Process & Design Technologies LLC. Will be presenting two technical papers at ANTEC 2009 Wednesday June 24^th 2009 @ 10:00 am

W14

Mold Making and Mold Design

New Advances in Moldmaking

10:00 AM

0106–Uniform Mold Cavity Venting Is Far More

Critical To Balance Fill of Multi-Cavity Molds

Than Any Other Single Item

Terry Schwenk

Process & Design Technologies LLC.

Venting is a major cause of in-balance filling of multi-cavity injection molds. Typically venting isn’t looked at closely because the perception venting is fine as along as there is no evidence of burning on the part. DO NOT under estimate the effects of back pressure in the cavity due to poor venting.  The volume of air in the cavity needs to be displaced by the molten plastic. Like a syringe barrel the plunger cannot be pushed forward if the end of the needle is too small or pinched off. The size of the needle orifice will determine how fast and how much pressure is required to push the plunger forward. If you have poor venting, it will require more pressure and time to displace the air.

10:30 AM

0109–New Patented Device for Checking Injection

Mold Vents

Terry Schwenk

Process & Design Technologies LLC.

Non uniform venting is a major cause of in-balance filling of multi-cavity injection molds. The size and position of vents have been determined by either tool designers or software. The consistency and tolerance of mold vents are entirely in the hands of the tool builder. Most of the time vents sizes, position and tolerances go unchecked until there is a problem. Once it has been determined, there is venting issues the toolmaker will verify vent sizes of individual components and makes adjustments.  Until know there hasn’t be any way to check the venting of an assembly. This new device can check and verify overall vent sizing and uniformity from cavity to cavity.

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