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In general, once a material is contaminated with a hard material such as sand, it will become highly abrasive to the grinder, screw, barrel, hot runner, and mold. To regrind that much material in such a state will most likely cause significant damage, requiring repairs and possible replacement of many components. Likewise, such an abrasive material would damage the screw and most likely require a new check ring after re-processing.

If the reground material is sold or any products are sold molded with this material without the customer’s approval such an act would be unethical and most likely illegal.

Since many of the costs associated with regrinding this material depend on the material, grinder, region, as well as repair costs, it is impossible to estimate with any degree of accuracy.

This is one of the reasons it is critical to teach your employees the importance of proper handling of materials, parts, and regrind to ensure that contamination does not occur.

-Andy

Although there are many regulations, and interpretations, most manufacturers and regulatory groups can agree that safety glasses should be worn under the following machine conditions…

1) Whenever a safety gate is opened, it is considered violated, and eye protection is required. This includes mold or die changes, machine maintenance, mold or die cleaning, clearing a stuck part, and semi-automatic operation.

2) Whenever polymer is purged from the barrel, high pressures and temperatures are being released. Both eye and face protection should be used in the form of a face shield.

-Andy