Thermoplastic injection moulding

One consequence of this is that in a thermoplastic injection moulding the molecular orientations will vary from place to place according to the flow pattern. This may well set up sufficient stresses in the moulding to cause it to distort from its intended shape. Factors affecting the amount of orientation were discussed briefly in the previous chapter and by the author elsewhere. Sometimes the conditions required to minimise distortion may be such that the moulding cycle becomes too long to be economic. In these cases it may be necessary to modify the moulding or at least the position and number of feed... 

Structural foams are made of a cellular core with a dense skin. The technique is used for industrial and aesthetic goods for the automotive, electronics, household appliance and aeronautics sectors, such as housings of machines, TV cabinets, computer housings, roofs for caravans or ships, hard tops of 4WD (Jeep), luggage boxes, parts for washing machines. Structural foams are processed by thermoplastic injection moulding using ... 

It should be emphasized that in the case of thermoplastics, injection moulding will be referred to as low-pressure moulding for pressures not exceeding 5 MPa. This limitation provides a possibility to distinct confine the scope of our review and disregarding the processing by conventional automatic moulding machines. 

Thermoplastic injection moulded disk The disk was moulded in a high capacity moulding process, and then mechanically fixed onto the punched-out section of the cathode. 

The thermoplastic injection moulded disk was quickly abandoned because of electrolyte penetration into the aluminum under the plastic. This caused rapid corrosion, and lead to the premature failure of the cathode disk. Both the compression moulding and transfer moulding resulted in robust cathode disks, with good resistance to electrolyte penetration. In 1999, Kidd purchased 10,000 compression moulded, and 4000 resin transfer moulded cathodes. 

While injection molding machines designed specifically for processing thermoset materials are available, a number of manufacturers offer replacement screw and barrel assemblies and stuffer hoppers to convert conventional thermoplastic injection moulding machines to process thermosets. 

Ganster J, Pinnow M, Fink H-P (2006) High tenacity man-made cellulose fibre reinforced thermoplastics - injection moulding compounds with polypropylene and alternative matrices. Compos A 37 1796-1804... 

The process can be broken down into several unit operations, as shown in Fig. 6.6. A necessary condition for the success of easy mixing by impingement is that the reactants each possess low viscosity also only low pressures are needed to fill the mould and this reduces the costs of capital equipment, especially for large parts, which makes RIM economically attractive compared with a typical thermoplastic injection-moulding process. A comparison of RIM and thermoplastic injection moulding is shown in Table 6.5. 

Cracknell, P and Dyson, R, Handbook of thermoplastic injection mould design. Chapman and Hall (1993). 

M. Akay and D. Barkley, Fibre orientation and mechanical behaviour in reinforced thermoplastic injection mouldings. Journal of Materials Science, 26, 2731-2742 (1991). 

Something like 50 billion connectors are manufactured in the world each year. They are essential to every kind of electrical component and appliance, and modern technological society would be inconceivable without them. Nearly all of them involve a thermoplastic injection moulding. There are on average about 200 in every car, which means that the motor industry accounts for one fifth of the world connector market. 

Thermoplastic injection moulding is by far the most common moulding process in use, as well as being amongst the most complex. Normally, injection moulded parts have features which are formed parallel to mould opening (two-dimensional features). Features perpendicular to mould opening are possible... 

Guide Values and Processing Instructions for the Most Important Thermoplastic Injection Moulding Compounds... 

Sometimes, problems occur in producing parts of the desired quality. In most cases, the surface quality of thermoplastic injection moulded parts is the main criterion for their quality. Due to the complex interrelationship between the moulded part and the mould, the moulding compound and the processing, it is often very hard to recognise the origin of problems and thus to take immediate action. This chapter is based on the experience and knowledge of many experts. It was written during a three-year team project, which involved intensive work by 30 companies. 

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