Page 103 - Injection Molding Advanced Troubleshooting Guide
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88 9 Drying
9.4 Material Handling
It is important to understand that just because a material has been dried to an
adequate level does not mean it will stay there. If you expose dried material to am-
bient air that has humidity in it the material will begin to absorb the moisture like
a sponge. Many materials will be too wet to effectively process if exposed to ambi-
ent humidity for longer than 15 minutes. To avoid this creating splay problems,
ensure that minimal material is allowed to be outside the drying hopper as it is
transported to the press. This can be accomplished in a couple of different ways
in cluding:
Use of small one-shot hoppers on the molding machine (see Figure 9.4):
This will keep the volume of material outside of the drying hopper minimized.
Set the proximity switch on the one-shot hopper according to the required shot
volume.
Figure 9.4 One-shot hopper
