DRAGGING ZINC DIE CASTING OUT OF THE DOLDRUMS.

Using an Engineering Materials Requirements Board grant of POUND 200,000 the Zinc Development Association and the BNF Metals Technology Center have been spending the past two years measuring the characteristics and capabilities of zinc die casting machines both in the laboratory and in the field. The ZDA has now combined this work with research into die design done in Australia and the USA, as well as at BNF, to devise a graphical process for matching machine performance with the needs of the casting. A graph representing the capabilities of the chosen machine is overlaid with another representing die characteristics. From these the range of possible die filling conditions can be predicted. This is a straightforward manual approach. However, the calculations involved in the new approach lend themselves to computerization. A computer program has been developed which contains information about the injection performance of die casting machines and is generally tailor-made for the equipment which the particular customer is operating. In operation the designer decides which die casting machine he wants to use and enters into the computer details of the weight of the casting or castings. The computer will calculate a range of possible combinations of gate area, gate velocity and cavity fill time and this information is displayed on a VDU in the form of a table. From this the designer can decide on the best gate area to use.