Optimization of mold temperature profile and process parameters for weld line reduction and short cycle time in rapid heat cycle molding

Kitayama, Satoshi; Ishizuki, Ryoto; Takano, Masahiro; Kubo, Yoshikazu; Aiba, Setsuya

doi:10.1007/s00170-019-03685-3

Cited by 21 publications

(11 citation statements)

References 27 publications

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“…Some important factors which may have an impact on the finishing are the process parameters, mold design, and properties of plastic materials [ 52 , 73 , 74 ]. One of the factors that determines the quality of injection molded parts is the weld line [ 50 , 75 , 76 ]. The weld line refers to the process in which the liquid material is divided into two or more flows in the cavity during the injection process and merged together after a period of time [ 51 , 77 , 78 , 79 ].…”

Section: Injection Molding Processmentioning

confidence: 99%

“…The mold is rapidly cooled after the filling stage to harden the molten plastic. After the cooling stage, the plastic parts are finally ejected [ 76 ]. The solid line in Figure 5 shows a demonstrative example of a mold temperature profile, where Tg denotes the material’s glass transition temperature.…”

Section: Rapid Heat Cycle Moldingmentioning

confidence: 99%

“…The heating time is indicated by the symbol t h . The injection, packaging, and cooling times are denoted by the letters t inj , t p , and t c , respectively [ 76 ].…”

Section: Rapid Heat Cycle Moldingmentioning

confidence: 99%

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Potential of Rapid Tooling in Rapid Heat Cycle Molding: A Review

et al. 2022

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Rapid tooling (RT) and additive manufacturing (AM) are currently being used in several parts of industry, particularly in the development of new products. The demand for timely deliveries of low-cost products in a variety of geometrical patterns is continuing to increase year by year. Increased demand for low-cost materials and tooling, including RT, is driving the demand for plastic and rubber products, along with engineering and product manufacturers. The development of AM and RT technologies has led to significant improvements in the technologies, especially in testing performance for newly developed products prior to the fabrication of hard tooling and low-volume production. On the other hand, the rapid heating cycle molding (RHCM) injection method can be implemented to overcome product surface defects generated by conventional injection molding (CIM), since the surface gloss of the parts is significantly improved, and surface marks such as flow marks and weld marks are eliminated. The most important RHCM technique is rapid heating and cooling of the cavity surface, which somewhat improves part quality while also maximizing production efficiencies. RT is not just about making molds quickly; it also improves molding productivity. Therefore, as RT can also be used to produce products with low-volume production, there is a good potential to explore RHCM in RT. This paper reviews the implementation of RHCM in the molding industry, which has been well established and undergone improvement on the basis of different heating technologies. Lastly, this review also introduces future research opportunities regarding the potential of RT in the RHCM technique.

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Section: Injection Molding Processmentioning

confidence: 99%

Section: Rapid Heat Cycle Moldingmentioning

confidence: 99%

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Potential of Rapid Tooling in Rapid Heat Cycle Molding: A Review

et al. 2022

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“…is includes fine-tuning the injection molding unit to deliver proper injection pressures and speeds (which affects the filling time), designing the product to have minimum wall thickness (which affects the filling time), making adjustments on the injection unit, such as mold opening and closing (which affects the ejection time), as well as other adjustments on the process parameters. Experienced plastic engineers who have gained insights on the process generally make these adjustments [6].…”

Section: Introductionmentioning

confidence: 99%

Experimental-Based Optimization of Injection Molding Process Parameters for Short Product Cycle Time

Mukras

2020

Advances in Polymer Technology

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This paper presents a framework for optimizing injection molding process parameters for minimum product cycle time subjected to constraints on the product defects. Two product defects, namely, volumetric shrinkage and warpage, as well as seven process parameters including injection speed, injection pressure, cooling time, packing pressure, mold temperature, packing time, and melt temperature, were considered. Injection molding experiments were conducted on specifically chosen test points and results were used to compute the volumetric shrinkage and warpage (at each test point). Thereafter, three relationships between the product cycle time (one relationship), the two product defects (two relationships), and the injection molding parameters were constructed using the kriging technique. An optimization problem to minimize the product cycle time (described by the first relationship) subject to constraints on the product defects (described by the latter two relationships) was then formulated. A combination set of points between the lower and upper extreme values of acceptable product defect was generated to serve as constraints for the two product defects. The optimization problem was then solved using the Fmincon function, available in the Matlab optimization toolbox. A plot of the optimization results revealed an appreciable tradeoff between the cycle time and the two product defects. To validate the optimization, an additional injection molding experiment was conducted for one of the optimization results. Results from the additional experiment showed reasonably close agreement with simulation optimization results differing in the cycle time, the warpage and volumetric shrinkage by 6.7%, 3.2%, and 8%, respectively.

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“…Table 1 shows the parameters and response variables considered by various authors during the optimization of injection moulding process parameters (Bensingh et al, 2019;Chen et al, 2016;Gao et al, 2018;Khamis et al, 2019;Kitayama et al, 2019;Kumar et al, 2016;López et al, 2016;Oliaei et al, 2016;Sánchez-Sánchez et al, 2018;Singh et al, 2018;Zhang et al, 2016;Zhao et al, 2015). It is clear from the table that certain parameters like filling time, back pressure, holding time, and holding pressures are not important parameters and are not considered.…”

Section: Introductionmentioning

confidence: 99%