Cost Savings Solutions

Purging High & Low Temperature Changeovers

Asaclean® is uniquely positioned to help you avoid temperature-related contamination. Whether you’re running super-engineering resins like ULTEM & PEEK or low-temperature commodity resins like FPVC & TPU, we have products and recommendations to help you eliminate carbon and other contamination issues. Many processors also struggle during material changes where they must “step down” or “step up” their heats for their next production material. Don’t worry. We have you covered there, too.

Here’s how Asaclean® can help you solve your processing issues with high and low processing temperatures.

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Purging High-Temp Super-Engineering Resins

Super-engineering resins have steadily replaced other building materials over the past twenty years. Originally designed for aerospace, these resins now provide significant value in medical, electronics, telecommunications, automotive, and other markets. They’re far lighter than steel and can be molded into very small parts. These resins are incredibly beneficial and have become far more common in molding shops and extrusion plants in recent years.

pvc plastic tubes

For all their strengths, their high costs make it imperative that you run your production efficiently. Once you get above 700°F, that becomes harder to do. If you've never performed a change with super-engineering resins, the first thing you'll learn is that they tend to take much longer than typical changeovers with engineering or commodity resins. When you combine this with the much higher material costs, your changeovers can get very expensive in a hurry. Some super-engineering resins require heats well above 700°F. If you don’t monitor or attend machines immediately if they alarm out, things can get very dangerous. Things go wrong much quicker in these temperature ranges, and scrap is far costlier.

A lack of proper purging can result in resin degradation during subsequent runs. In other cases when the system is cooled before pulling the screw for maintenance cleaning, the resin is challenging to remove from the screw flights. Super-engineering resins require purges with greater thermal stability as well as premium cleaning performance. Fortunately, Asaclean® offers the best-performing products on the market for super-engineering resins.

63%

On average, Asaclean® customers save 63% purging super-engineering resins.

black and white purging compounds next to electric circuit parts

Asaclean® offers PX2 Grade & PF Grade—both engineered to solve your issues at processing temperatures from 280°C (535°F) to as high as 420°C (790°F). There are not any other competitive products available that work effectively at the high end of this temperature range. Purging with PF or PX2 is imperative to clean and stabilize the system when needed to avoid the high cost of material and scrap. Consider doing this as a best practice during tooling validations, off-shifts, shift changes, and weekend skeleton crews. Let’s take a closer look.

PX2 Grade is a specialized product designed to help remove your super-engineering resins from your screw and barrel and avoid costly contamination. If you experience contamination, PX2 can usually clean your machine effectively avoiding the need for a screw pull. Its cleaning power rivals our EX Grade but performs at incredibly high temperatures.

We run a $25/lb material and we were dealing with carbon. We started using Asaclean® PX2 and were seeing good parts in 15 minutes. Some people worry about cost, but $30 of purge paid for itself in one cycle. We saved significantly more than I could've hoped for.”
Umberto C. , Senior Injection Molding Manager, Custom Molder, Georgia

 

PF Grade is an excellent choice for color andplastic gears material changeovers at high temperatures. It’s safe for hot runners and is even effective for sealing your machines before maintenance, weekend, and holiday shutdowns. Its superior thermal stability allows it to run at the same high temperature as your processing resins and effectively prevents oxidation within your machine during downtime and when you start back up. Sealing with PF is necessary when you are shutting down a machine in the middle of a production run. Purging the barrel empty with your super-engineering resin and letting it sit over a shift or the weekend will cause degradation. These materials are as strong as steel and it is VERY difficult to get these materials out once they degrade and set up in the barrel.

When I first heard there was a compound that could get PEEK off a screw and barrel instead of a manual cleaning, I was very skeptical. We were able to go from black PEEK to natural polypropylene without a manual screw and barrel clean and without any contamination using the new high-temperature PX2. Asaclean® is the only purging compound I’ll ever use.”
Steve , Process Engineer, Medical Molder, California

Super-engineering materials are very expensive and when you run into trouble it is surprising how quickly the material scrap cost can add up. Being prepared with the proper purging compounds and procedures can help mitigate the damages and get you back running production as quickly as possible.

