Motion control for uniaxial rotational molding

Adams, Jonathan; Jin, Yan; Barnes, David; Butterfield, Joseph; Kearnes, Mark

doi:10.1002/app.49879

Cited by 7 publications

(11 citation statements)

References 30 publications

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“…Both the mold wall, powder, and internal air temperature are increasing because of the externally applied heating power of the IR heaters. It can be stated that depending on the applied dynamic boundary conditions the mold wall to powder heat transfer can change 19,26,27 . From the temperature evolutions it can be seen that the powder bed and air temperature are following each other closely.…”

Section: Resultsmentioning

confidence: 99%

“…It can be stated that depending on the applied dynamic boundary conditions the mold wall to powder heat transfer can change. 19,26,27 From the temperature evolutions it can be seen that the powder bed and air temperature are following each other closely. Resulting in the conclusion that the powder to air heat transfer is dominating over the mold wall to air one.…”

Section: Description Of the Different Phases Within The Heating Stagementioning

confidence: 89%

“…Due to the dynamic nature of the rotational molding process, not only the degree of sintering and sintering speed is influencing local heat transfer, the thermal boundary conditions are also continuously changing between wall to powder and wall to air contact. Dynamic powder contact times depend on the free flowing powder bed volume, mold motions, mold shape, and dynamic powder flow properties 15,25–33 …”

Section: Introductionmentioning

confidence: 99%

“…Dynamic powder contact times depend on the free flowing powder bed volume, mold motions, mold shape, and dynamic powder flow properties. 15,[25][26][27][28][29][30][31][32][33] In order to achieve a comprehensive model of the process, a combined solution of the sintering, thermal as well as dynamic powder motion equations is required. In the past, a few modeling attempts have already been made.…”

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confidence: 99%

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Validation of a 1D dynamic thermal finite difference model for the rotational molding of an amorphous polycarbonate resin

Vandaele

Buffel

Callewaert³

et al. 2023

Polymer Engineering & Sci

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This study focuses on the heating stage of the rotational molding process. When the mold wall reaches the tacky temperature, free flowing powder starts to adhere, melt, and sinter. In this work, a new modeling strategy is proposed. Compared with the models found in the literature, the model combines the use of a tacky temperature for the adherence of powder, changing boundary conditions, and thermophysical properties as function of temperature and the degree of sintering. The changing boundary conditions are introduced to take into account both wall to air and wall to powder contact. The calculation of the temperature evolution is done by applying the thermal finite difference principle to elements with a fixed polymer mass. The modeling of a uniaxial rotating cylinder is chosen as a case study. The validation is done for an amorphous polycarbonate resin. The performance of the model is evaluated not only by the comparison of temperature‐time data as is the case in most literature, but also by the decrease in free flowing powder weight as function of time, visual data from an in‐mold looking camera, and through thickness analysis of the molded pieces at various moments in the heating process.

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Section: Resultsmentioning

confidence: 99%

Section: Description Of the Different Phases Within The Heating Stagementioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Validation of a 1D dynamic thermal finite difference model for the rotational molding of an amorphous polycarbonate resin

Vandaele

Buffel

Callewaert³

et al. 2023

Polymer Engineering & Sci

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“…The speed control for uniaxial rotational molding as affect process efficiency and product quality. powder flow regimes exhibiting different levels of mixing and temperature uniformity was studied [4]…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Small Plastics Products Using Roto Molding Model

2022

IRJMETS

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Small product of roto molding process is not an economically competitive way to produce hollow plastic materials such as blow molding process, hence the study of parameters of small products is very important for design techniques, in this study parameters such as percentage of plastic powder conversion into final product, product thickness and rotational speeds Using a cylindrical mold (diameter = 61, height = 111 mm) and an experimental model of the rotational molding process. The obtained results showed that the percentage 58.4 to 77.9% is the percentage converted into a product from the weights of the samples that were used at operating conditions of 200 ° C and the heating time of 20 minutes, and this percentage increases with the increase in the quantity of samples weight. As a result of the applied speed ratio 1:4 for the major/minor axes respectively, there was a difference in product thickness between cover and wall of 0.5 mm for all sample weights and the difference was due to the shape of the cylindrical mold and it was not spherical or cuboidal.

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Characterization of polymer foam evolution in unpressurized melt systems

Pritchard,

Martin,

McCourt

et al. 2023

Polymer Engineering & Sci

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The evolution of foam in unpressurized melt processing techniques, such as rotational molding, is different from high‐pressure processes like injection foam molding, making comparisons difficult. This has driven the need for a dedicated technique for studying these systems. A unique test procedure was developed to capture and characterize foam evolution in test tubes under unpressurized conditions. A validation study found the procedure to be reliable, producing repeatable samples (height average (AVG) 39.69 ± 1.70 mm and density AVG 0.319 ± 0.012 g/cm3) and delivering comparable results to samples produced using the industrial rotational foam molding process. A study examined the effect of polymer particle size on the foam structures produced. Finer (>90 μm <106 μm) polymer powders produced more desirable structures, achieving 38.6% lower foam density and 43.8% taller peak foam height than coarser powders (>425 μm < 500 μm). Cycle times were much shorter (~15 min) in comparison with the industrial rotational molding process (>40 min) and required smaller amounts of materials, making it useful for rapid characterization. Future work is planned to apply the new procedure to investigate the effects of material and processing conditions on the foam structures produced under unpressurized conditions.Highlights Evaluation of existing unpressurized foam characterization methods. Rapid test procedure developed to characterize unpressurized foam evolution. Variability study of foam structures produced using the new procedure. Effect of rotational molding polymer powder and considerations for foaming. Results validated with industrial unpressurized rotationally molded samples.

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Motion control for uniaxial rotational molding

Cited by 7 publications

References 30 publications

Validation of a 1D dynamic thermal finite difference model for the rotational molding of an amorphous polycarbonate resin

Validation of a 1D dynamic thermal finite difference model for the rotational molding of an amorphous polycarbonate resin

Experimental Study of Small Plastics Products Using Roto Molding Model

Characterization of polymer foam evolution in unpressurized melt systems

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