Pro/Forums - View Single Post - Designing heat die

|kbn| · 09-30-2004, 04:10 PM

Electrically I it will be insulated compleatly. The only path for current will be through the graphite - this could either be accross the length of the graphite, or from the bottom and through the base of the copper block. Would there be any problems with this? It could probably allow the die to be made smaller.

Btw the graphite bits are heated with very low voltage, 4v for the lower current models, and 2v for the higher current ones. Seems stange at first, but only so much power can come from 415v 3phase :E
The cross sectional area of the graphite is typically 50*70mm.
The current on the 4v model can be ~1000A while on the 2v model it can goto 6kA - sounds a lot but its only 12kW!

I have no idea the resistivity of the graphite (apart from the above, but thats not really accurate), Ill measure it later.

How do I find out how much power is converted into heat?
Im a bit confused how conductors make heat, I assume its volts dropped * current. So for that its got to be fairly resistive or its just going to create a short. Unfortunatly I think the resistance is quite low, less than 2ohm

I mostly need help working out what voltage and current for the heat I want (30 - 120w?

I was speaking to someone that knows more about it - its carbon mixed with some kind of cement. When it gets too hot, the cement vaporises and then the carbon can just crumble off.. - so I dont think electrically it gets damaged, only from overheating. Hopefully it wont get damaged very much. I will probably use a very thin peice of copper for heat spreading. I think using steel could affect the results and Id prefer to keep this simple, I doubt I will use it enough to damage the copper surface too much.

Id like the final die sim to be fairly accurate, but I doubt it will be to BillA standards. The problem is that theres no way to calibrate a die sims accuracy in transfering the correct amount of heat...

Also I will need advice of where to locate the thermocouples, but that can wait untill the heater is nearer finnished.

Another thing I need to consider is how do I get a perfect mount? I know there has been some testing with different mounting methods.. is it just a case of using much stiffer springs?

09-30-2004, 04:10 PM	#4
\|kbn\| Cooling Savant Join Date: Feb 2004 Location: W. Sussex, UK Posts: 329	Electrically I it will be insulated compleatly. The only path for current will be through the graphite - this could either be accross the length of the graphite, or from the bottom and through the base of the copper block. Would there be any problems with this? It could probably allow the die to be made smaller. Btw the graphite bits are heated with very low voltage, 4v for the lower current models, and 2v for the higher current ones. Seems stange at first, but only so much power can come from 415v 3phase :E The cross sectional area of the graphite is typically 5070mm. The current on the 4v model can be ~1000A while on the 2v model it can goto 6kA - sounds a lot but its only 12kW! I have no idea the resistivity of the graphite (apart from the above, but thats not really accurate), Ill measure it later. How do I find out how much power is converted into heat? Im a bit confused how conductors make heat, I assume its volts dropped current. So for that its got to be fairly resistive or its just going to create a short. Unfortunatly I think the resistance is quite low, less than 2ohm I mostly need help working out what voltage and current for the heat I want (30 - 120w? I was speaking to someone that knows more about it - its carbon mixed with some kind of cement. When it gets too hot, the cement vaporises and then the carbon can just crumble off.. - so I dont think electrically it gets damaged, only from overheating. Hopefully it wont get damaged very much. I will probably use a very thin peice of copper for heat spreading. I think using steel could affect the results and Id prefer to keep this simple, I doubt I will use it enough to damage the copper surface too much. Id like the final die sim to be fairly accurate, but I doubt it will be to BillA standards. The problem is that theres no way to calibrate a die sims accuracy in transfering the correct amount of heat... Also I will need advice of where to locate the thermocouples, but that can wait untill the heater is nearer finnished. Another thing I need to consider is how do I get a perfect mount? I know there has been some testing with different mounting methods.. is it just a case of using much stiffer springs? __________________ Waterblocks Last edited by \|kbn\|; 09-30-2004 at 04:20 PM.