Multi-quality Index Optimization of Injectionof injection Compression Process Parameters Based on Grey Robustness

Aiming at the balance optimization of multiple mass indexes, such as sink marks, warpage and residual stress in the injection compression molding process of optical products, from the perspective of robust design, the experiment of injection compression processing of wedge-shaped light guide plate with five factors and four levels was designed by orthogonal experiment method. The optimal combination of process parameters, the order of influence and the trend of change were obtained by S/N analysis. Finally, the grey relational theory was used to transform the multi-quality index optimization problem into the single objective optimization of grey relational degree, and the optimal process parameter combination considering multiple quality indexes were obtained. Compared with before optimization, each quality index decreased by 23.89%, 8.87% and 24.68% respectively. The research shows that the optimization technology based on grey robustness can effectively solve the problem of balance optimization among multiple mass indexes, and can realize the overall optimization of injection compression process parameters.

Integrasi Statistical Process Control dan Failure Mode And Effect Analysis Guna Meminimalisasi Defect Pada Proses Produksi Pipa PVC

<p><em>Quality can be referred as fitness to use. Furthermore, Quality standard is considered as a way in order to meet customers’ need. PT AZ is a manufacture enterprise which produce polyvinyl chloride (PVC) pipes. This firm has been implementing a Standard Operating Procedure (SOP) in maintaining defect with no more than 2,5% reject product during process production. However, such defects have been happened in production line which were not meet company standards. This study aims to evaluate defect along production process in order to find suitable solution in improving product quality. Seven Tools and Failure and Mode and Effect Analysis (FMEA) were used as research method. The results showed that there were 3 types of defects, namely spot defect, sink marks ant scratch defect. Furthermore, the results of the Cause-and-effect diagram show that human error, </em><em>material</em><em>s and machine are considered as main factors in contributing such defect. In addition, result from FMEA analysis detect that analysis and calculation of the highest RPN 147, namely the human factor is considered as the highest Risk Priority Number with 147 score. This study suggest that further training and supervision should be give to employees in order to improve employers’’ knowledge</em></p><p><em><br /></em></p>

Experimental And Numerical Studies of Shrinkage and Sink Marks On Injection Molded Polymer Gears

Injection molding is an efficient and most economical process employed for the mass production of plastic gears and helps to reduce the processing time and cost required to produce the desired geometry. However, significant process and product qualification of plastic gears face the shrinkage and sink marks issues during cooling and after ejection. In present work, the best gate locations and flow resistance analysis along with a polypropylene (PP) were carried out using Autodesk Moldflow Insight 2019.05. The numerical and experimental study was conducted to evaluate the effect of packing pressure, packing time, and melt temperature on diametric shrinkage, mass, and sink marks of PP gear. The results show that by increasing packing pressure and packing time, the diametric shrinkage decreased but mass increased. However, as the melt temperature increased the diametric shrinkage also increased but the mass decreased. The minimum diametric shrinkage of 0.562% was found in numerical analysis and 1.619% found in an experimental analysis at the same injection molding process parameters. Mostly, the sink marks were observed in the gear surface between hub and dedendum circle.

PENGARUH SUHU INJECTION MOULDING TERHADAP MINIMALISASI SINK MARKS PADA MATERIAL LIMBAH PLASTIK ACRYLONITRILE BUTADIENE STYRENE (ABS)

Plastik merupakan bahan yang terbentuk dari produk polimerisasi sintetik. acrylonitrile butadiene styrene (ABS) merupakan salah satu jenis plastik. ABS dapat dicetak dengan berbagai proses yaitu cetak injeksi, cetak kompresi, ekstrusi, roto moulding, dan thermoforming. Proses injection moulding merupakan teknik yang sering digunakan dalam pembentukan produk berbahan plastik. Tujuan dari penelitian ini adalah mengetahui dan menganalisis pengaruh temperatur injeksi terhadap cacat sink marks dengan pengujian densitas, uji tarik dan uji struktur makro. Proses injection moulding dilakukan dengan variasi pemanasan menggunakan heater pada temperatur 180°C, 200°C, 220°C, 240°C dan 260°C kemudian diinjeksikan ke dalam cetakan standar ASTM D638 dengan tekanan konstan injeksi 0,68 N/mm2. Sink marks adalah cacat produk berupa penyusutan. Faktor yang mempengaruhi sink marks adalah tekanan, suhu, waktu, dan pendinginan. Hasil pembahasan penelitian ini ada pengaruh suhu injection moulding untuk memperoleh minimum sink marks pada uji densitas, uji tarik dan foto makro. Kata kunci : acrylonitrile butadiene styrene (ABS), Injection moulding, sink mars

