Tensile Strength of Welds

Keywords: fractional design, Taguchi design, two-level design, dispersion effects.

Description

This is a highly fractionated two-level factorial design employed as a screening design in an off-line welding experiment performed by the National Railway Corporation of Japan. There were 16 runs and 9 experimental factors. The response variable is the observed tensile strength of the weld, one of several quality characteristics measured. All other variables are at plus and minus levels.


	Variable		Description

	Rods		Kind of welding rods
	Drying		Period of drying
	Material		Welded material
	Thickness		Thickness
	Angle		Angle
	Opening		Opening
	Current		Current
	Method		Welding method
	Preheating		Preheating
	Strength		Tensile strength of the weld in kg/mm

Download

Data File (tab-delimited text)

Source

Taguchi, G., and Wu, Y. (1980). Introduction to Off-Line Quality Control. Central Japan Quality Control Association, Nagoya, Japan.

Box, G. E. P., and Meyer, R. D. (1986). Dispersion effects from fractional designs. Technometrics 28, 19-27.

Carroll, R. J., and Ruppert, D. (1988). Transformations and Weighting in Regression.Chapman and Hall, New York, pages 107-110.

Bergman, B., and Hynén, A. (1997). Dispersion effects from unreplicated designs in the 2^k-p series. Technometrics 39, 191-198.

Nelder, J. A., and Lee, Y. (1998). Letter to the Editor: Joint modeling of mean and dispersion. Technometrics 40, 168-171.

Huele, A. F., and Engel, J. (1998). Response to Nelder and Lee. Technometrics 40, 172-175.

Smyth, G. K., Huele, F., and Verbyla, A. P. (2001). Exact and approximate REML for heteroscedastic regression. Statistical Modelling: An International Journal. Volume 1 #3. To appear. (Zipped Postscript).

Analysis

> jDrying <- jitter(Drying,factor=3)
> plot(jDrying,Strength,type="n",xlab="Drying")
> points(jDrying[Material==-1],Strength[Material==-1],col=2)
> points(jDrying[Material==1],Strength[Material==1],col=4)