Carbon fibre is available in many grades both strength and stiffness. It is initially supplied to the impregnator in spools containing several thousand metres. The "tows"of carbon fibre consisting typically of either 1000, 3000, 6000 or 12000 filaments of fibre are pulled through combs and then aligned into sheets for impregnating with resin. The selection of the type of carbon and the ratios and patterns used in a TT-R are a very important part of the rod's design. There is a complex formula for achieving the right ratios and types and this is underpinned by research, development, process equipment and feedback.
Below is a carbon fibre impregnator. The tows of carbon fibre are feed into the machine and pressed against a special paper carrier covered in an epoxy resin film. This epoxy resin has been carefully blended and tested before application to the carrier paper.
The impregnator at Advanced Composites Ltd spreads the resin around the fibres under considerable heat and pressure through a system of heated rollers. The purpose of the epoxy resin or matrix as it will be called in the final rod is to carry the load between the individual fibres. It is therefore critically important to the function and performance of the rod. The chemistry is complex and it is carefully controlled.
The continuous roll of carbon fibre pre preg is now ready for cutting into shapes that will give the finished rod the action that we have determined. The carbon fibres have a layer of polythene applied during the impregnation stage to stop it sticking to itself and to protect the fibres in transit. Here the colour is red. Accuracy is critical during the cutting process. When ultra high modulus carbon fibres are being used - just a few millimetres out - can dramatically affect the rod's action.
This machine cuts to an average accuracy of 5 microns. Repeatedly - day in and day out. Here patterns are being cut that will assist the rod's torque or twisting resistance.
The next stage is to wrap the pattern around a special steel mandrel. The mandrel has been ground to exact dimensions and chromium plated for toughness and to maintain dimensional accuracy. The exact diameter is also based on the final coefficient of thermal expansion of the mandrel and the maximum temperature reached in the subsequent cure cycle.
The mandrel with the attached pattern is placed on the lower platen of the rolling table and then the upper platen comes down and the lower platen moves horizontally to wrap the sheet of carbon fibre prepreg around the mandrel. The lower and upper platens of the table are multi gimballed - so that the patterns receive as little stress as possible whilst simultaneously being subject to pressures up to 5 bar (80psi).
Century uses the latest electric pneumatic rolling tables that give considerable individual profile and pressure programmable selections - to produce the finest rods. The rod is now beginning to take shape and will have had several patterns of carbon fibre introduced into the wall of the blank to generate its unique action.
From the rolling table the blank and mandrel are then placed in a special bag to which a vacuum is applied. We are now getting into the domain where aspects of what makes Danny's TT-R so different from conventional rods and there is not much technical detail that can be described on an open web site. Suffice to say that what we are looking to achieve is an absolutely void and air free composite laminate that will both withstand the rigours of casting at World Record level and ensure the rod does not loose its action.
This vacuum process is picked up when the bag is transferred to the autoclave. This is very similar to the process used in the Century factory to create carbon fibre Formula 1 race car parts and the technology that we apply to these two different but highly competitive sports is very similar.
The bag and the rod blank are transferred to the autoclave for the cure cycle. This is where the resin matrix is hardened and the rod is finally made rigid. The process is computer monitored throughout and the cycle is precisely run with predetermined temperature ramp and de-ramp rates. What we achieve is a very pure wall that has less than 2% air void content. Any air trapped in the wall of a blank will lead to premature softening and a less dense composite structure.
The fact that we have achieved all the recognised World Casting Records in 100 gram and in 125, 150 and 175 gram events - over 300 yards, is an indication on how important this process is contributing to the integrity and performance of the TT-R.
The blank is now ground in the areas that are deemed helpful to the action and the latest taper grinding machines are used to remove precisely the right amount of sacrificial surface carbon plies. The joint is then machined in a centreless grinder to a very tight tolerance.
Danny likes to have a certain level of cosmetic finish applied to his rods. He knows they are going to be seen by many people so they have a coat of 2 pack epoxy varnish applied to them and then his guides are actually taped onto the rod using the factory Century SiC rings and spacings determined by experience. Clearly the factory rod for general sale will have the rings applied by more conventional means! So there you have it - the process that Century uses to make World Record rods.
Most of the processes shown here are applied to all the rods that carry our Autoclave Technology logo. They are certainly some of the most unique available anywhere in the world and we hope that the insight we have given to what goes on inside the wall and design of a rod gives you a better appreciation of how we do things differently at Century.
Danny is the only caster to cast over 300 yards at UKSF and CIPS World Casting Championships and also holds the World Record OTG (off the ground) casting record on 150 gram at 280 yards.