Technical and Economical Comparison of Micro Powder Injection Molding

Atre Sundar V.,Wu Carl L.,Hwang Chul-Jin,Zauner Rudolf,Park Seong-Jin,German Randall M. 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

In recent years, micro powder injection molding is being explored as an economical fabrication method for microcomponents in microsystems technology (MST). Technical and economic comparison was performed for processes. Molding experiment and simulation during the filling process were performed to evaluate several different geometries and processing conditions. The influence of material parameters and process conditions on mold filling were examined as a function of features size using microchannels as an example. It was found that the heat conductivity and viscosity of feedstock, geometry and mold temperature were the most critical parameters for complete filling of micro features.

Effects of process parameters in plastic, metal, and ceramic injection molding processes

이시우,안석영,황철진,박성진,Sundar V. Atre,김주권,Randall M. German 한국유변학회 2011 Korea-Australia rheology journal Vol.23 No.3

Plastic injection molding has been widely used in the past and is a dominant forming approach today. As the customer demands require materials with better engineering properties that were not feasible with polymers, powder injection molding with metal and ceramic powders has received considerable attention in recent decades. To better understand the differences in the plastic injection molding, metal injection molding, and ceramic injection molding, the effects of the core process parameters on the process performances has been studied using the state-of-the-art computer-aided engineering (CAE) design tool, PIMSolver The design of experiments has been conducted using the Taguchi method to obtain the relative contributions of various process parameters onto the successful operations.

Rheological and thermal debinding properties of blended elemental Ti-6Al-4V powder injection molding feedstock

Lin, Dongguo,Sanetrnik, Daniel,Cho, Hanlyun,Chung, Seong Taek,Kwon, Young Sam,Kate, Kunal H.,Hausnerova, Berenika,Atre, Sundar V.,Park, Seong Jin Elsevier Sequoia 2017 Powder technology Vol.311 No.-

<P><B>Abstract</B></P> <P>The rheological and thermal debinding properties of a feedstock play an important role in the molding and debinding stage of powder injection molding (PIM), and can directly determine the quality of final PIM product. This work focuses on the rheological and thermal debinding properties of blended elemental Ti-6Al-4V (BE Ti64) PIM feedstock with a comparison study of pure titanium (Ti) feedstock. The effects of 60Al-40V alloy addition, on the attributes of BE Ti64 feedstock; including critical solids loading, rheological behavior, and binder decomposition behavior, were studied using torque rheometry, capillary rheometry, and thermogravimetric analysis. The critical solids loading of BE Ti64 (66vol.%) was somewhat lower value than the Ti feedstock (69vol.%), due to the different in particle characteristics. Both BE Ti64 and Ti feedstocks exhibited non-Newtonian shear-thinning behavior. The difference in flow activation energies for the two feedstocks indicates that the BE Ti64 feedstock is more sensitive to temperature compared to the Ti feedstock. During thermal debinding, both the feedstocks exhibited a dual-sigmoid, binder-decomposition behavior with only minor differences in activation energy.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The rheological properties of BE Ti64 MIM feedstock were studied. </LI> <LI> The thermal debinding properties of BE Ti64 MIM feedstock were studied. </LI> <LI> A comparison study of pure Ti feedstock has been conducted. </LI> <LI> Effects of Al-V on processing abilities of BE Ti64 feedstock were studied. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Effects of process parameters in plastic, metal, and ceramic injection molding processes

Lee, Shi-W.,Ahn, Seok-Young,Whang, Chul-Jin,Park, Seong-Jin,Atre, Sundar V.,Kim, Jook-Won,German, Randall M. 한국유변학회 2011 Korea-Australia rheology journal Vol.23 No.3

Plastic injection molding has been widely used in the past and is a dominant forming approach today. As the customer demands require materials with better engineering properties that were not feasible with polymers, powder injection molding with metal and ceramic powders has received considerable attention in recent decades. To better understand the differences in the plastic injection molding, metal injection molding, and ceramic injection molding, the effects of the core process parameters on the process performances has been studied using the state-of-the-art computer-aided engineering (CAE) design tool, PIMSolver$^{(R)}$ The design of experiments has been conducted using the Taguchi method to obtain the relative contributions of various process parameters onto the successful operations.

