Papers by Keyword: Thermoforming

Abstract: Conventional hard-bait lure prototyping relies on manual shaping, full-body additive manufacturing or early-stage injection moulding, each associated with limitations in geometric repeatability, development time or tooling cost. This paper evaluates a hybrid approach combining thermoformed PETG outer shells with additively manufactured internal frames to produce batches of geometrically consistent lure bodies with tuneable internal mass layouts. Across several educational development projects, the process enabled fast replication of outer form, systematic variation of ballast and harness configuration, and prototype assembly suitable for qualitative hydrodynamic observation. Compared with full additive manufacturing or manual crafting, the method reduced fabrication effort for multi-variant batches and delivered mould-like surface quality. Joining reliability of shell halves emerged as the dominant limitation, with elastic polyurethane adhesives outperforming brittle cyanoacrylate and poorly controllable low-energy fusion. The results position thermoforming as a methodologically valuable prototyping tool where external geometry is stable but internal behaviour requires iterative adjustment. Future work should address seam design, cage-shell tolerances and sealing repeatability to support quantitative hydrodynamic testing and assess whether the process has potential beyond prototyping applications.

Abstract: The use of 3D-printing simplifies and accelerates the development of moulds for a thermoforming process. This article examines several aspects of the effective design of 3D-printed polymer moulds. The focus is on prototyping and applications in engineering education. Experiments are conducted on PLA mould to determine the actual temperature loads and permanent deformations. Measures to improve the durability of the moulds are discussed and approaches to material and cost optimization are investigated. Examples of the use of PLA-moulds in thermoforming are presented.

Abstract: Thermoforming of thermoplastic fiber-reinforced composites enables cost-effective production of complex, high-volume components, yet wrinkling and shear-induced thickness variations remain persistent challenges in compound-curvature geometries, often leading to nonuniform consolidation. This work presents a predictive virtual process simulation that integrates discrete mesoscopic finite element modeling with targeted blank design strategies to address these limitations. The approach, developed by the Sherwood Group and implemented in LS-DYNA, is applied to the thermoforming of a UHMWPE unidirectional cross-ply composite system (DSM® Dyneema® HB210). A thickness-stretch shell formulation (SHELL ELFORM25), coupled with a user-defined material model, is employed to simultaneously capture in-plane shear, through-thickness deformation, and frictional interactions during forming. A parametric study is conducted to evaluate the combined effects of tooling geometry and strategically introduced slits in the blank, including side-and corner-oriented configurations. The results demonstrate that the proposed formulation provides an effective balance between computational efficiency and predictive accuracy while explicitly reducing shear-induced thickening. Notably, corner-oriented slits at 45° to the fiber directions significantly reduced thickness variability and wrinkle severity compared to unmodified blanks and side-slit configurations. These findings highlight the novelty of integrating thickness-aware forming simulations with geometric blank modification as a robust pathway for achieving near-uniform thickness and improved preform quality in thermoformed composite parts.

Abstract: This paper presents a comprehensive fully integrated polymer composite thermoforming process simulation chain developed in ANSYS LS-DYNA®, covering the full manufacturing sequence from automated preform creation to final part cooling. The entire simulation consists of three distinct phases, namely, thermoforming, cooling (within the tool) and manufacturing-induced dimensional distortion after demolding (spring-back), where distortions develop as the part is removed from the tooling and finally cools to room temperature. The simulation framework employs a modular model structure consisting of tooling, a preform holding system, and a detailed preform representation based on a semi-discrete unit cell approach. Individual laminate plies are modeled using a combination of beam, solid, and shell elements to accurately capture temperature-dependent bending, shear, and thermal behavior of the preform. To ensure industrial applicability, an automated preform meshing strategy has also been developed, utilizing tape placement path planning data exported from the automated tape laying process to generate simulation models with minimal manual effort. The simulation results enable the prediction of spring-angle distortions (spring-in or spring-back) and can be validated against experimental distortion measurement data from manufacturing trials of several different representative CFRTP components. The presented approach demonstrates the capability of the newly developed simulation chain to support thermoforming process development, tool geometry compensation, and robust manufacturing of complex thermoformed CFRTP structures.

Abstract: Polymers have been around for a while now, and for the time being they play a fundamental role in our society. As time passes, the number of polymer-based items increases. Thermoforming is a conventional polymer manufacturing process with high potential. This paper explores the surface quality of 3D printing dies after being used in a thermoforming process. A polylactic acid (PLA) die was printed using a Fused Deposition Modelling (FDM) The polymeric blanks formed were Polycarbonate (PC) and Polyvinyl chloride (PVC) sheets of 1.5 mm. The results reveal the effects of the temperature, the thermoforming process time and vacuum time on the wear of the top surface dis not surpass 1mm in the worst zone, and does not affect the polymeric formed sheets.

Abstract: Out of autoclave composite manufacturing is a process that achieves same quality as an autoclave process but through different method and one of them is thermoforming process in which, it can save the process cost and time. Recently, the fabrication process to fabricate thermoplastic composites by using thermoforming method becoming more popular among the thermoplastic research area. The simulation process is applied to enable the prediction of defects as well as to study the behavior of the process at early stage using simulation analysis to avoid trial and error during fabrication. To simulate the simulation, there are several factors and parameters need to be considered so that the defects could be avoided due to the excellent and poor formability will be linked between the fabricated samples in Aniform and the manufactured products. In this study, Two-Folded Clip panel mold type has been chosen to simulate the fabrication process. The results show the tensioner of AUY-50 is the best tensioner to be used in this research due to the significant of the result of press formed laminate quality with no voids appeared.

Abstract: 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.

Abstract: Plastic materials have played a very important role in the development of our modern civilization. It can be said that plastic materials are a tribute to man’s creativity and inventiveness. Plastic materials are the key to the innovation of many products and technologies in various sectors such as electrical and electronic equipment, packaging, civil engineering, agriculture, power generation, medical and pharmaceutical industry, aerospace and not last automotive industry. An increasingly important aspect in the automotive industry, in terms of fuel consumption is the lower weight of the components, while maintaining a very high stiffness. The difficulties of the design process of thermoformed parts is mainly due to the lack of knowledge by designers about the constraints and forces that are required during the process of thermoforming.

Abstract: 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.

Abstract: In order to sustainably establish carbon fiber reinforced polymer composites (CFRPC) in the market on an industry scale, solutions on how to recycle these new materials have to be developed. Quasi-continuously aligned carbon staple fiber structures in organic sheets made of recycled carbon are one approach which will be dealt with in this article. The process chain as well as the mechanical properties will be presented. Moreover, the specific feature of staple fiber yarns to be able to plastically deform under process temperature, enabling new degrees of deep-drawing of CFRPC organic sheets in the thermoforming process, will be highlighted.