Often, customers approach us with a drawing of a plastic component and ask to have our engineers critique it before having the component quoted for price and delivery. On other occasions, a customer may not have time to have their print reviewed, or they are looking to be proactive in the design process. Let me outline some key features to include or not to include in your next project and show how they can save you time and money.
- Radii vs. Chamfers – Unless otherwise specified (UOS), we typically apply a light break edge or chamfer to nearly all external corners. When you design a part with radiused corners, the difficulty is greatly increased over a chamfer because there is a tangent point to be met with both faces. This drives up fixturing and work-holding costs significantly. In turned components, it is typical to expect an inside radius on internal corners (UOS).
- Stock tooling geometry – In order to reduce lead times, avoid creating geometry which cannot be milled, drilled, tapped, or otherwise machined without special tooling. Utilize SAE ports for fittings, standard threads/pitches, standard Parker O-ring groove profiles, etc. Contact us for a list of common tool manufacturers we use.
- Material choice – The higher the performance of the plastic material you choose, typically the higher the price will be. Careful plastic material selection has the potential to help hold the lowest possible cost in the life of the component. If you’ve determined the correct resin type for your part, then consider selecting a generic description of “acetal” versus a brand-specific name of “Tecaform” or “Acetron”.
- Surfacing vs. “Basic” geometry – If your ideal internal pocket has radiused corners, but you know square corners will get you 85% of the data you need, then go with square corners. If you’ve got a complex lofted profile on a surface that is part of your company’s logo- avoid it on prototype parts, consider a sticker or stamped logo as an alternative.
- Tolerancing – evaluate tolerances and determine if they are necessary. If you’ve got a thru-hole for a bolt, you don’t need the counterbore for the bolt head to be ±.0005” on the diameter.
After you’ve reviewed any applicable points outlined here, please feel free to submit your revised print/drawing to our sales engineering staff for review and efficient design evaluation. If you are looking for further improvement, or suggestions for part price reduction, be sure to note this in your inquiry.