Press moulding fabrication process techniques

This process has been described in a previous chapter as a means to process unreinforced resins. Fibre-reinforced composites can be fabricated in a similar way. The resin and fibre can be combined by usual hand lay-up or spray-up techniques. Glass fibre content up to 70 wt% or 50 vol% can be achieved for fibre composites processed by this technique. Press moulding offers obvious advantages like fast cycle time, good finish, structural integrity and high reinforcement content. 

Ever increasing demand for faster composite manufacturing has pressed the composite industry to replace hand lay-up technique with alternative fabrication processes such as liquid composite moulding techniques. 

Unsaturated polyester (Butanox M-60) mixed with 1.5% of Methyl Ethyl Ketone Peroxide (MEKP) as catalyst was selected as a resin for the current work. Treatedbetelnut fiber reinforced polyester (T-BFRP) composite was fabricated using hand lay-up technique. In composite preparation, a metal mould (100 x 100 x 12 mm) was fabricated. The inner walls of the mould were coated with a thin layer of wax as release agent. The first layer of the composite was built by pouring a thin layer of polyester. A prepared mat was placed carefully on the polyester layer. Steel roller was used to arrange the mat and eliminate trapped bubbles. This process was repeated until the composite block was built containing 13 layers of fiber mats and 14 layers of polyester. The prepared blocks were pressed at approximate pressure of 50 kPa in order to compress the fiber mats and to force out the air bubbles. The blocks were cured for 24 hr and then machined into specimens in the size of 10 x 10 x 20 mm. 

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