1. A comparison of titanium MIM parts produced using various furnace conditions. © Paul Ewart: December 2013

2. Introduction Metal injection moulding (MIM) is an established manufacturing method. Metal powders are mixed with a thermoplastic binder to form a feedstock that can be moulded to formed complex shapes (green parts). The binder is removed (debinding) and the powders are consolidated (sintered) to form the final part with the desired metal composition. © Paul Ewart: November 2013

3. Overview Research aims Feedstock Moulding Debinding Sintering Conclusion © Paul Ewart: November 2013

4. Research aims To investigate impurity uptake in relation to sinter conditions To define defect formation with respect to metal composition within sintered parts © Paul Ewart: November 2013

5. Feedstock Binder combination of bees wax (BW), carnauba wax (CW), linear low density polyethylene (LLDPE), polyethylene glycol (PEG) and polypropylene (PP) The powder was titanium alloy (Ti-6Al-4V of 200 mesh, HDH)

6. Moulding Process temperature above all melting points and below the degradation points Feedstock flow a function of fluidity of the binder © Paul Ewart: November 2013

7. Debinding Solvent debinding targeted PEG with dissolution Thermal debinding targeted waxes by melt extraction, capillary pressure and volatilities Polyolefins and remaining residues removed early in sintering phase by pyrolysis @ < 93 % © Paul Ewart: November 2013

8. Sintering © Paul Ewart: November 2013 Incomplete debinding ? Furnace atmosphere ? Through part ?

9. External surfaces do not necessarily represent the metal composition of the part Micro-structure analysis to investigate residual binder levels, elemental diffusion and density Density 91, 93 and 96 % respectively Metal composition © Paul Ewart: November 2013

10. Conclusion Static atmosphere produced the highest level of impurities Vacuum sintering removed more residue but impurities remain from pore disconnection Sweep gas during heat-up enhanced residue removal and with vacuum atmosphere impurities were reduced. © Paul Ewart: November 2013

11. Thank you. Questions please? Acknowledgements: Aamir Mukhtar and the Titanium Industry Development Association (TiDA), Tauranga, NZ for analytical support. ProMould Custom Moulding Ltd, Hamilton, NZ for part moulding. AME Powder Technology Limited, Hamilton, NZ for sample preparation and sintering assistance. © Paul Ewart: November 2013