Sometimes it is appropriate to adjust the design of the part to accommodate the need for ejection pins to push the part out of the mold. For example, Figure 2 illustrates how an injector pin "landing pad" has been integrated into the wall of a part design in order to provide sufficient material for the full diameter of the pin to meet the part. Landing pads may also be used to provide additional support for the ejection of thin curved walls, and in some cases the pins themselves can be contoured to fit the shape of the part.

Of course, always remember to provide as much draft as possible so that the ejector pins can do their job, especially for applications where it isn't possible to use mold-release lubricants to help the part eject more easily.

Each situation is different, but a good understanding of the use of ejector pins is important when designing a part to be Rapid Injection Molded.

You can visit the Protomold Design Guide for other helpful Rapid Injection Molding design information.

February Designer Survey: How would you rank your level of expertise in designing plastic injection molded parts?

January Designer Survey Results:

We asked, "How many new part designs do you prototype on an annual basis?"

More than three-fourths of the roughly 200 respondents prototype a new design at least once a quarter, and many as often as more than once per month. Given the conventional lead time of 6-8 weeks for conventional injection molding, the advantages Rapid Injection Molding are clear.