TY - GEN
T1 - Rheological investigation of MIM feedstocks for reducing frictional effects during injection moulding
AU - Rane, K. K.
AU - Date, P. P.
PY - 2014/6/1
Y1 - 2014/6/1
N2 - An experimental investigation of the rheological properties for abrasive Metal Injection Moulding feedstocks is presented for different materials with dissimilar particle sizes and shapes. Tribological issues are inevitable since feedstock has up to 93 wt. % powder loading in the feedstock. In this study, each of the relatively soft carbonyl iron powder and the hard, abrasive Iron oxide powder are mixed with binder system, consisting of HDPE (High-density polyethylene), Paraffin Wax and S.A. (Stearic Acid) at different magnitudes of volumetric powder loading. The rheological properties such as flow rate (cm3/s), shear rate (s-1) and viscosity (Pa.s) are investigated for varying conditions of temperature and pressure. The properties of the feedstocks made from the two materials showed significant variation in flow behaviour (due to difference in inter-particle frictional behaviour) with changing process parameters as well as material parameters. Furthermore, to study flow behaviour of feedstocks apparent viscosity is plotted against temperature and shear rate in order to establish the sensitivity of temperature and pressure. Flow behaviour index was determined by analysing variation of viscosity with shear rate of feedstock. As expected, results show that the feedstock having iron oxide powder with hard irregular shaped particles exhibits a higher viscosity if compared to the spherical particles in the Carbonyl iron powder feedstock. It was observed that the feedstock containing iron oxide powder (75 wt. % powder loading) gives higher shear rate but the feedstock dissociates faster with increasing temperature, whereas carbonyl iron powder feedstocks (90 wt. % powder loading) were found to be more stable (dissociate less) at higher temperatures and flowed at a smaller shear rate. Additions of graphite powder to the hard and abrasive iron oxide powder (to facilitate reduction of the iron oxide during sintering) would also be expected to improve the flow behaviour of the iron oxide feedstock on account of the superior lubricating properties of the graphite powder.
AB - An experimental investigation of the rheological properties for abrasive Metal Injection Moulding feedstocks is presented for different materials with dissimilar particle sizes and shapes. Tribological issues are inevitable since feedstock has up to 93 wt. % powder loading in the feedstock. In this study, each of the relatively soft carbonyl iron powder and the hard, abrasive Iron oxide powder are mixed with binder system, consisting of HDPE (High-density polyethylene), Paraffin Wax and S.A. (Stearic Acid) at different magnitudes of volumetric powder loading. The rheological properties such as flow rate (cm3/s), shear rate (s-1) and viscosity (Pa.s) are investigated for varying conditions of temperature and pressure. The properties of the feedstocks made from the two materials showed significant variation in flow behaviour (due to difference in inter-particle frictional behaviour) with changing process parameters as well as material parameters. Furthermore, to study flow behaviour of feedstocks apparent viscosity is plotted against temperature and shear rate in order to establish the sensitivity of temperature and pressure. Flow behaviour index was determined by analysing variation of viscosity with shear rate of feedstock. As expected, results show that the feedstock having iron oxide powder with hard irregular shaped particles exhibits a higher viscosity if compared to the spherical particles in the Carbonyl iron powder feedstock. It was observed that the feedstock containing iron oxide powder (75 wt. % powder loading) gives higher shear rate but the feedstock dissociates faster with increasing temperature, whereas carbonyl iron powder feedstocks (90 wt. % powder loading) were found to be more stable (dissociate less) at higher temperatures and flowed at a smaller shear rate. Additions of graphite powder to the hard and abrasive iron oxide powder (to facilitate reduction of the iron oxide during sintering) would also be expected to improve the flow behaviour of the iron oxide feedstock on account of the superior lubricating properties of the graphite powder.
KW - activation energy
KW - frictional effects
KW - MIM
KW - rheology
KW - abrasive metal injection moulding feedstocks
KW - flow behaviour
UR - http://www.scopus.com/inward/record.url?scp=84903973590&partnerID=8YFLogxK
U2 - 10.4028/www.scientific.net/AMR.966-967.196
DO - 10.4028/www.scientific.net/AMR.966-967.196
M3 - Conference contribution book
AN - SCOPUS:84903973590
SN - 9783038351276
VL - 966-967
T3 - Advanced Materials Research
SP - 196
EP - 205
BT - Tribology in Manufacturing Processes and Joining by Plastic Deformation
T2 - 6th International Conference on Tribology in Manufacturing Processes and Joining by Plastic Deformation, ICTMP 2014
Y2 - 22 June 2014 through 24 June 2014
ER -