Slide Products Sticky Situations Enewsletter
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2-Shift Purge Process Reduced from 16-24 Hours to 35-45 Minutes

It was taking up to 24 hours to make a color change.

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Two-shift purge process slashed to minutes
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Two-shift purge process slashed to minutes

A maker of twist-off bottle caps constantly needed to make color changes. The problem was it took 16–24 hours of purging and cleaning to accomplish a single color change. Using a procedure they developed in-house, the molder would purge over and over using several different types of material. Equipment was shut down for 2-3 shifts.

It’s not unusual to find molders using resin to purge. The cost/pound of resin is less than the cost/pound of a purging compound. But what this molder experienced amplified where the real cost of purging is found...the time invested in purging is time molders aren’t making product.

Located in Mexico with few technical resources to help them find a better procedure to re-capture lost time, they contacted one of their distributors for plastics processing supplies, located in Mexico City, for on-site support.

Recapturing two-shifts of production

The distributor contacted Slide Products and a technician from Slide’s headquarters in Illinois went to the molder’s Mexico plant. The technician’s expertise and understanding of all the issues involved, such as completely clearing all old resin from the barrel, hot runners and mold, plus selecting the appropriate purging compound, helped to initially reduce purging time to just 3 hours. The molder instantly re-captured two full shifts of production.

Reducing purge time to minutes

The next goal...reduce purge times to just 60 to 90 minutes. This required a great deal more research. Slide’s technician invested more time investigating the molder’s equipment, materials and procedures.

Armed with this wealth of information, Slide’s technician again flew to Mexico, and along with the help of the local Slide representative and the molder’s foreman, purged the barrel, screw AND the mold in just 55 minutes. A few more tweaks and purge times shrunk to 35-45 minutes.

The right purge and the right procedure

Today, the molder continues to have positive results using the right purging compound with their new molding procedures, now molding parts instead of cleaning a machine.

A phone call wouldn’t have the same results

Phone support can help most molders achieve a faster purge. But some issues benefit from hands-on support. In this instance, where so much time was lost to purging, on-site problem-solving was worth the investment.

The Slide technician recommended N.P.T. purging compound, based on the resin being used, the issue with color changes, as well as an audit of the equipment being used. N.P.T. effectively operates at temperature ranges from 160°-600°F. and removes all traces of barrel residue.

N.P.T. consists of concentrated purge pellets that react chemically to heat, quickly and effectively, cleaning machinery without extra soak time, excess downtime or lost productivity.

For technical assistance to help reduce your purge times, review the purging options and even use a purge cost calculator, go to

Learn more about mold releases, cleaners and rust preventives

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