Statistical Analysis of Binder Behavior during Debinding Step in Powder Injection Molding (PIM)

The aim of this paper is to propose the approach for applying statistical methods (linear regression and statistical hypothesis testing) to study the behavior of binder during binder removing (debinding) step in powder injection molding (PIM) and also the parameters that affect the binder removing rate. In this work, the binder system under the investigation is the composite binder of 85wt% polyethylene glycol (PEG) and 15 wt% poly (methyl methacrylate) (PMMA) where PEG can be removed from the green product by using warm water while PMMA is removed later during sintering. At 0.05 level of significance, the linear regression method and the statistical hypothesis test prove that the dissolution behavior of PEG can be described using Avarami equation. Furthermore, the dissolution rates of PEG were independent of all parameters used in this study including binder contents in the green products, temperatures, and powder sizes.

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Powder Injection Molding of Mullite: The Study of Mechanical and Physical Properties of the Sintered Products Using Statistical Methods

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.690.92 ◽

2016 ◽

Vol 690 ◽

pp. 92-96

Author(s):

Parinya Chakartnarodom ◽

Nuntaporn Kongkajun ◽

Nutthita Chuankrerkkul

Keyword(s):

Flexural Strength ◽

Injection Molding ◽

Statistical Methods ◽

Sintering Temperature ◽

Hypothesis Test ◽

Polyvinyl Butyral ◽

Powder Injection Molding ◽

Statistical Hypothesis ◽

Powder Injection ◽

Statistical Hypothesis Test

The aim of this work is to propose the application of statistical methods (linear regression and statistical hypothesis test) to analyze the effect of parameters used in powder injection molding including sintering temperature and the feedstock composition on the flexural strength, the porosity and the density of the sintered specimens of mullite prepared by powder injection molding (PIM) and using the composite binder consisting of 80 wt% polyethylene glycol (PEG) and 20 wt% polyvinyl butyral (PVB) for molding. The lab-scale plunger type PIM machine was used to prepare the specimens. The feedstock compositions were 50 to 54 vol% mullite, and the sintering temperatures were 1300 and 1400 °C. At level of significance 0.05 for statistical analysis, feedstock composition did not affect flexural strength, porosity, and density of the sintered specimens. For sintering temperature, the specimens sintered at 1400 °C have the greater density and the lower porosity. However, the flexural strength of the specimens sintered at 1300 °C and 1400 °C are statistically similar.

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Powder Injection Molding of Mullite: The Study of Binder Dissolution Behavior during Debinding Step Using Statistical Methods

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.690.87 ◽

2016 ◽

Vol 690 ◽

pp. 87-91

Author(s):

Parinya Chakartnarodom ◽

Nuntaporn Kongkajun ◽

Nutthita Chuankrerkkul

Keyword(s):

Polyethylene Glycol ◽

Injection Molding ◽

Statistical Methods ◽

Hypothesis Test ◽

Powder Injection Molding ◽

Water Soluble ◽

Statistical Hypothesis ◽

Powder Injection ◽

Dissolution Behavior ◽

Composite Binder

The purpose of this work is to use the statistical methods including linear regression and statistical hypothesis test to study the dissolution behavior of polyethylene glycol (PEG), a water-soluble binder, during debinding step of the green specimens of mullite formed by powder injection molding (PIM). Two systems of composite binders were investigated including (A) 80 wt% polyethylene glycol (PEG) and 20 wt% polyvinyl butyral (PVB) and (B) 78 wt% PEG, 20 wt% PVB, and 2 wt% steric acid (SA)The lab-scale plunger type PIM machine was used to prepare the green specimens consisting of mullite powder and the composite binder. The possible solid loadings of the green specimens that could be prepared by this machine were 50, 52, and 54 vol% mullite (50, 48, and 46 vol% binder). The debinding was done by soaking the green specimens in the warm water at 40 or 60 oC to remove PEG. At level of significance 0.05 for statistical analysis, the dissolution behavior of PEG can be fitted with Avarami equation. In addition, from the Avarami equation obtained from each experimental condition, the dissolution rate of PEG was independent of the parameters used in this study including solid loading in the green specimens, water temperatures for debinding, and composite binder systems.

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Application of Statistical Analysis in the Powder Injection Molding (PIM) of Mullite

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.659.53 ◽

2015 ◽

Vol 659 ◽

pp. 53-57

Author(s):

Parinya Chakartnarodom ◽

Nuntaporn Kongkajun ◽

Nutthita Chuankrerkkul

Keyword(s):

Statistical Analysis ◽

Flexural Strength ◽

Injection Molding ◽

Hypothesis Test ◽

Least Square Method ◽

Powder Injection Molding ◽

Least Square ◽

Statistical Hypothesis ◽

Powder Injection ◽

Mullite Powder

In this work, the statistical analysis methods, including least square method and statistical hypothesis testing, were used to study the flexural strength and density of the specimens formed from mullite powder by powder injection molding (PIM). The feedstock for PIM consist of mullite powder and the composite binder consisting of 78 wt% polyethylene glycol (PEG), 20 wt% polyvinyl butyral (PVB), and 2 wt% stearic acid (SA). The PIM machine used in this work was the lab-scale plunger type. The compositions of the feedstock that could be injection molded by this machine were 50, 52, and 54vol% mullite. After molding, PEG in the green specimens was removed prior to sintering by soaking the specimens in the water at 60 °C for 24 hours while PVB and SA were removed during sintering. The sintering temperatures were 1300 to 1450°C. At significance level of 0.05, the least square method and the statistical hypothesis test showed that both feedstock compositions and sintering temperatures used in this work affected the densities of sintered specimens. However, the increasing of the flexural strength of sintered specimens was mainly by the increasing of the sintering temperature.

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Cost-Benefit Analysis as a Statistical Hypothesis Test: An Example from Urban Transportation

Environment and Planning A Economy and Space ◽

10.1068/a020323 ◽

1970 ◽

Vol 2 (3) ◽

pp. 323-339

Author(s):

J. O. Ledyard

Keyword(s):

Cost Benefit Analysis ◽

Hypothesis Test ◽

Urban Transportation ◽

Cost Benefit ◽

Single Equation ◽

Transportation System ◽

Transportation Systems ◽

Statistical Hypothesis ◽

Statistical Hypothesis Testing ◽

Statistical Hypothesis Test

A method to evaluate the estimated social benefits and costs of many urban transportation decisions is presented, based on the techniques of statistical hypothesis testing. After a slight critique of current practice in cost-benefit analyses, a general equilibrium model is formulated that includes many of the relevant variables and decisions which interact with an urban transportation system. The model is based on individual behavior assumptions (as opposed to macro-behavior) and uses the concept that commodities provide attributes. The significant omissions are mentioned and discussed. It is next shown that if the model is true, then hypotheses involving the Pareto-superiority (and Pareto-optimality) of various decisions with respect to transportation systems imply hypotheses restricting the values of parameters of a single linear equation. This allows the testing (i.e. falsification) of the original hypotheses by using the familiar T and F tests of regression analysis. These tests are based on a single-equation regression only using observations on the rates of use of, the attributes provided by, and the inputs to, the transportation system. The simplicity of the tests seems to indicate that revisions of the model towards reality would be very productive.

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