Measurements of Powder??Polymer Mixture Properties and Their Use in Powder Injection Molding Simulations for Aluminum Nitride

Kate, K. H.,Onbattuvelli, V. P.,Enneti, R. K.,Lee, S. W.,Park, S. J.,Atre, S. V. Springer Verlag 2012 JOM Vol.64 No.9

Predicting Powder-Polymer Mixture Properties for PIM Design

Kate, K.H.,Enneti, R.K.,Park, S.-J.,German, R.M.,Atre, S.V. CRC PRESS LLC 2014 CRITICAL REVIEWS IN SOLID STATE AND MATERIALS SCIE Vol.39 No.3

Powder injection molding (PIM) is a high-volume manufacturing technique for fabricating ceramic and metal components that have complex shapes. In PIM design, it is important to know the injection molding behavior at different powder-polymer compositions so as to understand the trade-offs between ease-of-fabrication, process throughput, and part quality at the design stage. A limited database of materials properties at different powder-polymer compositions is a significant challenge that needs to be addressed in order to conduct accurate computer simulations that aid part and mold design in PIM. However, accurate material property measurements are expensive and time-consuming. In order to resolve these conflicting challenges it is hypothesized that experimental measurements of material properties of a filled polymer at a specific filler content combined with similar measurements of unfilled polymer will be adequate to estimate the dependence of properties on filler content using rule-of-mixture models. To this end, this article focuses on a literature review of experimental data obtained from measurements of rheological, thermal, and mechanical properties for a wide range of powder-polymer mixtures at various filler volume fractions. The experimental data were compared to property estimates using various predictive models. It is expected that the current review will be valuable in selecting appropriate predictive models for estimating properties based on the input data requirements for commercially available mold-filling simulation platforms such as Moldflow (R) and PIMSolver (R). The combined protocol will be useful to design new materials and component geometries as well as optimize process parameters while eliminating expensive and time-consuming trial-and-error practices prevalent in PIM.

PROXIMAL TYPE CONVERGENCE RESULTS USING IMPLICIT RELATION AND APPLICATIONS

O. P. Chauhan,B. Chaudhary,H. Atre 경남대학교 수학교육과 2024 Nonlinear Functional Analysis and Applications Vol.29 No.1

The goal of this study is to instigate various new and novel optimum proximity point theorems using the notion of implicit relation type $\beth$-proximal contraction for non-self mappings. An illustrated example is used to demonstrate the validity of the obtained results. Furthermore, some uniqueness results for proximal contractions are also furnished with partial order and graph. Various well-known discoveries in the present state-of-the-art are enhanced, extended, unified, and generalized by our findings. As an application, we generate some fixed point results fulfilling a modified contraction and a graph contraction, using the profundity of the established results.

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>

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>

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>