Permanent Mould material

[BrianGar]

Im after a permanent mould material for a small batch of centrifugal cast items.

I was looking at graphite but Im finding it hard to get in Ireland. And shipping is a killer from the uk.

My next option is I guess cast Iron, because this is harder to obtain in my near mould shape I would have to cast/or machine a rough mould from it first and then finish machine.

This is where graphite would benefit me as it is easy machine, albeit dusty/dirty.

Have I any other options as to material choice? Material I am pouring is Lm25 aluminium alloy.

Can anyone think of any other suitable material that I could perhaps protect further with a slurry wash.

I will go for graphite if I have too, Im just putting this out there in case Im missing any material I had not thought of.

Thanks in advance

BG

 

[arunmrao]

Is copper readily available? Cost will be an issue too?You could consider using a copper slleve in a steel jacket ,with water cooling arrangement.

_____________________________________
"The richer we have become materially, the poorer we have become morally and spiritually." Martin Luther King Jr

 

[micalbrch]

I know that steel moulds are used for aluminum pressure casting but that doesn't make sense for a small batch.

Sand moulds are used for small batches but can't be called a permanent mould.

 

[unclesyd]

A tool steel permanent mold is going to cost a ton of money.
You might want to look at the Shell Molding Process, relatively inexpensive if the your quantity isn't too large.
Also look at the Lost Foam Process. If the part is fairly intricate.

http://www.industrialmetalcasting.com/shell-moulding.html

http://www.buildyouridea.com/foundry/lost_foam_howto/lost_foam_howto.html

 

[BrianGar]

Arunmao, I had not thought of copper, Using a double skin setup as you mentioned is something Ill think about, copper, I can get also, and its conduction properties would be of massive benefit both for pre heat and cooling, so thank you.

Micalbrch, sand is not of much use, something like an oil bond disintegrates with the centrifugal force, and if I use co2 cure cooling becomes a problem, since water will dissolve the co2 mould.

Metal moulds make full sense since this is a centrifugal cast operation, Im taking full advantage of the process for improved density/less-porosity/inclusions. And I can also control cooling with water.

I thought I was onto a good idea a while ago when looking at salt as a permanent mould, but this too will dissolve in water, and has a high pouring temperature, 800c approx. Its something I must keep in mind that could be of use for other operations though.

Thanks for the help guys,

BG

 

[BrianGar]

unclesyde, its a very simple part, think of a shot glass shape, where the main mould would form the outer wall, and a removable 2nd core mould 'cap' would form the void where the vodka would occupy in said glass! Its a little more complex than that with a few internal features, but not much. All features would only require the core mould to be machined, and draft angles/undercuts are non existent for the particular internal geometry's required.
What I mean is, the 2nd core mould will easily remove once part is cooled.

Hope that rather strangely worded post makes some sense.

BG

 

[MikeHalloran]

That sounds like a natural part for impact extrusion.



Mike Halloran
Pembroke Pines, FL, USA