Mould Carrier

Front-end carriers moulded in HPGF grades could be an economically better solution than those using LFRT polymers. 

The essence of the early 1960s process was that one injection unit fed 4, 6, 8, 10 or 12 vertical presses on a rotating mould carrier. Sometimes two injection units were used at different mould stations, one injecting a soft upper compound for a bootee and the other a harder sole compound. Sometimes two different coloured compounds were used. 

The oxidised waxes (containing various ratios of fatty acids, esters and alcohols) are used in the manufacture of various polishes, anti-corrosion coatings, tile glazing carriers, precision casting waxes, mould release agents, metal coatings etc. 

Injection Molten polymer flows into the injection cavity via the hot runner block, to produce the desired shape of the preform with a mandrel (the core pin) producing the inner diameter and the injection cavity the outer. After a set time the injection moulds and core pins part and the preform held in a neck carrier is rotated 90°. 

JMAC antimicrobial masterbatches are described. The products are based on the controlled release of silver ions. A silver chloride/titanium dioxide composite particle releases silver ions on contact with water and then maintains an equilibrium concentration in solution, releasing more ions as required to give effective preservation. Its antibacterial performance in PP mouldings, in thin section PE, itylon, PETP and PP fibres is reported. JMAC masterbatches are available in most polymeric carriers including PE, PP, polystyrene, ABS, PETP and nylon, with typical addition rates of around 1%. 

Over 95% of all the microcircuits made are packaged in plastic, usually a transfer moulded epoxy resin. Changes in packaging technology will occur away from the familiar PDIP (plastic dual-in-line package) to smaller SOT or chip carrier formats but plastics will continue to be the dominant packaging material for cost reasons. At the same time there is a need to improve the reliability of plastic encapsulated devices (PEDs) as they find further use in professional and certain military applications. 

The converting or moulding process may also include the use of processing aids, e.g. lubricants and mould release agents. Masterbatching may contain lubricants, mould release and a carrier or base diluent which assist the manufacture of a concentrated masterbatch containing colourants. 

Permanent mould coatings are typically formulated using water as a carrier, a high temperature binder (normally sodium silicate) and a refractory filler or blend of fillers. There are two categories of coatings ... 

Each mould carrier is usually provided with two pneumatic cylinders for opening and closing. Upon demand, the closing system can be actuated hydraulically or mechanically. 

Figure 3.9 A different degree of tilting can be obtained for each mould carrier, to optimise the evacuation of air from the moulds during the filling/ polymerisation phase.

As stated previously, the lower half of the mould carrier is composed of two independent platens. They are fitted with a guiding system to ensure maximum parallelism between the platens. 

In order to ensure equal clamping pressure and complete closure of the moulds over the entire parting line, pneumatically inflated tubes stroke each platen. They are inflated after the monld carrier has been closed and deflated just before opening. The total stroke is a few centimetres. The clamping force afforded by this system is 12,700 kg, using a working pressure for the air bags of 0.3 MPa. 

Individual thermoregulator units are nsed, one for each press. They are mounted on the rear of each monld carrier. This solntion affords complete autonomy to each press, making it possible to control the temperatnre of the moulds prior to being placed on the production line. Snbseqnently, when a press is placed on the moulding line, it is ready to commence production. 

The mould carrier concept for fixing and centring is designed for quick mould carrier removal or exchange. 

A dedicated station where service operations on moulds and mould carriers can be performed, without disturbing the production cycle, is foreseen for each moulding line (see Figure 3.10). 

Figure 3.10 All maintenance and setting operations on moulds and mould-carriers can be executed off-line, in a dedicated service station that performs all the line s movements and operative functions.

The service station comes with one complete mould carrier on its freestanding frame. It is equipped with a dedicated thermoregulator for warming of moulds destined to be inserted on the moulding line, along with all the required safety fences/light barriers, controls, and connections for air, water and electrical power. 

This system can easily be expanded to incorporate any new business obtained for that range of moulded products. Extensions are achieved by fitting an even number of new carriers to the line and extending the supporting frame accordingly. 

Figure 3.11 A modular oval conveyor for flexible foam moulding. It can be easily extended, adding modules of track and pairs of mould carriers, when higher productivity is required.

Polymerisation stations 7 Six arm rotating structure to support mould carriers 8 Central collector of signals, air and warm water 9 Supporting structure (and rotoi not shown)... 

A practical solution consists of a carousel line with a row of service positions where the operators can work on moulds that have been temporarily taken off-line (see Figure 3.13). When the press leaves the curing area, it passes in front of the first free operator and is automatically disengaged by the dragging system. The moulds can be serviced, taking all the time required, then, when the textile inserts have been positioned, the carrier can be reinserted in the first available position in the line. 

Figure 3.13 Oval moulding line with 16 double mould carriers, designed for in situ...

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