|First the AVI (Autoclaved Vacuum Infusion) process was developed as a response to a customer claim that autoclaved prepregs were lighter than resin infused parts. Resin infused carbon fibre parts has a fibre volume fraction (FVF) of around 45-55% and HOC therefore decided to develop a resin infusion manufacturing process with increased FVF.
AVI Le Mans Prototype parts for LMP 1The result is the inhouse developed AVI process where FVF up to 65% is available together with a pin hole free surface and practical void free laminate even at the highest FVF.
Thickness difference same lay-up AVI vs. resin infusion (65% vs. 54% FVF)
First after visiting Formula 1 teams the true potential of the AVI process started to show as the general trend with-in autoclaved F1 prepregs is that a FVF of 56-58% is achievable if surface and laminate quality is not to be sacrificed.
Formula 1 AVI carbon fibre partSo when supplying carbon fibre laminates at 65% FVF then a weight reduction or stiffness increase of approximately 10% is the result which will lead to more speed - This has been tested and verified by several Formula 1 teams.
|Composites Mass Manufacturing Process (CMMP) is a merge of several existing manufacturing concepts where everything unnecessary is cut away. The result is a new process which is super fast and simple and therefore being patented.
Tests in a manual set-up have shown potential to reach production cycles of around 5 minutes if automated and even in a manual state cycle times of around 10-15 minutes is achievable.
Microscopic images of a carbon fibre / epoxy laminate cross section performed by DTU
CMMP produces high quality laminates with a fibre volume fraction (FVF) in the region of 60% or higher together with a pratical void free laminate with void content around 0,2-0,3% and a ready to paint pin hole free surface.
|The FVF exceeds what is standard in Formula 1 where 56-58% is achievable if not sacrificing the quality and the void content is by far lower than the aerospace void content accept criteria of maximum 2%.
CMMP surface quality directly out of the mould
The traditional race tracking issues and extreme narrow lay-up tolerances have been eliminated, so a very fast lay-up is possible together with a very robust and simple processing.
All sorts of composite materials can be used i.e. carbon, aramid, bio and glass fibres together with epoxy, polyurethane, vinyl ester and hybrid based resins.
The production set-up is compared to the alternative mass production manufacturing processes simple, low cost and does not consume a lot of space or energy.
|This manufacturing process is spray-up of carbon fibres. Spray-up is one of the most cost effective ways of producing parts with larger surfaces, though it normally only produces low quality, stiffness and strength parts. By replacing the glass fibre reinforcement with carbon fibres the process suddenly competes with high quality and high stiffness glass fibre solution of prepreg or resin infusion, it is still cost neutral but has significant lower weight due to the lower density and higher stiffness of the carbon fibres.||Additional the carbon fibre spray-up pattern appears to be very visual appealing, and the process has the potential to be automated.|
|HOC is assisting material suppliers and manufacturers in testing new materials, often resins are being evaluated on regards to processing and mechanical properties.
HOC is also internally working with developing in example new high temperature epoxy resins systems as well as ceramic based systems in close collaboration with a few selected resin manufacturers.
A strong area of HOC is the ability to think existing material into new combinations leading to better properties and performance.
Furthermore HOC has a 10kN and a 100kN test bench for evaluating the mechanical properties.
|Due to client confidentiality details can’t be published about customer project work, but these are some of the fields of work HOC has been involved in: