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Warped Onyx Board V2

Posted: Fri Feb 16, 2018 12:44 pm
by dseebauer
Hi all,

I recently have had a lot of trouble getting consistent first layers on my V2 and tracked it down as best I could to a warped heated bed. I never really had great success with the printer despite the hours or trouble shooting, so this may have been the culprit all along. It just got much worse lately.

Below are a couple images of what was happening with the first layer no matter how many times I calibrated and accounted for the bed using Matter Control's leveling. I do not have a probe on my V2.

https://imgur.com/EWLxE2K

https://imgur.com/EbrShpj

And below is what I did about it given that you cannot buy the V2 beds anymore (though rumor has it they are on eBay). Hopefully my experience will help someone else get past it.

https://imgur.com/rZ4fXQL

I went old school and basically shimmed the glass. Since the glass bends to match the constrained bed, I decided to place a shim under each clip. To get the height correct (in my case this is 2 layers of index card stock with shuretape (.010" thick double sided tape we use for fixturing stuff) between the layers) I just added layers until the glass no longer spun freely on the bed (which is humped up in the center) as the friction of the shims at the perimeter held it stable. I suggest doing it heated up because the hump grows as it gets hot. Now with the clips in place the glass no longer deforms (as much) to the meet the bed.

I have had limited opportunities to fully test this out but it seems much better. Probably pretty obvious to most, but it took me a couple years to get this far. Maybe some others with these older machines will benefit.

If anyone has come up with a fix to reshape the bed without damage, I would love to hear about it.

Cheers!
Dave

Re: Warped Onyx Board V2

Posted: Sat Feb 24, 2018 12:27 am
by rollerm684
After studying the evolution of the Rostock Max evolution from V2 to V3 and the assembly guides for the Artemis, the problem with the heated beds on the V2 is the screws holding the Onyx board down. When the board heats up, it will want to expand in its longest dimension (radially). However, the screws around the perimeter are preventing the expansion, causing strain that bends the onyx PCB in the middle. In addition, the circuit traces on the onyx are not symmetric or radial, so there will be uneven warping. My V2 had warping in one radial direction, so the first layer always got really skinny/blocked the hotend when passing over the bed in that area of the bed. Loosening the screws could help, but then the glass gets lifted up and creates an air gap between the heated bed and the glass, which reduces the thermal performance of the bed. Shimming between the bed and the glass on your unit is basically the same thing.

I am in the process of upgrading my V2 (not to V3), and removing the screws altogether has improved the situation. However, now the bed is unsecured and it can move/tilt slightly, meaning the bed will need calibration all the time if I touch the printer. I am process of installing FSR's under the heated bed and a Duet so that I can do automatic calibration/compensation no matter what orientation the bed is. That isnt necessary, but I dont want to recalibrate so often.

Re: Warped Onyx Board V2

Posted: Mon Feb 26, 2018 3:48 am
by DeltaCon
I have a V2 with FSR and duet, and I can say that calibrating before each print is a must anyways. The constructional stiffness of a V2 is in my opinion not enough by far (at least mine is not) because of the melamine parts. That the onyx bends a little (or a lot in some cases) is a fact, but in my opinion not enough for bending the boro glass. It does however lead to significant different calibration at different bed temperatures. There is more than a layerheight difference between calibration at 50 and 90 C temp in my case.

After 2 years of fighting a (not built by myself) V2 and multiple updates I find myself asking if it was worthwhile. Stories about the Artemis keep me interested in Delta, but I am unsure if I am gonna follow that path again. I would like to rebuild my V2 with an all-metal frame though.

Re: Warped Onyx Board V2

Posted: Mon Feb 26, 2018 9:04 am
by geneb
You might look into an Artemis then. Very wide tower extrusions, ball-bearing linear rails, folded steel top & bottom chassis, and thick, glass-fillled nylon frame links at the top & bottom. The top, bottom, and towers are pre-assembled. You've got 12 bolts to install and some wires to connect and you're done. It weighs somewhere in the neighborhood of 55lbs +. (the shipping weight for mine was 62lbs and there was no filament in there)

g.