Medium Feed Rate Research Articles

Optimization of abrasive slurry assisted rotating ultrasonic machining for enhanced micro-channel fabrication on ceramic silicon wafer (111)

This study examined the impact of abrasive slurry assisted Rotating Ultrasonic Machining (RUM) using Boron Carbide (B4C) powder of three mesh sizes: 400 Mesh, 600 Mesh, and 800 Mesh. The effects of abrasive size, feed rate, and tool rotation on Material Removal Rate (MRR) and Surface Roughness (SR) were investigated. The highest MRR of 3.454 mm³/min was achieved with 400 mesh, 30 mm/min feed rate, and 1250 rpm due to larger abrasive size, medium feed rate, and medium tool rotation velocity, while the lowest MRR of 0.284 mm³/min was noted with 600 mesh, 30 mm/min feed rate, and 1500 rpm, attributed to intermediate abrasive size and high tool rotation. The lowest SR of 1.16 μm was observed at 800 mesh, 15 mm/min feed rate, and 1500 rpm, resulting from smaller abrasive size and higher tool rotation facilitating polishing action and vibrational dampening. The highest SR of 3.71 μm occurred at 400 mesh, 45 mm/min feed rate, and 1500 rpm, due to larger abrasive size, higher feed rate, and tool rotation, increasing surface corrosion. ANOVA and regression analyses highlighted mesh size as the most significant parameter for both MRR and SR, with strong model-experimental value correlations. The findings demonstrate the suitability of abrasive slurry assisted RUM for fabricating micro-channels in X-Ray, optoelectronic, and semiconductor applications.

Experimental Investigation and Optimization of Coaxiality Error Analysis with CNC Turning Process on Delrin for Assembly Fit

This paper mainly deals with the machining operation like turning operation, Material Removal Rate and Surface Roughness are the important parameter which is to be considered for quality product. The material selected for the experiment is DELRIN 500. Turning is one of the important processes that is widely used to create cylindrical components and it is also used for surface finish the product to make it smooth. Nowadays, plastic materials are widely used for making variety of components. To make a component with high dimensional accuracy, turning operation is used. The main concerns of turning are tooling cost and the effect of process on machinability characteristics. It can be seen that the output responses value has a minimum roughness average and a high degree of geometrical quality precision. High degree surface finish is induced by medium speed, feed rate, and small nose radius. The coaxial error was minimized by using medium speed, feed and larger nose radius. Experimentally found that third specimen (RPM -750) (FEED -0.08 mm/Rev) and (NOSE RADIUS 0.8) obtained minimum geometrical error along with minimum Surface roughness. Delrin is a crystalline plastic that offers an excellent balance of properties that bridge the gap between metals and plastics. Delrin possesses high tensile strength, creep resistance and toughness. It also exhibits low moisture absorption

Evaluation of additive manufacturing process parameters for improved mechanical properties of thermoplastic parts

In the present study, the tensile strength of additively fabricated components was investigated, corresponding to the combinations of three process parameters: layer height, nozzle temperature, and filament feed rate. The parameters are considered to achieve desired mechanical strength of parts for domestic applications bag hooks, hanger, etc. The experiments are designed using the Taguchi approach and analyzed considering the maximum is the better for the response. The samples are fabricated using Ultimaker S5’ printer as per ASTM D638 standards. The maximum tensile strength obtained is 33.963 MPa corresponding to lower layer height (0.1 mm) and higher nozzle temperature (240 °C) with medium feed rate (20 mm/s). The evaluated parameters are crucial for the mechanical properties of selected application parts. The findings of this study will be helpful for the designer of domestic appliances.

Experimental technique to analyze the influence of cutting conditions on specific energy consumption during abrasive metal cutting with thin discs

Specific energy consumption is an important indicator for a better understanding of the machinability of materials. The present study aims to estimate the specific energy consumption for abrasive metal cutting with ultra-thin discs at comparatively low and medium feed rates. Using an experimental technique, the cutting power was measured at four predefined feed rates for S235JR, intermetallic Fe-Al(40%), and C45K with different thermal treatments. The variation in the specific energy consumption with the material removal rate was analyzed through an empirical model, which enabled us to distinguish three phenomena of energy dissipation during material removal. The thermal treatment and mechanical properties of materials have a significant impact on the energy consumption pattern, its corresponding components, and cutting power. Ductile materials consume more specific cutting energy than brittle materials. The specific cutting energy is the minimum energy required to remove the material, and plowing energy is found to be the most significant phenomenon of energy dissipation.

