You've Got to Check This!
"Flaps 10 degrees………check, cabin air intake………check, landing light………check."
Ever dream about being a pilot running through your preflight checklist with your co-pilot? Well, now as a designer, you can have almost as much fun when you design plastic parts using the Protomold Plastic Part Design Checklist. You too can be confident you won't miss a single aspect of parts design when you use this handy resource tool.
Like a pilot's preflight routine, our checklist below is a handy reminder of some of the considerations to keep in mind when you're designing injection moulded plastic parts.
And, in addition to our checklist, we've catalogued dozens of tips that can aid in making your parts easier to manufacture, lighter, stronger and offer improved performance. Each tip is chock full of great manufacturability pointers, including coring out, preventing sink, drafting for easy ejection, adding text, and more. Some of these useful design tips are referenced in the designer checklist; or you can download our complete Design Tip compilation volumes here.
Also, you can access ProtoQuote® automated design analysis, which can help to identify potential design problems once a 3D CAD model has been submitted. These free services allow you to quickly see issues that are easy to overlook. Our suggestions and recommended design modifications are returned to you just one day after your part is submitted.
Try our Checklist! It's a practical tool that allows you, the designer, to spot potential issues and correct them beforehand.
PLASTIC PART DESIGN CHECKLIST:
Designing with Protomold in mind
Design Considerations
Are the cores and holes drafted towards the ejector pin side (low cosmetic side) of my part?
YES
Does my part design include sufficient draft for part removal from mould?
YES — We strongly advise using at least 0.5 degrees on all "vertical" faces. Learn more.
Do I need to add draft to my design?
MAYBE — For aluminum moulds, increments of 0.5 degrees (shallow features) to 3 degrees (deep features) should be added. A good rule of thumb is 1 degree per 25mm depth including cam/side pull cores.
Does my part have a wall thickness that is greater than 1mm and under 4.5mm?
YES
NO — Parts under 1mm may produce a part that has shorts, voids, weak knit lines; parts over 4.5mm may have excessive sink, internal voids, warp, poor texture pick-up.
Learn more — recommended uniform all thickness for Protomold
Materials
What do I need to consider when selecting a material that is best for my design?
- Selection of the proper material is crucial to part production. Designers should consider the mechanical characteristics, moulding properties, and cost of the resin used.
Learn more about material selection.
Dimensions
Does my part have two dimensions that are larger than 6.35mm and less than one of the following? (Dimensions (in mould) = X x Y x Z (depth of part))
- 770mm X 340mm X 6mm
- 720mm X 290mm X 25mm
- 670mm X 240mm X 50mm
- 620mm X 190mm X 76mm
YES — proceed to Volume
NO — My part is over 76mm.
My part is over 76mm deep, is my parting line in the middle of the part?
YES — Learn more.
NO — Protomold may not be able to mould your part
Volume
Does my part have a volume greater than 82mm3?
YES — proceed
NO — Protomold may not be able to mould your part
Does my part have a volume less than 966,837mm3?
YES — proceed
NO — Protomold may not be able to mould your part
Surface Area
Does my part have a surface area of less than 112,413 square mm?
YES — proceed
NO — Protomold may not be able to mould your part
Geometry
Is it a straight pull mould?
YES — proceed
NO — Off angle geometry may need to be modified or cams/side actions need to be applied
I DON’T KNOW — learn more.
Undercuts
Are the undercuts located towards the outside of my part?
YES — Proceed to next question, Protomold may be able to use cams/side actions to mould the undercut
NO — Pass through cores or filling in the undercut geometry will be required. Protomold can certainly mould your prototype parts, however may not be able to mould your production parts. You could cut the undercut geometry with a secondary operation for testing or low volume production.
Is the undercut on my part less than one 213.84mm X 60.38mm X 73.66mm? (Dimensions (in mould) = Horizontal x Vertical x Depth of cam pull)
YES — Protomold will use cam/side action to mould the feature
Learn more.
NO — Can you use sliding shut offs?
Read past Protomold Design Tips on Sliding Shut Offs:
October 2006
September 2007
