General Process for Plastic Molding

aPriori’s plastic molding process model assumes all the following:

• Single part (multiple mold cavities are supported, but each cavity must handle the identical part design)

• Single shot

• Single material

• Single color

• Two or three plate mold

IM and SFM support thermoplastic material only. RIM supports thermosetting plastic only.

Subprocesses and Machine Types

The model also does not support any of the following subprocesses and machine types:

• In-mold labeling

• In-mold assembled components

• Insert molding

• Co-molding

• Over molding

• Stack molding

Material Utilization

The process model assumes the following regarding material utilization:

• Flash is minimized due to the high clamping capabilities of the machines.

• Some setup time is required to test molding. All parts created during mold testing are scrapped, and costs for this scrap are included in the overall cost of the part. See Other Direct Costs for Plastic Molding.

• During processing, individual part waste is a function of the required volume of runners and (for IM and SFM) the available regrind amount. (No regrind allowance is made for RIM, since thermosetting polymers cannot be reused.) The percent yield of the process is also a function of the average utilization of the machine, as well as mold efficiency. Typical yields are 95%. See Operation-level Feasibility and Routing and Material Utilization for Plastic Molding for more information.

Additional Limitations

The model

• Does not attempt to estimate the required number of hot drops. You must enter this number manually by using Process Setup Options.

• Does not account for part defects like sink marks, short shots, bubbles, warping, or ejector marks.