Process Factor Optimization for Reducing Warpage and Shrinkage in Injection Molding Using Design of Experiments

2014 ◽  
Vol 541-542 ◽  
pp. 359-362 ◽  
Author(s):  
Gyung Ju Kang

This Paper Presents the Optimization of Injection Molding Conditions to Minimize the Warpage and Volumetric Shrinkage Using Design of Experiments and Taguchi Optimization Method. Considering the Process Parameters such as Injection Time, Packing Pressure, Packing Pressure Time, and Cooling Time, a Series of Mold Analysis are Performed. Orthogonal Arrays of Taguchi, the Signal-to-Noise(S/N) and Analysis of Variance (ANOVA) are Utilized to Determine the Optimization Parameter Levels and to Find out Principal Processing Parameters on Warpage and Volumetric Shrinkage. from the Results it is Clear that Warpage and Volumetric Shrinkage are Reduced. also, the Dominant Parameters were Cooling Time and Packing Time for Warpage, on the other Hand, the most Important Factor for Shrinkage was Injection Time. from this, it can be Concluded that Taguchi Method is very Suitable to Solve the Warpage and Volumetric Shrinkage Problems in Injection Molding Parts.

2012 ◽  
Vol 271-272 ◽  
pp. 1190-1194
Author(s):  
Hsueh Lin Wu ◽  
Ya Hui Wang

In this study, volumetric shrinkage at ejection of the chair base in the injection process, application of the 3D CAD software pro/e to design the shape of the product, and then combines moldflow simulation analysis and Taguchi method with L25 Orthogonal Array to determine the optimal injection molding parameters combination. In the Taguchi L25 experimental design, the six controlling factors used are melt temperature, mold temperature, injection time, packing time, packing pressure and cooling time, the result of experiment revealed that the optimum combination of parameters was the A2 (melting temperature 265°C), B3 (mold temperature 40°C), C2 (injection time 1.7sec), D4 (packing pressure 95%), E5 (packing time20sec), F5 (cooling time 20sec). The results show that the combination of Taguchi method and Moldflow can not only improve the molding process parameters effectively, but also optimize the quality of the products.


2012 ◽  
Vol 488-489 ◽  
pp. 269-273 ◽  
Author(s):  
G.S. Dangayach ◽  
Deepak Kumar

In the present era, competition gets tougher; there is more pressure on manufacturing sectors to improve quality and customer satisfaction while decreasing cost and increasing productivity. These can be achieved by using modern quality management systems and process improvement techniques to reduce the process variability and driven waste within manufacturing process using effective application of statistical tools. Taguchi technique is well known technique to solve industrial problems. This technique is fast and can pinpoint the chief causes and variations. Plastic injection molding is suitable for mass production articles since complex geometries can be obtained in a single production step. The difficulty in setting optimal process conditions may cause defects in parts, such as shrinkage and warpage. In this paper, optimal injection molding conditions for minimum shrinkage were determined by the Taguchi design of experiment (DOE) approach. Polypropylene (PP) was injected in circular shaped specimens under various processing parameters: melt temperature, injection pressure, packing pressure and packing time. S/N ratios were utilized for determining the optimal set of parameters. According to the results, 2400 C of melt temperature, 75 MPa of injection pressure, 50 MPa of packing pressure and 15 sec. of packing time gave minimum shrinkage of 0.951% for PP. Statically the most significant parameter was melt temperature for the PP. Injection pressure had the least effect on the shrinkage. The defect rate was reduced from 14% to 3%.


2017 ◽  
Vol 4 (3) ◽  
pp. 15
Author(s):  
U. Wahyudi

Produk kemasan kue atau toples adalah produk rumah tangga yang sangat dibutuhkan untuk menaruh berbagai macam-macam kue kering, Produk plastik ini terdiri dari badan dan tutup, kedua komponen ini pada saat dirakit memerlukan kepresisian yang lumayan bagus oleh karena material yang digunakan plastik, maka faktor penentuan penyusutan(shrinkage) memegang peranan sangat penting pada saat dicetak dengan mesin injection molding yang menggunakan material polistyrene. Pada saat produksi pernah terjadi kegagalan produk fitting terlalu kencang dan ada juga fitting yang kendor antara tutup dengan badan akibatnya produk tidak lolos produksi oleh quality control. Didalam tugas akhir ini penulis melakukan langkah-langkah bagaimana teknik menganalisa cacat penyusutan (shrinkage) material plastik terutama di khususkan material polystyrene dimulai dari proses injection molding lalu diambil sampel produk dengan tingkat pengujian yang berbeda lewat settingan parameter. Dengan waktu injeksi dan backpressure yang berbeda-beda akan menghasilkan ukuran produk dan nilai shrinkage yang berbeda pula. Nilai temperatur leleh yang baik digunakan untuk material polistyrene dengan ketebalan produk kemasan toples 0,75 mm, diameter produk 140,94 mm dan tinggi 58,29 mm. berkisar antara 2400C – 3100C. Cacat penyusutan pada material polystyrene pasti ada walaupun tidak sebesar pada material lain seperti PP dan LDPE dan bisa diminimalkan dengan setting parameter proses yang bagus. Nilai shrinkage yang baik dan ideal dan sesuai standar terjadi pada settingan backpressure 30 kgf/cm² dengan waktu injeksi yaitu 2 detik. Dengan  parameter yang konstan, mulai dari injection speed 120 cm/s, 65 cm/s. Injection pressure 1400 kgf/cm² dan pack pressure 1200 kgf/cm², pack time 0,5 sec, Shot size 55 mm, kemudian cooling time 2 detik dengan temperatur mold 600 C.


