New process technology for high volume production of composites

Michaeli, Walter; Wessels, Jan; Pöhler, Marco; Winkelmann, Lionel

doi:10.1515/polyeng.2011.010

Cited by 3 publications

(7 citation statements)

References 1 publication

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“…The ZS2 converts the pressure in the range of 0 to 500 mBar into corresponding voltage signals of 0 to 10 V, which was recorded with the data logger USB-6218 (manufacturer: National Instruments, USA) and the corresponding SignalExpress software. Additionally, the ZS2 was also used to read the pressure difference Δp (10).…”

Section: Pressure Measuring and Volume Flow Rate Determinationmentioning

confidence: 99%

“…By applying equation (10), the heating behaviour of the surface of the plies and thus the melting behaviour of the binder over time is approximated.…”

Section: Heating Behaviour Observed With Thermography and Thermocouplesmentioning

confidence: 99%

“…The series production of continuous fibre-reinforced polymer (FRP) components with small to medium dimensions by means of Liquid Composite Moulding (LCM) processes, such as Resin Transfer Moulding (RTM) or Vacuum Assisted Resin Infusion (VARI), is based on formed semi-finished fibre products that are referred to as preform. [1][2][3][4][5][6][7][8][9][10][11] The process steps for manufacturing a preform mainly comprise production of flat fabrics (e.g., woven or multiaxial non-crimp fabrics in rolls) and their CAD-supported preparation as single flat layers that are stacked on top of each other. The following main step is the draping or forming of the multi-layer stack into the desired three-dimensional, near-net-shape geometry.…”

Section: Introductionmentioning

confidence: 99%

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Development and characterization of a through-air thermobonding process with high heating rate for activating the binder and producing preforms for fibre-reinforced polymers

Hellmann,

Gereke,

Truemper

et al. 2024

Journal of Composite Materials

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This study focuses on the development of an advanced high heating rate thermobonding process for the manufacture of preforms and the metrological characterisation of the process. The process involves passing hot air, driven by pressure differential, through a textile stack consisting of several plies of a quadraxial fabric coated with a binder. Heat is transferred into the stack and into the binder by forced convection, melting the binder. The process is used in the same way to cool the stack and binder so that the plies are bonded together. The pressure differential compacts the stack. The comprehensive methodological characterisation of the process includes first determining the air permeability of the stack and thus the volume flow of air as a function of the number of plies stacked. Further characterisation focuses on a comprehensive determination of the heating behaviour in the individual plies as a function of time, using thermocouples and thermal imaging to determine the temperatures of hot air and textiles. These are compared and related using a mathematical approach as different values have been found. The results indicate high heating rates, reducing process time by at least 85% compared to previous binder activation methods. In addition, the cantilever method assesses the flexural stiffness of the processed stacks and shows a twofold improvement in bond strength compared to uncompacted stacks. Results and discussions include orifice based volume flow determination, thermography calibration, mathematical modelling, stiffness of bonded textile plies, process comparison, process control and potential energy savings.

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Section: Pressure Measuring and Volume Flow Rate Determinationmentioning

confidence: 99%

“…By applying equation (10), the heating behaviour of the surface of the plies and thus the melting behaviour of the binder over time is approximated.…”

Section: Heating Behaviour Observed With Thermography and Thermocouplesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Development and characterization of a through-air thermobonding process with high heating rate for activating the binder and producing preforms for fibre-reinforced polymers

Hellmann,

Gereke,

Truemper

et al. 2024

Journal of Composite Materials

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“…The mechanical properties of the CRTM part were discussed. [5][6][7] Michaeli et al 8 proposed the separation and parallelization of the process steps ''impregnation'' and ''forming and curing'' to manufacture the parts with high volume fraction of reinforcement.…”

Section: Introductionmentioning

confidence: 99%

Effect of process parameters on the surface quality of air cushion method

Chang

2015

Journal of Reinforced Plastics and Composites

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A new method of the vacuum-assisted resin transfer molding process, called air cushion method, has been developed to manufacture composite parts. The process utilizes additional air cushions bound into the bagging film beneath. After the preform is sealed by the bag and evacuated, distribution channels are created between air cushions to enhance resin flow during infusion. Once the resin infusion is completed, the binding interfaces between the air cushion and the bagging film are cut and distribution channels collapse. The vacuum bag entirely compacts the preform. The goal of this study is to utilize a 2 4 full factorial design to evaluate the effects of process variables, including the number of the air cushion (factor A), thickness of the air cushion (factor B), elasticity of the bagging film (factor C), and vacuum pressure in the cavity (factor D), on the surface quality of air cushion method components. Results show that the process parameters ranked in decreasing order of importance are B, D, A, and C for affecting the surface height difference. Compared with traditional vacuum-assisted resin transfer molding, air cushion method at the optimum settings reduces the infusion time by 68.4% but increases the surface height difference by 0.0312 mm.

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“…Investigations of the mechanical properties of the CRTM part are given in [18,19] . A new process, based on the separation and para llelization of the process steps " impregnation " and " forming and curing " , was also developed, to manufacture the parts with a high fiber volume fraction [20] .…”

Section: Introductionmentioning

confidence: 99%

Unsaturated polyester/E-glass fiber composites made by vacuum assisted compression resin transfer molding

Chang¹,

Lin²

2012

Journal of Polymer Engineering

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A variant process incorporating the method of bag compression into resin transfer molding (RTM), called vacuum assisted compression RTM (VACRTM), has been developed to reduce the cycling period and improve the quality of the part. The process utilizes a flexible bag placed between the upper mold and the preform compared with RTM. By controlling the stretchable bag, the resin is easily introduced into the cavity filled with a loose preform. Then, ambient pressure is applied on the bag that compacts the preform and drives the resin through the remaining dry preform. The objective of this research is to explore the simplified VACRTM feasibility and investigate the effects of process variables, including resin temperature, resin infusion pressure, mold cavity height and cure temperature, on the mechanical strength of the part, by applying Taguchi ' s method. The results show that VACRTM has advantages in terms of its being an easy and good seal among mold parts and the the lack of a need to clean the upper mold. The resin infusion pressure is a significant variable for improvement of the mechanical strength of the part. Optimal VACRTM reduces the filling time by 58 % and increases the flexural strength by 10 % , as compared with typical vacuum assisted RTM (VARTM).

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New process technology for high volume production of composites

Cited by 3 publications

References 1 publication

Development and characterization of a through-air thermobonding process with high heating rate for activating the binder and producing preforms for fibre-reinforced polymers

Development and characterization of a through-air thermobonding process with high heating rate for activating the binder and producing preforms for fibre-reinforced polymers

Effect of process parameters on the surface quality of air cushion method

Unsaturated polyester/E-glass fiber composites made by vacuum assisted compression resin transfer molding

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