Transient thermal analysis of close pressure thermoforming process

Patil, Jeet; Nandedkar, Vilas M.; Mishra, Sushil; Saha, Sandip K.

doi:10.1016/j.jmapro.2020.12.057

Cited by 10 publications

(7 citation statements)

References 34 publications

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“…In previous studies, [22][23][24] it was found that thermal gradient in sheet temperature has a significant impact on the deformation behavior of PMMA. Thus, in order to study the sole effect of pre-stretching on the deformation behavior of polymer sheets, the deleterious effect of thermal gradient was nullified by considering the isothermal deformation of the sheet during processing.…”

Section: Numerical Studiesmentioning

confidence: 96%

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Effect of hyperelastic pre-stretching on thickness distribution of pressure thermoformed products

Patil

Gaikhe

Vasavada

et al. 2022

Journal of Elastomers & Plastics

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Pressure thermoforming is one of the most used processes, but the thickness gradient in the formed parts limits its application. To control the product thickness distribution, pressure forming is assisted by a punch. However, due to punch contact with the sheet, the process is susceptible to surface defect, which is detrimental to the optical properties of the product. To produce optical parts with zero surface defects and controlled thickness distribution, a novel approach as a means for dimensional control by sheet pre-stretching is proposed and validated numerically. It was found that pre-stretching has a significant effect on the deformation behavior of the product.

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Section: Numerical Studiesmentioning

confidence: 96%

“…The maximum amount of uncertainty that can be associated with measuring temperature and pressure is 1%. 22 Thickness measurement was carried out using Rapid-I Vision Measuring System with an associated uncertainty of 0.8%. 1…”

Section: Verification Of Numerical Modelmentioning

confidence: 99%

Effect of hyperelastic pre-stretching on thickness distribution of pressure thermoformed products

Patil

Gaikhe

Vasavada

et al. 2022

Journal of Elastomers & Plastics

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“…The equation solved for the displacement velocity u ! m of the mesh nodes is given as Equation (7), with the diffusion coefficient field λ.…”

Section: Fluid Domain Meshmentioning

confidence: 99%

“…Patil et al by simulations and experiments investigated the behavior of a PMMA sheet thermoformed into a hemispherical mold, finding that for the employed setup, radiation heat transfer and contact modeling are of particular importance. [ 7 ] In addition, the cooling step after deformation was subject to recent research work. In a purely numeric study, Tomasoni et al investigated the benefits of complex cooling channel designs, which are possible to manufacture thanks to the new additive manufacturing techniques.…”

Section: Introductionmentioning

confidence: 99%

Fluid–structure‐interaction simulations of forming‐air impact thermoforming

Wagner

Sheikhi

Kayatz

et al. 2022

Polymer Engineering & Sci

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The authors present a thermally and dynamically coupled fluid–structure‐interaction (FSI) model of a thermoforming process variant along with simulation results. By purposeful arrangement of the inlet nozzles, the process variant under consideration seeks to improve the deformation behavior of a plastic sheet made of polyvinyl chloride (PVC), ultimately leading to a more uniform wall thickness distribution. In order to capture the complex interaction between deforming sheet and turbulent flow field in the pressure box, the numerical model must realistically reproduce both fluid and solid domain and accurately handle coupling between the simulation participants. Detailed information is provided on modeling aspects of the solid and in particular of the fluid domain. Wall thickness distributions obtained from experiments for two test cases are compared to results generated using varying parametrizations of the simulation model. The results in general are in line with experimental measurements, although some peculiarities in the measured data could not be reproduced. Despite its limitations concerning accuracy and the computational cost, the holistic simulation approach using FSI appears to be a helpful tool for investigating thermoforming due to the detailed resolution of the inflation process in time and space.

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“…The development of a thermoforming process is complex and costly to achieve by trial and error given the high material cost of CFRTP. Various research groups have investigated the heating stage in thermoforming, with majority of them focusing on the numerical approach to investigate the efficiency of IR heating and thermoformability of a material [3], [4], [5], [6].…”

Section: Introductionmentioning

confidence: 99%