High temperature protyping material 1

[asimpson]

I am looking for a machinable (conventional drilling , turning , milling) material for high temperature support structure custom electrical heater.

Must be electrically insulating.

Temperature: 1500C (2700F) in air

Dosnt have to be too strong . Similar strength to balsa wood.

I am considering ceramic foam:

http://www.m-r-c.co.il/media/Uploads/311SPEC(1).pdf

I would consider also moulding or modeling clay or high temperature cement. I tried this with Omegabond 400 but it is really not up to temperature I require.

I also tried Macor machinable ceramic . Difficult to machine and limited to lower temperatures.

Any ideas welcome.

Many thanks

 

[MikeHalloran]

McMaster-Carr carries six types of machinable ceramics but only one is rated for above 2000F.

The trick is to use very simple geometry, be careful tightening screws, and make multiple sets of spares for when you're learning about the screws.




Mike Halloran
Pembroke Pines, FL, USA

 

[asimpson]

Thanks Mike.

I'm outside USA and McMaster isn't to supply to us any more. Know any other suppliers?

 

[Medeski]

I can't remember what the name for them is, but there are mounts made for holding a printed circuit board when it's in the "pick and place" machine. The PCBs are then conveyed on the same mounts into a reflow oven. They were made from a black plastic(?) material. I tried searching for them, but I'm not coming up with anything. I think that the company that made the solder paste stencils made those for us as well.

 

[MikeHalloran]

Try cotronics.com .


Mike Halloran
Pembroke Pines, FL, USA

 

[Ceramicguy]

I recommend you consider a refractory fiber board of the type used in high temperature furnaces and kilns. There are several manufacturers and products. I would look at websites for Rath Performance Fibers and Zircar Products for examples. A typical product would be SALI board. You can order from them directly or use their descriptions to locate a manufacturer/distributor local to you. If you need a stronger, less porous material, you can try a bisque fired aluminum oxide however, over time there may be some shrinkage and cracking. Like Mike says, keep the design simple!

Bruce

Bruce

http://accuratus.com

 

[moltenmetal]

Another vote for a ceramic fibre mill-board material. Thermal Ceramics and UniFrax both make many suitable products. But 1500 C is pretty hot- what on earth are you going to use as a heating element material?

 

[asimpson]

Kanthal APM is heating wire. Sandvik say it can do 1450c on a limited lifespan.

http://www.kanthal.com/products/mat...heating-wire-and-resistance-wire/kanthal-apm/

 

[btrueblood]

The foamed silica will probably be your best bet. Sintered/hot pressed hexagonal boron nitride would have been my other suggestion, but it will likely react with, or be wetted by, the Fe/Ni/Co of the wire. Alumina would work, but I'm not aware of a foamed version of it to allow it to be easily machined, and in full dense form has much higher thermal conductivity than the other two. Not that silica won't react and degrade the wire at those temperatures too, but hopefully not as fast. Do realize that a wire filament of Kanthal at that temperature is going to convert itself to smoke pretty rapidly, and that smoke will plate out as a conductive film somewhere in your assembly where temperatures are a bit cooler.