By Brad Cleveland, Protomold
With vast amounts of revenue riding on virtually any new product brought to market, the cost of prototyping is not likely to be anyone’s first consideration in directing the development process. Still, cost matters; just ask your CFO.
Of course, the biggest cost you could possibly incur is that of bringing a poorly conceived or badly executed product to market. It could exceed everything you’ve spent on development, production, and marketing, not to mention lasting damage to your company’s reputation and position in the market. Another significant cost is the delay incurred by having to backtrack if problems are caught late in the development process due to inadequate prototyping. The costs we’re addressing here, however, are the simple, up-front costs of various prototyping methods.
The graph at the right represents the relative costs of the three prototyping options: Cut (e.g. CNC milling), Mold (e.g. rapid injection molding) and Build (e.g. 3D printing). The greatest disparity comes with the very first prototype: 3D printing is somewhat less expensive than CNC machining, and rapid injection molding, due to the cost of mold milling, is significantly more costly than either of the other two. The exact trajectory of each of the trend lines will, of course, depend on the material being used and the complexity of the part.
Because it has low fixed costs, the total cost of 3D printing starts low and climbs at a steady rate. The last copy costs the same as the first with no economies of scale.
Like 3D printing, CNC machining also has low fixed costs and total cost rises at a steady rate. Typically the cost of each machined part will be somewhat higher than that of a similar part produced by an additive process.
The cost of rapid injection molding is relatively high for the first 25 parts but climbs far less steeply than the cost of CNC or 3D printing.
Clearly, the relative cost per part will depend largely on the total number of parts required, and this will affect the way each method is used. For example, in the earliest phase of development, when the likelihood of change is great and parts are being made in small quantities, RP may be the ideal method. In the early phases of functional testing, when material properties are critical, developers might switch to CNC machining despite the somewhat higher cost per part. And finally, when a lot of parts are needed for extensive laboratory or market testing, rapid injection molding will be the most cost-effective alternative. And, of course, rapid injection molding is a very affordable approach for moderate-volume production or for bridge tooling while steel molds are being made.
|Cut, Mold, or Build|
|Part I||Three Ways to Make a Horse|
|Part II||Comparative Strength and Finish|
|Part III||Comparative Speed|
|Part IV||Comparative Cost|
About the Author
|Brad Cleveland, President and CEO
The Protomold Company, Inc.
1757 Halgren Rd.
Maple Plain, MN 55359 – USAPhone: 763 479 3680
Fax: 763 479 2679
|Brad Cleveland has been the president and CEO of The Protomold Company, Inc. since November of 2001. Prior to Protomold he was cofounder and vice president of AeroMet Corporation, a laser additive manufacturing company and subsidiary of MTS Systems Corporation.Protomold®, a Proto Labs service, is the world’s fastest source for custom injection molded parts. The company fills a unique niche in the manufacturing of plastic parts, using a combination of advanced, proprietary software and sophisticated equipment to produce prototype and low volume runs of custom injection molded parts. The material properties of Protomold’s real molded parts surpass those of parts produced by additive prototyping processes. At the same time, delivery is faster and costs are lower than those associated with traditional injection molding.|
The views, opinions and technical analyses presented here are those of the author, and are not necessarily those of UL, ULProspector.com or Knowledge.ULProspector.com. While the editors of this site make every effort to verify the accuracy of its content, we assume no responsibility for errors made by the author, editorial staff or any other contributor. All content is subject to copyright and may not be reproduced without prior authorization from Prospector.