• Elastomers and Composites
• /
• v.44 no.4
• /
• pp.373-377
• /
• 2009

Most of the plastics products are being manufactured by injection molding. Warpage in injection molded affects the product dimension and it causes assembling problem. In this study, warpages in the injection molded part been studied. Specimens are rectangular flat shapes with and without ribs. Amorphous polymers (PC and ABS) and crystalline polymers (PP and PA66) were used for material. Flat shape with ribs showed higher warpage than flat shape without ribs by 6 to 9%. The specimens with ribs that are located parallel to the flow direction has higher warpage than specimens with ribs that are located perpendicular to the flow direction by 25 to 39%. Crystalline polymers have higher warpage than amorphous polymers by 23 to 67%. Warpage decreases as packing time increases and it increases as injection temperature increases.

• Design & Manufacturing
• /
• v.6 no.1
• /
• pp.67-72
• /
• 2012

Most of the plastics products have been manufactured by injection molding. Molding trouble in injection-molded parts is caused by changing a molding product and molding process condition, etc. In this study, warpage in the injection molded part have been studied. Specimens are rectangular flat shape with and without ribs. Non-crystalline resins (ABS+GF30%, PC+GF30%) and crystalline resins (PP+GF30%, PA66+GF30%) were used for material. Flat shape ribs showed higher warpage than flat shape without rib by 10 to 41%. the specimens with ribs that are located parallel to flow direction has higher warpage than the specimens with rib that are located perpendicular to flow direction by 11 to 50%. crystalline resins have higher warpage than non-crystalline resins by 22 to 78%. Warpage decreases as packing time increases as injection temperature increases.

• Journal of Power System Engineering
• /
• v.18 no.3
• /
• pp.51-58
• /
• 2014

Injection molding simulation provided optimized design results by analyzing quality problems while the product is in assembly or in the process of manufacturing with make automobile plastics. Frequent change of design, change of injection molding, repetition of test injection which was held in the old way can now be stopped. And quality upgrade is expected instead. This report deals with the effect which the position of injection molding automobile console gate and number has on product quality including pressure at end of fill, bulk temperature at end of fill, shear stress of end of fill, residual stress at post filling end, product weld lines and warpage results. Simpoe-Mold simulates the complete manufacturing process of plastic injected parts, from filling to warpage. Simpoe-Mold users, whether they are product designers, mold makers or part manufacturers, can identify early into the design stage potential manufacturing problems, study alternative solutions and directly assess the impact of such part modification, whatever the complexity and geometry of such parts, shell part as plain solid parts.

• Transactions of Materials Processing
• /
• v.9 no.5
• /
• pp.512-525
• /
• 2000

Designers are frequently faced with multiple quality issues in injection molded parts. These issues are usually In conflict with each other, and thus tradeoff needs to be made to reach a final compromised solutions. The objective of this study is to develop an automated injection molding design methodology, whereby part defects such as warpage and weld line are optimized. The features of the proposed methodology are as follows: first, Utility Function approach is applied to transform the original multiple objective problem into single objective problem. Second is an implementation of a direct search-based Injection molding optimization procedure with automated consideration of process variation. The Space Reduction Method based on Taguchi's DOE(Design Of Experiment) is used as a general optimization tool in this study. The computational experimental verification of the methodology was partially carried out for a can model of Cavallero Plastics Incorporation, U. S. A. Applied to production, this study will be of immense value to companies in reducing the product development time and enhancing the product quality.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.11 no.2
• /
• pp.60-65
• /
• 2012

This paper deals with an CAE analysis and optimization of injection molding for a mobile phone cover. Two design goals are established in the optimization; one is to switch over the feed system from cold runner to hot runner for the purpose of reducing material costs, and the other is to minimize the warpage in order to improve product quality. By the full-factorial experiments for design parameters, we showed that the cold runner design could be changed to the hot runner design by replacing the current resin with a new resin of higher fluidity. In addition, we could significantly reduce the warpage of the cover product under the hot runner system by optimizing packing pressure and packing time.

• Proceedings of the KSME Conference
• /
• 2000.11a
• /
• pp.766-771
• /
• 2000

As using of insulating material of plastic to industrial electric field, thermoset has been gradually substituted for thermoplastic. But changing the material with crystalline has some problem, which is strength or warpage, Especially getting a strength to endure inner pressure is necessary when arc is occurred. So we use the material that is composed of glass fiber to compensate strength. By the way as the reinforced glass-fiber material is used in injection molding, unstableness of dimension is appeared frequently and it is difficult to know warpage pattern. So this paper will be contributed to know warpage pattern of mold product that is upper frame of magnetic contactor caused by glass-fiber orientation with fixed gate-system, when glass-fiber reinforced material with classification of poly-amide is used in injection molding.

• Journal of the Microelectronics and Packaging Society
• /
• v.25 no.1
• /
• pp.41-45
• /
• 2018

As the size of semiconductor chip shrinks, the electronic industry has been paying close attention to fan-out wafer level packaging (FO-WLP) as an emerging solution to accommodate high input and output density. FO-WLP also has several advantages, such as thin thickness and good thermal resistance, compared to conventional packaging technologies. However, one major challenge in current FO-WLP manufacturing process is to control wafer warpage, caused by the difference of coefficient of thermal expansion and Young's modulus among the materials. Wafer warpage induces misalignment of chips and interconnects, which eventually reduces product quality and reliability in high volume manufacturing. In order to control wafer warpage, it is necessary to understand the effect of material properties and design parameters, such as chip size, chip to mold ratio, and carrier thickness, during packaging processes. This paper focuses on the effects of thickness of chip and molding compound on 12" wafer warpage after PMC of EMC using finite element analysis. As a result, the largest warpage was observed at specific thickness ratio of chip and EMC.

• 한국금형공학회:학술대회논문집
• /
• 2008.06a
• /
• pp.175-181
• /
• 2008

The technologies of mold design, manufacturing, injection molding process and computer aided engineering(CAE) are developed rapidly with the growth of plastic product market. Injection molding process optimum design can not be easily determined. This study was determined factors and levels which carried out to analyze an influence of narrow pitch BGA socket warpage and performed investigating the main effect and interaction effect between factors using design of experiment. The result of this paper is injection time and packing pressure are affect on narrow pitch BGA socket warpage at injection molding.

• Journal of the Korean Society for Precision Engineering
• /
• v.13 no.5
• /
• pp.44-52
• /
• 1996

A procedure predicting warpage and post-deformation due to heat resistance test is presented. The procedure is applied to the injection molding processes of automotive plastic components, which are the door trim and the instrument pannel. The warpage of products is obtained from the residual stress after filling, packing and cooling process, and the post deformation due to the heat resistance test is calculated in the structural analysis of the product at the ejection temperature with the initial condition of residual stress, the boundary conditions and heat resistance conditions. The analyses give some useful guide lines in the design of automotive plastic parts which should satisfy heat resistance regulation.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.18 no.11
• /
• pp.1-8
• /
• 2019

In this study, we design the feed system and process conditions for a lamp garnish lens of an automobile. For this purpose, four design alternatives are presented and injection molding simulation analyses are performed. The optimal feed system is selected by considering the formability of the product and the cost of mold manufacture. The product formability is assessed by the weld line, warpage, sink mark and the maximum injection pressure, whereas the mold-making cost is estimated by the number of valve gates in the hot runner system. To improve the product formability, process conditions are optimized using an experimental design approach named one-factor-at-a-time. No weld line is generated as a result of the optimization. In addition, it is found the warpage and sink mark are reduced while the maximum injection pressure is increased, compared with those before the optimization.