Nichrome turns
Posted by Grogyan
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Nichrome turns May 18, 2010 11:14PM |
Registered: 14 years ago Posts: 458 |
I'm working on making better thermal conductivity while insuring the barrel is insulated.
Why does the nichrome have to be 6ohms?
Is there any reason why not to just have 1 set of turns the length of the exposed barrel?
I'll be having 1 more go tonight wrapping the nichrome with kapton, to see if no fumes are created, which I mentioned in a previous post, is currently a big problem.
Cheers
Why does the nichrome have to be 6ohms?
Is there any reason why not to just have 1 set of turns the length of the exposed barrel?
I'll be having 1 more go tonight wrapping the nichrome with kapton, to see if no fumes are created, which I mentioned in a previous post, is currently a big problem.
Cheers
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Re: Nichrome turns May 19, 2010 04:01AM |
Admin Registered: 17 years ago Posts: 7,879 |
You need between 6 and 8 Ohms you get about the right power when running from 12V. Depending on the nichrome diameter it can be one set of turns. You can use less and reduce the power with PWM as long as your drive can handle the extra current.
If you use less turns and don't limit the power then you need good thermal conduction to stop the nichrome getting too hot for the insulation.
[www.hydraraptor.blogspot.com]
If you use less turns and don't limit the power then you need good thermal conduction to stop the nichrome getting too hot for the insulation.
[www.hydraraptor.blogspot.com]
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Re: Nichrome turns May 20, 2010 06:05PM |
Registered: 14 years ago Posts: 43 |
6ohms is the number for 12V. If you have a different voltage supply, you can work out the resistance you need by the following. V is your supply voltage, R is your nichrome resistance.
R = (V^2)/(24), where 24W is 12^2/6 from the reference design.
When you buy nichrome, it should have a resistance/foot, so you can work out how long a length and consequently how many turns you need.
R = (V^2)/(24), where 24W is 12^2/6 from the reference design.
When you buy nichrome, it should have a resistance/foot, so you can work out how long a length and consequently how many turns you need.
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Re: Nichrome turns May 21, 2010 07:16PM |
Registered: 14 years ago Posts: 458 |
Cheers, however NopHead is right, from what I observe with the new windings is the Shoot through current heating up the wire beyond temp to induce a "faster" thermal inertia in the barrel and nozzle.
The new nozzle I have made up is 0.4mm, with a stepper motor from MakerBot driving the filament into the barrel.
I think that 0.4mm is the upper limit of what can be extruded with using PLA, the flow rate is quite slow.
Though I still think that a single set of turns will just fine too, but not prepared to dismantle the wrappings again just yet.
It still gives off fumes with using this new method I have done, gives better thermal conductivity, and the thermocouple gives a better reading, though doesn't go above 200 degrees anymore. It gives of far less fumes, but fumes are still present.
100 degrees seems to be a right temp for extruding at this point.
The new nozzle I have made up is 0.4mm, with a stepper motor from MakerBot driving the filament into the barrel.
I think that 0.4mm is the upper limit of what can be extruded with using PLA, the flow rate is quite slow.
Though I still think that a single set of turns will just fine too, but not prepared to dismantle the wrappings again just yet.
It still gives off fumes with using this new method I have done, gives better thermal conductivity, and the thermocouple gives a better reading, though doesn't go above 200 degrees anymore. It gives of far less fumes, but fumes are still present.
100 degrees seems to be a right temp for extruding at this point.
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Re: Nichrome turns May 21, 2010 08:04PM |
Admin Registered: 17 years ago Posts: 7,879 |
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Re: Nichrome turns May 21, 2010 08:09PM |
Registered: 14 years ago Posts: 458 |
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