Competitive advantage through Six Sigma at plastic injection molded parts manufacturing unit

2017 ◽  
Vol 8 (4) ◽  
pp. 411-435 ◽  
Author(s):  
Darshak Desai ◽  
Bhavikkumar Nileshbhai Prajapati

Purpose The purpose of this paper is to illustrate the successful application of Six Sigma at a small and medium scale plastic parts manufacturing unit. Overall operational excellence is one of the foundations of global competiveness. Indian industries are also keeping up with achieving and maintaining operational excellence through different improvement tools and methodologies. Plastic parts manufacturing industries in India are also on the move to increase their overall quality, productivity and profitability. However, it appears from the available literature that application of Six Sigma, one of the most effective breakthrough improvement strategies having direct impact on bottom line of the organization, is not being explored to its full potential, especially at plastic parts manufacturing industries in India. This study was thus undertaken at plastic products manufacturing plant to introduce Six Sigma to them by applying the same to their chronic problems and drawing improvements in quality, productivity and profitability. Design/methodology/approach This paper illustrates the real-life case study of improving quality and productivity of injection molding process by phase wiz application of define, measure, analyze, improve and control, the process improvement methodology of Six Sigma. Findings The critical defects, such as short molding, contamination, injection point and flash are reduced from the process leading to annual savings of INR 10.80 lacs. This is a considerable amount for a small concern in question. Research limitations/implications Because this was the pilot project and the firm was of small and medium size, data collection was the major issue, which consequently took considerable time and efforts at define and measure phases. Injection molding is a very salient process for plastic products manufacturing. Almost one-third of plastic products are made by this process. Thus, improving quality of products made out of injection molding process is of paramount importance. The paper is an attempt to exhibit how a small-scale plastic injection molded parts manufacturing unit can put fruitful efforts to achieve competitive advantage through Six Sigma. Originality/value From the review of literature, it appears that application of Six Sigma among plastic parts manufacturing units, especially small and medium, is very rare, not in India but across the globe. This case study has opened up the direction to small- and medium-scale plastic parts manufacturing units to implement Six Sigma and to move a step forward toward achieving competitive advantage.

2012 ◽  
Vol 468-471 ◽  
pp. 1013-1016 ◽  
Author(s):  
Hua Qing Lai

Molding is one of the most versatile and important processes for manufacturing complex plastic parts. It is a method of fabricating plastic parts by utilizing a mold or cavity that has a shape and size similar to the part being produced. Molten polymer is injected into the cavity, resulting in the desired part upon solidification. The injection-molded parts typically have excellent dimensional tolerance and require almost no finishing and assembly operations. But new variations and emerging innovations of conventional injection molding have been continuously developed to offer special features and benefits that cannot be accomplished by the conventional injection molding process. This study aims to improving the life of stereolithography injection mold.


2006 ◽  
Vol 326-328 ◽  
pp. 187-190
Author(s):  
Jong Sun Kim ◽  
Chul Jin Hwang ◽  
Kyung Hwan Yoon

Recently, injection molded plastic optical products are widely used in many fields, because injection molding process has advantages of low cost and high productivity. However, there remains residual birefringence and residual stresses originated from flow history and differential cooling. The present study focused on developing a technique to measure the birefringence in transparent injection-molded optical plastic parts using two methods as follows: (i) the two colored laser method, (ii) the R-G-B separation method of white light. The main idea of both methods came from the fact that more information can be obtained from the distribution of retardation caused by different wavelengths. The comparison between two methods is demonstrated for the same sample of which retardation is up to 850 nm.


Author(s):  
Sornkrit Leartcheongchowasak ◽  
Merwan Mehta ◽  
Hamid Al-Kadi ◽  
Keith Sequeira ◽  
Brian Snow ◽  
...  