Optimization of multiple performance responses of a fish feed pelletizer machine

This study details the assembling of a prefabricated fish feed pelletizing machine and optimization of some operational parameters such as die thickness, number of die holes, shaft speed and feed rate to produce high-grade fish pellets. The Taguchi methodology and Grey relational analysis (GRA) have been utilized to evaluate the multi-objective functions of interest such as pelletizing efficiency, throughput, energy requirements and pellets bulk density (g/cm3). The pelletizer machine performance evaluation test was carried at 3 levels of die thickness (8, 6 and 12 mm), number of die holes (30, 25, and 35), and feed rates (145, 130 and 160 g/h). The test for the performance indicators was conducted using L9 orthogonal array experimental design. The test data were analyzed using the Taguchi scheme employing the signal-to-noise ratio response with effects deduced. The GRA was utilized to assess multiple responses by fusing the Taguchi technique with the GRA. Thus the multi-objective optimization was transformed to a single equivalent objective function. The results of Taguchi optimization revealed that die thickness was the most influential parameter for the various control factors. In addition, optimum parameter combination was obtainable at medium die thickness (8mm), medium number of die holes (30), low shaft speed (200rpm) and medium feed rate of 145g/h. Analysis of variance for grey relational grade (GRG) reveals that die thickness and feed rate are the dominant parameters. The confirmation test performed shows that the GRG is enhanced by 2.19%.

Solution Blow Spinning of Food-Grade Gelatin Nanofibers.

The primary advantage of nanofibers over larger diameter fibers is the larger surface area to volume ratio. This study evaluated solution blow spinning (SBS) processing conditions for obtaining food-grade gelatin nanofibers from mammalian and fishery byproducts, such as pork skin gelatins (PGs) and high molecular weight fish skin gelatin (HMWFG). HMWFG had a highest intact collagen structure compared to PGs. PGs with different Bloom values, solution viscosities, and surface tensions were compared with HMWFG for their ability to produce nanofibers through SBS. Only HMWFG fibers were obtained irrespective of processing conditions, which looked like fluffy cotton candy. HMWFG nanofibers had round morphologies with a narrower diameter distribution and lower average fiber diameter (AFD) under medium gelatin concentrations, medium air pressures, and medium feed rates. The highest glass transition temperature (Tg ) values were obtained at medium concentrations, medium air pressure, and either high or low feed rate. The thinnest HMWFG nanofibers with an AFD of 80.1 nm and the highest Tg value of 59.0 °C could be formed by combining a concentration of 17.6% (w/v), an air pressure of 0.379 MPa, and a feed rate of 0.06 mL/min from the response surface analysis. HMWFG Brunauer, Emmett, and Teller surface area increased from 221 to 237 m2 /g, indicating their potential applicability for active compound carrier.

Experimental Research on Chemical Mechanical Sharpening of CVD Diamond Micro Tool

This Research is Focused on the Chemical Mechanical Sharpening of CVD Diamond Micro Tool, which has High Strength and Good Wear Resistance. the Diamond Grinding Wheels were Usually Used for Sharpening, but this Method could Not get High Quality Surface of the Diamond Efficiently and Small Cutting Edge Radius. in Order to Seek a Better Mode for Sharpening, the Copper Based Tungsten Carbide Disc and Abrasive were Used for Grinding. for Better Understanding the Effects of Different Parameters on the Grinding Process and Optimizing them, the Orthogonal Method was Used to Design the Experiments. Grinding Direction, Feed Rate and the Grinding Velocity were Investigated to Obtain Sharper Cutting Edge and Smooth Flank Face. Analysis of Range was Also Introduced to Evaluate the Contribution of each Parameter in Orthogonal Experiment. the Results Showed that down Grinding, Medium Feed Rate and Low Velocity could Achieve a Better Sharpening Result.

Performance Analysis of Cylindrical Grinding Process Parameters Using Grey Relational Technique<sup></sup>

The present research work involves investigating the cylindrical grinding process parameters of Al/SiC metal matrix composites during machining. The effect of grinding process parameters on grinding force, surface roughness and grinding temperature were investigated experimentally using L27 orthogonal array. Grinding process was carried out using different combination of wheel velocity, workpiece velocity, feed rate and depth of cut. The significant grinding process parameters have been determined by using ANOVA. The grey grades identify the optimum level grinding process parameters. From the grey relational grade, low wheel velocity, medium workpiece velocity, medium feed rate and medium depth of cut gives the best results.