We are so impressed with PF Grade. As usual, I pulled the screw for cleaning for my PEEK 450G run as I have experienced so many contamination issues. Much to my surprise, the screw and the barrel were clean! Thanks for such a great product!”
Matt M. , Molding Supervisor, General Industrial, Ohio

Purging Low-Temperature Resins

Low-temperature resins like PVC and TPU are incredibly versatile. Their characteristics make them perfect for sheet, flexible tubing/hoses, shoe bottoms, and piping. These resin types are thermally stable but only within narrow process temperatures and residence times. If machine settings and temperatures aren’t exactly perfect, you will develop carbon contamination. This is especially true during start-ups after shutdowns. Additionally, even if you effectively remove the previous resin, melt flow index and temperature range differences lead to resin issues during changeovers.

plastic machine

We've had absolutely perfect results with Asaclean®. We work with a low temp material, and E Grade has made our lives much easier. Thank you for the excellent technical support and training.”
Jake M. , Process Engineer, Compounder, Iowa
44%

On average, Asaclean® customers save 44% purging low-temperature resins.

plastic oxygen mask

Asaclean®’s E Grade is a solid choice for low-temperature applications. It’s thermally stable and was engineered with a low-residue formula. But there’s more to performance than picking the right product. Also, consider these simple tips that will set you up for success:

  1. Purge periodically even when running one color or material
  2. Aggressively displace your purge
  3. Purge during material changeovers
  4. Seal with Asaclean® to shutdown
Asaclean® Grade E works efficiently for us with Nylon12/NR blend. It makes it easy to clean the screw and barrel at 220°C processing temps.”
Saravalee S. , Engineer, University of Akron, Ohio

Two-Step Purging

We know that very few plants are only running super-engineering resins, engineering resins, or commodity resins. It’s great to know how to deal with these resins individually, but many Asaclean® customers come to us for help changing between low and high temperatures. You may run lots of different materials, and different materials usually require different processing temperatures.

We understand that due to customer demands, production needs, or scheduling requirements, a mold may need to move from machine to machine. This also causes excessive material changes. You can do everything right, but sometimes these increased changeovers may be out of your control. Often, we see these changes going from high to low melt temperatures. These are usually the most difficult changes to accomplish (especially when rushing to hit a customer deadline). What do you do when you’re on the clock and need to run good parts right away?

We have some good news and some bad news.

The bad news is that there isn’t an individual product that will solve the issue.

The use of a single purge does not allow you to change the temperature from normal process ranges to that of a super-engineering resin like ULTEM to something low temp like TPU.

Attempting this change would cause serious degradation of the low-temperature resins or freezing up of the ULTEM. In the long run, both cases cause black spots on the pieces and would likely necessitate a total teardown and screw pull.

The good news is that our Asaclean® Purging Experts have the products and the expertise to help you complete these changeovers quickly and easily. The winning solution is a two-step purge using a combination of two specialty grades of Asaclean® optimized for this production scenario.

We ran into a tough problem lately and the PF & EX did the trick! They helped us quickly go from a high-temp resin to a lower-temp resin. I really like the products and would recommend them to anyone!”
Ed W. , First Shift Foreman, Consumer Goods Molder, Wisconsin

Say you need to go from running PEEK to ABS.

You need to fully remove the PEEK from your screw and barrel, or you will have serious contamination issues.

Once you complete your work order and before you change your processing temperatures, it is vital that you fully remove all the PEEK from your screw and barrel, or you will have serious contamination and layering issues that will cause carbon build-up down the road.

First, purge the PEEK with PX2 or PF Grade following our purging procedures and gradually lower the temperature to the lower end of recommended temperature range. This will give you the confidence to know your barrel has been fully cleaned and that you are not creating layering.

Next, chase the PX2/PF Grade with our general-purpose purging compound U Grade or our stronger scrubber EX Grade and continue to lower temps and purge thoroughly. Once you are at your processing temps for the ABS you can simply flush out the U or EX and begin production with confidence knowing you have fully cleaned the barrel.

This simple two-step process allows you to make the transition from a temperature range above 700°F for super-engineering resins and painlessly step down to a lower range for engineering resins with safety and control in mind. Reverse the order and purge grades if you need to step back up to the higher range once more.

This is not a process you should try on your own. The risks are simply too high. Work with an Asaclean® Purging Expert to develop the best procedures and Purge Program for your plant.

Benefits of a Two-Step Purge

There are serious benefits of using two purging compounds for these kinds of changes.

In the short term, you don't have scrap from start-up.

In the medium term, you don't have to tear down or pull screws. This saves you from 3-16 hours depending on the size of the machine.

In the long term, these time and cost savings add up to more sellable parts and reduce overall operating costs.

While it may seem like more work, using a combination of two grades while following some easy instructions can save you hours of downtime and maintenance, as well as dramatically reduce your scrap.

interior of a car with various plastic parts

Request Your Free 10-Minute Expert Purging Consultation

If your location is struggling with high or low temperature purging, we are here for you. With over 200 years of processing experience and over 20 industry-leading Purging Compounds designed for your specific process, Asaclean® offers you the best possible combination of performance and service to get the most out of your process.

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