Abstract The most important problem, causing defective parts, in the injection molding process, is nonuniform shrinkage of molded parts. This leads to an iterative trial-and-error cycles of modification of mold cavity and core to arrive at the right dimensional size required which can occasionally to complete retooling. For this process, there are many factors that can be thrown out of control. Using the traditional scientific approach, engineers have longed to understand the mechanics of the process to control it, with limited success. In this paper, a design of experiments setup, using the Taguchi Methods, was done to reduce the nonuniform shrinkage. The company where the experiment was carried out is a precision parts molder for their own product lines. By using the internal experts from the company, a list of independent process parameters with no interactions which were thought the most responsible for dimensional size were listed. As there were 13 such parameters, it was decided to use the L27 orthogonal array. The optimum value that the company experts thought would produce the right part were used as the settings for the initial experiment. The 27 experiments were then performed, allowing sufficient time to let the machine stabilized between the experiments. The S/N ratio calculation for 27 experiments was explained. Next the calculations for the percentage that each parameter contributes to the dimension was determined. Finally, a confirmation experiment was performed to verify the results.


2017 ◽  
Vol 69 (3) ◽  
pp. 414-419
Author(s):  
Mimi Azlina Abu Bakar ◽  
Siti Norazlini Abd Aziz ◽  
Muhammad Hussain Ismail

Purpose This paper aims to investigate the vital characteristic of an innovative ceramic injection molding (CIM) process for orthopedic application with controlled porosity and improved tribological and mechanical properties which were affected by complex tribological interactions, whether lubricated like hip implants and other artificial prostheses. The main objective is to maximize the usage of palm stearin as a single based binder as the function of flow properties during injection molding process. Design/methodology/approach The binder used in this present study consists of 100 per cent palm stearin manufactured by Kempas Oil Sdn Bhd and supplied by Vistec Technology Sdn Bhd. The feedstock was prepared by using a Z-blade mixer (Thermo Haake Rheomix OS) and Brabender mixer model R2400. The feedstock prepared was injection molded using a manually operated vertical benchtop machine with an average pressure of about 5-7 bars. The firing step included the temporary holds at intermediate temperatures to burn out organic binders. At this stage, the green molded specimen was de-bound using a single-step wick-debinding method. Findings The maximum content of ceramic material is applied to investigate the efficiencies of net formulation that can be achieved by ceramic materials. The longer the viscosity will change with shear rate, the higher the value of n obtained instead. From the slope of the curves obtained in Figure 3, the value of n for the feedstock was determined to be less than 1, which indicates a pseudoplastic behavior and suitability for the molding process. Moreover, high shear sensitivity is important in producing complex and intrinsic specimens which are leading products in the CIM industry. Originality/value The feedstock containing HAp powder and palm stearin binder was successfully prepared at very low temperature of 70°C, which promoting a required pseudo-plastic behavior during rheological test. The single binder palm stearin should be optimized in other research works carried out, as palm stearin is most preferred compared to other polymeric materials that provided high energy consumption when subjected to the sintering process. Besides the binder is widely available in Malaysia, low cost and harmless effect during debinding process.


Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1740 ◽  
Author(s):  
Ana Elduque ◽  
Daniel Elduque ◽  
Carmelo Pina ◽  
Isabel Clavería ◽  
Carlos Javierre

Polymer injection-molding is one of the most used manufacturing processes for the production of plastic products. Its electricity consumption highly influences its cost as well as its environmental impact. Reducing these factors is one of the challenges that material science and production engineering face today. However, there is currently a lack of data regarding electricity consumption values for injection-molding, which leads to significant errors due to the inherent high variability of injection-molding and its configurations. In this paper, an empirical model is proposed to better estimate the electricity consumption and the environmental impact of the injection-molding process. This empirical model was created after measuring the electricity consumption of a wide range of parts. It provides a method to estimate both electricity consumption and environmental impact, taking into account characteristics of both the molded parts and the molding machine. A case study of an induction cooktop housing is presented, showing adequate accuracy of the empirical model and the importance of proper machine selection to reduce cost, electricity consumption, and environmental impact.


2011 ◽  
Vol 271-273 ◽  
pp. 1224-1227
Author(s):  
Fang Qi Cheng

To avoid the defects of plastic products and improve product quality have been an important problem for mold designers. In this paper, Autodesk Moldflow software are applied to a plastic control cover injection molding process simulation and find out the actual molding process and true conditions of the dynamic filling, pressure and cooling process in the process of forming. The forming process of parameters such as pressure, temperature and speed are given in order to improve the accuracy of the mould design and product precision.


