Analysis of infrared radiation heating of plastics.

Miyanaga, Toshiyuki; Nakano, Yoshiharu

doi:10.1541/ieejias.110.975

Cited by 6 publications

(2 citation statements)

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“…Spectra data will be used as a database in the numerical simulation (see Section 3) as well as for the surface temperature distribution measurements. In the literature, we found few papers referring to polystyrene spectral properties measurements [7,8]. 1.63 mm white PS sheets were processed by extrusion moulding.…”

Section: Ps Spectral Properties Characterisationmentioning

confidence: 99%

Modelling of infrared heating of thermoplastic sheet used in thermoforming process

Schmidt

2003

Journal of Materials Processing Technology

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Thermoforming consists of warming a plastic sheet and forming it into a cavity or over a tool using vacuum, air pressure and mechanical means. The process begins by heating a thermoplastic sheet slightly above the glass transition temperature, for amorphous polymers, or slightly below the melting point, for semi-crystalline materials. As the final thickness distribution of the part is drastically controlled by the initial temperature distribution inside the sheet, it is very important to optimise the heating stage. In most of the thermoforming machine, this step is performed using an infrared oven constituted of long waves infrared emitters. The goal of this study is to determine the efficiency of short waves infrared emitters (halogen lamps) for the heating step. The infrared heating of thermoplastic sheets will be modelled following two steps: an experimental setup developed in our laboratory permits to measure the influence of parameters such as heaters temperature, incidence of the radiation, heat transfer coefficient, etc. An 880 LW AGEMA infrared camera is used to evaluate the surface distribution of the transmitted heat flux by measuring the temperature distribution on the surface of the thermoplastic sheet. In addition, a numerical model using control volume method (software called PLASTIRAD) has been developed to simulate the heating stage. In particular, it takes into account the spectral properties of both heaters and plastic sheet as well as the heaters directivity. Comparisons between experimental data and numerical simulations allow validating the numerical model using different types of emitters and polystyrene (PS).

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Section: Ps Spectral Properties Characterisationmentioning

confidence: 99%

Modelling of infrared heating of thermoplastic sheet used in thermoforming process

Schmidt

2003

Journal of Materials Processing Technology

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“…Table 3 summarizes the extensive research completed using numerical solutions for temperature distributions across or through the sheet. [1][2][3][4][5][6] Whereas textbook or handbook treatments give view factors for total heat flux, 7,8 we need the heat flux distribution over the surface of the sheet. Sheet curvature, either from thermal expansion of the solid sheet before softening (called bowing) or from self-weight of the solid sheet (called droop) 9 has been obtained previously and analytically, 10 as has curvature from the gravitational flow of a molten plastic sheet after softening (called sag).…”

Section: Introductionmentioning

confidence: 99%

Sheet temperature in thermoforming

Michaud¹,

Giacomin

2011

Journal of Plastic Film & Sheeting

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In thermoforming, flat plastic sheets are transformed into complex shapes by first softening by radiant heat transfer, and then by shaping. During the softening step, the sheet first bows while still solid, then sags while soft. In this article, we derive the heat flux distributions over both faces of a bowing or sagging sheet, along with the corresponding temperature profiles through and across the bowing or sagging sheet. These predictions can help plastics engineers to present a sheet of uniform temperature to a thermoforming mold. A worked example is included to show how to use the results.

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Assessing mental capacity and susceptibility to undue influence

Spar

Hankin

Stodden

1995

Behavioral Sci & The Law

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Clinicians are commonly asked to participate in the determination of an individual's mental capacity and susceptibfity to undue influence. Vague statutory definitions and lack of operational criteria for both determinations have contributed to inconsistency in the quality and usefulness of expert input to these determinations. Questionnaire responses of 119 probate judges from the U.S. indicate that this input is quite influential despite the problems mentioned above. This paper presents and discusses the judges' views on selected procedural and conceptual aspects of expert evaluation and testimony.The legal system employs concepts called "mental capacity" (MC) and "susceptibility to undue influence" (SUI). Despite

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Analysis of infrared radiation heating of plastics.

Cited by 6 publications

References 0 publications

Modelling of infrared heating of thermoplastic sheet used in thermoforming process

Modelling of infrared heating of thermoplastic sheet used in thermoforming process

Sheet temperature in thermoforming

Assessing mental capacity and susceptibility to undue influence

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