Modern Machine Shop and MoldMaking Technology present ADDITIVE MANUFACTURING, a quarterly supplement reporting on the use of additive processes to manufacture functional parts. More at additivemanufacturinginsight.com.
Issue link: https://am.epubxp.com/i/542042
AdditiveManufacturingInsight.com August 2015 — 11 hours. Thus, the lead time of this process is already competitive with conventional 3D printing. It's just the labor requirement that has to be improved. The company's success in manufacturing for an unmanned aircraft involved a component that sees high stresses during landing. CBAM delivered a part resilient enough to withstand the required duty, and the part is now fying on several planes. Mr. Swartz says this is an example of the right kind of application for the process—a functional part for which the strength and material properties matter. Unlike many 3D printing processes, this process is not directed toward design models, except where those models themselves are functional. An example of this is wind-tunnel models, which is another application for which CBAM is being used. 3D printing often can't produce effec- tive wind-tunnel models, because the force of the testing can break or deform these parts. Instead, manufacturers invest in production tooling to create wind tunnel models that are very near to production components. But as an alternative, a truck maker recently used CBAM to quickly produce various iterations of a blower fan that, in carbon fber, were strong enough to hold up to the testing. Larger ovens and larger presses will eventually let Impossible Objects scale beyond its current maximum part size, which is about 9 inches diam- eter by 4 inches high. One promising application for a scaled-up version of this process is the subject of a collaborative research and devel- opment agreement with Oak Ridge National Laboratory. The company says Oak Ridge is exploring the use of CBAM to make tooling for composite lay-up structures. Today, tooling for composites is often made from Invar, a metal alloy that is challenging to machine, but used because it has the same low coeffcient of thermal expan- sion as carbon fber composite. Invar allows the tooling to follow the part in and out of the oven. However, if the tooling itself was made from the same carbon fber as the part, then this tool obvi- ously would also have the same low coeffcient of expansion. Therefore, with CBAM, a tool demand- ing diffcult machining could be replaced with a tool requiring not only no machining, but also no critical machine movement at all in applying this tool's composite material. Feed fber sheet into gantry machine Load CAD slices into machine and print layer shape of object on fber sheet Deposit polymer powder onto printed sheet Remove dry polymer powder Stack sheets in order, heat to melting temperature of polymer, and compress stack to fnal part height Remove unbonded portions of sheet fbers to obtain net fnal part The CBAM process involves applying a fuid to fber sheets in the profle of the part layer, then dusting the part with thermoplastic powder so it adheres within that precise layer. Sheets are stacked and the plastic is melted to create the strong composite part. 01 02 03 04 05 06 The application of the fuid, which is not a signifcant component of the ultimate material of the part, is the only step in the process involving precisely controlled motion. The part material itself is not applied or shaped with any selective operation.