Automated wet compression moulding of load-path optimised TFP preforms with low cycle times

The Innovate-UK-funded Composite Lightweight Automotive Suspension System (CLASS) project, led by Ford Motor Company and partnered by Gestamp UK, GRM Consulting and WMG, investigated the use of carbon fibre reinforced composite materials to decrease the weight of a complex automotive rear suspension component in support of reduction in vehicle emissions. A multi-material design comprising discontinuous fibre composite (C-SMC), aligned fibre composite laminate (prepreg) and steel was developed. A high volume hybrid compression moulding manufacturing process was developed at WMG, achieving total press cycle times of around 5 minutes. Prototype parts were manufactured and evaluated using materials characterisation techniques to validate the manufacturing methods. The optimum C-SMC charge pattern was investigated to achieve complete fill with minimal pre-processing. Destructive and nondestructive analysis of the hybrid parts was performed to understand resultant hybrid material macrostructure. This innovative design and manufacturing process resulted in a component 35% lighter than the original multi-piece steel design.

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Modelling and analysis of the thermal characteristic of thermoplastic composites from hybrid textiles during compression moulding

Journal of Thermoplastic Composite Materials ◽

10.1177/0892705719875204 ◽

2019 ◽

pp. 089270571987520

Author(s):

Maximilian Koerdt ◽

Michael Koerdt ◽

Tobias Grobrüg ◽

Marco Skowronek ◽

Axel S Herrmann

Keyword(s):

Optical Sensors ◽

Thermal State ◽

Process Analysis ◽

Thermal Characteristic ◽

Thermoplastic Composites ◽

Compression Moulding ◽

Cycle Times ◽

Reinforced Plastics ◽

Thermoset Resin ◽

Thermoplastic Matrix

A promising strategy to decrease cycle times for manufacturing continuous-fibre–reinforced composites is processing of thermoplastic matrix systems due to their fast processability, since no cross-linking of molecular chains is required as for thermoset resin systems. Nevertheless, thermoplastic carbon fibre-reinforced plastics nowadays are predominantly manufactured with pre-impregnated sheet materials, which result in limited drapability and freedom of design. Hybrid textiles, consisting of thermoplastic and carbon fibres, can avoid these disadvantages. This class of reinforcements combines the drapability of dry textiles with thermoplastic matrices, which furthermore allow near net-shape processes. Relative shifting between the fibres and, consequently, draping is possible in a preforming step. The objective of this article is to expand our knowledge about hybrid textiles with regard to their thermal behaviour during compression moulding. Accordingly, the necessary parameters for modelling the thermal state of the dry textile and the impregnated laminate are investigated. Moreover, an in situ process analysis based on the reflection spectra of glass fibre-optical sensors, which are embedded inside the stacking, is investigated to provide information about the state of aggregation and to validate the thermal model.

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Development of a Modular Draping Test Bench for Analysis of Infiltrated Woven Fabrics in Wet Compression Molding

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.809.35 ◽

2019 ◽

Vol 809 ◽

pp. 35-40

Author(s):

Fabian Albrecht ◽

Clemens Zimmerling ◽

Christian Poppe ◽

Luise Kärger ◽

Frank Henning

Keyword(s):

Test Bench ◽

Compression Molding ◽

Woven Fabrics ◽

Forming Process ◽

Process Step ◽

Cycle Times ◽

Reinforced Plastics ◽

Local Material ◽

Comprehensive Knowledge ◽

Wet Compression

The wet compression molding (WCM) process enables short cycle times for production of fiber-reinforced plastics due to simultaneous infiltration, viscous draping and consolidation in one process step. This requires a comprehensive knowledge of occurring mutual dependencies in particular for the development of process simulation methods and for process optimization. In this context, it is necessary to develop suitable test benches to enable an evaluation of the outlined viscous draping behavior. In order to evaluate and suitably design the draping process, grippers are mounted on a surrounding frame, which enables targeted restraining of the local material draw-in during forming. In supporting the development of the new test bench, first experimental and simulation results are compared, which thereby enables a first validation of the simulation approaches. Results show a good agreement between experimental and numerical results in terms of shear deformation and final gripper displacement under dry and viscous conditions. Results recommend that future development for investigations of viscous draping effects should focus an enabling measurement of gripper displacement during the forming process. Beyond that, the modular test bench design enables experimental and virtual draping optimization and deduction of blank holder concepts for WCM tools.

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