Application of RSM to Optimize Moulding Conditions for Minimizing Shrinkage in Thermoplastic Processing

2016 ◽  
Vol 700 ◽  
pp. 12-21 ◽  
Author(s):  
S.M. Nasir ◽  
K.A. Ismail ◽  
Z. Shayfull

This study focuses on the analysis of plastic injection moulding process simulation using Autodesk Moldflow Insight (AMI) software in order to minimize shrinkage by optimizing the process parameters. Two types of gates which is single and dual gates have been analysed. Nessei NEX 1000 injection moulding machine and P20 mould material details are incorporated in this study on top of Acrylonitrile Butadiene Styrene (ABS) as a moulded thermoplastic material. Coolant inlet temperature, melt temperature, packing pressure and cooling time are selected as a variable parameter. Design Expert software is obtained as a medium for analysis and optimisation to minimize the shrinkage. The polynomial models are obtained using Design of Experiment (DOE) integrated with RSM Center Composite Design (CCD) method in this study. The results show that packing pressure is a main factor that contributed to shrinkage followed by coolant inlet temperature, while melt temperature and cooling time has less significant for both single and dual gates. Meanwhile, single gate shows a better result of shrinkage compared to the dual gates.

2015 ◽  
Vol 754-755 ◽  
pp. 775-783 ◽  
Author(s):  
S.M. Nasir ◽  
Khairul Azwan Ismail ◽  
Z. Shayfull ◽  
M.A. Fairuz

This study focuses on the analysis of plastic injection moulding process simulation using Autodesk Moldflow Insight (AMI) software in order to correlate between process parameters as an input and warpage as an output for single and dual gates mould design. Nessei NEX 1000 injection moulding machine and P20 mould material details are incorporated in this study on top of Acrylonitrile Butadiene Styrene (ABS) as a moulded thermoplastic material. Coolant inlet temperature, material melt temperature, packing pressure and packing time are selected as a variable parameter. Design Expert software is obtained as a medium for analysis and optimization of input variables in order to minimize the warpage. RSM method as well as Analysis of Variance (ANOVA) has been applied in this study. The results of ANOVA show that some interactions between factors are significant towards warpage existence, which is coolant inlet temperature, material melt temperature and packing pressure. Furthermore, the model created using RSM can be used for warpage prediction and improvement due to a minimum value of error. From this study, the dual gate is the best solution which able to improve the warpage up to 80% instead of single.


2013 ◽  
Vol 748 ◽  
pp. 544-548 ◽  
Author(s):  
Nik Mizamzul Mehat ◽  
Shahrul Kamaruddin ◽  
Abdul Rahim Othman

This paper presents the original development of an experimental approach in studying the multiple tensile characterizations as key quality characteristics for several different plastic gear materials related to various parameters in injection moulding process. In this study, emphases are given on a new low-cost mechanism for the testing of the injection moulded plastic spur gear specimens with various teeth module. The testing fixture are developed and validated to provide uniform state of tension with series of plastic gear specimens produced in accordance with the systematically designed of experiment. The effects of changes in the process parameters including melt temperature, packing pressure, packing time and cooling time at three different levels on the elongation at break and ultimate strength of plastic gear is evaluated and studied through the proposed experimental approach.


Author(s):  
N Khoshooee ◽  
P D Coates

The consistency of polymer melt production in the injection-moulding process has been studied using a Taguchi design-of-experiment method for acrylonitrile butadiene styrene (ABS) and high-density polyethylene. Systematic experimentation with injection-moulding machine settings helped to establish both qualitative and quantitative process understanding in attempting to control the melt quality, assessed here by the shot weight variability. Optimum machine settings were determined which gave the lowest variations in the shot weight. In the case of ABS, uncontrollable influences (noise factors; here the injection stroke and moisture content) were incorporated in the study in such a way that the optimum levels recommended by the analysis make the process (i.e. shot weight) insensitive to variations caused by the noise factors. The set melt temperature and screw-back pressure were observed to be the most influential control factors affecting the shot weight variability for both polymers.


2017 ◽  
Vol 889 ◽  
pp. 51-55 ◽  
Author(s):  
M.H. Othman ◽  
Sulaiman Hasan ◽  
Mohd Halim Irwan Ibrahim ◽  
Siti Zubaidah Khamis

The purpose of this research is to optimise the processing condition of injection moulding towards samples made from polypropylene-nanoclay-bamboo fibre with compatibilizer. The defects that have been controlled upon the optimisation were shrinkage and warpage. The selection of injection moulding processing condition was packing pressure, melt temperature, screw speed and filling time. The research started by drying the bamboo fibres at 120°C. Then, the 1 wt. % fibres were mixed with 79 wt. % of polypropylene, 15 wt. % of compatibilizer and 5 wt. % of nanoclay. The mixing process was performed by using Brabender Plastograph machine. After that, pallets were produced by using Plastic Granulator machine for injection moulding process. The optimisation process was accomplished by adopting the Taguchi method. According to the results, the value of warpage defect between compounding for 1 wt. % fibre and without fibre content was not significant. However the optimum setting of 170°C melt temperature, 35% packing pressure, 30% screw speed and 2 seconds filling time can significantly reduce shrinkage. In conclusion, the optimum processing condition of polypropylene-nanoclay, fibre bamboo had been achieved, and the existence of fibre obviously giving a promising manufacturing opportunity to improve the quality of the injected moulding products.


2015 ◽  
Vol 761 ◽  
pp. 8-11 ◽  
Author(s):  
Mohd Amran ◽  
Siti Salmah ◽  
Raja Izamshah ◽  
Mohd Shahir ◽  
Mohd Amri ◽  
...  