Analysis and optimisation of machining parameters in micro turning using RSM

Miniaturisation of industrial products has been the trend of technological development for creating smaller and precision components which plays an important role in today's need. Titanium alloy Gr.2 is one of the most extensively used Ti alloys for high temperature application components, because of its low weight and high strength even at elevated temperatures for applications like aerospace gas turbine compartments. In this paper, the performance of micro turning of titanium alloy with cermet insert is investigated using response surface methodology and Box-Behnken design (BBD). Two empirical models have been developed for predicting the tool wear and surface roughness. The analysis reveals that the cutting speed and feed rate are more influencing parameters on responses. The optimisation results showed that the combination of medium spindle speed, feed rate, and high depth of cut are necessary to minimise the tool wear and surface roughness. A verification experiment is conducted and compared.

Optimization of the Grinding Parameters for CVD Diamond Micro-Tools

This study is focused on the optimization of the grinding process parameters for the grinding of the CVD diamond micro-milling tool. Two types of CVD diamond i.e. CDM and CDE are used for the study. Feed rate and the grinding velocity are used as the grinding parameters. The optimizations of the parameters are done by studying the two results i.e. grinding force and cutting edge radius. Highest grinding velocity and medium feed rate is found to have the best result for the grinding of the CVD diamond. Keywords: CVD diamond, Grinding, Micro-tool

Multi response Optimization of Induction Hardening Process -a New Approach

Abstract In this present paper, an investigation has been performed to find out the combination of input process parameters for induction hardening of AISI 1045 steel component based on desirability function. To enhance the mechanical properties of steel components using induction hardening process, quality responses like effective case depth (ECD) and hardness values are analysed for different combinations of medium frequency power, feed rate, quench pressure and temperature in a selected range. The experimental trials are conducted, based on the design matrix obtained from the rotatable central composite design (CCD), with the help of an induction hardening station equipped with a 150 kW power converter. A significant regression model is also developed to predict these quality responses using response surface methodology (RSM). To establish desirability index in a multi-response process like induction hardening, a new approach has been devised. This approach i.e. selection of both, heating and quenching parameters proved significant, which is considered as one of the major contribution of presented research work. A non destructive evaluation technique, based on dynamic response, is also developed which will further combine with optimization strategy to develop an innovative quality assurance system for industrial induction hardening process.

Computational study of the multiphase flow and performance of dense medium cyclones: Effect of body dimensions

This paper presents a numerical study of the gas–liquid–solid flow in 1000 mm dense medium cyclones (DMCs) with different body dimensions, which includes the spigot diameter, cylinder length, cone length and inlet size by means of a computer model which we recently proposed. In this model, mixture multiphase model is used to describe the flow of the dense medium (comprising finely ground magnetite contaminated with non-magnetic material in water) and the air core, where the turbulence is described by the well-established Reynolds Stress Model. The stochastic Lagrangian Particle Tracking method is used to simulate the flow of coal particles. It is found that the spigot size is very sensitive to the performance. The operational head and medium split reporting to overflow, decrease dramatically as the spigot diameter increases. The density differential decreases rapidly, and then passes through a minimum and increases slowly. The long body including cylinder and cone is helpful to particle separation, particularly for fine and heavy particles. The inlet size plays a remarkable role on the performance on DMCs. The operational head, the density differential and the medium split increase dramatically as the inlet size decreases. Both the upward flow and the downward flow become very strong in the DMC with a small inlet when medium feed rate is constant, which results in a very low Ep.

A study on optimisation of cutting parameters and prediction of surface roughness in end milling of aluminium under MQL machining

The aim of this study is to find the influence of cutting parameters on surface roughness and optimum conditions for better surface quality in end milling of aluminium 6063 under minimum quantity lubrication (MQL). The most important parameters like cutting speed, depth of cut and feed rate are considered. Taguchi experimental design method is applied to conduct the experiments. This study also attempts to develop models to predict surface roughness. Multiple regression and artificial neural network (ANN) techniques are applied to predict the surface roughness. The results of the prediction models are quite close with experiment values. ANOVA is carried out and the influence of cutting parameters on surface roughness is found. The feed rate is the most dominant factor in influencing surface roughness. The results also show that the highest cutting speed, medium feed rate and medium depth of cut produces lowest surface roughness. This study provides the optimum cutting conditions for end milling of aluminium 6063 under minimum quantity lubrication machining.

