
After a purge, operators need to know whether the machine is actually clean.
If that verification requires repeatedly running incoming production material until contamination disappears, good resin is being consumed simply to answer the question.
PEKUTHERM® is designed to help processors confirm machine cleanliness without wasting excess incoming material.
That is especially relevant when the incoming material is expensive, when color purity matters, or when startup scrap has a significant effect on changeover economics.
Instead of viewing purge cost strictly as cost per pound, processors can consider the complete changeover:
Purge material + production resin consumed + scrap + labor + machine downtime
That’s a more meaningful measure of changeover performance.
One Mechanical Principle Across Different Changeovers
Not every changeover is the same.
Machine size changes.
Materials change.
Processing temperatures change.
Injection molding and extrusion applications differ.
PEKUTHERM® formulations are therefore selected according to application type, machine size and processing temperature rather than treating every machine as the same application.
Across the product family, PEKUTHERM® supports processing temperatures from 175°F to 752°F (79°C to 400°C), covering conventional thermoplastics as well as high-temperature engineering resins and ultra-low-temperature applications.
The formulation changes.
The underlying cleaning principle does not:
Self-adhering. Thermoelastic. Mechanical soft-scouring.
A Changeover Is Production Time
It is tempting to think of purging as the period between two production runs.
Operationally, however, that time matters just as much as the time spent making parts or extruding product.
Every additional minute required to reach clean production is machine capacity that isn’t producing saleable material.
Every additional pound of incoming resin used for flushing adds to the real cost of the changeover.
And every remaining piece of contamination creates the possibility that the process will have to stop again.
That’s why we think about PEKUTHERM® differently.
It isn’t simply material put through the machine between jobs.
For material and color changeovers, PEKUTHERM® is a production tool designed to help clean the machine and move the processor from one production run to the next.
More Than a Purge. It’s a Tool.
Material and color changeovers are only one way processors use PEKUTHERM®.
The same thermoelastic mechanical cleaning action can also be used for contamination and carbon removal, preventive maintenance, screw-pull preparation, cleanliness verification and as part of machine troubleshooting.
Talk to UniTemp
Not sure which PEKUTHERM® formulation fits your material or color changeover?
Tell us your application, machine size and processing temperature, and the UniTemp team can help identify the appropriate formulation.
Use our Contact Page https://www.pekutherm.org/contact-us
Or call today: (269) 408-0280
Samples are available for processors who want to evaluate PEKUTHERM® in their own equipment.
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