Optimized Thermoforming Process for Conformable Electronics

Model-based quality control has the potential to reduce the reject rate in the production of fiber-reinforced plastics (FRP) components. After all the cross-market establishment of FRP, undesirable quality deviations often occur with new materials or component shapes. The quality control uses the component quality (e.g. component angle, crystallinity, fiber orientation, pore content) as the control variable. As a key component of the control, a process model is developed to link the process parameters (press pressure, press duration and tool temperature) with the quality parameters. Knowledge of the process-determining cause-effect relationships is necessary to ensure that different quality parameters are in the target value at the same time. Based on experimental tests, these interrelationships are determined using methods of statistical test planning and serve as the basis for model-based quality control. As a result, it has been shown that the targeted control of the component angle is possible in a range of about ±1° by using the control parameters, tool temperature and pressure, which have a significant influence on the quality. In the next step, further quality characteristics are included in the control system in order to demonstrate the ability to control the quality of complex component specifications. Model-based quality control is particularly promising for the reduction of the process run-in phase and thus for the reduction of the reject rate.

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Morphological Characterisation of Long Glass Fibre Composites for the Thermoforming Process

International Polymer Processing ◽

10.3139/217.1589 ◽

2000 ◽

Vol 15 (2) ◽

pp. 208-214 ◽

Cited By ~ 2

Author(s):

S. F. Bush ◽

F. G. Torres

Keyword(s):

Glass Fibre ◽

Morphological Characterisation ◽

Fibre Composites ◽

Thermoforming Process

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Design and Manufacturing of Customized Braces for Scoliosis Treatment

Volume 1: 22nd Computers and Information in Engineering Conference ◽

10.1115/detc2002/cie-34477 ◽

2002 ◽

Author(s):

H. Wu ◽

D. Xue ◽

J. Harder ◽

J. L. Ronsky ◽

P. Poncet ◽

...

Keyword(s):

Geometric Model ◽

Milling Machine ◽

Cnc Milling ◽

Optical Scanning ◽

Cnc Milling Machine ◽

Design And Manufacturing ◽

Scoliosis Treatment ◽

Noise Data ◽

Thermoforming Process ◽

Design And Manufacture

A new method to design and manufacture customized braces is introduced in this research for scoliosis treatment. In this method, a geometric model of a scoliosis patient’s torso is achieved using a laser optical scanning device. The brace geometry is obtained by generating the offset geometry of the torso’s surface, selecting vertical boundaries, removing holes and noise data, creating symmetrical geometry, and modifying the geometry near the pelvis curves. Manufacturing of the brace is conducted by producing a male die with a sculptured surface using a custom-designed 5-axis CNC milling machine and creating the plastic brace using a thermoforming process.

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Measurement & Modelling of Slip during Plug-Assisted Thermoforming

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.504-506.1105 ◽

2012 ◽

Vol 504-506 ◽

pp. 1105-1110 ◽

Cited By ~ 2

Author(s):

Peter Martin ◽

Hui Leng Choo ◽

Ciaran P.J. O'Connor

Keyword(s):

Thickness Distribution ◽

Critical Role ◽

Processing Parameters ◽

Deep Draw ◽

Frictional Properties ◽

Wall Thickness Distribution ◽

Sheet Materials ◽

Process Simulations ◽

Thermoforming Process ◽

Temperature Work

Plugs are a common feature of most deep-draw thermoforming processes and are used to ensure that the wall thickness distribution in the final product is controlled and balanced. Through contact with a moving mechanical plug, the heated sheet is locally captured and protected from excessive deformation and thinning. Previous work has clearly demonstrated that slip plays a critical role during this process and that its magnitude is determined by frictional properties that are strongly dependent on temperature. Work to discover the appropriate friction relationships has been very limited to date and this has greatly hampered the progress towards effective thermoforming process simulations. In this paper the magnitude of slip that occurs during the plugging stage of the thermoforming process was experimentally investigated. Preform shapes were created by pushing a specially designed plug into a heated sheet and then freezing it at the end of the plug displacement. A variety of processing parameters such as the plug and sheet materials, the temperature and plug displacement were evaluated. The results show that large variations in slip occur when different combinations of plug and sheet materials are employed and these are most affected by the contact temperature. A finite element based simulation of the plugging process is currently being constructed and it will be used to investigate different friction relationships and compare their performance with the experimental behaviour.

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Rheological measurement of the nonlinear viscoelasticity of the ABS polymer and numerical simulation of thermoforming process

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-020-04979-7 ◽

2020 ◽

Vol 107 (5-6) ◽

pp. 2449-2464

Author(s):

Jemyung Cha ◽

Hyeong Yong Song ◽

Kyu Hyun ◽

Jeung Sang Go

Keyword(s):

Numerical Simulation ◽

Nonlinear Viscoelasticity ◽

Rheological Measurement ◽

Thermoforming Process

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The Effect of Thermoforming on Tear Strength of Ethylene Vinyl Acetate Mouthguard Material in Various Thicknesses

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.751.657 ◽

2017 ◽

Vol 751 ◽

pp. 657-662

Author(s):

Phakphum Srinuan ◽

Jeerapatr O. Baiyokvichit ◽

Rasana Boonpeng ◽

Tanapol Wongwisatekit ◽

Pacharaporn Pattanasukwasan ◽

...

Keyword(s):

Vinyl Acetate ◽

Testing Machine ◽

Ethylene Vinyl Acetate ◽

Strength Test ◽

Tear Strength ◽

Universal Testing ◽

Significant Difference ◽

The Mean ◽

Thermoforming Process ◽

One Way Anova

The effect of thermoforming on the tear strength of ethylene vinyl acetate (EVA) mouthguard material (Bioplast®) has not been widely investigated. The present study compared the tear strengths of non-processed and processed EVA specimens in various thicknesses. Two groups of EVA sheet (non-processed and processed) in three different thicknesses of 3, 4 and 5 mm were used in specimen fabrication. The processed EVA sheets were achieved by forming the EVA sheet on the cylindrical stone model with the pressure-molding device (Biostar®). Twelve of tear strength specimens of non-processed and processed group in each thickness were prepared following the modified ASTM D 624-00 guideline. The tear strength test was conducted using universal testing machine (Lloyd® 1K series) with the speed of 500 mm/min. The mean thickness and tear strength of the non-processed and processed specimens in each thickness were compared using independent T-test. The differences in the mean tear strength for each thickness of non-processed and process specimens were determined using one-way ANOVA. The mean tear strength and mean thickness of processed EVA specimens was significantly lower than the non-processed EVA specimens for every thickness (P ≤ 0.05). There was no significant difference in the mean tear strength of EVA specimens among each thickness in both non-processed and processed groups. It can be concluded that the thermoforming process has the significant effect on the tear strength of the EVA mouthguard material formed by pressure molding device in every thicknesses. The tear strength of processed specimens were significant lower than the non-processed. Thus, it is more relevant for testing properties of the processed mouthguard material that the mouthguard material before processing.

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