7760Re: PCB as heated build bed
- Dec 6, 2012On 06/12/2012 16:11, email@example.com wrote:
> Hi GrahamNo, Graham is completely right.
> The Peltier device is not a pump, it is a Low voltage solid state heater or
> a cooler simply by changing the polarity. The Copper, Brass or aluminium
> build platform is the attached heat sink.
> The 12VDC supply is switched on or off by open circuiting the yellow and
> grey leads on the computer power supply via the relay on the temperature
> controller. All at low voltage except for the mains powered temperature
> controller that is designed for purpose.
> Simples !
The Peltier device is a thermoelectic heat pump. Used as a heater, you
need a heatsink to harvest heat as he says. It is not as bad used as a
heater, as when used as a cooler. For the latter, you need a heatsink to
dissipate both the heat being pumped, and the heat generated by the unit
itself. Going the other way as a heater, quite a bit of the heat comes
from the inefficiency of the device itself.
> On 5 December 2012 21:05, Graham Stabler<grezmos@...> wrote:
>> Don't forget that you also need a big heat sink to efficiently harvest
>> heat from the surroundings as it is just a pump.
>> A 250w cartridge heater is 2 quid on eBay and a good alternative to the
>> slightly costly silicone pads.
>> These could be used with the same controller but it might be wise to go
>> with a totally low voltage system unless you know what you are doing.
>> To return to the original poster, a number of people have just used some
>> nichrome wire and taped it to the underside of the bed with kapton tape,
>> I've even seen a few people use power resistors screwed underneath.
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