Study on Burr Formation in Face Milling of Stainless Steel with Chamfered Cutting Tool

Due to the properties such as high strength and high toughness, burr was commonly produced in the machining of stainless steel 1Cr18Ni9Ti, especially when a chamfered cutting tool was used. This study investigated the effects of chamfering geometry of cutting edge and machining parameters on burr formation and presented active control methods to minimize burr size on the exit end based on the experimental research in milling of 1Cr18Ni9Ti. Experiments of face milling with various cutting edge geometric features were conducted. Maximum height and thickness of exit burr and exit side burr were measured. As a result, a proper chamfering geometry that combined the advantages of enhancing the cutting edge strength and obtaining favorable burr types was presented. The experimental results also showed that a relatively high cutting speed was helpful in reducing burr formation; proper medium feed rate and axial depth were favorable for the minimization of burr size. This research is beneficial for precise machining of stainless steel.

Dependence on glucose limitation of the pCO2 influences on CHO cell growth, metabolism and IgG production

The culture levels of glucose and CO(2) have been reported to independently have important influences on mammalian cell processes. In this work the combined effects of glucose limitation and CO(2) partial pressure (pCO(2)) on monoclonal antibody (IgG) producing Chinese Hamster Ovary cells were investigated in a perfusion reactor operated with controlled cell specific medium feed rate, pH and osmolality. Under high glucose conditions (14.3 +/- 0.8 mM), the apparent growth rate decreased (from 0.021 to 0.009 h(-1)) as the pCO(2) increased to approximately 220 mmHg, while the cell specific IgG productivity was almost unchanged. The lactate yield from glucose was not affected by pCO(2) up to approximately 220 mmHg and glucose was mainly converted to lactate. A feed medium modification from high (33 mM) to low (6 mM) glucose resulted in <0.1 mM glucose in the culture. As a result of apparently shifting metabolism towards the conversion of pyruvate to CO(2), both the ratio of lactate to glucose and the alanine production rate were lowered (1.51-1.14 and 17.7-0.56 nmol/10(6) cells h, respectively). Interestingly, when the pCO(2) was increased to approximately 140 mmHg, limiting glucose resulted in 1.7-fold higher growth rates, compared to high glucose conditions. However, at approximately 220 mmHg pCO(2) this beneficial effect of glucose limitation on these CHO cells was lost as the growth rate dropped dramatically to 0.008 h(-1) and the IgG productivity was lowered by 15% (P < 0.01) relative to the high glucose condition. The IgG galactosylation increased under glucose- limited compared to high-glucose conditions.

Enhanced productivity of Chaetoceros calcitrans in airlift photobioreactors

The various modes of cultivation of Chaetoceros calcitrans in airlift photobioreactors (ALPBRs) were examined. The batch system illustrated that the airlift configuration was superior to the bubble column as the airlift supported the circulation of the cell within the system, leading to a better light utilization. The cultivations in both semi-continuous and continuous systems resulted in a high cell productivity, although the steady state cell concentrations in both systems were lower than that obtained from the batch system. The behavior of the large-scale airlift system was not significantly different from the conventional bubble column where the diatom could only be produced at low cell density. Despite this, among all of the systems investigated in this work, the large-scale system gave the highest productivity. The main limiting factor for the large-scale airlift culture was the availability of light. Based on economical analysis, the continuous cultivation in the 2.8 L ALPBR with a medium feed rate of 3 mL min −1 was most attractive where the operation cost could be maintained at a minimum of approx. 7.95 × 10 −4 THB L −1 h −1. However, this continuous small-scale system still suffered from relatively low cell productivity (8.10 × 10 4 cells s −1).

On the direct osmotic concentration of liquid foods. Part I: Impact of process parameters on process performance

In a series of two articles, this paper (part I) deals with the impact of process parameters on process performance, while part II deals with process modelling. In this study, a pilot scale, direct osmotic (membrane) concentration unit was developed and its performance was studied. The unit was built around a flat geometry membrane module with a contacting area of 0.09 m 2 (1 ft. 2). Flat, square, reverse osmosis-type membrane sheets with varying characteristics were used with the osmotic module (cell). Model fluids, such as deionised water and low-concentration sucrose or glucose solutions, were utilized as feed fluids to study (and model) the impact of experimental parameters on process performance. Solutions of sodium chloride (NaCl) were used as osmotic media. Membrane characteristics, feed and osmotic medium concentrations, feed and osmotic medium flow rates, all had a significant impact on the performance of the osmotic module, as measured by the water permeation flux. Experimental data gave a clear indication that at high flow rates compaction of the supporting membrane fabric can in fact cancel the positive effect of improved contacting (larger film coefficients) on water flux.

Optimization of cell density and dilution rate in Pichia pastoris continuous fermentations for production of recombinant proteins.

