FIBRE Mechanics / NTPT Case Study
Process-efficient, high-quality prepreg panels for the boatbuilding sector
A collaboration between FIBRE Mechanics and North Thin Ply Technology
Today we see a trend towards collaborative working, with specialists coming together to create project-specific teams. An example of this is the collaboration between FIBRE Mechanics and North Thin Ply Technology™. Using the expertise of both companies – the FIBRE Mechanics team have built several thousands of prepreg structures, and NTPT are experts in prepreg automation technology – structures such as bulkheads, girders, and interior joinery panels are built offsite as structurally-optimised, efficiently-manufactured prepreg composite panels, made to the exact specification, shape and size required by the design.
Benefits for the client:
- A boatyard can work with FIBRE Mechanics to determine the specification of the panel, and the finished panel is delivered in time to be incorporated into the vessel, so the yard can focus on other areas of construction.
- The yard or project manager has a single point of contact, removing the need to order, ship and freeze small amounts of the required multi-axial prepreg for the skin and patching, as well eliminating the storage and manual cutting of core, and then dealing with the waste removal of both materials.
- The automation process reduces the overall labour time and cost for building complex structural parts.
- The process removes human error from the equation, such as incorrect materials being picked from the shelf or backing paper being left on, so there is consistency in the quality and therefore in the structural reliability of the part, giving the end user confidence in the overall boat.
It started as an investigation into improved accuracy for component manufacture by FIBRE Mechanics. The thought was that the optimisation of laminates could be improved using low weight unidirectional prepregs, rather than conventional woven or stitched multi-axial prepregs. When Geoff Stock, Managing Director of FIBRE Mechanics, saw how the NTPT Automated Tape Laying (ATL) machine was plotting unidirectional tapes more precisely and far more quickly that could be done manually, and in addition the cutting beam could trim the preforms in a matter of seconds, he saw that this was the way to tackle the key challenges of composite construction in the boatbuilding sector: quality and accuracy, weight, cost and time.
“We have worked with thousands of carbon and glass composite structures over the years and have learned what works and what doesn’t,” says Stock. “Our processes have developed with an ever increasing build quality of structural panels, with highly engineered laminates, reinforcements and core kits. The NTPT Automated Tape Laying process takes quality and precision to the next level while at the same time reducing labour hours and shortening supply chains.”
Unidirectional prepreg is the most cost and structurally efficient prepreg, and with the NTPT ATL machine the required specification can be achieved more efficiently than weaving or multi-axial stitching machines, and offer mechanical performance benefits as there is no crimping of fibres. The speed and accuracy of the automated approach allows very specific reinforcement patching to be incorporated more easily and conversely does not depose material in way of penetrations, with the machine working to sub-millimetre accuracy.
FIBRE Mechanics is a team of highly accomplished boat builders and project managers, regarded globally as some of the most experienced in the marine industry. The client (boatyard, designer or owner) can call on their expertise in whatever way it is required for the project. In the case of composite panels, FIBRE Mechanics acts as a single point of contact for the client, from the initial definition of an appropriate laminate and detailing specification through to ensuring the high quality panels are delivered on time and on budget to the client.
NTPT’s expertise in automation started with the invention of the technology behind 3Di™ sails, so offering the benefits of Thin Ply Technology® and conventional prepreg automation to other boatbuilding applications was an obvious development for the company. NTPT manufactures a range of unidirectional carbon prepreg, with varying weights and resin formulations, at their facility in Poland. Using proprietary software, the company’s ATL machine plots prepreg preforms into near net shapes for the bulkhead skins, including patching and reinforcement areas. Once again efficiency of time and material is front of mind, as multiple bulkheads (or other structures) are nested on a large format table (4m x 11m), with a maximum single panel size around 3.3m x 9.9m.
A CNC-cut core kit, supplied according to the FIBRE Mechanics design (including recesses, tapers and apertures), joins the prepreg preforms and the FIBRE Mechanics-manufactured reinforced core inserts in Poland. With all the components in place, the final panels are assembled by NTPT, under the supervision of the FIBRE Mechanics boatbuilding team.
The finished panels are delivered directly to the client from NTPT in Poland, with FIBRE Mechanics liaising with the client throughout the process.
Through the automation of this process by FIBRE Mechanics and NTPT, key challenges for – and often barriers to - composite construction of both custom and series production boats are addressed: labour time to produce complex parts is much reduced; accuracy and high quality of manufacture is consistent and repeatable; supply chains are reduced; and the resulting panels are optimal in terms of weight, cost and structural performance.