cold slug

cold slug

[′kōld ‚sləg]
(engineering)
The first material to enter an injection mold in plastics manufacturing.
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References in periodicals archive ?
It also offers options with which users can specify runners, sprues, and Cold slug wells.
This process results in a lower cavity and gate area temperature, lower injection pressures at injection start and no pushing into the product a cold slug as is normally the case with single heater hot runner systems.
Or, in one example, "a PVC pipe was found to have a crack that was caused by a cold slug from the molding process." Such cracks can ultimately lead to part failure, and potentially, litigation.
We all know it is a good idea to have a runner overflow well at every runner turn, to capture any potential cold slug. The same logic applies to the end of the runner.
According to the company, the exact location of the tip in the cavity insert--reaching all the way to the part surface--ensures that there will be no cold slug; instead, a clean gate break is produced.
A dimple can be used to aid flow at the gate because it permits a well for the frozen cold slug to be blown into.
If it is fully solidified, it is called a cold slug. Cold slugs typically cause a spike in the initial injection pressure as the screw tries to push this solid mass out of the nozzle tip.
This causes excessive heat loss that will result in a cold slug, drooling, or stringing, all of which cost molders thousands each day.
This cold slug remains in the gate during the mold-open step, part ejection, and mold-close motion.