This paper provides an approach for optimizing the cell density (Xc) and dilution rate (D) in a chemostat for a Pichia pastoris continuous fermentation for the extracellular production of a recombinant protein, interferon tau (INF-tau). The objective was to maximize the volumetric productivity (Q, mg INF-tau l(-1) h(-1)), which was accomplished using response surface methodology (RSM) to model the response of Q as a function of Xc and D within the ranges 150< or = Xc < or =450 g cells (wet weight) l(-1) and 0.1 microm< or = D< or =0.9 microm (microm=0.0678 h(-1), the maximum specific growth rate obtained from a fed-batch phase controlled with a methanol sensor). The methanol and medium feed rates that resulted in the desired Xc and D were determined based on the mass balance. From the RSM model, the optimal Xc and D were 328.9 g l(-1) and 0.0333 h(-1) for a maximum Q of 2.73 mg l(-1) h(-1). The model of specific production rate (rho, mg INF-tau g(-1) cells h(-1)) was also established and showed the optimal Xc 287.7 g l(-1) and D=0.0361 h(-1) for the maximum rho (predicted to be 8.92 x 10(-3) mg(-1) g(-1) h(-1)). The methanol specific consumption rate (nu, g methanol g(-1) cells h(-1)) was calculated and shown to be independent of the cell density. The relationship between nu and mu (specific growth rate) was the same as that discovered from fed-batch fermentations of the same strain. The approach developed in this study is expected to be applicable to the optimization of continuous fermentations by other microorganisms.

Optimization and control of perfusion cultures using a viable cell probe and cell specific perfusion rates.

Consistent perfusion culture production requires reliable cell retention and control of feed rates. An on-line cell probe based on capacitance was used to assay viable biomass concentrations. A constant cell specific perfusion rate controlled medium feed rates with a bioreactor cell concentration of approximately 5 x 10(6) cells mL(-1). Perfusion feeding was automatically adjusted based on the cell concentration signal from the on-line biomass sensor. Cell specific perfusion rates were varied over a range of 0.05 to 0.4 nL cell(-1) day(-1). Pseudo-steady-state bioreactor indices (concentrations, cellular rates and yields) were correlated to cell specific perfusion rates investigated to maximize recombinant protein production from a Chinese hamster ovary cell line. The tissue-type plasminogen activator concentration was maximized ( approximately 40 mg L(-1)) at 0.2 nL cell(-1) day(-1). The volumetric protein productivity ( approximately 60 mg L(-1) day(-1) was maximized above 0.3 nL cell(-1) day(-1). The use of cell specific perfusion rates provided a straightforward basis for controlling, modeling and optimizing perfusion cultures.

Effect of branch frequency in Aspergillus oryzae on protein secretion and culture viscosity.

Highly branched mutants of two strains of Aspergillus oryzae (IFO4177, which produces alpha-amylase, and a transformant of IFO4177 [AMG#13], which produces heterologous glucoamylase in addition to alpha-amylase) were generated by UV or nitrous acid mutagenesis. Four mutants of the parental strain (IFO4177), which were 10 to 50% more branched than the parental strain, were studied in stirred batch culture and no differences were observed in either the amount or the rate of enzyme production. Five mutants of the transformed parental strain (AMG#13), which were 20 to 58% more branched than the parental strain, were studied in either batch, fed-batch or continuous culture. In batch culture, three of the mutants produced more glucoamylase than the transformed parental strain, although only two mutants produced more glucoamylase and alpha-amylase combined. No increase in enzyme production was observed in either chemostat or fed-batch culture. Cultures of highly branched mutants were less viscous than those of the parental and transformed parental strains. A linear relationship was found between the degree of branching (measured as hyphal growth unit length) and culture viscosity (measured as the torque exerted on the rheometer impeller) for these strains. DOT-controlled fed-batch cultures (in which the medium feed rate was determined by the DOT) were thus inoculated with either the transformed parent or highly branched mutants of the transformed parent to determine whether the reduced viscosity would improve aeration and give higher enzyme yields. The average rate of medium addition was higher for the two highly branched mutants (ca. 8.3 g medium h(-1)) than for the parental strain (5.7 g medium h(-1)). Specific enzyme production in the DOT controlled fed-batch cultures was similar for all three strains (approx. 0.24 g alpha-amylase and glucoamylase [g of biomass](-1)), but one of the highly branched mutants made more total enzyme (24.3 +/- 0.2 g alpha-amylase and glucoamylase) than the parental strain (21.7 +/- 0.4 g alpha-amylase and glucoamylase).