Fabrication process for thermoplastic composite parts
A fabrication method of forming a thermoplastic composite laminate material with tailored and varying thickness in a continuous process. This process utilizes automated equipment or hand lay-up to collate parts or components into a multi-layer stack. Each stack contains all plies, including ply build-up areas, tacked in the proper location to maintain orientation and location. The consolidation tooling contains all necessary part features and is coordinated to the customized multiple ply stacks to form a single integrated thermoplastic composite laminate potentially having areas of differing thickness from these multiple ply stacks.
1. An automated and continuous method of manufacturing a finished thermoplastic composite laminate having a thickness that varies over the length of the laminate, the method comprising steps of:
collating a plurality of full and partial plies of a thermoplastic material onto a conveyor to form a collated multi-layer stack having a non-uniform thickness and non-uniform contours, the conveyor supporting the multi-layer stack continuously throughout the method;
tacking the plies of the collated multi-layer stack together at predetermined locations in the plies;
pre-forming the collated multi-layer stack into a pre-formed part having a desired shape by bending at least one of the plies of the collated multi-layer stack at a first elevated temperature;
providing at least one consolidation tooling member having contours which substantially mirror the non-uniform contours of the collated multi-layer stack, the consolidation tooling member and the collated multi-layer stack being combined such that the thickness variations of the collated multi-layer stack are aligned with the contours of the consolidation tooling member, and such that the consolidation tooling member and the collated multi-layer stack are moved through a consolidation device together; and
consolidating said pre-formed part under pressure at a second elevated temperature higher than the first elevated temperature to form a single integrated thermoplastic pressed part, the pre-formed part and the consolidation tooling member repeatedly alternating between moving incrementally forward a predetermined distance and stopping for a predetermined period of time during consolidation.
2. An automated method of manufacturing a finished thermoplastic composite laminate having a thickness that varies over the length of the laminate, the method comprising steps of:
collating a plurality of full and partial plies comprising a thermoplastic material and a resin onto a conveyor to form a collated multi-layer stack having a non-uniform thickness with non-uniform contours, the conveyor supporting the multi-layer stack continuously throughout the method; then
tacking the plies of the collated multi-layer stack together at predetermined locations in the plies to form a tacked multi-layer stack; then
pre-forming the tacked multi-layer stack into a tacked pre-formed part having a desired shape by bending at least one of the plies of the multi-layer stack at a first elevated temperature below the temperature at which the resin in the thermoplastic material flows freely; and then
consolidating the tacked pre-formed part under pressure at a second elevated temperature higher than the first elevated temperature with a consolidation tooling member in a consolidation device to form a single integrated thermoplastic pressed part, the second elevated temperature being sufficient to cause a polymeric component of the thermoplastic resin to flow freely, the pre-formed part repeatedly alternating between moving incrementally forward a predetermined distance and stopping for a predetermined period of time during consolidation, the consolidation tooling member having contours which substantially mirror the non-uniform contours of the non-uniform thickness multi-layer stack, the consolidation tooling member and multi-layer stack being combined such that the thickness variations of the multi-layer stack are aligned with the contours of the consolidation tooling member and such that the consolidation tooling member and the multi-layer stack are moved through the consolidation device together.
3. The method of claim 2 , wherein:
consolidating said pre-formed part comprises bringing one or more standardized tooling members to bear against the consolidation tooling member at a pressure sufficient to consolidate the plies of the multi-layer stack when the pre-formed part is stopped.
4. The method of claim 3 , wherein each time the pre-formed part is stopped, the pre-formed part is subjected to a different temperature.
5. The method of claim 4 , further comprising:
cooling the pressed part to a temperature below the free flowing temperature of the polymeric component of the thermoplastic resin to harden the pressed part.