Production Machining

DEC 2017

Production Machining - Your access to the precision machining industrial buyer.

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Rappach says volatile materials such as aluminum and titanium powders pose a significant explosion risk. Simply plugging something into a wall outlet could be enough to set off a flash explosion, so special outlets have been installed, and the 3D printing operations are separated from the other machining. For additional safety, copper rod runs around the perim- eter of the room and into the powder recovery room. When an operator is working on a machine, whether it's open or even if he's only moving components around, he is tethered to the grounding rod to take the static energy out. Rather than the typical sprinkler system, a halon gas system is installed in the ceiling for fire suppression. And beyond fire safety, for employee health concerns, the HVAC system includes special filters, and operators wear suits and masks to protect them from the powders, which at 20- to 100-micron particle size, can quickly get into the atmosphere. To reduce contamination risk with the parts, Slice uses strictly titanium with its current 3D printers, although as the need arises for other materials, the company is prepared to add additional dedicated printers for that work. Mr. Rappach says using different materials within the same printer would present relentless cleaning qualifica- tion challenges with the FDA. It is important in medical work to qualify the build process, including the powder that is in the machine, the gun, the filaments, and so on. Changing the material would require an exten- sive revalidation process; going through several small test builds, with chemical, fatigue and tensile testing and detailed documentation, this could take as long as a month. The Birth of a Part Mr. Rappach says his company is one of only a few in the U.S. running Arcam machines, which are mostly applied in aerospace and internal medical device :: The Willemin-Macodel machines are set up with automated parts handling. The robot grabs the hip cup for measuring on the laser system and relays the information to the CNC to call the correct program. :: This system is set up for automated blasting of the acetabular hip cups. The cup is articulated around the blast field so that all surfaces are blasted evenly, creating 100-percent uniform surface roughness. ADDITIVE MANUFACTURING 36 PRODUCTION MACHINING :: DECEMBER 2017

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