Abstract:
Debinding is one of the most critical and time consuming stage in metal injection
moulding (MIM). German and Bose (1997) reported that early debinding practice relied on thermal
binder degradation, requiring up to 300 hours for complete binder removal. Today multi-stage
debinding techniques are introduced cutting down the debinding time to as little as 2 hours. This
work investigates solvent debinding variables for samples made by MIM Ti6Al4V powder prior to
thermal debinding. Solvent debinding is carried out in n-heptane. Wax and stearic acid are the target
binder components being leached out from the green bodies, with wax as the major constituent in
the binder formulation. Debinding is conducted at 50, 55, 60 and 65°C for 1-4 hours at each
temperature. Weight loss measurements were done. For porosity and surface appearance, scanning
electron microscope (SEM) analysis and visual inspection were done.Samples debound at 65°C
showed an appreciable amount of mass loss; however, surface cracks and warping were observed. A
60°C temperature and time of 4 hours demonstrated best results i.e. a satisfactory mass loss,
absence of surface cracks and no warping. Mass loss is directly proportional to temperature and
time. SEM results are discussed in the paper.
