Riser Proper Place 1

[MetalEng]

I have heard the risers should be placed on the sprue side of the mold cavity. Is this matter related to appropriate temperature gradient creation? Thanks to all.

 

[metman]

I thought it was because the risers are there to assist the sprue in filling the mold as it shrinks during rapid cooling and into crystallization temperatures.

 

[swall]

Gravity.

 

[arunmrao]

Metal Eng
I think you are asking about side risers. It all depends on the feeder requirements. If it is a hollow casting and the opposite side to the runner bar needs to be fed ,in that case you would need to place the feeders over there too.

Interesting,but also consider the alloy processed, molding and core practice, level of soundness required etc.

Hope it helps.

 

[MetalEng]

swall,
Could you please explain a little more detailed.

 

[arunmrao]

MetalEng
If you need to take advantage of gravity feeding then top riser will be more beneficial.

 

[swall]

MetalEng--I understood your question to be "should risers be placed in the top half of the mold vs the bottom ?". The answer is emphatically yes, since risers have to rely on GRAVITY to feed metal into the shrink prone areas of a casting.

 

[MetalEng]

swall
I just mean in which cases the riser should be nearer to sprue. Gravity effects are pretty obvious.

 

[swall]

Basically, you put the riser where the shrinkage problem is. You should have the riser feed the area directly, if possible, since the sprue could freeze off before the riser has fed enough metal into the shrink prone area.