For multiple quality indices, the above two classes of optimization focus on searching the single optimal com- bination of process parameters. However, it is known that the trade-off relationships exist among multiple quality in- dices, so the searching task of the single optimum is not easy. Castro et al. (2007) used DEA technique to find the
efficient frontier when six quality indices (related with the part’s geometry) were considered. This research proposes to combine several techniques including experimental de- sign, analysis of variance (ANOVA), multiple regression analysis, and DEA to find the efficient frontier of the process parameters when three essential quality indices, warpage, shrinkage, and volumetric shrinkage at ejection, are under consideration simultaneously.
Materials and product
This study demonstrates how to determine the efficient frontier of process parameters for injection molding by taking an example of the thin cover of a digital camera. The CAD software, Solidworks, is the first to prepare the geometry of the product as shown in Figure 1.
Next, the commercial CAE simulation software tool, Moldflow, is utilized to create the finite element model and uses the finite element and finite difference method to solve pressure, flow, and temperature fields of injection molding (Walsh 1993; Mackerle 2005; Shoemaker 2006).
Table 1 Material properties of GE Cycoloy C2950 PC/ABS
Material property Value
Recommended mold surface temperature (°C) 70
Recommended melt temperature (°C) 275
Melt density (g/cm3) 0.97618
Solid density (g/cm3) 1.1161
Eject temperature (°C) 113
Maximum shear stress (MPa) 0.4
Table 2 Key process parameters and their ranges of operation
to affect products’ quality. Table 2 shows nine process parameters and their ranges of operation suggested by
Parameter Variable Initial value
Range of operation
Moldflow. Three indices of quality, warpage, shrinkage, and volumetric shrinkage at ejection, are considered in
Injection time INT (x1) 1 s 0.5 to 1.5 s
Injection pressure INP (x2) 120 MPa 100 to 140 MPa Packing pressure PP (x3) 100 MPa 80 to 120 MPa Packing time PT (x4) 10 s 7.5 to 12.5 s Cooling time COTI (x5) 19 s 14 to 24 s
7
Melt temperature MET (x8) 275°C 270°C to 280°C
this paper.
The warpages are measured at four reference nodes, and the shrinkages are measured at four edges in this paper; these nodes and edges are depicted in Figure 4 of the XY horizontal plane. In Figure 4, four reference nodes N1991, N1962, N1955, and N2261 are shown, while four edges are formed by these four nodes and are denoted by E1, E2, E3, and E4, respectively. 塑料注塑工艺参数英文文献和中文翻译(3):http://www.youerw.com/fanyi/lunwen_84177.html