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That's pretty cool KAS. I see a much smoother image on the final video. The hotspot seems like its a few degrees cooler compared to the others.

How thick is the heat spreader? I have a .0625" one on my printer and it works quite well. Big improvement from none.

Looks like the same as yours JFettig. On my calipers it's measuring 1.60mm or 0.0625"



More official looking results

[img]http://s1.postimg.org/6r2im40in/Onyx_PC ... _Bed_1.png[/img]


[img]http://s27.postimg.org/ub4o5bwxf/Trick_ ... ader_1.png[/img]

Just playing with set ranges. I'm noticing that my bed always heats from between Z and Y towers. I'm curious if I pre-heat the lower left with a blow dryer if that side would come to temp first.


100c on a stock power supply with no glass or heat spread was interesting to watch. The thermistor in the middle was always lagging way behind untill it hit 100c, then it was the last to cool causing somewhat drastic temp swings across the bed.


Onyx Heated bed set at 50c range 46-53
[youtube]http://www.youtube.com/watch?v=hoYtL42loB8[/youtube]


Onyx Heated bed set at 60c range 53-63
[youtube]http://www.youtube.com/watch?v=OqUJiApaQBw[/youtube]

Onyx Heated bed set at 80c range 70-94
[youtube]http://www.youtube.com/watch?v=KklWnPXDMAo[/youtube]


Onyx Heated bed set at 100c range 95-110
[youtube]http://www.youtube.com/watch?v=vLzX8OnO_5c[/youtube]

MeanWell SP-750-24, (24v 750W)
10 Gauge Silicone Wire, pure copper 1000 stranded.
Trick Laser aluminium heat spreader.

Heated from room temperature to 100c reported via the Onyx bed thermistor. Achieved 100c in 3:35 minutes, then turned off for the remaining video.


[youtube]http://www.youtube.com/watch?v=gOQZ5vs8P5I[/youtube]

KAS wrote:MeanWell SP-750-24, (24v 750W)
10 Gauge Silicone Wire, pure copper 1000 stranded.
Trick Laser aluminium heat spreader.

Heated from room temperature to 100c reported via the Onyx bed thermistor. Achieved 100c in 3:35 minutes, then turned off for the remaining video.


[youtube]http://www.youtube.com/watch?v=gOQZ5vs8P5I[/youtube]

WOW! that is wicked fast. I like it.!!


Solid state relay setup or running through Rambo board?

What is the warm line under the bed?

It's a Crydom SSR with a DC/DC converter running the smoothieboard and everything else @ 12v.


As for the warm line, I'm not sure which part you're talking about. The small line under the bed at 0:37 looks like the 24v wire connection to the Onyx; possibly acting as a heatsink. The Orange rectangle floating in the middle of the base at the same time-frame is the SSR mounted on top of the power supply.

I would be very interested in a thermal video of the bed with heat spreader heating to 100 C.

bot wrote:I would be very interested in a thermal video of the bed with heat spreader heating to 100 C.

You want just the aluminium heat spreader without glass to 100c? Right now my temps are off @ the surface because of thermistor placement, but I can crank the heat to 120c and that should be enough for the surface to hit 100.

No, I'm an idiot and I hadn't noticed that you already did the test with the heat spreader. Thanks, though! I mean, I just noticed the photos, but a video would be cool.

No worries, I'm going to do it again with the 24v supply anyways. I really want to figure out how to offset the actual temp at the surface, but it looks like I might have to move the thermistor up higher in the layers to make it work.

Let me know how that goes. I've been designing a delta machine, and a lot of it is based off some of the experiments you've been doing. So thank you, you're very inspiring. Speaking of layers:
From the top down: Aluminum retaining ring, PEI, Octagonal mirror ($10 at michaels), aluminum heat spreader, Onyx Heat bed, two pieces of cork, and an acrylic (red) base. Second retaining ring underneath that also mounts to the onyx bed. Does that seem like a good heat bed sandwich? Where would you put the thermistor?

Wow that looks great. What I'm seeing is a Onyx mounted thermistor reading of 100c followed by the aluminium heat spreader & borosilicate glass showing 20c cooler at the surface. I believe the temp reading at the thermal conductor in the middle would be optimal. although that should in theory increase the actual temp of the Onyx and I'm not sure what the rated range it was designed for. Right now, if I want a true 100c top surface I have to heat to around 120c.

I like the idea of the cork at the bottom of your layers. Is that to insulate the heat from the acrylic or give fine adjustments to leveling the surface?

Interesting - I didn't know the discrepancy was so big. I run "100" to "110" so I'm guessing I don't even come close to 100 at the surface on my rostock.

Yeah, the cork is to protect the acrylic from temps. No fine adjustments in the bed other than equally torquing the retaining ring. Now that you mention it, I guess that would give me some flexibility to do micro adjustments, by compressing the cork more or less. Hmmm... my original thoughts were that the acrylic will be the fairly rigid and flat surface (.250"), the cork would simply protect it from heat (and help the bed heat up faster), the onyx will be mounted rigidly to the bottom retaining ring independent of the top retaining ring. The top retaining ring is just to hold the PEI flat against the mirror, because I don't like gluing the PEI down and the sheets come with a bow to them.

I finally took the time to get the heat spreaders finished and up on web site.
http://www.tricklaser.com/Heat-Spreader ... R-ONYX.htm\n

bvandiepenbos wrote:I finally took the time to get the heat spreaders finished and up on web site.
http://www.tricklaser.com/Heat-Spreader ... R-ONYX.htm

I guess it's no surprise I've been running this for a few months and it absolutely works wonderfully. Well worth the cost and out performs the carbon fiber wafer I was using before.

Thanks again for the opportunity!