Warpage deflection is one of the common pitfalls in plastic injection moulding which is always affected the quality and accuracy of the plastic products. It occurs due to the influences of mould temperature during injection moulding process and it is related to the number of cooling system existed in the mould. Therefore, this paper studies the effect of cooling channels on warpage of dumbbell plastic part having different number of cooling channel using Moldflow software. Warpage analysis was run using four and eight cooling channels. Parameters involved in this study are injection time, packing time, melt temperature and mould temperature. The result of warpage from simulation analysis was projected on the graphic having different colour which is presented the actual value of warpage. It is found from warpage simulation result that the maximum warpage for four cooling channels is 1.283mm and the maximum warpage for eight cooling channels is 1.280mm. It shows that the increasing of the number of cooling channel from four to eight channels in the injection mould reduces the warpage deflection about 0.2%. Thus, the result shows that the number of cooling system in the mould plays an important role on the quality of plastic part during injection moulding process.


Author(s):  
Carlos A Costa ◽  
Carlos R Altafini ◽  
Fabio R Visioli ◽  
André P Baccin

This work presents a study regarding the influence of the cooling process, as a result of different mould insert materials, on ceramic parts dimensions obtained by low-pressure injection moulding process. Discs of ceramic with Ø80 × 2 mm, composed by 86 wt.% alumina (Al2O3) and 14 wt.% organic vehicle, were produced. An experimental injection mould was designed and manufactured with built-in heating and cooling systems, controlled by a DAQ (Measurement Computing – USB-TC) and thermocouples K type. Four types of insert materials were used: aluminium alloy (AA7075-T6), electrolytic copper, brass alloy (C36000) and SAE1045 steel. Tests were carried out considering injection moulding parameters constant, i.e. initial mould temperature, injection pressure and time and extraction temperature. All the post-process (debinding by wicking; final debinding and sintering) parameters were also kept constant. Parts were analysed considering dimensions, mass, geometry, visual aspects and defects. The results showed that the cooling rate resulting from the thermal conductivity of each material has influenced more significantly the dimensional shrinkage and mass reduction of the samples during the intermediate post-processes phases. The geometric deviations were different for each condition throughout the process and they increased in the final parts. The parts produced with higher cooling rate had higher geometric deviations.


2022 ◽  
Vol 58 (4) ◽  
pp. 102-113
Author(s):  
Sukran Katmer ◽  
Cetin Karatas

The shape memory effect, as the most important ability of shape memory polymers, is a working property and provides the design ability to shape memory polymer features. Shrinkage and warpage are important parameters to control the dimensional accuracy of permanent and temporary shapes of an injection moulded shape memory polyurethane (SMPU) part. In this study, the effects of injection moulding parameters on the shrinkage and warpage of the permanent shape of moulded SMPU parts were experimentally investigated. The parameters of injection pressure, melt temperature, mould temperature, packing pressure, packing time, and cooling time, were chosen as the injection moulding control factors. Taguchi�s L27 orthogonal array design table was used with six injection moulding parameters and their three levels. The results showed that the part has different shrinkage ratios in three main directions, namely, the flow direction, perpendicular to the flow direction, and the direction through the thickness. The results of the analysis of variance showed that the cooling time is the most influential parameter on both the shrinkage (except in thickness) and warpage. The shrinkage in the flow direction as well as in perpendicular to the flow direction decreased with increasing the cooling time. Warpage also decreased with increasing the cooling time. Injection pressure and melt temperature were found to be effective on shrinkage in thickness. Effects of mould temperature, packing pressure, and packing time were found to be limited. A statistically significant relationship has been noticed among shrinkage, warpage, and residual stresses during the study.


2015 ◽  
Vol 830-831 ◽  
pp. 116-119 ◽  
Author(s):  
Gurjeet Singh ◽  
Mohan Kumar Pradhan ◽  
Ajay Verma

Quality control is important aspect of manufacturing process. The quality of product in injection moulding is influenced by injection moulding process parameter. A study of the influence of process parameters on the injection moulding process is presented. Statistically based model approach were studied. In this the process parameter that affect the injection moulding process are like injection time, injection pressure, packing pressure, packing time, cooling time, coolant temperature mold temperature, melt temperature are studied and compared. This paper deals with design of experiment approach to fine out optimal parameter setting. The comparison shows effect of parameters on injection moulding process.Key words: Plastic injection moulding, Orthogonal array, Cycle time


e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Shia-Chung Chen ◽  
Ming-Hsiu Chung ◽  
Yu-Wan Lin ◽  
Ping-Shun Hsu ◽  
Shyh- Shin Hwang ◽  
...  

AbstractThere are several benefits of using the supercritical fluid microcellular injection moulding process. The part weight, melt temperature, viscosity, moulding pressure, shrink/warpage, and cooling/cycle time are all significantly reduced. The purpose of this study is to investigate the rheological behaviour of PS melt dissolved SCF of nitrogen during Microcellular Injection Moulding process applied with Gas Counter Pressure (GCP) technology. The application of gas into the mould cavity prior to the melt filling provides a counter force against the melt front advancement, restricting the foaming process during the melt filling stage. A slit cavity is designed to measure the pressure drop of polystyrene mixed with 0.4wt% supercritical nitrogen fluid under different mould temperatures (185°C, 195°C, and 205°C), injection speeds (5, 10, and 15 mm/s) as well as counter pressures (0, 150, 300 bars). It was found that melt viscosity is reduced by up to 30% when GCP is increased from 50 to 150 bar as compared to conventional injection moulding. The non-nucleation mixture melt obtained by using a GCP of 300 bar has 32~49% lower viscosity. In addition, the glass transition temperature, Tg, was found to be reduced from 96 °C to 50 °C when the applied GCP is 300 bar.


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