3 Tips for Unexpected Shutdowns: Why You Need to Seal With Purge


Dealing with unexpected downtime.

When dealing with an unexpected shutdown, you are in a great position to conduct preventative maintenance and make sure you are running perfectly at startup. Today we will give some tips on how to deal with a shutdown. Then we will focus on why sealing with a purging compound may be the smartest thing you can do when you need to take a break from production.

1.) Pull the screw.  You should pull screws from machines to give a manual inspection to ensure all the equipment is in perfect working condition. It’s also a great opportunity to make any necessary repairs without impacting efficiency.  While screw pulls can cause headaches, there are some purging compounds that make the process much easier.  Check out the short 90-second comparison of a screw pull with Black ABS vs. a screw pull with Asaclean EX Grade to see the difference a purging compound can make.  

2.) Look for resin deals. As some companies try to reduce inventories, take advantage of affordable resin buys.  Some resin suppliers would like to get any excess inventory off the books.  If you think ahead, you could be rewarded for your planning.

3.) Seal the machine. The next suggested best practice comes just prior to shutting down. If you don't pull the screw and plan on going straight into shut down from last production, I strongly encourage you to seal using a purging compound. This will save you substantial time when you start back up after break.   Apply a full barrel at the end of the production run immediately before you shut down.  The sealing grade will coat the screw and barrel preventing any oxidation to occur while the machine sits idly for the holiday break.  At time of start-up when the machine gets up to temperature, displace the purge and enjoy a fast start up with better part-to-part quality.

Why is this so important? 

I’ve listed 3 basic reasons why you should shutdown & seal with Commercial Purge Compounds (CPC’s):

  1. Neutralize & Stabilize
    With the presumption that the plastic processing machine has been thoroughly and effectively cleaned (or purged) prior to shutting it down, you want to park the shutdown purge inside and let it reside in there for the duration of it being idle. This will neutralize & stabilize the machine. Over the long run, this will reduce wear and tear on the equipment and prolong the life.
  2. Preventing Degradation:
    Generally, there are 3 main components that can cause production resins to burn and inevitably lead to contamination issues: 1.) Time; 2.) Heat; and 3.) Oxygen. By leaving a thermally-stable shutdown purge parked in the machine, you prevent oxygen from entering the system. By removing one of these 3 main components, you put yourself in a much better position to prevent degradation, due to the simple fact that presence of oxygen is not there. Furthermore, when the temperature zones drop on shutdown and the machine cools off, the shutdown purge will follow suite, cool off too and shrink. As the shutdown purge shrinks and it pulls away from the barrel and screw surfaces, it ingests (or attaches to) the contamination and pulls it out with itself one the start-up.
  3. Promotes faster and easier start-ups while generating less rejects: This is the “Holy Grail.” In my opinion, this is where the most value of the shutdown purge is squeezed out. Minimizing machine downtime, while lowering production resin waste, purely saves money and increases productivity. Who doesn’t want this, right?

For more information on shutting down and sealing, please request a free consultation with one of our Purging Experts.


Topics: Troubleshooting, Injection Molding, color contamination, carbon specs, carbon contamination, Screw Pulls, preventative purging, value added, Cost-per-purge, cost-per-pound

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