Where larger quantities of castings are required with tighter tolerances, smoother surfaces and sharper defined sections, we use the Aluminium Gravity Die Casting process. Our sub-contract gravity die maker produces a cast iron permanent mould split in two halves operated by rack and pinion or hydraulics from our customer’s drawings. All our dies are mounted permanently on steel plates with a box section tube table.
The aluminium gravity die casting process starts with the gravity die being heated up to a temperature of 150 ºc – 200 ºc. Once this has been achieved the cores, if any are required, are placed into the die, the two die sides are closed and secured together with clamps. Now the die caster can pour molten metal into the cavity where it quickly solidifies. Aluminium Gravity Die Castings in the Barron Clark foundry
After a matter of a few seconds the die sides can be parted, the casting ejected and the process repeated. Because the gravity dies can be used tens of thousands of times in their lives, un-like sand moulds which are used once, we are able to produce hundreds of castings a day from a single die. Although on the whole aluminium gravity die castings are cheaper than sand castings, the cost of tooling is considerably more expensive so this process should only be used where a long run of thousands of parts are required.
BENEFITS OF ALUMINIUM GRAVITY DIE CASTING
- High production rates are achieved by using single impression gravity dies and often can be improved by utilising multiple impression gravity dies.
- Excellent dimensional tolerances can be achieved.
- Thinner wall sections are possible over sand castings.
- There is more chance of reducing further operations such as fettling/machining.
- If a casting requires inserts to be ‘cast in’ such as spigots, shafts, nuts, threaded inserts etc this can be done without any problems.
- Cast surfaces such as smooth, textured or cross hatching can be achieved.
- Up to 100% aluminium yield.