H - Polymer Processing Glossary of Terms

Hardness - The resistance of a material to compression or indentation. Among the testing methods Brinell, Rockwell, and Shore
HDPE - High density polyethylene
Heat deflection or distortion point - The temperature at which a standard test bar deflects 0.010 inches under a stated load of either 66 or 264 psi. Indication of maximum temperature that you can eject a part from a mold.
Hold (2nd Stage Pressure) - Sufficient pressure applied to cavity that doesn't allow plastic to flow into or out of the cavity until the gate is frozen.
Hopper - Feed reservoir into which material is loaded from which it falls into a mold machine's injection unit.
Hot runner mold - Type of runnerless mold. Runner is not ejected with part each cycle

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