Optimizing the Performance of Plastic Injection Molding Using Weighted Additive Model in Goal Programming

Author(s):  
Abbas Al-Refaie ◽  
Ming-Hsien Li

Injection molding process is increasingly more significant in today’s plastic production industries because it provides high-quality product, short product cycles, and light weight. This research optimizes the performance of this process with three main quality responses: defect count, cycle time, and spoon weight, using the weighted additive goal programming model. The three quality responses and process factors are described by appropriate membership functions. The Taguchi’s orthogonal array is then utilized to provide experimental layout. A linear optimization based on the weighted additive model in goal programming model is built to minimize the deviations of the product/process targets from their corresponding imprecise fuzzy values specified by the process engineer’s preferences. The results show that the average defect count is reduced from an average of 0.75 to 0.16. Moreover, the average cycle time becomes 13.06 seconds, which is significantly smaller than that obtained at initial factor settings (= 15.10 seconds). Finally, the average spoon weight is exactly on its target value of 2.0 gm.

2011 ◽  
Vol 1 (2) ◽  
pp. 43-54 ◽  
Author(s):  
Abbas Al-Refaie ◽  
Ming-Hsien Li

Injection molding process is increasingly more significant in today’s plastic production industries because it provides high-quality product, short product cycles, and light weight. This research optimizes the performance of this process with three main quality responses: defect count, cycle time, and spoon weight, using the weighted additive goal programming model. The three quality responses and process factors are described by appropriate membership functions. The Taguchi’s orthogonal array is then utilized to provide experimental layout. A linear optimization based on the weighted additive model in goal programming model is built to minimize the deviations of the product/process targets from their corresponding imprecise fuzzy values specified by the process engineer’s preferences. The results show that the average defect count is reduced from an average of 0.75 to 0.16. Moreover, the average cycle time becomes 13.06 seconds, which is significantly smaller than that obtained at initial factor settings (= 15.10 seconds). Finally, the average spoon weight is exactly on its target value of 2.0 gm.


2014 ◽  
Vol 599-601 ◽  
pp. 564-567
Author(s):  
Xu Xia Zhu ◽  
Hai Xiao Zheng

In this paper, based on the characteristics of shell part, the application of hot runner system for the shell parts injection molding process was analyzed by Moldflow. According to this research, design parameters obtained were optimized. The result shows that hot runner system enables injection mold cooling faster , shortens the molding cycle time , and also improves the quality of the shell part.


2020 ◽  
Vol 2020 ◽  
pp. 1-15 ◽  
Author(s):  
Saad M. S. Mukras

This paper presents a framework for optimizing injection molding process parameters for minimum product cycle time subjected to constraints on the product defects. Two product defects, namely, volumetric shrinkage and warpage, as well as seven process parameters including injection speed, injection pressure, cooling time, packing pressure, mold temperature, packing time, and melt temperature, were considered. Injection molding experiments were conducted on specifically chosen test points and results were used to compute the volumetric shrinkage and warpage (at each test point). Thereafter, three relationships between the product cycle time (one relationship), the two product defects (two relationships), and the injection molding parameters were constructed using the kriging technique. An optimization problem to minimize the product cycle time (described by the first relationship) subject to constraints on the product defects (described by the latter two relationships) was then formulated. A combination set of points between the lower and upper extreme values of acceptable product defect was generated to serve as constraints for the two product defects. The optimization problem was then solved using the Fmincon function, available in the Matlab optimization toolbox. A plot of the optimization results revealed an appreciable tradeoff between the cycle time and the two product defects. To validate the optimization, an additional injection molding experiment was conducted for one of the optimization results. Results from the additional experiment showed reasonably close agreement with simulation optimization results differing in the cycle time, the warpage and volumetric shrinkage by 6.7%, 3.2%, and 8%, respectively.


