Matched-die moulding

To achieve a more uniform distribution of resin throughout the reinforcement, more automated systems have been developed [12]. In matched-die moulding pre-mixed resin and hardener are injected under pressure from a pressure pot into the reinforcement placed in a closed matched cavity tool [13]. The resin spreads out radially from the point of injection, permeating through the reinforcement until the cavity is completely filled with resin. 

A development of the matched-die moulding process is to vacuum assist the resin into the tool. Dry reinforcements are placed in an open tool. The layup is sealed by a flexible vacuum bag and vacuum is applied. The resin is forced under pressure into the... 

Particulate microcomposite Silica, carbon black, calcium carbonate, glass bead, glass balloons, silicon carbide Mechanical mixing and casting, compression moulding, matched-die moulding... 

Closed mould (or matched-die moulding) processes are used in the composites industry for fabrication and manufacturing of three dimensional compounds and products. There are different closed moulding processes. Within these, there are transfer moulding, compression moulding, resin injection moulding, injection moulding, pultrusion and extrusion. 

Matched die moulding method of moulding reinforced plastics products in which a preform of the reinforcing material is placed in a mould, the required amount of resin is added and the mould is closed. Similar to the compression moulding of dough moulding compounds (qv). 

A variation of thermoforming which does not involve gas pressure or vacuum is matched die forming. The concept is very simple and is illustrated in Fig. 4.53. The plastic sheet is heated as described previously and is then sandwiched between two halves of a mould. Very precise detail can be reproduced using this thermoforming method but the moulds need to be more robust than for the more conventional process involving gas pressure or vacuum. 

Cold Press Moulding—A low pressure, low temperature process in which fibres are impregnated with a cold cure resin and then pressed between matched dies. 

Hot Press Moulding—Heated matched dies are loaded with thermosetting compound and pressed together until cured. 

Contact Filament Pressure bag Pultrusion Matched-die Continuous moulding winding moulding moulding laminating... 

For mass production purposes matched metal moulding techniques are employed. Here the preform or mat is placed in a heated mould and die resin poured on. The press is closed and light pressure ( 501bf/in ) applied. Curing schedules are usually about three minutes at 120°C. It is possible to produce laminates using less resin with pressure moulding than with hand lay-up techniques and this results in better mechanical properties. 

This was the first technique used for forming plastics in production quantities. The mould comprises a matched pair of male and female dies. A measured quantity of partially cross-linked polymer (this technique is not now used for thermoplastic polymers) is placed between the two halves of the mould. The upper die is then lowered and the polymer compressed it is simultaneously heated by heat transfer from the heated mould. Before setting, the hot polymer completely fills the mould. It is then left to cure. The mould is finally opened and the part removed. The metering of the appropriate amount of polymer, and also some preheating, is being increasingly performed by screw machinery. This can increase by up to 400%... 

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