Micromanufacturing processes are expanding in their length and breadth as long as the related research and development (R&D) activities and applications are concerned. Products are getting miniatur...

Micromanufacturing: A review—part II

Performance evaluation of nano-enhanced phase change materials during discharge stage in waste heat recovery

A volumetric heat source is used in numerical modeling of selective laser melting (SLM) of Ti6Al4V powder. Single track and multi-track SLM simulations are performed by varying the two key process parameters-laser power and scan speed. The model is validated with the published experimental results for melt pool shape, size and temperature. The predictions are in good agreement with the experiments at low to medium energy density. The validated model is used for investigating the thermo-fluidic transport during SLM of Ti6Al4V and examining the dependence of the melt pool characteristics on the process parameters. As-solidified porosity is calculated numerically for the multi-track simulations and its formation is delineated with the transport phenomena. The predicted porosity compares reasonably well with the experimental values. Solidification parameters, such as temperature gradients and cooling rate are calculated at the instantaneous location of the solidification front and analyzed. This analysis suggests the formation of fully columnar grains of different sizes along the width and depth of the melt pool. Overall, the model provides a good description of thermo-fluidic transport in SLM of Ti6Al4V powder and the resulting temperature field, melt pool characteristics, as-solidified porosity and the expected grain structure. Based on the current analysis, an optimum processing window of 50–70 J mm−3 energy density is suggested for SLM of Ti6Al4V powder.

Numerical and experimental analysis of the effect of volumetric energy absorption in powder layer on thermal-fluidic transport in selective laser melting of Ti6Al4V

Comparative analysis of TIG welding distortions between austenitic and duplex stainless steels by FEM

Modeling of PCM melting: Analysis of discrepancy between numerical and experimental results and energy storage performance

Effects of mould filling on evolution of the solid-liquid interface during solidification

A numerical model of the entire casting process starting from the mould filling stage to complete solidification is presented. The model takes into consideration any phase change taking place during the filling process. A volume of fluid method is used for tracking the metal–air interface during filling and an enthalpy based macro-scale solidification model is used for the phase change process. The model is demonstrated for the case of filling and solidification of Pb–15 wt%Sn alloy in a side-cooled two-dimensional rectangular cavity, and the resulting evolution of a mushy region and macrosegregation are studied. The effects of process parameters related to filling, namely degree of melt superheat and filling velocity on macrosegregation in the cavity, are also investigated. Results show significant differences in the progress of the mushy zone and macrosegregation pattern between this analysis and conventional analysis without the filling effect.

http://iopscience.iop.org/article/10.1088/0965-0393/17/3/035006/pdf

Effects of the filling process on the evolution of the mushy zone and macrosegregation in alloy casting

Implementations of the present disclosure generally relate to a susceptor for thermal processing of semiconductor substrates. In one implementation, the susceptor includes a first rim surrounding and coupled to an inner region, and a second rim disposed between the inner rim and the first rim. The second rim includes an angled support surface having a plurality of cut-outs formed therein, and the angled support surface is inclined with respect to a top surface of the inner region.

New susceptor design to reduce edge thermal peak

In one embodiment, a susceptor is provided and includes a first major surface opposing a second major surface, and a plurality of contact structures disposed on the first major surface, each of the contact structures being at least partially surrounded by one or more of a plurality of radially oriented grooves and an annular groove, wherein each of the plurality of contact structures includes a substrate contact surface, each of the substrate contact surfaces is between two parallel planes separated by a distance of 0.1 millimeters, and the substrate contact surfaces define a substrate receiving surface.

Flat susceptor with grooves for minimizing temperature profile across a substrate

A processing chamber may include a gas distribution member, a metal ring member below the gas distribution member, and an isolating assembly coupled with the metal ring member and isolating the metal ring member from the gas distribution member. The isolating assembly may include an outer isolating member coupled with the metal ring member. The outer isolating member may at least in part define a chamber wall. The isolating assembly may further include an inner isolating member coupled with the outer isolating member. The inner isolating member may be disposed radially inward from the metal ring member about an central axis of the processing chamber. The inner isolating member may define a plurality of openings configured to provide fluid access into a radial gap between the metal ring member and the inner isolating member.

Nitin Pathak

Papers

Effects of mould filling on evolution of the solid-liquid interface during solidification

Effects of the filling process on the evolution of the mushy zone and macrosegregation in alloy casting

New susceptor design to reduce edge thermal peak

Flat susceptor with grooves for minimizing temperature profile across a substrate

Semiconductor processing chambers and methods for cleaning the same