The latter is based on a high-pressure liquid beam which reaches a velocity of 2.5 times the speed of sound, creating a pressure on the fabric which is higher than the compression resistance of the material and resulting in a net cut. The former is obtained through a convergent radiation beam which vaporizes the material underneath and uses pressurized gas to remove the volatile particles and the melted material. There are also completely contact-free cutting techniques, such as laser cutting and water jet cutting, both usually embedded on CNC machines. An alternative process with less friction is the ultrasound method, which consists of cutting the fabrics with a blade actuated by high-frequency mechanical vibrations, produced by an internal source integrated into the system. These methods require different skills from the operator and provide different finish precisions, but they all are mechanical procedures and have one major disadvantage in common: the physical contact between the cutting tool and the fibres. More automatized alternatives are die-cutting systems, which allow higher production rates to be reached while limiting overall costs, as they allow more layers of fabric to be cut simultaneously. #7: cut materialĪs far as cutting tools are concerned, the most common are scissors, cutters, knives and saws. This process can be manual, semi-automatic or completely automatic. Even though the fibres, in general, have high tensile strength, the shear strength is usually quite low, so they are fairly easy to cut. Cutting Ĭutting fabrics is the first stage of the Lay-Up process. Hence, nowadays, it is mainly suitable for small series production runs of 10 to 1000 parts. Even though some of the production steps can be automated, this process is mainly manual (hence often referred to as the Hand Lay-Up process), leading to laminates with high production costs and low production rates with respect to other techniques. The main stages of the Lay-Up process are cutting, lamination and polymerization. On the contrary, as Wet Lay-Up does not allow uni-directional fabrics, which have better mechanical properties, it is mainly adopted for all other areas, which in general have lower requirements in terms of performance. ![]() ![]() It can be divided into Dry Lay-up and Wet Lay-Up, depending on whether the layers are pre-impregnated or not.ĭry Lay-up is a common process in the aerospace industry, due to the possibility of obtaining complex shapes with good mechanical properties, characteristics required in this field. A Lay-Up process is a moulding process for composite materials, in which the final product is obtained by overlapping a specific number of different layers, usually made of continuous polymeric or ceramic fibres and a thermoset polymeric liquid matrix.
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