Effects of Powder Characteristics on Flowability of Feedstock and Deformation During Thermal Debinding in MIM.

Miura, R.; Takamori, Sejij

doi:10.2497/jjspm.40.479

Cited by 10 publications

(4 citation statements)

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“…There are lots of investigations focused on factors causing defects (bloating, cracking, deformation etc.) . Trunec and Cihlar proposed that some defects were caused by the nonuniform removal of binder …”

Section: Introductionmentioning

confidence: 99%

Theory and practice of rapid and safe thermal debinding in ceramic injection molding

Xie

Jiang

Yang

et al. 2019

Int J Applied Ceramic Tech

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In this paper, the dynamic process of thermal debinding was analyzed. The critical thickness of debinding was defined as the thickness at which the steps to control dynamics change from diffusion of gas products in liquid binder to diffusion or permeation in pores. Subsequently, the equation of critical thickness was deduced. The results show that the critical thickness of debinding is independent of the thickness of the green body, but mainly depends on the particle size, solid content, and binder composition. Moreover, larger particle diameter and higher solid loading will contribute to a greater critical thickness, which means that higher heating rate can be used in the initial stage of debinding. The prediction is in agreement with the experimental results. In addition, the effect of binder composition on the formation of cracks during thermal debinding was investigated by thermogravimetry combined with FTIR spectrometry (TG-FTIR) analysis of binders and thermogravimetric curves of feedstocks. It suggests that the feedstock containing polystyrene and acrylic resin is helpful for rapid and safe thermal debinding. K E Y W O R D Sbinders/binding, ceramic engineering, defects, thermal debinding | 1099 XIE Et al.

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Section: Introductionmentioning

confidence: 99%

Theory and practice of rapid and safe thermal debinding in ceramic injection molding

Xie

Jiang

Yang

et al. 2019

Int J Applied Ceramic Tech

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“…3 The flow by viscous creep during thermal debinding is a major cause of compact deformation, 4 and spherical powders show much lower resistance to debinding deformation than irregular powders. 5 Mathematical models help in the optimisation of MIM processes in reduction in flaws and defects. For formulating mathematical models, good thermophysical data are needed.…”

Section: Introductionmentioning

confidence: 99%

“…The damage during thermal debinding can be explained as a result of the development of internal stresses due to imbalance between degradation of the polymer and outward transportation of the resulting products 3. The flow by viscous creep during thermal debinding is a major cause of compact deformation,4 and spherical powders show much lower resistance to debinding deformation than irregular powders 5…”

Section: Introductionmentioning

confidence: 99%

Finite element investigation of backbone binder removal from MIM copper compact

Mohsin¹,

Lager²,

Hohenauer³

et al. 2012

Powder Metallurgy

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Finite element (FE) model based on kinetic analysis was developed to describe the thermal debinding process of previously solvent debinded metal injection moulded (MIM) copper compacts. Thermophysical properties (specific heat, density, thermal diffusivity and thermal conductivity as a function of temperature) of MIM copper compact were measured using differential scanning calorimeter, laser flash analyser, thermogravimetry analyser and pushrod dilatometer. The proposed model is solved numerically to study binder removal and binder distribution during thermal debinding. The investigations included the analysis of residual (backbone) binder content for cylindrical MIM copper compacts at different temperatures and positions. The FE calculations are strongly based on measured thermophysical data and kinetic analysis of copper system. The FE simulated and experimental results were compared to validate the underlying FE model based on FE temperature field calculations. Drawing the real furnace temperature conditions in finite calculation can result in obtaining more accurate data.

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“…Particle shape has a large effect on the success of the process. Irregular particles exhibit better part shape retention during debinding, the packing coordination number and density are degraded by irregular particle shape [42]. Thus, more densification is needed in sintering to compensate for the poor initial packing.…”

Section: Literature Reviewmentioning

confidence: 99%

Development and analysis of micro powder injection molding

Fu¹

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Micro powder injection molding (pPIM) is a potential process for the mass fabrication of metal or ceramic micro-structures. It has many advantages such as low cost, high productivity, suitable for fabricating micro-structures with complex geometry. This thesis deals with the molding and demolding of high aspect ratio 3 16L stainless steel micro-structures. pPIM was first used to fabricate 316L stainless steel micro-structures using existing conventional mold and silicon mold insert with micro-cavities etched by deep reactive ion etching (DIXIE). It was found that incomplete filling and demolding problem were two main hindrances to the successful fabrication of micro-structures, especially in the case of micro-structures with high aspect ratio. To mold high aspect ratio microstructures, a variotherm mold was designed and fabricated (rapid mold temperature variation technology is termed as variotherm). The new variotherm mold is equipped with rapid mold heatinglcooling system, hot sprue system, cavity vacuuming system to prevent air entrapment and combined pressure and temperature sensor. The variotherm mold facilitates the injection molding of high aspect ratio micro-structures because it improves the complete filling of the micro-cavity at the elevated mold temperature. Variotherm mold heating /cooling system enables the rapid adjustment of demolding temperature. Thus,

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Effects of Powder Characteristics on Flowability of Feedstock and Deformation During Thermal Debinding in MIM.

Cited by 10 publications

References 0 publications

Theory and practice of rapid and safe thermal debinding in ceramic injection molding

Theory and practice of rapid and safe thermal debinding in ceramic injection molding

Finite element investigation of backbone binder removal from MIM copper compact

Development and analysis of micro powder injection molding

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