Vol. 2.0650 1.9610 2.0680 2.8260 3.3670
where Ykm is the value of the mth output generated by the kth DMU, Xkn is the value of the nth input con- sumed by the kth DMU, Vn and Um are Xkn’s and Ykm’s weights, respectively, whose values are determined by solving the model, Hk is the relative efficiency of the kth DMU, and ε is a small positive number. After solving the CCR DEA model, a DMU is on the efficient frontier
if its relative efficiency, Hk, is equal to 1.
Three quality indices, warpage, shrinkage, and volu-
produces M outputs. Then, the DEA CCR model can be
metric shrinkage at ejection, are considered in this paper. Among these three indices, warpage is treated as the output, while shrinkage and volumetric shrinkage at ejection are two inputs in the DEA model. Because the
output in DEA model needs to be maximized and warp- age is apparently the minimized quality index, the trans- formation, 1-warpage, is adopted.
Table 8 Relatively efficient DMUs
DMU Score
44 100
45 100
840 100
871 100
1,151 100
54 97.82
52 97.80
53 97.13
43 96.88
560 94.19
DMUs in italics represent the efficient ones suggested in this study.
The DEA software, Banxia Frontier Analyst 3, is used to find the efficient frontier of process parameters. The dataset used is the dataset of 1,225 data points created in the previous subsection. Each data point is treated as a DMU. After running Banxia Frontier Analyst 3, data points on the efficient frontier are found in Table 5. There are nine DMUs on the efficient frontier, among which five DMUs have at least one reference count as shown in Table 6. Therefore, these five DMUs with positive refer- ence counts are treated as the efficient frontier of process parameters in this paper. The levels of each process par- ameter for these five DMUs are shown in Table 7, where the forecasting value of a quality index is its value derived from the corresponding regression equations and the real value of a quality index means its value by re-running Moldflow on this combination of process parameters. The plot of DEA results is shown in Figure 8.
To verify the efficiency of five DMUs found in this paper, we re-run Moldflow on each DMU and then the results are compared with those of 34 = 81 data points which are utilized to set up the regression equations in
‘Setting up the regression response model to create the complete dataset’ subsection. The comparison is accom- plished by executing DEA on 5 efficient DMUs found in this paper and 81 data points. The results are shown in Tables 8 and 9. From Table 9, it can be observed that
Table 9 Efficient DMUs with positive counts
among five efficient DMUs found in this paper, three DMUs are still on the efficient frontier and one DMU is relatively highly efficient with 94.18% DEA score. Only DMU 1,186 is not quite efficient with 71.28% DEA score, and this may be due to the error of the regression equation at this DMU. It is fair to suggest that the error induced by the regression equation at most of the points is fairly small. Therefore, the efficient frontier of process parameters found by this paper with only 108 (=27 + 81) repeats of experiments can really provide good combina- tions of process parameters for decision making. 塑料注塑工艺参数英文文献和中文翻译(6):http://www.youerw.com/fanyi/lunwen_84177.html