molds are becoming more and more complex, and as a result it is getting ever more difficult to create the proper conditions for effective mould temperature control. Except in the case of simple parts,

mould temperature control systems are always a matter for compromise. For this reason, the following list of recommendations should be seen as rough guidelines only.

1) Temperature control of the shape to be moulded must be taken into consideration at the mold design stage.

2) When designing moulds that have a low shot weight and large mould dimensions, it is important to allow for good thermal transfer in the construction.

3) Be generous when in dimensioning flow cross-section in the tool and in the feed pipes. Do not use fittings that cause a major restriction to the flow of the mould temperature control fluid.

4) Use pressurised water as the temperature control medium, if possible. Provide flexible pipes and manifolds that are capable of withstanding high pressures and temperatures (up to 8 bar and 130 °C).

5) Specify the performance of the temperature control equipment to match the mold. The mold-maker’s data sheets should supply the necessary figures for flow rates.

6) Use thermal insulation plates between both halves of the mold and the machine platens.

7) Use separate temperature control systems for the moving half and the fixed half of the mould.

8) Use separate temperature control systems for any side actions and the core, so that you can work with different start-up temperatures to get the mould running.

9) Always connect different temperature control circuits in series, never in parallel. If circuits are in parallel, small differences in the flow resistance cause different volumetric flow rates of the temperature control medium, so that bigger temperature variations can occur than with circuits connected in series. (This series connection will work properly only if there is less than 5 °C difference between mould inlet and mould outlet temperatures.)

10) It is an advantage to have a display showing the supply temperature and return temperature on the mould temperature control equipment.

11) For purposes of process control it is recommended to have a temperature sensor built into the mold, so as to be able to check its temperature during actual production.