Production Methods

Fibreglass Developments Limited uses several methods of mould production in the factory. Each process has its own characteristics as well as limitations as to part size, shape, production rate, compatible reinforcements and suitable resin systems.

Hand Lay

The basic system where everyone starts - "Bucket and Brush". Used for low to medium volume production, the hand lay process provides only one finished surface. At FDL we use this method for production of children's rides.

The hand lay method involves placing the fibre reinforcement, in the form of chopped strand mat, into the mould and applying the catalysed resin by hand - usually from a bucket, using a brush. Other higher strength reinforcements can also be added this way. This method offers good control of materials, enabling control of thickness and resin to glass ratio.

Spray Up

Also used for low to medium volume production, spray moulding is used for similar products as hand lay, but allows for greater shape complexity. A chopper gun is used to deposit the chopped strand reinforcement and resin. This method is more operator dependant to get the desired result, but this is additionally monitored by the use of flow meters and scales for materials. Its advantage is that it is quicker and cheaper for production of large items, or large numbers. As size diminishes it becomes more wasteful due to overspray.

At FDL we use this method for production of Breeze Bustas (truck air deflectors)

Resin Inject, RTM (Resin Transfer Moulding), Closed Moulding

The resin injection method is used where high production rates or specific criteria such as critical wall thickness or two moulded faces are required. A high production rate is only possible if using a pigmented resin and a non-gelcoated industrial surface is acceptable. Production rates drop dramatically if gelcoat is required. If there are no specific criteria that demand RTM, then due to the expense and time required to make RTM moulds, it can often be more economical to make many open moulds to meet the production requirement and produce a cheaper article. RTM products require more expensive reinforcement, the resin pigment is an additional cost, there is considerable waste, and post moulding trimming is always required to remove the flash. Open moulded products can be trimmed to size in the moulds.

Reinforcement is placed in the bottom half of the mould. The mould is then closed and clamped, and catalysed resin is then pumped into the mould under pressure until the mould is filled. This method was used at FDL for production of the Post Office sorting trays project

Vacuum Bag

The Vacuum Bag process is used in production to increase product quality by reducing voids, decreasing weight, and obtaining a better fibre-to-resin ratio that will lead to stronger laminates. It is used for pressing cores into standard or high-tech laminates to ensure good adhesion (e.g. plyglass panels for truck and trailer manufacturers), or producing high-tech laminates giving extremely high strength to weight ratios. The vacuum ensures thorough wet-out of the fibre reinforcements, while excess resin is drawn off and absorbed into a 'bleeder' cloth. This type of laminate is usually for a specific task and is often comprised of expensive fibres such as Carbon and Kevlar. The vacuum bagging materials (peel ply, perforated film, bleeder cloth, and breather cloth) are all usually discarded after one article, adding to the expense.