2013 ◽  
Vol 347-350 ◽  
pp. 1163-1167
Author(s):  
Ling Bai ◽  
Hai Ying Zhang ◽  
Wen Liu

Moldflow software was used to obtain the best gate location and count. Influence of injection molding processing parameters on sink marks of injection-piece was studied based on orthogonal test. The effects of different process parameters were analyzed and better process parameters were obtained. Results of research show that decreasing melt temperature, mold temperature, the increasing injection time and packing pressure can effectively reduce the sink marks index.


2010 ◽  
Vol 37-38 ◽  
pp. 570-575 ◽  
Author(s):  
Bao Shou Sun ◽  
Zhe Chen ◽  
Bo Qin Gu ◽  
Xiao Diao Huang

To optimize injection molding warpage, this paper applies the uniform design of experiment method to search for the optimal injection molding processing parameters. The warpage. simulation analysis is accomplished by emplying Moldflow software. The melt temperature, mold temperature, injection time and packing pressure are regarded as processing parameters, and processing parameters are optimized through establishing a regression equation, and the optimization result and influence factors are analyzed. The results show that uniform design of experiment can reduce number of experiments used effectively and the quality of the product is greatly improved by the optimization method.


2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Nik Mizamzul Mehat ◽  
Shahrul Kamaruddin ◽  
Abdul Rahim Othman

The performance of plastic gears in wide variety of power and motion transmission applications is rather limited due to weak mechanical properties and divergent mechanism of failures. A methodical simulation is carried out to analyze the gear performance with various gating system types, gate locations, and processing parameters via grey-based Taguchi optimization method. With the obtained optimum results in simulation stage, the flow patterns of polymer melt inside the mould during filling, packing, and cooling processes are studied and the plastic gear failures mechanism related to processing parameters are predicted. The output results in the future can be used as guidance in selecting the appropriate materials, improving part and mould design, and predicting the performance of the plastic gear before the real process of the part manufacturing takes place.


2012 ◽  
Vol 217-219 ◽  
pp. 2065-2069 ◽  
Author(s):  
Ji Ping Chen ◽  
Zhi Ping Ding

Based on experimental method of factorial design, numerical simulation of injection molding using Moldflow software has been done. The effects of the gate number-distribution, melt temperature, packing pressure, packing time, injection time, etc. on volumetric shrinkage and the two-way interactions among factors in injection molding of plastic part have been researched. The regression model for volumetric shrinkage of plastic part has been obtained through multiple linear regression analysis of the experimental data. The optimization model has been established to optimize processing parameters setting leading factors which effect volumetric shrinkage as design variables and regression model of volumetric shrinkage as objective function. The volumetric shrinkage value of plastic part is less than the minimum volumetric shrinkage value of the main experiment, which indicates that the method has a good practical value in engineering.


2015 ◽  
Vol 1096 ◽  
pp. 366-370
Author(s):  
Yong Cheng Huang ◽  
Hong Bin Liu ◽  
Hai Tao Wu

Considering the importance of the reasonable injection molding technology.Based on the application of moldflow in injection molding of the helmet .By adjusting the mold temperature, melt temperature, injection time, packing pressure, hold time and so on the injection molding process parameters to develop appropriate technology methods to get the best injection molding parameters.


2011 ◽  
Vol 31 (5) ◽  
Author(s):  
María G. Villarreal-Marroquín ◽  
Mauricio Cabrera-Ríos ◽  
José M. Castro

Abstract Injection molding is the most important process for mass-producing plastic products. To help improve and facilitate the molding of plastic parts, advanced computer simulation tools have been developed. While modeling is complicated by itself, the difficulty of optimizing the injection molding process is that the performance measures involving the injection molding process usually show conflicting behaviors. Therefore, the best solution for one performance measure is usually not the best in some other performance measures. This paper introduces a simulation optimization method which considers multiple performance measures and is able to find a set of efficient solutions without having to evaluate a large number of simulations. The main components of the method are metamodeling, design of experiments, and data envelopment analysis. The method is illustrated and detailed here using a simple test example, and it is applied to a real injection molding case. The performance of the method using a different design of experiments is also discussed.


Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3419
Author(s):  
Chao-Ming Lin ◽  
Yun-Ju Chen

Plastic is an attractive material for the fabrication of tubular optical instruments due to its light weight, high strength, and ease of processing. However, for plastic components fabricated using the injection molding technique, roundness and concentricity remain an important concern. For example, in the case of a telecentric lens, concentricity errors of the lens barrel result in optical aberrations due to the deviation of the light path, while roundness errors cause radial stress due to the mismatch of the lens geometry during assembly. Accordingly, the present study applies the Taguchi design methodology to determine the optimal injection molding parameters which simultaneously minimize both the overall roundness and the overall concentricity of the optical barrel. The results show that the geometrical errors of the optical barrel are determined mainly by the melt temperature, the packing pressure, and the cooling time. The results also show that the optimal processing parameters reduce the average volume shrinkage rate (from 4.409% to 3.465%) and the average deformations from (0.592 mm to 0.469 mm) of the optical barrel, and the corresponding standard deviation values are reduced from 1.528% to 1.297% and from 0.263 mm to 0.211 mm, respectively. In addition, the overall roundness and overall concentricity of the barrel in the four planes are positively correlated.


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