Plastic Injection Mold Design Checklist

Why use a checklist?

It might not seem necessary to use a checklist, but it is a very good idea. Some of the obvious reasons are as follows:

Everyone follows the same procedure. As a mold maker, it is frustrating to have designs by different designers who follow different standards. Probably the worst is to have the views done differently. Talk about a formula for disaster!

Errors are minimized. With a checklist it helps to reduce the chance for error. Often the title block has skimpy information and this only wastes time for the mold maker, who must find out the steel type, or customer number, etc.

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Preliminary Drawing Checklist Items:

General layout

"A" side plan

"B" side plan

Front Section

Side Section

Title block is completely filled out on all drawings

Abbreviated BOM with ordering information for the Mold Base and primary Steels

Cavity Location

Parting line locations (Acceptable to customer)

Ejector Pin Layout (Acceptable to customer)

Waterline Layout

Balanced Runner layout

Gate type, and size specified

Side Action types & locations are shown

Concept of Tool operation

"O"  & "R" Dimensions noted

Note "Top of mold" & "Operator Side"

Will the tool fit in the correct press size

Knock out Locations

Support pillar layout

Final Drawing Checklist Items:

All Preliminary Mold Drawings Requirements completed

Full Bill of Materials, Base Information, stamping notes, ejector information, special notes

Detailed views of every non-standard component.

Enough views, sections, iso views exist to adequately show part detail

All details are labeled with the detail number, name, material type, number required, Hardness, and surface finish.

Check All water lines for interference, including clearance for jiffy-plugs

Check Guide Pin length and clearance

Spring loads calculated & checked

Drawings appear to be adequately dimensioned

Critical Dimensions are noted

All "fit" areas are specified for each insert, side action, and core.

All draft is specified for cavity area, core pins, ribs, etc.

Check all side action angles and travel

Check for bad steel conditions (sharp edges, thin sections, too little shutoff, too little angle)

A & B Plan assembly views have been compared

All details from the assembly and plan views have been compared to the detail sheets.

All surface finishes are specified

Drawings are checked to the "Mold Info Sheet".

*  Typically, by approving the Final designs the customer certifies that the drawings are dimensionally accurate, that critical areas have been noted, and that we can proceed with final machining, fit, and finishing.

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