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 157

Fig. 8.11 Normal probability chart, experiment DOE2

Table 8.11 Main process settings used for injecting specimens
Parameter Settings

1 6 12 24

Injection time (s) 1 6 12 24

Injection temperature (C) 240 240 240 240

Mold temperature(C) 52 49 48 51

Packing pressure (MPa) 47.2 35.8 37.4 39

Packing time (s) 10 10 10 10

Residual stress (MPa) 34.5 33 29.5 26

Figure 8.13 shows the photographs obtained through electron microscopy of the
four trials described in Table 8.11 . In these cases, as packing pressure is lower
than injection pressure, one can observe that for low injection times the surface
was more severely attacked (injection times 1 and 6 s). Part bleaching was
observed upon visual inspection. For higher injection times, 12 and 24 s, specimen
surface showed no bleaching or acid attack, therefore no micro cavities were
present at this scale of observation. Through the similarity of simulated and
parameters obtained experimentally, the four results on response surface of

Fig. 8.12 were highlighted. These are indicated by points 1, 6, 12, and 24.
Figure 8.12 also shows the presence of two cases separated by an isoline, those
which were attacked by the acid and those which were not. Therefore, the
hypothesis is that by following an isoline corresponding to point 24, one can obtain