Parameter Optimization of PET Plastic Preform Bottles in Injection Molding Process Using Grey-Based Taguchi Method

Table 6

Comparison results.

Performance characteristic	Parameters at optimal setting
	Parameters at initial setting	Prediction	Experiment
Levels’ setting	A3B2C3D2	A1B2C1D2	A1B2C1D2
Average diameter shrinkage (%)	2.455		2.058
Average length shrinkage (%)	2.518		2.048
Grade of grey relation	0.612	0.853	0.750
Improvement of the grey relation grade = 0.138