Rheological investigation of MIM feedstocks for reducing frictional effects during injection moulding

K. K. Rane, P. P. Date

Research output: Chapter in Book/Report/Conference proceedingConference contribution book

10 Citations (Scopus)

Abstract

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.

Original languageEnglish
Title of host publicationTribology in Manufacturing Processes and Joining by Plastic Deformation
Pages196-205
Number of pages10
Volume966-967
DOIs
Publication statusPublished - 1 Jun 2014
Event6th International Conference on Tribology in Manufacturing Processes and Joining by Plastic Deformation, ICTMP 2014 - Darmstadt, Germany
Duration: 22 Jun 201424 Jun 2014

Publication series

NameAdvanced Materials Research
Volume966-967
ISSN (Print)1022-6680
ISSN (Electronic)1662-8985

Conference

Conference6th International Conference on Tribology in Manufacturing Processes and Joining by Plastic Deformation, ICTMP 2014
Country/TerritoryGermany
CityDarmstadt
Period22/06/1424/06/14

Keywords

  • activation energy
  • frictional effects
  • MIM
  • rheology
  • abrasive metal injection moulding feedstocks
  • flow behaviour

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