Fabrication of micro-sized piezoelectric structure using powder injection molding with separated mold system

Park, Jae Man,Han, Jun Sae,Gal, Chang Woo,Oh, Joo Won,Kim, Jong Hyun,Kate, Kunal H.,Atre, Sundar V.,Kim, Youngmoo,Park, Seong Jin Elsevier 2018 Ceramics international Vol.44 No.11

<P><B>Abstract</B></P> <P>In this research, a powder injection molding process was developed to fabricate a micro-sized piezoelectric structure with high aspect-ratio. The separated mold system was prepared by the X-ray micromachining process. The optimal solids loading was determined to be 52 vol% considering the critical solids loading. To ensure a homogeneous powder-binder mixture, the mixing process was performed three times. For complete filling in micro-powder injection molding, rheological properties of the mixture were evaluated using a capillary rheometer with various shear rates and temperatures. The measured flow index <I>n</I> and activation energy <I>E</I> were values of 0.45 and 20.11 kJ/mol, respectively. Based on the rheological analysis, complete filling into the micro-cavity of the separated mold was achieved at the injection velocity of 140 mm/s. The green part was successfully demolded from the separated mold without showing any slanted or broken structures. For extraction of binders from the green part, optimal debinding conditions were determined based on the thermal decomposition behavior of binders and lead (Pb) loss measured by thermo gravimetric analyzer (TGA). After the sintering process was completed, the high-aspect-ratio piezoelectric microstructures were precisely fabricated.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Separated mold system was prepared by X-ray micromachining process. </LI> <LI> The optimal solids loading was determined to be 52 vol%. </LI> <LI> Rheological properties such as viscosity, shear sensitivity, temperature sensitivity were evaluated. </LI> <LI> Injection velocity was the key factor to achieve a complete filling into micro-cavity. </LI> <LI> Thermal decomposition behavior of the powder-binder mixture was analyzed. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Effect of binder composition on rheological behavior of PMN-PZT ceramic feedstock

Park, Jae Man,Han, Jun Sae,Gal, Chang Woo,Oh, Joo Won,Kate, Kunal H.,Atre, Sundar V.,Kim, Youngmoo,Park, Seong Jin Elsevier 2018 Powder technology Vol.330 No.-

<P><B>Abstract</B></P> <P>An investigation of the effect of binder composition on rheological behavior of lead magnesium niobate–lead zirconate titanate (PMN-PZT) ceramic feedstock is presented in this paper. Rheological behavior is the key factor for manufacturing a micro-sized structure with high aspect-ratio. Each binder composition was categorized into three groups to analyze the effect based on the variation of ratio within filler (first), within backbone (second), and between filler and backbone (third). The critical solids loading for each feedstock was evaluated using a torque rheometer. To compare the net effect of binder composition, all the feedstocks were mixed with the solids loading of 45 vol%. The effects of binder composition on rheology were analyzed using a capillary rheometer with different shear rates and temperatures. The main rheological parameters, such as viscosity, shear sensitivity, and temperature sensitivity, were closely related to the molecular weight difference in binder composition. First, the viscosity increased as the ratio of binders with higher molecular weight increased for each group. Second, the sensitivity of viscosity on shear rate was enhanced with the increase of polyethylene (PE) in the second and backbone in the third, respectively. Third, the sensitivity of viscosity on temperature was lowered as the amount of binders with higher molecular weight increased for each group. Based on the experimental results, the moldability index as a function of viscosity, shear sensitivity, and temperature sensitivity was calculated. The feedstock with the largest amount of filler showed the best rheological property for powder injection molding.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effect of binder composition on rheological behavior of feedstock was analyzed. </LI> <LI> The solids loading of each feedstock was set to 45 vol%. </LI> <LI> Molecular weight difference has a significant effect on rheological properties. </LI> <LI> Moldability index was more sensitive to reference viscosity. </LI> <LI> Feedstock with the lowest reference viscosity showed the best rheological property. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>