Wednesday, March 23, 2011

Plastic Part Quote From Using My Inventor Parts

I recently sent a couple of small part files out for quote to several injection molding companies. Most of these were local companies or companies we'd done business with in the past. But for the sake of due diligence (and curiosity) I sent these parts to as well. I thought I'd take a moment and share some of the feedback I received from them. 

First off, I should state that the Protomold price and lead time were very competitive with most of the other shops we obtained quotes from.

One of things that was nice about the Protomold quote is that it was provided online and was adjustable in the Specifications area, which allowed me to change various options such as Finish, Quantity, Material, etc. and see the price per piece update based on the changes. This was particularly useful on this project, as part of the design decision was deciding if it was cost effective to have these parts injection molded (versus buying and machining off the shelf components). 

(some information has been "black blocked" for privacy)

The next part of the quote is the Review Issues section. For this particular part Protomold found 7 issues with the STEP file I submitted. These issues were categorized, and in my case I had 2 issues that "Required Changes". Both of these were due to my part file containing incorrect drafts on the faces of holes that I added or changed at the last minute, but forgot to adjust the draft on.  I had 3 "Moldability Advisories" which included suggestions about the texture of the finish, etc. 

These issues could have been caught in Inventor had I remembered to use the Analysis tools again after making changes to the model. I used these to verify the changes I made after the Protomold pointed them out (better late than never, huh?).

There were also 2 "Other Info" issues,  informing me of minor changes that would be made to the finished product, due to the milling process. In my case these involved sharp edges in my model that would actually end up being small radii in the real part, and were not of concern.

Of course many of the other shops I spoke with provided feedback on the models I submitted as well. As is common, they suggested minor changes to the parts to allow them to manufacture them in a more cost effective way  via email or over the phone.  But being a CAD person, the Protomold feedback was particularly interesting. 

So the next time you're requesting quotes for injection molded parts, you might submit it to as well, for some very helpful feedback and a competitive quote.