scholarly journals Computer-Aided Reengineering towards Plastic Part Failure Minimization

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6303
Author(s):  
Tiago Pinho ◽  
Tatiana Zhiltsova ◽  
Mónica Oliveira ◽  
Andreia Costa

The work reported here intends to identify and mitigate the causes for failure in a plastic faucet holder, a part of an integral float faucet with a well-documented history of fracture occurrence. A methodology for the identification of hidden internal defects in plastic parts and the elaboration of the required corrective actions towards quality improvement is, therefore, presented. Firstly, part defects were identified via injection moulding process numerical simulation. The latter has enabled the prediction of an excessive volumetric shrinkage at the core of the faucet holder, highlighting the presence of internal voids and, hence, the possible deterioration of the load-bearing capacity. The supposition was later confirmed by X-ray topography scans. Part reengineering, consisting of localized thickness reduction, was the option chosen for decreasing the high shrinkage at the core. For validation purposes, structural analyses were carried out, with and without accounting for the injection moulding processing history. The results obtained during part structural analysis have enabled us to conclude that, when taking into account the residual stresses generated during injection moulding, the analysis more closely reflects the experimental data and allows us to implicitly envisage the propensity to fracture. Moreover, the part modifications, undertaken during the faucet holder reengineering, led to the reduction of the cumulative (processing and imposed by load) stresses by 50%, when compared to the original design analysed.

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.


2014 ◽  
Vol 555 ◽  
pp. 524-529 ◽  
Author(s):  
Andrei Adam ◽  
Cristian Cosma ◽  
Andrei Pop

Processing by injection is the technological process by that the thermoplastics material is injected, under pressure, in the cavity of a mould, where it cools down and solidifies. This process is the most common method for obtaining plastic materials. Injection moulding of thermoplastics has emerged as the premier vehicle for delivering high quality, value added commercial products. Continued global competitiveness has increased standards for product capability and quality while requiring reduced product development time and unit cost. Despite advanced design methods and new process technologies, it is becoming apparent that the injection moulding process is neither flexible nor robust. This paper presents a set of experiments that focused on particular processing conditions of injection through narrow section, thin-wall injection and microinjection. In these cases, the ultrasonic activation does not play an important role as single influence factor but could amplify or strengthen the influence of classical setting parameters of the process: mould temperature, injection pressure and temperature


2013 ◽  
Vol 802 ◽  
pp. 174-178
Author(s):  
Bhawan Muangwaeng ◽  
Surasit Rojananan ◽  
Siriporn Rojananan

The aim of this work is to investigate the effect of injection parameters on morphology in stainless steel 316L metal injection moulding. In the experiment, samples were prepared by injection moulding process with varies parameters such as gate locations, pressures and speeds. The physical appearance of green parts was examined. After that, the cross sections of samples were investigated by scanning electron microscope including chemical analysis of the phase determined by x-ray energy dispersive spectroscopy. The experimental results showed that a perpendicular gate injection caused a separate section between outer skin and core at the cross section of specimens. The high pressure and speed for both injection directions caused crack. In conclusion, a parallel gate injection of feedstock with low pressure and speed was successful to mould the homogeneous samples without black streak, crack and phase separation. Therefore, the observed results could be useful to establish guideline for moulding in order to receive the complete green parts without defects


2018 ◽  
Vol 225 ◽  
pp. 06012
Author(s):  
Wafiuddin Md Ghazali ◽  
Daing Mohamad Nafiz Daing Idris ◽  
Azizul Helmi Sofian ◽  
Januar Parlaungan Siregar ◽  
Mohamad Firdaus Basrawi

Injection moulding process is one of the common processes to produce plastic parts from simple to complicated parts. This paper focuses on the injection process analysis of a 25 tooth spur gear. Three runner system are proposed for the gear and each system will be analysed using Autodesk Simulation Moldflow Advisor. The most suitable design will then be chosen based on the results obtained from the simulation. The design undergoes cooling quality, sink mark, fill + pack, and warp analysis. Based on these analyses, Design 1 gave the better results compared to Design 2 and 3. From there, Design 1 runner system is chosen for the injection moulding mould which will be fabricated later in the research.


2015 ◽  
Vol 825-826 ◽  
pp. 522-529 ◽  
Author(s):  
André Albert ◽  
Welf Guntram Drossel ◽  
Wolfgang Zorn ◽  
Wolfgang Nendel ◽  
Dirk Raithel

The use of lightweight structures is a major trend in the reduction of fuel consumption and CO2 emissions, especially in transport. Metal plastic hybrid structures are an efficient solution to use the best material at every point in the design space. In the state of the art production technologies, the metal parts are produced separately from the plastic parts. The injection moulding process is only used for forming the plastic parts and for joining. These process chains are very extensive. The article shows the development of new process combinations. The aim is a combination of metal forming and injection moulding in one die and one process. One part should be produced with every single stroke of the press.In the first step, deep drawing, injection molding and media based forming with the plastic melt were successfully merged in one tool and one process. It was possible to integrate the injection moulding process into a deep drawing machine. In the next step, it was possible to successfully combine hydroforming and injection molding. For this process combination the hydroforming process is integrated into an injection moulding press. Different surface structures of the metal tubes, such as sandblasting, knurling and laser structuring, were systematically tested regarding to their properties as an adhesion promoter. The target is to establish a purely mechanical connection between the hydroformed metal component and the injection moulded component from glass fibre reinforced plastic instead of the chemical bonding agents often used previously, such as Vestamelt®.


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