DIE CASTINGS-AUTOMOTIVE PRESS
Moulding methods have altered little over the years, most
involve the use of a solid patterns made from wood, resin or aluminium onto which sand is rammed. When the pattern is removed a cavity is left in the sand which represents the outside form of a casting. In order for the pattern to be drawn out of the sand, taper is left on the pattern. The problem is that all tapers must be formed in the same direction, otherwise it is impossible to draw the pattern without breaking the sand mould. When producing a complex shape such as an automotive press die it is seldom possible to design the die casting in this way. One traditional way to over come this problem is to create a die casting in wax which can be melted out after the sand has been rammed. This method has many limitations and therefore for many years automotive press dies were fabricated in steel. 
With the advent of stronger and more durable S.G. (ductile) iron it was desirable to develop a way to make automotive press die castings using these materials. After much development work it was found that a pattern could be made in polystyrene, which when coated with a suitable semi-permeable coating could be rammed into a sand mould and then have the metal cast into it. Coupe Foundry quickly recognized the potential of this technique and embarked on a program of development to manufacture automotive press die castings with various factions of the motor industry. This method of manufacture of automotive die castings is now widely used by the major motor manufacturers and Coupe Foundry has become the largest supplier of automotive press die castings in the UK.
The experience gained in the motor industry is now being adopted by other areas of general engineering, particularly where a one off or a short run of castings is required as the patterns can be more complex than conventional moulding and the pattern costs are lower.
As the largest supplier of this full mould method in the UK, with over a quarter of a century expertise and experience in this area, Coupe Foundry is able to advise on a practical level where this technique can be beneficial.
For a press die casting or polystyrene pattern solution please contact us
