Stamping of Continuous Fibre Reinforced Thermoplastic Composites

Ref-Nr: TD021

Technology abstract

The Composite Materials & Structures Unit of a R&D institute based in Portugal is experienced in continuous fibre thermoplastic matrix composites hot stamping process and offers product development inc. structural simulation and tools and jigs manufacturing for the prototypes production. The outcomes based in a short cycle time process are lightweight structural components based on carbon and glass fibres. 

Technology Description

The Institution has a thermoplastic stamping cell with an Automated 2D Unidirectional Layup machine that is able to manufacture blanks made of tapes with predefined position and orientation and using a good range of materials  (from PEEK - Polyether ether ketone - to PP - Polypropylene). The matrix of the tapes and the fibre can be selected according to customer specification.
The blanks are then consolidated with heat and pressure provided by the hot plates into one sheet that is cooled to ambient temperature.
This sheet is then placed on the transport system heated in the oven and placed and subsequently stamped in the mould.
A 3D shaped part is removed from the mould that will be trimmed to specification and that can be placed in an injection machine to be over moulded with a compatible plastic. This enables the possibility of further enhancing the structural properties of the component through ribbing and it is a flexible method for implementing connection inserts.
Available equipment:
-       Automated Layup Machine (ALM)
-       A 200ton 1x1m plate Hydraulic Press
-       Consolidation Hot Plates (1x0.8m, Max temp:400ºC)
-       Oven and transport system
The Institution has been involved in national funded projects that are focused in space, aeronautics and automotive applications and has a dedicated team to develop thermoplastic composites components for these sectors.
It has produced high impact prototype shielding for military applications and lightweight high impact structural components for both the automotive and aerospace sectors.
The proposed technology successfully replaced high-strength steel components with 60% lighter thermoplastic composite alternatives. 

Innovations & Advantages

The thermoplastic composite hot stamp forming processing techniques are suitable for structural applications, replacing typical metal stamped applications. One of the main emphasis points of the technology is the use of unidirectional (UD) prepreg tapes that present considerable advantages over prepreg woven fabrics, namely, waste reduction, optimal fibre orientation and consequent improvement of mechanical properties while maintaining lightweight features.
When compared to the most recent composite processes (such as tape laying, fibre placement or textile forming) and their advantages and limitations regarding mass production of 3D complex shaped components, a case can be made that the cost of the initial investment for the two referred processes is still excessive. On the other hand, hot plate thermoplastic composite stamping presents itself with a better cost-to-production ratio.
Nowadays, thermoplastic stamp forming is making significant strides in high volume markets but, using reinforcement fabrics as a starting point, optimization of fibre location, orientation and consequently rigidity and strength is limited.
By using thermoplastic unidirectional prepreg tapes on stamp forming systems one is able to overcome some of the complications found in Tape-Laying and in textile conforming, specifically higher stamping speeds with fibre orientation and structural optimization at an intermediate cost.

Further Information

Current and Potential Domains of Application

Aeronautics: components such as aircraft parts
Automotive: replacement of metal parts; door panels, body panels and seat backs
IT industry: thin housings (hardware)