If a casting of a given shape is to be doubled in volume, describe the effects on mold design..?

Question

including the required change in the size of the risers, runners, chokes, and sprues.

Answer 1

If a casting shape is to be doubled in volume, obviously the dimensions should also be increased and therefore the allowances for Solidification Shrinkage and liquid shrinkage will also adjust. As for the risers, Liquid shrinkage is the one responsible for this because it is the contraction of the molten metal as it cools from its superheat temperature to the point at which it starts to solidify (the liquidus). This shrinkage does not normally cause the foundry man any trouble provided he has sufficient feed metal in the risers. For the sprues, which are small tool to make on the lathe; this tool creates the vertical-pouring hole, which directs the hot metal to the in-gate, or flow channel that you created and into the mould cavity. The sprue will also act as a choke to control the flow of metal into the mould cavity. Upon knowing this, the sprue to be used should also be bigger because the volume increased. The strategic placement of risers or feeders will also promote sound castings and even solidification. It is not unusual to find almost as much metal used for gates and risers, as that which is used for the casting is wasted. Patterns, Gates & Runners can be mounted permanently on the pattern board for rapid mould making operations. When both drag & cope have been rammed up, all the channels are already formed ready to pour. Upon knowing this the runner should also increase in size since it is used for mounting. The same is true for the chokes as for the sprues.

Answer 2

THE UNAS IS DOUBLED THE AREA IS UNAS AND THE FINAL PRODUCT IS UNAS KALBO.