Analysis of the Surface of Parts Injected with ABS and Treated with Acetic Acid: Influence of Process Settings - Visual Computing: Scientific Visualization and Imaging Systems - page 154

Table 8.6 Parameters and levels of experiment DOE1

Parameter Level

Minimum Middle Maximum

Injection time (s) 1 12 24

Packing pressure (MPa) 30 60 90

Table 8.7 Settings of the central composite experiment DOE2

Settings Injection time [s] Packing pressure [MPa] Surface residual stress [MPa]

1 1 30 38.42

2 1 90 27.63

3 24 30 27.60

4 24 90 16.93

5 1 60 31.86

6 24 60 22.31

7 12 30 32.60

8 12 90 19.61

9 12 60 24.05

Table 8.8 Variance analysis of experiment DOE2

Parameter SS df MS F 0 P-value

(1) Injection time (L) 160.8908 1 160.8908 185.8545 0.000168

Injection time (Q) 13.4958 1 13.4958 15.5898 0.016841

(2) Packing pressure (L) 197.6919 1 197.6919 228.3656 0.000112

Packing pressure (Q) 3.3640 1 3.3640 3.8860 0.119993

Interaction between 1L and 2L 0.0086 1 0.0086 0.0099 0.925410

Error 3.4627 4 0.8657

Total 379.1306 9

Data from Table 8.7 were used as input values for the software STATISTICA
and to carry out variance analysis of experiment DOE2 presented in Table 8.8 .
Due to the high p-value of the parameter Interaction between 1L and 2L, it can
be disregarded in this study. Consequently, a new variance analysis is presented in
Table 8.9 .
Just as in DOE1, one can infer that all parameters taken into account in
Table 8.9 are relevant for the behavior of Surface Residual Stresses of ABS-
injected specimens. In a Pareto chart of experiment DOE2 (Fig. 8.9 ), the param-
eter Injection Time is shown to have a higher relevance than the Packing Pressure
parameter. Together, they account for 95 % of variance in analysis of Surface
Residual Stresses of experiment DOE2.
The response surface that correlates Surface Residual Stresses with parameters
Injection Time and Packing Pressure obtained through the STATISTICA software