Cost Saving Solutions

Preventative Purging

Purging is usually included as part of preventative maintenance mostly in terms of helping with screw pulls. This section focuses more on how to use purging preventatively to avoid issues in the first place. Preventative purging is a smart addition to any preventative maintenance plan. Your overall approach to purging impacts your ability to produce efficiently. If you wait until you notice contamination in your finished product to clean your machines, the result is usually longer production runs and excessive machine downtime. If you’ve never considered purging as part of your preventative maintenance before, you’re in luck. Asaclean® Purging Experts have seen it all and can share easy suggestions on how to improve efficiency with a proactive approach to purging.

Practice Preventative Purging During Preventative Maintenance

A lack of a preventative purging program may be costly in terms of plastics processing inefficiencies and production downtime. Preventative purging is focused almost solely on ensuring better part quality to give plastics processing equipment greater availability. When you focus on making your machines run better, precision and high output are naturally achieved.

The key is to not let your extruder or injection molding machine condition get so bad that a purging compound isn’t sufficient for a thorough cleaning. In these poor conditions, a manual screw pull may be necessary (which results in even more costly downtime). A preventative purging program helps to reduce production downtime going forward. Consult your Purging Expert for proper preventative purging procedures.

The Best Offense is a Good Defense

In plastics processing, waiting, and reacting to carbon or color contamination is a recipe for draining your profits. Many companies think of purging costs solely as the price of the purging compound they use. But this is an incomplete picture. The time it takes to start-up and begin producing quality products, your scrap and reject rates, and machine downtime are just some of the costs associated with purging, and they all have a significant impact on your bottom line. If any of these figures are too high, you’re missing out on critical cost savings. We can help.

The U Grade keeps the screw and tips clean and eliminates the need to pull the screw for anything but regular preventative maintenance. This has been a major cost savings for us. I estimate that for this product line, U Grade reduced restart time by 60 percent, and eliminated unscheduled screw pulls (possibly 12 per year). Asaclean® has raised the bar for all purging compounds."

Mike N. , Process Technician, Consumer Goods Molder, North Carolina

66%

Asaclean® customers save an average of 66% when dealing with Color Contamination.

Here are four preventive purging procedures to help you reduce scrap rates:

1. Use an Adequate Amount of Asaclean®

Insufficient purging during downtime and changeovers is one of the most common causes of high scrap rates. When plastics processors don’t use enough purging compound, defect rates increase. Some companies tell machine operators to use a specific amount of purging agent, encouraging a one-size-fits-all approach.

However, the required amount of purging compound for each changeover varies by situation. For example, the more time that has passed since a screw pull and manual cleaning, the more contamination you’ll see in your system.

We will train operators to purge until cleaning is complete, within a certain tolerance range, prior to contacting a supervisor. Putting a machine back into production after using a preset amount of purging compound is not advisable.

Overuse is also a potential issue here. You don’t want your operators using more Asaclean® than is necessary, because waste is the enemy of profitability. Overuse isn’t in anyone’s best interest.

2. Seal Your Machines During Shutdown

To prevent contamination, it’s important to seal your machine with a thermally stable purging compound like Asaclean® U Grade during machine shutdowns and excessive downtime events such as PMs. Residual polymer degradation can delay machine startup and lead to excess material waste. Whether during a temporary or extended shutdown, sealing your machine is an essential step toward minimizing scrap rates.

3. Purge During Startups

At startup, extrude the sealing purge and follow up with one or two barrels of fresh purging compound before starting production. This aggressively removes contamination and carbon buildup that was pulled away from metal surfaces during sealing. Implementing this purge as part of your startup procedures helps reduce the time required to get up and running.

4. Purge Between Color & Material Changes

Whenever you change resins or materials, it’s critical that you purge your machines to remove previously run materials and protect against color contamination in your next batch. Although this is an additional step, the cost of including it in your purging procedures pales in comparison to the wasted materials caused by rejects.

Many plastics processing companies suffer from excessive material waste due to contamination during startup and changeovers. This is an unnecessary and avoidable cost. To avoid costly machine downtime and increased scrap rates, take a preventive approach to your purging procedures.

How Preventative Maintenance Impacts Your Profitability

Carbon buildup and contamination require screw pulls. Though screw pulls may be mandatory on a periodic basis, manufacturers who fail to take preventative measures will suffer from unplanned downtime and be forced to manually clean their screws far more frequently. The costly impact of machine downtime has long been documented.

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

But there’s another side effect of abrasive, manual screw cleaning: Over time, it slowly erodes the screw and limits its useful life. Because preventative maintenance and purging minimizes the need to take such drastic measures, it extends your screw and tooling life.

In addition, a proper maintenance program reduces your scrap rates, customer rejects, and line shutdowns. Many plastic processors suffer from incredible material waste due to contamination during startup and changeovers. This is an unnecessary and avoidable cost.

You must take a preventative approach to purging procedures to avoid costly machine downtime and increased scrap rates. Stop killing your profitability and start taking calculated measures to maximize your efficiency.