2014 ◽  
Vol 606 ◽  
pp. 141-145
Author(s):  
Che Ku Abdullah Che Ku Kairulazam ◽  
M.I. Hussain ◽  
Zuraidah Mohd Zain ◽  
Nabilah A. Lutpi

High gloss plastics part in injection molding industries were widely used in Malaysia. However the high rejection rate in this industries were major problem affecting the economic aspects. Therefore this paper presents an approach of implementing six sigma method to reduce the rejection rate in a plastic injection molding process for high gloss plastics part. Define, Measure, Analyze Improve and Control (DMAIC) methodology was applied as basis of the study. By using current process, the average of rejection is 40.6% and the aim of this study is to reduce the rejection rate to less than 10 % . All potential factors were taken into account to identify the significant factors. The improvement process was made base on the analysis output. This study was successful with increment in sigma level from 1.74 σ to 3.00 σ. .


2005 ◽  
Vol 11 (3) ◽  
pp. 167-173 ◽  
Author(s):  
Mary E. Kinsella ◽  
Blaine Lilly ◽  
Benjamin E. Gardner ◽  
Nick J. Jacobs

PurposeTo determine static friction coefficients between rapid tooled materials and thermoplastic materials to better understand ejection force requirements for the injection molding process using rapid‐tooled mold inserts.Design/methodology/approachStatic coefficients of friction were determined for semi‐crystalline high‐density polyethylene (HDPE) and amorphous high‐impact polystyrene (HIPS) against two rapid tooling materials, sintered steel with bronze (LaserForm ST‐100) and stereolithography resin (SL5170), and against P‐20 mold steel. Friction tests, using the ASTM D 1894 standard, were run for all material pairs at room temperature, at typical part ejection temperatures, and at ejection temperatures preceded by processing temperatures. The tests at high temperature were designed to simulate injection molding process conditions.FindingsThe friction coefficients for HDPE were similar on P‐20 Steel, LaserForm ST‐100, and SL5170 Resin at all temperature conditions. The HIPS coefficients, however, varied significantly among tooling materials in heated tests. Both polymers showed highest coefficients on SL5170 Resin at all temperature conditions. Friction coefficients were especially high for HIPS on the SL5170 Resin tooling material.Research limitations/implicationsApplications of these findings must consider that elevated temperature tests more closely simulated the injection‐molding environment, but did not exactly duplicate it.Practical implicationsThe data obtained from these tests allow for more accurate determination of friction conditions and ejection forces, which can improve future design of injection molds using rapid tooling technologies.Originality/valueThis work provides previously unavailable friction data for two common thermoplastics against two rapid tooling materials and one steel tooling material, and under conditions that more closely simulate the injection‐molding environment.


2013 ◽  
Vol 561 ◽  
pp. 239-243 ◽  
Author(s):  
Yong Nie ◽  
Hui Min Zhang ◽  
Jia Teng Niu

This article is using Moldflow analysis and orthogonal experimental method during the whole experiment. The injection molding process of motor cover is simulated under various technological conditions.After forming the maximum amount of warpage of plastic parts for evaluation.According to the range analysis of the comprehensive goal, the extent of the overall influence to the processing parameters, such as gate location, melt temperature, mold temperature and holding pressure is clarified.Through analyzing the diagrams of influential factors resulted from the simulation result,the optimized process parameter scheme is obtained and further verified by simulation.


2011 ◽  
Vol 88-89 ◽  
pp. 279-284
Author(s):  
Feng Li Huang ◽  
Mei Peng Zhong ◽  
Jin Mei Gu ◽  
G.W. Liu

Based on single objective robust design of injection molding process, a bi-objective robust design model based on mean and standard deviation of molding quality and a multi-objective ant colonies algorithm with crossover and mutation based on Pareto optimization are proposed. Aimed at the craft parameters of plastic injection for the top and down shell of remote controller, a model of bi-objective robust design based on mean and standard deviation of warpage quantity is established with an example. And the model is solved by multi-objective ant colonies algorithm of crossover and mutation. The result shows that partial performances of algorithm are superior to that of NSGAII. The actual plastic injection was done by means of the parameters which were gotten by multi-objective robust optimization. The quality of plastic parts was high, and the fluctuation was small.


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