Cost Saving Solutions

Screw Pulls

Screw pulls (or screw pushes in extrusion) are one of the biggest headaches that processors and maintenance teams face. If you’re not using purging compounds to assist with screw pulls, your production stops in its tracks and your team can spend countless production and man hours on one aspect of production. This derails your profit potential.

Let’s take a deeper look at how Asaclean® can help you transform how your plant deals with screw pulls/pushes.

There are two main kinds of screw pulls: reactive (contamination-related), and proactive (preventative or application-related). Asaclean® offers the industry’s best solution for both scenarios.

Asaclean® helps you all but eliminate reactive, contamination-related screw pulls. For the proactive scenarios where screw pulls are necessary, our EX Grade is a secret weapon that facilitates the easiest and fastest screw pulls you’ve ever seen.

How to Avoid Contamination-Related Screw Pulls

When it comes to contamination-related screw pulls, you have two options.

They can either be inevitable or they can be unnecessary.

These choices depend largely on how your plant approaches preventative maintenance and purging. In our experience, most screw pulls are unnecessary.

Because screw pulls are commonly performed only after a problem is detected, most plants are focused on addressing the immediate problem, and not on how costly the cleaning truly is.

Removing your screw from your machine without a purge requires great effort, and the cleaning itself takes hours of manual, tedious scrubbing. You must remove the layers of resins or contaminants that have accumulated around the screw. This excessive downtime is certainly affecting your company’s bottom line.

If you’re running until failure, or running until you experience severe contamination, there are easy solutions that can make your life much easier in a hurry.

EX Grade is an unbelievable product for pulling screws for our maintenance department. It helps us get back up and running in a matter of minutes.”

Vincent Zirkle , Blue Ridge Molding, Plant Manager, Consumer Goods

92%

Asaclean® customers save up to 92% on screw pulls.

Here are 4 easy ways Asaclean® can help reduce screw pull frequency:

1. Purge during color/material changes to keep your screw and barrel clean

We recommend purging between each color or material changeover. This will reduce changeover time and will prevent contamination from occurring in the screw and barrel.

Of course, you should rely on your data (such as scrap rate & defect percentage) to determine how often you should purge as a preventative measure.

2. Purge periodically on longer runs to avoid layering or carbon deposits

Many processors who lean on reactive screw pulls do so because they are running one kind of material or the same colors all the time. We understand this approach might be tempting but running without periodic purging is no different than purging with regrind/virgin.

Eventually, layering will occur, and you will be forced to stop production. Spending a little bit of time purging is much more beneficial than an hours-long teardown. How frequently you should purge depends on the materials you’re processing.

We use an Asaclean® Purge Program for preventative maintenance. It is great for preventing screw pulls & downtime. If you do need to pull a screw, it makes them a breeze.”

Troy F. , Maintenance Technician, Medical Molder, Indiana

3. Seal with a purge during extended shutdowns

Sealing your screw and barrel with an appropriate, thermally stable purging compound is critical during machine shutdowns. Whether during weekends or extended holidays, you must create an airtight environment to remove oxygen from your barrel and eliminate the possibility of degradation. Production resins are not designed to clean. Starting up with purge in your machine will help you start production with good parts.

4. If you do notice contamination, purge with a strong cleaner like EX Grade

When you notice black specks or other contamination, the situation might not be severe enough to justify a complete teardown. If you catch the problem early, scrubbing grades like Asaclean® EX Grade can efficiently remove all contamination and get you back to running good parts in no time.

The EX Grade has always been great with avoiding screw pulls and removing carbon. The EX completely cleaned out all the degraded material. We followed the EX with the U Grade and then were able to go directly into production on one of our clear styrene parts with no contaminants. Without Asaclean® we would certainly have had extended downtime and scrap.”

Lucas G. , 2nd Shift Lead, Custom Molder, Consumer Goods, Southeast

The best way to combat contamination is not to make it in the first place.

Using Asaclean® at regular intervals will keep contamination from beginning, and it typically only takes 1-3 barrels full of purging compounds to prevent or correct contamination. Most operations would much rather have a short, planned purging-related downtime event, than an unplanned screw pull.

It sounds simple because it is. If you follow these 4 steps, you’ll avoid unnecessary screw pulls and countless hours of tedious work and downtime.

Now that we’ve looked at ways to avoid most screw pulls, let’s take a quick look at some of the more common situations where screw pulls are necessary.

How to Optimize Planned Screw Pulls

Most successful plastics companies pull/push screws as part of preventative maintenance. They do so not just to clean the screw, but also to get wear measurements on the screw and barrel. Extruders require screw pushes because they sometimes need different screw designs when running different kinds of materials. This is especially common amongst compounders. This kind of change cannot be avoided. We also see mandatory screw pulls in the medical and pharmaceutical markets, as well as in food packaging. Also, sometimes things just happen. Someone might forget to turn the heats off, or a shift might forget to purge between runs.

Just because these planned screw pulls are necessary, doesn’t mean they have to be a nightmare.

Screw pulls are not a big deal anymore. EX has drastically reduced the screw pull and replace time. In fact, when we do a screw pull, removing the Asaclean® is like peeling a banana. We can quickly do our inspection and rebuild without any difficult cleaning. So we cut the time from 12 hours to 4 hours, and our cost from $2,160 to $741.”

Rich M. , Production Manager, Film Extrusion, Packaging, KY

Asaclean® EX Grade will completely transform your screw pulls. This product was engineered specifically for deep cleaning and was optimized for screw pulls. It is the strongest cleaner available, and it comes off the screw like a banana peel. You won’t need a wire brush or intense manual labor. Watch the video. It’s that easy. This will save you countless labor hours spent cleaning the screw. Those team members can work on other projects and you can run more finished products.

With Asaclean® EX we can pull a screw and it is spotless. We had a screw supplier examine the screw after purging with EX and he was amazed by how clean it was. He told me he’s never seen a screw come out that clean. I too was amazed since that press runs a lot of black 10% glass-filled PC. After purging with Asaclean®, it was clean. I mean spotless.”

Brad B. , President, Custom Molder, Ohio

Here are some of the main benefits of using Asaclean® EX for screw pulls/pushes:

The easiest solution for changeovers or severe contamination
Reduces required force
Minimizes manual cleaning
Less screw handling = fewer injuries
Decreases overall changeover time

Consider this recent customer example. A wire extruder reached out to us for help with screw pushes. He was spending 12 hours on each screw push. This cost them approximately $1,500 in downtime. Overhauling seven extruders every three months, the manufacturer lost $42,000 a year.

We gave them EX Grade to use to help with every screw push. The company cut their downtime from 12 to three hours and saved over $25,000 each year. We’re working with them to implement a preventative Purge Program which will help them save even more.

A good technical sales rep will be able to assist in determining the best temperature range and techniques for a specific grade when pulling a screw. It is important to request specific procedures for this from the purge provider as it is critical to pull the screw at the correct temperature to avoid either difficult pulls at the low end, or messes at the high end. The purge should have just the right viscosity to assist the operator in pulling, while remaining stuck to the screw, and not on the floor.

While it may seem more costly to purge on a periodic basis, preventative measures significantly reduce the risk of reactive measures that are incredibly expensive. Rather than put your profits in jeopardy, start implementing purging procedures that combat color and carbon contamination, and cut down on the need to perform manual screw cleanings. When screw pulls are necessary, using glass-filled purging compounds can facilitate the screw pull process and significantly reduce the downtime.

If this all sounds simple, it’s because it is. If you do these things, you’ll avoid countless hours of work.