Technology of Thermoforming

Throne, James L.

doi:10.3139/9783446402478.fm

Cited by 68 publications

(81 citation statements)

References 6 publications

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“…View factor between finite extension elements (-) g Lamps switch off temperature when they are controlled by a traditional pyrometer (K) T s Softening temperature of PVC (K) th Pipe thickness (mm) x Generic coordinate along lamp extension (mm) x Non-dimensional coordinate along lamp extension in a transversal plane perpendicular to cylinder axis (-) x 1 Non-dimensional coordinate x calculated at the first end of the lamp (-) x 2 Non-dimensional coordinate x calculated at the second end of the lamp (-) …”

Section: F I→jmentioning

confidence: 99%

“…In industrial applications like thermoforming, aimed at obtaining products by deforming polymeric preforms or sheets, the study of the thermal stage allows to get a successful forming process and directly affects the mechanical properties of the end product [2]. Moreover, studying the heating stage in the design phase of such processes can lead to a significant increase in the process efficiency, with consequent energy savings and reduced environmental impact.…”

Section: Introductionmentioning

confidence: 99%

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Effects of pipe angular velocity and oven configuration on tube temperature distribution in the radiative heating of PVC pipes

Lucchi

Lorenzini

2018

Int J Energy Environ Eng

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Several manufacturing processes in polymer industry aim at obtaining products by deforming preforms or sheets after a heating process. A thorough knowledge of the operating parameters of such heating processes is fundamental to fulfill the often high production requirements with the least energy consumption and to avoid unacceptable defects in the final product. A common example of such an application is the end-forming process of polyvinyl chloride (PVC) tubes, which are enlarged at one end in order to allow pipes connections. The heating phase which comes before the deformation process is usually carried out in ovens equipped with short wave infrared lamps; to ensure uniform heating, pipes rotate with a given angular velocity, which represents a fundamental parameter for the success of the whole manufacturing process. In this work, a transient analysis of the radiative heat exchange between rotating PVC pipes and infrared lamps in an oven for end-forming process has been conducted by means of a finite element model, in order to investigate the influence of cylinder angular velocity on the temperature distribution in the tube. Local view factors have been calculated for different oven configurations and have been expressed as a function of angular velocity, allowing pipe rotation to be simulated as a time-dependent boundary condition, instead of using a moving mesh. Simulations were carried out for different tubes geometries and angular velocities and results were compared with the case of a uniformly irradiated tube in terms of temperature displacement. For a given oven configuration, the results obtained by the numerical model can be used to find a critical angular velocity over which further increase does not lead to appreciable improvements in temperature evenness. The effect of the lamps' relative position was also investigated, showing a significant influence on critical angular velocities obtained. The model realized represents a potential tool to characterize the end-forming process in terms of critical angular velocity, leading to reductions in machine set-up time and product waste due to thermal failure.

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Section: F I→jmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of pipe angular velocity and oven configuration on tube temperature distribution in the radiative heating of PVC pipes

Lucchi

Lorenzini

2018

Int J Energy Environ Eng

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“…Thermoforming is a generic term for manufacturing plastic components through a vacuum or a pressure forming process (Throne, 1996). It is composed of three basic phases: heating, forming and solidifying (Figure 2).…”

Section: Thermoforming Processmentioning

confidence: 99%

Agent-based control of manufacturing processes

Albadawi

Boulet

DiRaddo

et al. 2006

IJMR

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“…In time, engineers' thermoformed reinforced and flame-retardant plastic sheets and these products were used in many industrial areas. In course of time packaging covers, welded steel material on the food cans, glass in the jars, drinking cups, and thermoset composites in the airplane industry were replaced with the products which were manufactured by using thermoforming [1,2].…”

Section: Introductionmentioning

confidence: 99%

“…Numerical (computer) and physical models are important tools for engineers, scientists, and experts in any field to help understand physical phenomena, to analyze physical objects and systems, as well as to perform design. Physical models range from simple bone models mounted on a testing jig to more complex bio-models rendered in solid form that can be produced by engineering technologies such as rapid prototyping technologies, which replicate the morphology of the bone structure [1,2].…”

Section: Introductionmentioning

confidence: 99%

Effects of manufacturing defects on thermoformed product quality

Ekşi

Erdoğan²

2014

uujms

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In this study, 5% and 15% in weight carbon fiber reinforced polypropylene (PP) sheets were formed under appropriate vacuum and temperature conditions by using truncated cone-shaped thermoforming mold. In addition to this, 5% in weight glass fiber reinforced High Density Polyethylene (HDPE) sheets were formed using truncated cone-shaped, cylindrical, and cubic shaped thermoforming molds by thermoforming. Composite sheets used in this work were produced with a laboratory-type plastic extruder which has a screw diameter of 50 mm. In production of HDPE composite sheets, as a reinforcing material, chopped glass fibers (E-glass) which were provided from glass fiber manufacturer SISECAM A.S. Company were used. Using the same procedure PP (Borealis BE50-7032) thermoplastic granules were used as a matrix material in production of carbon fiber composite sheets. In carbon fiber reinforced sheets, chopped fibers were added during manufacturing. After thermoforming, composite semi-products were examined by visual inspection. Visual defects that affect product quality were obtained. Also carbon fiber distribution was investigated on different sections which were taken from the thermoformed semiproducts by Scanning Electron Microscopy (SEM). Through this experimental study, it is aimed to investigate the effect of defects during plastic extrusion on thermoformed product quality.

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Technology of Thermoforming

Cited by 68 publications

References 6 publications

Effects of pipe angular velocity and oven configuration on tube temperature distribution in the radiative heating of PVC pipes

Effects of pipe angular velocity and oven configuration on tube temperature distribution in the radiative heating of PVC pipes

Agent-based control of manufacturing processes

Effects of manufacturing defects on thermoformed product quality

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