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DIRECT DIGITAL MANUFACTURING PART TWO:ADVANTAGES AND CONSIDERATIONS

3D PRODUCTION SYSTEMS

By Scott Crump, CEO, Stratasys, Inc.Direct digital manufacturing (DDM) is a new, unique alternative for the production of end-use items. Having little in common with traditional manufacturing methods, the uniqueness of DDM changes the decision-making process, overturns old principles and creates new criteria. The primary advantage of DDM is that it removes constraints imposed by traditional manufacturing processes, such as injection molding or die casting. DDM fundamentally alters many of the “facts” and principles that govern conventional manufacturing enterprises. Since DDM is an additive process that eliminates tooling, there are many advantages that simply are not available with traditional processes. Additionally, the additive processes introduce new considerations for gauging the viability of a DDM implementation.Because it imparts fundamental changes, it is important to have a deep appreciation for both the advantages and limitations of DDM. With an understanding of the innovative benefi ts and unique characteristics of the process, companies can identify the manufacturing opportunities where DDM is a powerful alternative to conventional manufacturing methods.
Figure 1: Components for this robotic gripper were fi rst prototyped, then manufactured, using the FDM process

ADVANTAGES OF DDM

Rapid Deployment When a component’s design is complete, manufacturing can begin immediately. The lead time for fi rst articles of fi nished goods is now measured in minutes and hours, not days, weeks or months. Just moments after the CAD data is complete, manufacturing can begin because there is no production delay while waiting for tooling. Instead of waiting six to 12 weeks to complete tooling design and construction, companies can simply export the CAD data as an STL fi le and begin production.The short cycle time for delivery of manufactured items aids in reducing time-to-market and preserves on-time delivery when last minutes challenges arise. Low Capital Expenditure Eliminating tooling not only reduces time-to-market, it also reduces the cost for manufacturing. Traditional manufacturing methods demand tools and dies that are expensive. With DDM there is no need for tooling. Therefore, the initial cash outlay to ramp up manufacturing is dramatically reduced. Additionally, other capital investments, such as those for new manufacturing lines, assembly lines or specialized manufacturing equipment may be avoided or minimized.By reducing the initial outlay, companies can protect their cash fl ows, fund more new products and justify products for markets with low annual demand. Unlimited Complexity DDM promotes the design of parts for the best performance. Since DDM constructs parts with an additive fabrication process, like FDM, the design complexity is unlimited. Design complexity is not only unlimited, it is free. There is no additional cost to manufacture sophisticated, intricate and complex designs. Also, the time to manufacture a complex part is no different than that for a simple design. DDM breaks all of the rules associated with traditional manufacturing methods. The design for manufacturability (DFM) and design for assembly (DFA) rules that govern products made from traditional manufacturing methods no longer apply. Without these constraints, designs can take forms that were previously impractical or impossible. With DDM, anything that a designer can envision can be manufactured. DDM lets the imagination run free; it promotes product innovation; and it allows design to be highly optimized for performance. Severing the relationship between design complexity, time and cost is a fundamental advantage of DDM that is called “freedom of design.” Freedom to Redesign Equally powerful to the design freedoms offered by DDM are the new-found freedoms to redesign a part at any time in the product life cycle and as often as desired (fi gure 2 and 3). Since
Figures 2 and 3 : University of Central Florida electronics enclosure and the under water vehicle it belongs to. The orange vehicle frame was fi rst prototyped, then manufactured from ABSi using the FDM-based machine

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