I hear mixed opinions about these:
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[www.soliforum.com]


VS


I just need my whole bed area to be hot enough for ABS to stick to it, even close to the edges.
Some say PCB beds provides even heat distribution and parts don't lift/warp on the edges and say silicone pads do not provide even heating and have high fail ratio,
Then others saying the complete opposite that PCB beds have 10-15C temperature variation from middle to edges and silicone pads below an aluminum bed are better as the aluminum allows the temperature to become more even unlike say glass on top of PCB.

So who's right?
Or just share your stories. What's the biggest you've printed with your heater of choice with no warping / lifting.

If you want to improve the evenness of the heat from a PCB bed heater, put an aluminium heat spreader plate on top of it, and the glass bed on top of that. This is the standard arrangement on the Ormerod.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

I use a much smaller PCB heater for (12x12) with aluminum heat spreader on a 16inch round glass plate. Its the only way I can heat up the glass plate semi evenly. However with that said the heat is not even really. I would say 20c difference is about norm on my non heated chamber. I suspect it will be less on a non heated chamber. I cant recommend thermal paste enough though, it should help the heated bed live longer and help the glass heat up sooner, it will reduce heat spots as well.

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My Personal Blog. Build blog.
[engineerd3d.ddns.net]

Modicum V1 sold on e-bay user jaguarking11

I have just been through all the options for heated beds including building my own from scratch, so here are some thoughts for you.

I use Marlin firmware and RAMPS electronics mostly. Different boards have different capabilities regarding heated beds. DUET for example has a pin to drive an electronic relay so you can power a bed from a separate power supply. RAMPS is limited to 9 or 11amps for the bed (can't remember which) while Sanguilino will slurp what it can get.

1) Even for the standard store bought pcb or orther heatbeds the quality of your PSU matters. I use the LED lighting integrated 12V PSUs because it's simple. I went from maximum temperatures of about 90c to 120c just by getting a better PSU (from ooznest fyi).
2) PCB ones are lighter BUT don't seem to get as hot at the edges. That said, it's still my preferred choice at the moment because it is light.
3) Ali versions weigh significantly more, but are stiffer and get warmer at the edges. Be careful with the different versions btw, more on this later.
4) Silicone pads. Always seem to have a bloody big lump on one side where the thermistor and other connectors are. They're also not rigid so you need to mount them and then have extra scaffolding which all means weight. Probably good if your bed doesn't work. I found it no better than the PCB versions, but I believe it can be driven with more ampage than the PCB/Ali heat beds.
5)Build your own. best bet if you really need a lot of heat, or want it quickly and don't mind running a second PSU and can deal with some extra electronics. I gave up on this route after a while simply because actually I don't need it.

Heat up times vary as well. My home made model would get to 150degrees in a few minutes while my PCB one takes about five minutes perhaps longer to reach 120. I do put a little reflective cushion on it to help it warm quicker.


The ali version of the heated beds don't have holes through the connectors. This is by design, don't try adding them. Also, read the instructions carefully on both the PCB and ali models as depending on what model you have, with two or three connectors, you have to wire it differently depending on whether you have 12 or 24 v. Failure to do it properly gives you half power at 12v. Very common mistake.

As for getting stuff to stick, I use 110c with a PCB heat bed under glass with kapton and slurry. The slurry can be surprisingly thin, you don't have to have mucky prints. Anyway, I don't get lift at all with ABS any more.

I've personally only used a kapton/polyimide heater. They seem to have only advantages except maybe for price/availability. They are light, thin, fast, reliable and come in many shapes.
I use mine under an aluminum, heatsink grease, glass sandwich, printing directly on glass. Directly glued to glass you may get problems with uneven heating, not sure.

/Andreas

Quote
jaguarking11
I use a much smaller PCB heater for (12x12) with aluminum heat spreader on a 16inch round glass plate. Its the only way I can heat up the glass plate semi evenly. However with that said the heat is not even really. I would say 20c difference is about norm on my non heated chamber.

Your heat spreader plate is probably too thin. A thicker heat spreader will spread the heat better, but take longer to heat up.

As a rough guide, a 120W heater (e.g. MK2 heated bed PCB, 1.2 ohms and normally driven from 12V) is enough to heat a bed 200mm square to ABS printing temperatures, but not very quickly. If you use a cheap ATX power supply, you may get less than 12V out of it and may struggle to reach ABS temperatures. If you use a LED power supply, you can increase the voltage above the usual 12V to get faster heating. Power increases with the square of voltage, so at 14V you get 36% more heating power - if your electronics board is capable of supplying the extra current (e.g. RAMPS has a 11A fuse on the heated bed circuit).

For larger beds, the required power increases approximately with the area (a bit less if you are prepared to wait longer). For very large beds, a mains-voltage heater controlled by a zero-crossing SSR is the best option.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

What is the normal way to attach a silicone heated bed to a metal heat spreader? I've been searching around and haven't came across any good answers yet :-/