Reducing the Sink Marks of a Crystalline Polymer Using External Gas-Assisted Injection Molding

External gas-assisted injection molding (EGAIM) has been used to reduce the sink marks of amorphous polymer products, but that of crystalline polymer products has not yet been reported. EGAIM of a crystalline polymer product was investigated in this study, and the influences of process parameters on the sink marks were discussed based on experiments. An isotactic polypropylene (iPP) product was fabricated by EGAIM under different process conditions. A uniform design was applied as an experimental design to investigate the influences of the process parameters on the sink marks. A regression equation was established to describe the quantitative relationship between the important parameters and sink marks in which a data-processing method was applied to determine the optimal value of Fα at significant level α to reduce the possibility of omission of some important parameters. The results show that EGAIM was effective in reducing the sink marks in these iPP products, and the most important parameters were the cooling time, gas pressure, and gas time. This study also provides the quantitative relationship between the important parameters and sink marks as reference for the research of EGAIM on crystalline polymer.

Minimization of Sink Mark Defects in Injection Molding Process Optimization of a Composite Drive Shaft Used in Automobiles

The motive for this paper is to show an included technique for improving the excellent attributes of the infusion fashioned component (Honda Upper Part) being fabricated at assembling industry (Pakistan), wherein the dismissal price for Honda higher element became entrance ramp due to sink marks abandons. The proposed coordinated method grasps the concept of Design of Experiments (Taguchi Approach) and Response floor structure philosophy for infusion forming procedure enhancement. The Taguchi Method (TM) was utilized to brief rundown the elements that effectsly affect the sink tests in infusion shaped components. Moreover, the development method of Response Surface Methodology (RSM) changed into used for the trial research to comfy a forecast model that may be applied to decorate infusion shaping process as some distance as firstrate sink marks decrease. The outcome suggests that the sink marks lower Anticipated by way of the coordination of the Taguchi Method and RSM in truth dwindled from zero.0088 (Taguchi's final results) all the way down to 0.0080 mm. The genuine effects find that the becoming a member of of the Taguchi Method and RSM should safely improve the great. Essentially with those examinations, we attempted to open the imaginative and prescient of manufacturers and architects with regard to using included RSM/Taguchi approach using instantly cum connection relapse version with selected parametric/ranges placing for the dimensional exactness of the infusion shaped part, and in this way contributing closer to progress in procedure's unwavering high-quality. The incorporated method with relapse model for enhancement would not simply supply hypothetical well worth to the writing and makers/fashioners but can likewise be applied to diverse assembling organisations for high-quality elements technology.

Multiobjective Optimization Method for Polymer Injection Molding Based on a Genetic Algorithm

To solve the quality problem of polymer injection parts, a quality prediction and multiobjective optimization method is established. In this method, the parameters that have an important effect on the part quality are selected using an orthogonal testing method, and then a central composite design experiment is performed using these parameters. A mathematical model considering an objective and impact factors is developed using the response surface method. The optimal combination of the impact parameters is determined using a multiobjective genetic algorithm. The injection molding of a typical interior trim part of a car, i.e., the seat belt cover plate, is used as an example to demonstrate the method. The two most troublesome problems in this process—the sink marks and warpage—are multiobjectively analyzed using the established method, and the optimal combination of impact parameters that minimized the defects is determined. The errors of the sink marks and warpage between the experimental and theoretical values were 7.95% and 0.2%, respectively. The optimized parameters were tested in actual injection molding. The results show that the shrinkage and warpage of the parts are obviously improved by optimization using the proposed method, allowing the parts to satisfy the requirements of assembly and appearance.

Visualization of potential sink marks using thickness analysis of finely tessellated solid model

Sink marks are unwanted shallow depressions on the molded plastic surface caused by localized shrinkage during the hardening process of injection molding. Sink marks appearing in the exterior impair the aesthetic quality of the product. In this study, a novel method for extracting potential sink marks that can occur on the part surface is proposed. The thicker portion of the part shrinks with a greater amount than that of the thinner portion. This difference in the shrinkage amount is the main cause of the sink mark. In the plastic part design practice, engineers often check the thickness distribution to predict potential sink marks in the part surface. Our method can be considered as an automated technique of such manual inspection task. A polyhedral solid model of the part with sufficiently small triangles of nearly the same size is prepared. The amount of shrinkage at each polygon is estimated based on its thickness and the shrinkage ratio of the part. The developed algorithm extracts the potential sink marks by analyzing the shrinkage distribution on the part surface. Highlights A novel method for extracting potential sink marks on part surface is proposed. Polygons of input model are tessellated into a set of sufficiently small triangles. The shrinkage of each model polygon is estimated by using the thickness. Potential sink marks are extracted by analyzing the shrinkage distribution.