Open Mould and Hand Lay Up
Wet Lay-up/Hand Lay-up
Also known as contact moulding hand lay-up is a production technique suitable for prototypes and low volume production of fibre composite material parts. Hand lay-up is the most basic form of moulding process and is also the least capital intensive. A pattern of the product to be manufactured is made to its exact dimensions. A mould is made using this pattern (negative of the original).Hand layup is the oldest and simplest method used for producing reinforced plastic laminates. Capital investment for hand layup processes is relatively low. The most expensive piece of equipment typically is a spray gun for resin and gel coat application. Some fabricators pour or brush the resin into the molds so that a spray gun is not required for this step. There is virtually no limit to the size of the part that can be made. The molds can be made of wood, sheet metal, plaster, and FRP composites.
In a particular hand layup process (otherwise known as wet layup), high solubility resin is sprayed, poured, or brushed into a mold. The reinforcement is then wet out with resin. The reinforcement is placed in the mold. Depending upon the thickness or density of the reinforcement, it may receive additional resin to improve wet out and allow better drape ability into the mold surface. The reinforcement is then rolled, brushed, or squeegeed to distribute the resin uniformly, to remove entrapped air and to compact it against the mold surface.
Hand lay-up is an open molding method suitable for making a wide variety of composites products from very small to very large. Production volume per mold is low; however, it is feasible to produce substantial production quantities using multiple molds. Hand lay-up is the simplest composites molding method, offering low cost tooling, simple processing, and a wide range of part sizes. Design changes are readily made. There is a minimum investment in equipment. With skilled operators, good production rates and consistent quality are obtainable.
Raw Material
Available resins include unsaturated polyester, vinyl ester and epoxy. Fiberglass can be of many types, including chopped strands or mats of e-glass or carbon fiber. Additional materials offered upon consultation.
Gel coat is first applied to the mold using a spray gun for a high-quality surface. When the gel coat has cured sufficiently, roll stock fiberglass reinforcement is manually placed on the mold. The laminating resin is applied by pouring, brushing, spraying, or using a paint roller. FRP rollers, paint rollers, or squeegees are used to consolidate the laminate, thoroughly wetting the reinforcement and removing entrapped air. Subsequent layers of fiberglass reinforcement are added to build laminate thickness. Low density core materials such as end-grain balsa, foam, and honeycomb, are commonly used to stiffen the laminate. This is known as sandwich construction.
Fully-finished or paint-ready surfaces can be achieved by utilizing an appropriate gel coat during the molding process.
Simple, single cavity molds of fiberglass composites construction are generally used. Molds can range from small to very large and are low cost in the spectrum of composites molds. Typically, composite molds, which offer low cost and fast speed to market, excellent for prototyping. Tool lead times are typically 8 weeks or less, shorter than many other composite applications.
Advantages
Ideal for Lower Volume Programs
Modest equipment and tooling requirements make the hand lay-up process ideal for prototypes and lower volume programs. It is often a process choice for one-off specialty products.
Low Cost Tooling
Hand lay-up molds may be produced from almost any material, including wood, composites and even plastics. The process uses only one mold (open mold), resulting in even lower tooling costs. Molds can be “splashed” off of another part or model of almost any material, further reducing their cost.
Faster Speed to Market
The nature of hand lay-up tooling allows very rapid product development. Molds can be produced in as little as 1-2 weeks for simple part geometries, and in less than 8 weeks for almost any part design.
Localized Material Properties
The placement of reinforcing fibers prior to resin application allows part performance to be locally optimized. Additional (or varied forms of) fiber can be precisely positioned in areas likely to experience high stress.
We at Prazastinav Compositech Pvt Limited use hand lamination for producing large parts, when the clients wants to minimize costs. We can produce complex parts with high-quality surface. We have more than 100 combined years of experience in executing composite hand lay-up projects (HLU’s) of all shapes and sizes. Our main manufacturing facility in Vadodara, Gujarat has sufficient space to take on jobs big and small. Using advanced design and production control composite manufacturing technology, we can ensure repeatable, high-quality products using this process.