Simple Solutions That Work! Issue 16

FLEXIBLE MANUFACTURING & ENGINEERING TRENDS 55 Continued on next page CHRIS BECK Manager of Operations/ Co-Owner Innovative 3D Manufacturing ARTICLE TAKEAWAYS: • •DMLS metal parts vs traditional cast counterparts. • Considerations for using DMLS Additive Manufacturing for Aerospace Components T he hottest and trendiest topic in manufacturing today is Additive Manufacturing. Additive Manufacturing (AM) also known as 3D Printing can produce parts from plastic and metal. There are 3 common plastic processes and 5 common metal processes available today. Our article will focus on DMLS (Direct Metal Laser Sintering) also known as SLM (Selective Laser Melting) and sometimes referred to as Powder Bed Fusion. This process lays out layers of powdered metal from 20 to 100 micron then melts the area of the part to the prior layer. It’s a truly amazing technology that creates parts that are 99.5% dense. PARTS FOR AEROSPACE There is a fair amount of skepticism regarding the quality and density of parts that are built by the DMLS process. Frankly, I was one of those guys too. When we first started researching the process and looking for capital equipment to purchase it was a true eye opener. Not only can you make near net complex shapes with internal passages but the parts are denser (on average 99.5%) than a casting. We looked at this as a win-win. A few years ago, the first parts we machined were amazing. There was no visual porosity – the parts looked like they were machined from solid bar stock. For the aerospace market, this is a huge advantage. Now, we are able to print the most common aerospace alloys including Inconel 625 and 718, Cobalt Chrome, Aluminum and Titanium. You are truly only limited by your design imagination and your check book. Innovative 3D always includes 2 vertical and 2 horizontal tensile test bars, a material test plug and loose powder sample for every certified part build. We are able to check composition, tensile strength, hardness, and microstructure in our inhouse materials lab. MATERIALS One of our powder vendors has atomized over 1000 different powders for the DMLS process. This sounds great to the customer but it does create a bit of an issue for the people running the equipment. For example if you are building a tall prototype part and want the part to be built from Haynes 282 material, it may cost around $20,000 to buy enough powder to fill the machine to make one part. Then a company has to develop a machine laser parameter set that work in order to achieve high density and good surface finish. Therefore, the one-off prototype may not make sense with that specific material type. If the customer is fine with using a similar material for the test like Inconel 718 then the prototype can be much more cost effective as Inconel 718 is a very popular AM powder. The takeaway on this, is that engineers need to be flexible with materials when developing working prototypes. There are many considerations to determine which parts are best for the DMLS machines. First and foremost, remember that most DMLS machines are 10”x10”x12” LxWXH. After that, take into considering the size, weight, part geometry, surface finish and tolerance. PART WEIGHT Powder is very expensive, $30 to $130 per pound. The more the part weight the longer it takes to print which drives the price up. Material price is never the limiting factor—it’s always print time, which is how most service bureaus including Innovative 3D price their parts.