TY - JOUR

T1 - Effect of metal particle size and powder volume fraction on the filling performance of powder injection moulded parts with a microtextured surface

AU - Ammosova, Lena

AU - Cano Cano, Santiago

AU - Schuschnigg, Stephan

AU - Kukla, Christian

AU - Mönkkönen, Kari

AU - Suvanto, Mika

AU - Gonzalez-Gutierrez, Joamin

N1 - Publisher Copyright: © 2021 The Author(s)

PY - 2021/11

Y1 - 2021/11

N2 - Metal injection moulding of miniaturized devices demands unique feedstock materials and mould designs with high dimensional accuracy. In this work, the influences of the powder size and powder content of 17–4 PH stainless steel feedstock and the influence of mould design on the successful production of micro-scaled structures were investigated. Ni mould inserts with high dimensional accuracy and texture sizes of 50–200 μm using a new microtexturing technique were manufactured. 17–4 PH stainless steel feedstocks with powder sizes (D 90) of 10 and 22 μm and powder contents of 60 and 65 vol.-% were compounded. The rheological properties of the obtained feedstocks were characterized with a capillary rheometer to assess their flowability. The results showed that 10 μm sized particles caused a slight but not significant increase in the viscosity. The highest viscosity increase occurred when the powder content increased from 60 to 65 vol.-%. Feedstocks with the 10 μm powder particles ensured complete filling within microtextures for all mould variations. However, when using feedstocks with 22 μm particles, the filling capabilities of the 50 and 100 μm microtextures decreased with increasing powder content. The shape retention was better for those micropillars produced with mould inserts with 200 μm cavities than for the micropillars replicated with the inserts having cavities of 50 and 100 μm. The results indicated that the proposed mould insert preparation technique opens new possibilities for mass production using the μMIM process to create micro-scaled components using feedstocks without nanoparticles.

AB - Metal injection moulding of miniaturized devices demands unique feedstock materials and mould designs with high dimensional accuracy. In this work, the influences of the powder size and powder content of 17–4 PH stainless steel feedstock and the influence of mould design on the successful production of micro-scaled structures were investigated. Ni mould inserts with high dimensional accuracy and texture sizes of 50–200 μm using a new microtexturing technique were manufactured. 17–4 PH stainless steel feedstocks with powder sizes (D 90) of 10 and 22 μm and powder contents of 60 and 65 vol.-% were compounded. The rheological properties of the obtained feedstocks were characterized with a capillary rheometer to assess their flowability. The results showed that 10 μm sized particles caused a slight but not significant increase in the viscosity. The highest viscosity increase occurred when the powder content increased from 60 to 65 vol.-%. Feedstocks with the 10 μm powder particles ensured complete filling within microtextures for all mould variations. However, when using feedstocks with 22 μm particles, the filling capabilities of the 50 and 100 μm microtextures decreased with increasing powder content. The shape retention was better for those micropillars produced with mould inserts with 200 μm cavities than for the micropillars replicated with the inserts having cavities of 50 and 100 μm. The results indicated that the proposed mould insert preparation technique opens new possibilities for mass production using the μMIM process to create micro-scaled components using feedstocks without nanoparticles.

KW - metal injection moulding

KW - powder injection moulding

KW - microtextured surfaces

KW - feedstock

KW - 17-4 PH steel

KW - rheology

KW - viscosity

UR - http://www.scopus.com/inward/record.url?scp=85110339610&partnerID=8YFLogxK

U2 - 10.1016/j.precisioneng.2021.06.014

DO - 10.1016/j.precisioneng.2021.06.014

M3 - Article

VL - 72.2021

SP - 604

EP - 612

JO - Precision Engineering

JF - Precision Engineering

SN - 0141-6359

IS - November

ER -