In Reply to: Quoting Formulas posted by Wayne Bogardus, Jr. on 09/25/03 at 10:09 AM:
I'd like to be able to post standard forumulas for injection molding, but it's generally more complicated than a single equation. Variables include material cost, cycle time, # of cavities, press size, and the type of material itself. Annual volume also plays a role in pricing.
If you are doing high volume production (>200k units/year), you SHOULD be able to buy your parts for between 2.5 and 3X material cost. If you are doing less volume, or working with a special material or process, all bets are off.
Part costs will be very dependent on design, so it is important that you have a competent plastics designer review your parts. Otherwise, you could be unnecessarily paying too much for your parts for the life of a tool.
Hope this helps, and good luck!