Large heated bed (300x300mm)
Posted by konwiddak
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Re: Large heated bed (300x300mm) January 10, 2013 06:40PM |
You might also try to contact the trinitylabs guys. They are making a 300x300 printer, so maybe you can talk them into selling you a heated bed? 
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Re: Large heated bed (300x300mm) January 20, 2013 02:42AM |
I do have large kapton heaters in 290mm x 290mm size in 24V in two power sizes. One of them I already have in stock is 200W 24V and the real deal version that shos up monday according to fedex is 24V 400W sized.
We use these heaters with a 0.8mm thin aluminum heat spreader that we stick the kaptron heater to the bottom of then we put a 300mm x 300mm borosilicate glass plate on top of the heat spreader and clamp together the 3 layer sandwhich.
We learned early on *DO NOT STICK THE KAPTON HEATER DIRECTLY TO YOUR GLASS*. The current that flows through the heater element is strong enough and the coefficient of thermal expansion difference between the copper heating element in the kapton and the borosilicate plate is enough that when current flows the heater will actually cause the glass to go slightly concave and then back to flat as the current is turned off or lowers.
This caused very hard to diagnoze banding issues on prints for a while that appeared to be Z wobble but were in fact artifacts of the kapton heating element current getting turned on and off and flexing the glass enoughto show up in the prints.
The answer is to stick the kapton to a thin aluminum heat spreader and put the glass on top of that, this way of the current flows and tries to flex the aluminum, the glass will be unaffected since it is not directly stuck to the kapton heater element plane that is flexing.
Hard lesson learned that one.
Anyway I will put these heaters up in the store early next week when they are in stock and unlike other places that sell these kapton heater elements I do not try to rape folks on the price. The 290mm x 290mm 24V 200W version is $30 and the 290mm x 290mm 24v 400W version is $35.
We also have the best prices on borosilicate print surfaces in the most sizes as well. 300mm x 300mm 3mm thick with ground edges are $30 and 320mm x 320mm 3mm thick with ground edges are $32.50
I won't link to my store in this forum out of respect but my email address is ez@trinitylabs.com if you have any questions and I am sure you can find the store if you look hard enough at my email address
Another little piece of advice here though. We ordered the 290 x 290 200W kapton heaters for our 300 x 300 print bed and they are not powerfull enough for ABS, they can only get the bed up to about 82C with a 24v 17amp 400W PSU.
So the Aluminatus printer is shipping with *2* PSU's. One of them is a 24V 400W 17amp PSU that only gets used for the 400W heat bed and the other is a 24V 250W 10AMP PSU that runs the steppers and all other electronics. So trying to get a 300 x 300 heated bed crosses some limits in power and size that will make you think hard about how to power the heated bed and still power the resat of your system.
24V PSU.larger then 400W 17amp seem to skyrocket in cost from well under $40 to well above $200-$300 and more. So you may end up with 2 PSU's if you want ot have a fast high performance 300 x 300 heated bed. With the 400W heater and a 24V 400W PSU all dedicated to it we can get this 300 x 300 bed up to temp in 2 minutes or so to 110C easily and with the 200W version I had a hard time getting above 85C or so.
Just my 2cents after messing with large heated beds for a long time here.
Cheers-
-Ezra
We use these heaters with a 0.8mm thin aluminum heat spreader that we stick the kaptron heater to the bottom of then we put a 300mm x 300mm borosilicate glass plate on top of the heat spreader and clamp together the 3 layer sandwhich.
We learned early on *DO NOT STICK THE KAPTON HEATER DIRECTLY TO YOUR GLASS*. The current that flows through the heater element is strong enough and the coefficient of thermal expansion difference between the copper heating element in the kapton and the borosilicate plate is enough that when current flows the heater will actually cause the glass to go slightly concave and then back to flat as the current is turned off or lowers.
This caused very hard to diagnoze banding issues on prints for a while that appeared to be Z wobble but were in fact artifacts of the kapton heating element current getting turned on and off and flexing the glass enoughto show up in the prints.
The answer is to stick the kapton to a thin aluminum heat spreader and put the glass on top of that, this way of the current flows and tries to flex the aluminum, the glass will be unaffected since it is not directly stuck to the kapton heater element plane that is flexing.
Hard lesson learned that one.
Anyway I will put these heaters up in the store early next week when they are in stock and unlike other places that sell these kapton heater elements I do not try to rape folks on the price. The 290mm x 290mm 24V 200W version is $30 and the 290mm x 290mm 24v 400W version is $35.
We also have the best prices on borosilicate print surfaces in the most sizes as well. 300mm x 300mm 3mm thick with ground edges are $30 and 320mm x 320mm 3mm thick with ground edges are $32.50
I won't link to my store in this forum out of respect but my email address is ez@trinitylabs.com if you have any questions and I am sure you can find the store if you look hard enough at my email address
Another little piece of advice here though. We ordered the 290 x 290 200W kapton heaters for our 300 x 300 print bed and they are not powerfull enough for ABS, they can only get the bed up to about 82C with a 24v 17amp 400W PSU.
So the Aluminatus printer is shipping with *2* PSU's. One of them is a 24V 400W 17amp PSU that only gets used for the 400W heat bed and the other is a 24V 250W 10AMP PSU that runs the steppers and all other electronics. So trying to get a 300 x 300 heated bed crosses some limits in power and size that will make you think hard about how to power the heated bed and still power the resat of your system.
24V PSU.larger then 400W 17amp seem to skyrocket in cost from well under $40 to well above $200-$300 and more. So you may end up with 2 PSU's if you want ot have a fast high performance 300 x 300 heated bed. With the 400W heater and a 24V 400W PSU all dedicated to it we can get this 300 x 300 bed up to temp in 2 minutes or so to 110C easily and with the 200W version I had a hard time getting above 85C or so.
Just my 2cents after messing with large heated beds for a long time here.
Cheers-
-Ezra
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Re: Large heated bed (300x300mm) January 20, 2013 05:15PM |
Thanks 
I have actually successfully built my stripboard based bed now. Only cost £10 for all the materials. It is able to sustain 70C which is more than enough for Pla, but if I wanted to use abs I would need to investigate a solution along the lines of what you guys have suggested
I have actually successfully built my stripboard based bed now. Only cost £10 for all the materials. It is able to sustain 70C which is more than enough for Pla, but if I wanted to use abs I would need to investigate a solution along the lines of what you guys have suggested
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