Machine or mould? The choice is yours01 March 2008Protomold promoted the services of its new First Cut Prototype division to the medical sector last month. The company can now produce CNC machined prototypes in production-intent materials at the same rate as its RIM serviceRapid injection moulding (RIM) specialist, Protomold launched its new First Cut Prototype division to the medical sector at last month's MedTec 2008 event in Birmingham. The new division is dedicated to producing plastic prototype parts CNC machined directly from solid resin as quickly and easily as they can be made using a traditional rapid prototyping (RP) process, but with superior overall results. CNC machined parts have greater strength, better surface finish and more accurate dimensions compared with RP parts, which are rarely produced in production-intent materials and often display evidence of the way they were formed.
Since it began its European operations just two years ago, Protomold has built up an impressive portfolio of designers wanting to turn their 3D CAD drawings into injection-moulded parts as quickly and inexpensively as possible. Orders placed via the company's website using its innovative ProtoQuote facility typically range from 25 to tens of thousands of parts, and turnaround times can be as short as the next business day, though some restrictions do apply (the Protomold website gives details).
First Cut Prototype allows customers to make functional prototypes of products earlier in the development cycle using production intent resins. As a result, the component's physical attributes are not substantially compromised, as is often the case with common RP type processes and materials. Clearly, the mechanical properties of injection moulded and CNC parts machined from the solid do differ, but not to the extent of RP parts, which have a laminar structure.
The First Cut process is currently limited to three-axis milling from two sides. Milling commences from the one side, the part is then rotated through 180 degrees, and then milled from the other side. At the time of writing, undercuts or secondary operations are not supported by the service. An initial generous offering of prototype materials includes ABS, acetal copolymer, clear acrylic, Delrin, HDPE, nylon, polycarbonate, polypropylene, PTFE and PVC.
So, what's the difference between the many CNC machine shops that offer to cut plastic parts and Protomold's First Cut service? Protomold UK's John Tumelty explains:
"Firstly, just like when using Protomold, First Cut Prototype customers can upload their CAD models to receive a FirstQuote, a detailed cost and manufacturing analysis. Once the model is finalised, First Cut Prototype's software - running on large-scale parallel processing computers - automatically produces the tool paths and then programmes the CNC machines. This eliminates the upfront programming costs and delays typically encountered with CNC machining, turning it into a fast and affordable process for quantities of between one and ten. With conventional subcontract machining, one-offs cannot be obtained with short lead times and are prohibitively expensive."
If you're a product designer and you need all the advantages of RP - fast quotes, delivery in 1-3 days, and low cost - but with better accuracy, better surface finish and better material selection, First Cut Prototype is a very attractive proposition for these quantities. And if you need higher quantities, then there's always the established Protomold RIM service, based on fast turnaround aluminium tools, to fall back on.
"From now on, there's no need to settle for a prototype part that resembles the finished part in appearance only," John Tumelty continues. "Whatever material the designer specifies - ABS, Nylon, etc. - a part produced by First Cut Prototype will embody many of the mechanical features and qualities anticipated in the production version."Contact Details and Archive...Related Articles...Most Viewed Articles...<< Back to company search results
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