Modern Machine Shop

JUN 2018

Modern Machine Shop is focused on all aspects of metalworking technology - Providing the new product technologies; process solutions; supplier listings; business management; networking; and event information that companies need to be competitive.

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Page 42 of 204

ADDITIVE INSIGHTS MMS JUNE 2018 40 Understanding Industrial 3D Printing The Many Possibilities of AM Additive manufacturing (AM) provides design and material freedoms for making parts that are impossible or too expensive to fabricate with traditional manufacturing processes such as milling and casting. Although design for additive manufacturing (DFAM) has its limitations, it also enables new opportunities like lattice structures, conformal cooling channels and more. We often think only at the part level for DFAM, but it can be applied at the assembly and system levels as well (see figure below), and different benefits accrue at the different levels. The many possibilities of AM outweigh the limitations. Yet being enamored with these attractive pos- sibilities—the "what" and the "how" of AM—still doesn't get us to the "why," the ultimate reason for using AM. It has to deliver on a value proposition. As William Brindley from Pratt & Whitney once told me, "We aren't going to fly a 3D-printed part just because it's cool. It has to buy its way onto the engine just like any other part." Cost is only one factor that potentially drives this acceptance. Quality and time (speed) are the other two main drivers, and AM can help improve all of these when used effectively. For instance, lattice structures can be used to create lighter-weight components with better strength-to-weight ratios. This improves part quality while reducing the cost of AM by using less material and build time to make the part. This may even enable a material substitu- tion, improving the life and durability of the part. In medical applications such as implants, lattice struc- tures improve osseointegration, which improves bond strength and helps patients recover faster. Over time, this leads to fewer implant revisions, fewer replacements and ultimately fewer surgeries. Topology optimization also can be used to create lightweight structures for aerospace or space struc- tures. Why is light weight good in these applica- tions? I have seen estimates that saving 1 kilogram of weight on a plane saves $3,000 a year in fuel costs. In space applications, the savings jumps to $10,000 per kilogram of weight saved, or the com- pany can trade the weight savings to haul more payload, making the launch more profitable. Com- panies also save money because they improve their material-use buy-to-fly ratio, which I have seen as high as 80-to-1 in some cases. Less material is needed to make a topology-optimized component, reducing material costs and build time, and less scrap is produced. AM also can be used for functional prototyping and replacement parts. This gives companies a speed advantage, improving flexibility and agility by reducing product development time and man- ufacturing lead time. Printing replacement parts on demand can reduce inventory carrying costs in companies and improve logistics and support in military operations, especially in remote locations. Reduced tooling needs make AM useful for TIMOTHY SIMPSON | COLUMNIST Design for additive manfuacturing can be applied at the par t level (restrictive and oppor tunistic) as well as at the assembly level and the system level to improve cost, time and qualit y. Why would anyone want to use additive manufacturing? Localize with AM Optimize for AM Simplify with AM Customize with AM Replicate with AM SYSTEM DFAM ASSEMBLY DFAM OPPORTUNISTIC DFAM RESTRICTIVE DFAM COST TIME QUALITY Adapt for AM

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