Global Polytec Ltd.,Part.

Question by Filosun: Plastic Injection Molding Suggestions?
I plan on making a large plastic tray, HDPE (overall 26″ x 20″ x .5″)

The main panel area will be a mesh design with trapezoid/diamond shaped holes. Each hole will have 4 sides 2″ each with angles 60°, 120°,60°, 120°.
The mesh will be 0.08″ thick and 0.7″ wide.

I figure such a flat item with large surface area and thin pathways will be difficult for plastic to flow through, and I dont’ want to heat it up too much because I’ve run into shrinkage problems before.

Right now I’m thinking 450 tons or 600 tons of force, not sure about how many injection points.

Does anybody have any suggestion for how much pressure I should apply and if I need multiple injection points?

Best answer:

Answer by miggitymaggz
A picture of your tray (or 3D image) would be beneficial here.

From justifying that you have thin pathways and complex shaped holes, multiple injection sites are a probably a good idea to avoid weld lines or cold fronts, flow lines, voids, etc.

Depending on the viscosity of your resin, heat, etc. will also determine # of injection sites. There are analysis tools for composite flow, which can predict where defects are most likely to occur.

What do you think? Answer below!

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