Author(s):  
Abbas Al-Refaie ◽  
Ahmad Musallam

The performance of the polyethylene extrusion process used in the plastic industry was optimized using mixed goal programming. Four responses, the roll weight, production cycle time, distance between emitters, and thickness, are crucial. After a combination of initial factor settings was determined, individual and moving range control charts were established for each response. Two-phase optimization was implemented using L18 and L9 arrays for conducting experiments. A two-phase fuzzy goal programming model was formulated and employed to determine the combination of optimal factor settings, which was used to perform experiments. The results showed a significant reduction in the average production time from 13.0 to 11.316 min. Moreover, the average respective relative percentages of variability reduction for the roll weight, production cycle time, distance between emitters, and thickness were 48.547%, 49.048%, 47.174%, and 63.704%, respectively, and the corresponding estimated process capability indices for the combination of initial (optimal) factor settings were 0.202 (1.440), 0.330 (0.914), and 0.460 (1.456). Such improvement results in significant reduction in quality costs.


Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 889 ◽  
Author(s):  
Youngjae Ryu ◽  
Joo Seong Sohn ◽  
Chang-Seok Yun ◽  
Sung Woon Cha

Shrinkage and warpage of injection-molded parts can be minimized by applying microcellular foaming technology to the injection molding process. However, unlike the conventional injection molding process, the optimal conditions of the microcellular foam injection molding process are elusive because of core differences such as gas injection. Therefore, this study aims to derive process conditions to minimize the shrinkage and warpage of microcellular foam injection-molded parts made of glass fiber reinforced polyamide 6 (PA6/GF). Process factors and levels were first determined, with experiments planned accordingly. We simulated designed experiments using injection molding analysis software, and the results were analyzed using the Taguchi method, analysis of variance (ANOVA), and response surface methodology (RSM), with the ANOVA analysis being ultimately demonstrating the influence of the factors. We derived and verified the optimal combination of process factors and levels for minimizing both shrinkage and warpage using the Taguchi method and RSM. In addition, the mechanical properties and cell morphology of PA6/GF, which change with microcellular foam injection molding, were confirmed.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Muhammad Khan ◽  
S. Kamran Afaq ◽  
Nizar Ullah Khan ◽  
Saboor Ahmad

Cycle time of a part in injection molding process is very important as the rate of production and the quality of the parts produced depend on it, whereas the cycle time of a part can be reduced by reducing the cooling time which can only be achieved by the uniform temperature distribution in the molded part which helps in quick dissipation of heat. Conformal cooling channel design is the solution to the problem which basically “conforms” to the shape of cavity in the molds. This paper describes the analytical study of cooling analysis of different types of cooling channel designs. The best cooling channel design is also selected on the basis of minimum time to reach ejection temperature, uniform temperature distribution, and minimum warpage of part. “Creo Elements/Pro 5.0” is used to model the case study, its molds, and the cooling circuit whereas analytical study is done using “Autodesk Moldflow Advisor 2013 (AMFA).”


Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2288
Author(s):  
Pham Son Minh ◽  
Minh-Tai Le

In injection molding, the temperature control of the dynamic mold is an excellent method for improving the melt flow length, especially of thin-wall products. In this study, the heating efficiency of a novel heating strategy based on induction heating was estimated. With the use of this heating strategy, a molding cycle time similar to the traditional injection molding process could be maintained. In addition, this strategy makes it easier to carry out the heating step due to the separation of the heating position and the mold structure as well as allowing the ease of magnetic control. The results show that, with an initial mold temperature of 30 °C and a gap (G) between the heating surface and the inductor coil of 5 mm, the magnetic heating process can heat the plate to 290 °C within 5 s. However, with a gap of 15 mm, it took up to 8 s to reach 270 °C. According to the measurement results, when the mold heating time during the molding process increased from 0 to 5 s, the flow length increased significantly from 71.5 to 168.1 mm, and the filling percentage of the thin-wall product also increased from 10.2% to 100%. In general, the application of external induction heating (Ex-IH) during the molding cycle resulted in improved melt flow length with minimal increase in the total cycle time, which remained similar to that of the traditional case.


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