Effect of cavity surface coating on mold temperature variation and the quality of injection molded parts

Chen, Shia‐Chung; Chang, Yu Han; Chang, Yeon‐Pun; Chen, Yen‐Chen; Tseng, Chia-Yen

doi:10.1016/j.icheatmasstransfer.2009.06.020

Cited by 62 publications

(27 citation statements)

References 8 publications

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“…However, there are other subjects that deserve our attention, namely the heat insulation and/or heat transfer phenomena that cannot be neglected with the coating application, constituting a new concern in the coating selection process [15]. Effectively, the coating must help to improve the wear resistance but it must also help to maintain or even decrease the injection cycle time, leading to a productivity improvement by keeping or improving the part cooling process after injection.…”

Section: Introductionmentioning

confidence: 99%

Improving the Wear Resistance of Moulds for the Injection of Glass Fibre–Reinforced Plastics Using PVD Coatings: A Comparative Study

et al. 2017

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Abstract:It is well known that injection of glass fibre-reinforced plastics (GFRP) causes abrasive wear in moulds' cavities and runners. Physical vapour deposition (PVD) coatings are intensively used to improve the wear resistance of different tools, also being one of the most promising ways to increase the moulds' lifespan, mainly when used with plastics strongly reinforced with glass fibres. This work compares four different thin, hard coatings obtained using the PVD magnetron sputtering process: TiAlN, TiAlSiN, CrN/TiAlCrSiN and CrN/CrCN/DLC. The first two are monolayer coatings while the last ones are nanostructured and consist of multilayer systems. In order to carry out the corresponding tribological characterization, two different approaches were selected: A laboratorial method, using micro-abrasion wear tests based on a ball-cratering configuration, and an industrial mode, analysing the wear resistance of the coated samples when inserted in a plastic injection mould. As expected, the wear phenomena are not equivalent and the results between micro-abrasion and industrial tests are not similar due to the different means used to promote the abrasion. The best wear resistance performance in the laboratorial wear tests was attained by the TiAlN monolayer coating while the best performance in the industrial wear tests was obtained by the CrN/TiAlCrSiN nanostructured multilayer coating.

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Section: Introductionmentioning

confidence: 99%

Improving the Wear Resistance of Moulds for the Injection of Glass Fibre–Reinforced Plastics Using PVD Coatings: A Comparative Study

et al. 2017

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“…Chen et al proposed electromagnetic induction heating [10,11], combined with mold temperature cooling. [12]. Chang et coworkers [10] and Yu and coworkers [11] developed systems based on infrared heating.…”

Section: Introductionmentioning

confidence: 99%

Effect of fast mold surface temperature evolution on iPP part morphology gradients

Liparoti¹,

Sorrentino²,

Guzman³

et al. 2016

AIP Conference Proceedings

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Influence of mold surface temperature on polymer part warpage in rapid heat cycle molding AIP Conference Proceedings 1593, 189 (2014) The control of mold surface temperature is an important factor that affects the sample surface morphology as well as the structural gradients (orientation crystal size, and type) as well as cooling stresses. The frozen layer thickness formed during the filling stage also has a very significant effect on the flow resistance and thus on the resulting pressure drop and flow length in thin wall parts. The possibility to have a hot mold during filling and a quick cooling soon afterward is a significant process enhancement particularly for specialized applications such as micro injection molding and for the reproduction of micro structured surfaces. Up to now, several methods (electromagnetic, infrared, hot vapor fleshing etc,) were tried to achieve fast temperature evolution of the mold. Unfortunately, all these methods require a complex balance between thermal and mechanical problems, equipment cost, energy consumption, safety, molding cycle time and part quality achievable.In this work, a thin electrical resistance was designed and used to generate a fast and confined temperature variation on mold surface (by joule effect). Since the whole temperature evolution can take place in a few seconds, one can couple the advantages of a high surface temperature during filling with the advantages of a low mold temperature, fast cooling and low heating dissipation. Some experiments were performed with a commercial iPP resin. The effects of the surface temperature and of the heating time (under constant electric power) on surface finishing and on the final morphology (thickness and structure of the different layers) are explored and discussed.

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“…Generally, the mold temperature is controlled by adjusting the rate and the temperature of the coolant that moves inside the mold channels. In literatures [1][2][3] is well documented how a high mold temperature has a great positive effect on the surface appearance, strength, size, and shape accuracy of the molded part, moreover, it also decreases the required injection pressure and clamping force of the molding machine [4]. However, the corresponding long cooling time, resulting from the high mold temperature, decreases the productivity and increases the costs.…”

Section: Introductionmentioning

confidence: 99%

“…Different techniques have been proposed to reach this objective, such as induction coils [2], radiation source [1] or proximity heating [5] for the local heating of mold surface. These solutions require additional design and tool cost.…”

Section: Introductionmentioning

confidence: 99%

Rapid control of mold temperature during injection molding process

Liparoti

Hunag

Sorrentino

et al. 2015

AIP Conference Proceedings

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Effect of fast mold surface temperature evolution on iPP part morphology gradients AIP Conference Proceedings 1713, 170001 (2016) Abstract. The control of mold surface temperature is an important factor that determines surface morphology and its dimension in thickness direction. It can also affect the frozen molecular orientation and the mold surface replicability in injection molded products. In this work, thin thermally active films were used to quickly control the mold surface temperature. In particular, an active high electrical conductivity carbon black loaded polyimide composites sandwiched between two insulating thin polymeric layers was used to condition the mold surface. By controlling the heating time, it was possible to control precisely the temporal variation of the mold temperature surface during the entire cycle. The surface heating rate was about 40°C/s and upon contact with the polymer the surface temperature decreased back to 40°C within about 5 s; the overall cycle time increased only slightly. The effect on cross section sample morphology of samples of iPP were analyzed and discussed on the basis of the recorded temperature evolution.

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Effect of cavity surface coating on mold temperature variation and the quality of injection molded parts

Cited by 62 publications

References 8 publications

Improving the Wear Resistance of Moulds for the Injection of Glass Fibre–Reinforced Plastics Using PVD Coatings: A Comparative Study

Improving the Wear Resistance of Moulds for the Injection of Glass Fibre–Reinforced Plastics Using PVD Coatings: A Comparative Study

Effect of fast mold surface temperature evolution on iPP part morphology gradients

Rapid control of mold temperature during injection molding process

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