Modding How to mold metal into shape

Hey guys, sorry if thos post is not in the right section, but I didn't know where to put it. I have a question regarding molding metal into certain shapes. I'm an electrical engineering student, so I have no idea about how to do that.....what I'm doing is trying to build an electronically controlled silent cooling system for a PC for our senior project, think of it like a mini AC.
Right now, my group consits of computer engineers and electrical engineers, and we don't have any mechanical engineers to work with. To build my cooling system, I will need to build a strong housing for it. I was thinking of either doing it with aluminum or copper, whichever we can get our hands on. As of right now, we have a hard time getting our hands on a aluminum or copper in the states.
What I do have is a bunch of old heat sinks, all made of aluminum. Does anyone know how I would be able to mold them and make 2inch x 2inch square block out of it? I have 0 knowledge of metal work, so I was hoping someone would guide me in the right direction. My only thoughts of how to work this would be to melt them and mold it.

 

Home-molding of aluminum isn't that easy because of the oxide coating, and allso the oxide buildup when it's molten.

You need some kind of process to separate oxide from the molten aluminium.

making a re-usable form is quite a lot of work while making a one time form is pretty straight forward, can be made out of any material that can handle the temperature and is easy to break afterwards, like concrete or plaster.

 

I'm not entirely sure I understand what you want to do. Could you be more specific or add a sketch? Molding metal isn't terribly hard, providing you have the tools. Roller presses, fly presses, air hammers. The list is quite long and any good metal shop should have at least a few of these. When you get into molten metals, things get a bit more complicated. If you really want to do foundry work, stay away from aluminum. It's a head ache. Copper is a lot easier to work with.

Copper and aluminum are relatively easy to come by, there are quite a few online metal dealers around that sell both sheet stock and bar stock. Some one has posted one that looked really nice. IIRC it was called online metals, but I might be wrong there. Edit: I, in fact, was correct! Also see here.

 

Your best chance of getting this done quickly and easily is to steal a MechE student, they'll be familiar with everything you need to know to get this done correctly the first time. If you supply some sketches we could get you help you out quite bit though.

 

Just a thought . . . .

Why not forget the entire molding thing altogether and get a bunch of peltiers?

Put one of the hetsinks on the inside of the case with it attached to the cold side of the pelt, and the hot side outside the case with another hetsink on it. This way the air temp of the case will be cold due to the cold heatsinks and the hot heatsinks will naturally give off thier heat due to thermal convection. You could also have a 120 mm fan inside the case blowing the air around. This is also good since the case could be completely sealed and still have the level of cooling you need, just get a good heatsink for the processor, perferablly a heat-pipe setup, or use a small pelt on the cpu too, but have the other side on just a heatsink.

Note that with this type of a setup, ou would have to start the pelts and the fan before the computer to ensure that the air was cool to begin with, but it could be done. All the pelts would be on thier own P/S, or at least I would wire it that way!

Damn it, now I want to try this setup! Just had to add my 2 cents worth!

~SongCloud~

 

[Cough] Brown out! [/Cough]

 

I think your right with what you have said, but now, molding is not really a hard thou guys... you jsut need some molding machines to make the metal molding or aluminum molding less harder....




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Rapid Tooling

 

For a bunch of computer and electrical engineers you dont have the ability to do some decent research into the process via google. I am amazed considering the whole point of higher education is to build your research skills up.

moulding can be too things, either hard forming such as forging, or using a foundry to turn the material into a pourable form to then cast into a mold.

A cast part has no internal stress points like a manchined part would, however a forged part where the material is beaten into shape has the strongest mechanical properties.

For what you are doing, you are better off going to an aluminium supplier and sourcing the material you require, rather than trying to melt aluminium at home, as you would have to hit on average 650 degrees celsius depending on the alloy used.

Also that bunch of heatsinks could be various types of alloy, and you cant just tell by looking at them.

Basically you need a machine shop with some skills labour to help, especailly if you want a product that will work and gain you the marks you require to pass.


Also buying off the shelf parts and controlling them via automated software is a big enough project in its own right let alone making everything from scratch!

 

Aluminum intended for casting is typically high in silica to increase its fluidity. You can buy cast aluminum pellets to be turned molten. What you should do is get some high density foam (HDPE) and literally carve your desired shape out if it; Styrofoam is low density (LDPE) but will probably be sufficient for you. If you require enough precision that you're going to be using a ruler, make the mold about 10% larger than your desired part. Also your mold should have a conical sprue somewhere you wouldn't mind some finish machining (unseen), that should be at least a half inch at the base and closer to 1.5 inches at the top. Think of that part as a funnel.

You then bury your part in sand, making a ring-like mount around the sprue. Pour your aluminum "into" the sprue. The foam will melt away giving you an aluminum piece in the shape of the foam mold.

Your heatsinks were probably extruded and then cut to length (assuming they're the cheap comb style sinks), so they won't be made of high silica aluminum.

A little googling of lost foam casting should give you some more information.

 

Thanks guys! rvk2 will be happy to have a solution to his problem over 3 1/2 years later.....

 

I think we'll draw the curtains on this one...