Metal AM Autumn 2016

Page 81

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AMPM2016: Binder jetting technology

AMPM2016: Developments in binder jetting technology highlighted at Boston conference For the third consecutive year, the Metal Powder Industries Federation’s Additive Manufacturing with Powder Metallurgy (AMPM) conference was held in parallel with its long established POWDERMET conference. This year’s event took place in Boston, Massachusetts, USA, from June 5-8, 2016. In the first of our reports Dr David Whittaker reviews three presentations that focused on the binder jetting process.

The binder jetting process uses a glue-like binder selectively deposited from a print-head to form 3D shapes, layer by layer, with debinding and sintering of the built component being included in the post-build operations. The build process itself is a low energy and low thermal input process that has the capability to work with any material that can be processed into powder and bonded together. One of the major questions with binder jetting is what process parameters, for both the materials and machine, are optimum for printing parts.

Bulger and Paul Gangopadhya (Netshape Technologies, USA), described a process optimisation study for the binder jet building of a Type 420 stainless steel and introduced a numerical model for thermal debinding accompanying its application to binder jetting. The 420 stainless steel powder used had a median particle size of 12 µm and the chemical composition

is shown in Table 1. The binder used for the process was Lab Binder 04, a solvent based binder supplied by ExOne. This binder uses polyvinylpyrrolidine (PVP), a water soluble polymer, as its main bonding agent. The parts built in these trials were 7.5 mm cubes. An ExOne M-Lab machine was used to create parts. This binder-jetting machine features a 50 x 70 x 34.5 mm build bed.

Binder jetting of metals and ceramics A presentation made by Dongguo Lin (Pohang University of Science and Technology, South Korea) and co-authored by Sundar Atre, Jason Porter, Tim Batchelor and Kunal Kate (University of Louisville, USA), Seong Jin Park (also Pohang University of Science and Technology) and Matthew

Vol. 2 No. 3 © 2016 Inovar Communications Ltd

Fig. 1 The binder jetting process can be used to print complex designs from a number of materials [1]

Metal Additive Manufacturing | Autumn/Fall 2016