New Delta Design

[Khalid Khattak]

What firmware you are planning to use with which hardware (controller)..

[JFettig]

Thanks for the link but my rev3 onyx on 24v takes 3-4 minutes to get up to 80c.

I'm running standard smoothie firmware

[JFettig]

Somewhere along the line I overlooked something because when the heated bed heats up, it moves like crazy! It seems that if I let it stabilize for about 20 minutes, it'll be repeatable, but if I give it the normal 5-7min 90C heat up, Z height is variable. I tested the home switches and they seem to be accurate to .0005".

Other action items on my end are - calibrate x-y size with diagonal rod length, it actually is printing large right now.

I'm running a .8mm Volcano nozzle right now - I haven't been able to get very good results with this yet, especially when I try to print thick layers(more than .35mm) I'm tempted to swap in the .4mm nozzle I got for the Volcano to see if that helps at all.

[KAS]

I get the exact same issue on the v2 when heating the Onyx with the 24v supply. With a dial indicator I'm seeing about .005" vertical movement then it slowly lowers to zero after about 15min. It's worse with the aluminium heat spreader so I assumed it had something to do with thermal expansion. Or maybe a combination of the melamine star, PCB, Heat spreader, Glass, PEI.

Kind of negates having fast heating times...

[JFettig]

Just put my indicator on and turned it up, bed went up about .006, held until it hit 90C, then rapidly went down to -.006 and its hovering +/-.001 of the -.006" mark, seems to be holding -.007". I'll shut down and repeat. I didn't get the indicator positioned until it hit 40C so it I imagine results will change just a little bit.

EDIT - all of this data was improperly taken, see future post.

[bot]

Even at 12v, my onyx doesn't take long to heat up. I'm gonna get a dial indicator tonight or soon and see what it's like with 12v. Are you guys running the rev3 at 24v? Maybe that specific design had this flaw?

[JFettig]

so when mine came back to room temp the indicator was .018" off where I started, and the base wasn't super tight. I"m going to run this test again but I had to go machine something so I had to steal my indicator back. I'll report back tomorrow.

Yes I have the rev3 Onyx

I stuck a not very good .0001" indicator on there while my mill was running, simply powering it on and off caused the bed to raise and lower more than a couple thou! I could power on, power off within seconds and it would go back and forth!

[KAS]

Mine is the newest (I think) Rev 7. I had decent repeatability by measuring the distance at various times vs leaving it on the bed 100% of the time. I was wondering if the shaft of the indicator was expanding causing the exaggerated values.

[bot]

They unintentionally made a PCB muscle! This is kind of neat. Like a reverse strain gauge. I'm hoping to get a dial indicator soon, but I don't have a car and the store is far away.

[JFettig]

They unintentionally made a PCB muscle! This is kind of neat. Like a reverse strain gauge. I'm hoping to get a dial indicator soon, but I don't have a car and the store is far away.

From what I remember of the thermal images kas took, it heated up from center out, it would make sense based on thermal expansion for it to do this.

[bot]

I'm noticing the same phenomenon on my machine with an onyx rev 7. I don't have an indicator yet, but printing a .1mm first layer I can see the layer get thicker and thinner directly correlated with the bed heater being on and off. It's still printing the .1mm layer well, though, so it doesn't seem to be a big deal. likely less than .05mm difference. I'll try and adjust the PID to make the oscillation lower in amplitude, higher in frequency.

[KAS]

.006" = .1524mm. That might be the reason I get that drastic variation when printing .15-.20 on a .4 nozzle.

I've learned to just run a simple first layer test before printing anything important. Once the temps have equalized, everything seems fine and I can just start a print and walk away with confidence.


On a side note, hows that new printer design working for you? Have you posted a full machine pic somewhere?

[JFettig]

Other than this and the calibrations I need to complete, its working quite well! The printer is much more solid, my accelerations are at 7000mm/s/s where a rostock runs less than 2000 IIRC for printing. It will corner much faster - I need to determine if this causes any adverse effects once I get it calibrated properly.

Just took a ~15 min video of it heating up - its like watching paint dry but it probably got up to +.026" and stabilized around .0085+/-.001 for a while, now its holding about +.007". After 1/2 hour its about +.004" Another 25 minutes and we're back to zero.
I'll post up the video when its uploaded - not too exciting except to see how it flexes while heating up, at 90C it shuts off the heater, it climbs to 95C and falls slightly but as soon as it hits 95C it falls faster, when it hits 89 it starts climbing, holds 88 for a little bit, crosses over 90 and falls back down, once the temperature stabilizes it holds steady pretty close.

A couple pics:
[img]http://i.imgur.com/dUzZbtq.jpg[/img]
[img]http://i.imgur.com/70GN0W3.jpg[/img]

[JFettig]

[youtube]http://www.youtube.com/watch?v=lbpigGw9baI[/youtube]

its long, but you get the idea. You can probably skip forward to the point its around +.025 to see where it drops and oscillates with power applied by PID.

[KAS]

After this print, I'll let everything cool down to room temp and perform the same test.
I believe we have the same layer setup except for your larger melamine sheet under the Onyx. My cheap indicator is only .001 resolution, but should be noticeable on camera.

Do you think your glass is warping or just being lifted? Curious if having more clips around the bed would help.

[JFettig]

Keep in mind, the one in the collet holder is a .0001" indicator and the one in the base is .0005"

I clicked preheat on octoprint, turned around and started the video and they were both off zero already.

[youtube]http://www.youtube.com/watch?v=Jyan7uc3Ww4[/youtube]

[JFettig]

I gave up on the .8mm nozzle for printing actual parts. I could not get it to print very nice. Anytime I tried to crank up the speed I had all sorts of issues I could not figure out. I threw in my .4mm Volcano nozzle and have been printing with that ever since.

Print currently in progress:
[img]http://i.imgur.com/JvKqIHb.jpg[/img]

As you can see - temporary breeze shields are in place

[JFettig]

Just started my first print with a RADDS+DUE board running Repetier .91 and DRV8825 drivers. I wish I would have never messed with the smoothieboard. I never got that thing printing very well, it was a pain to configure and use that config file, and the modified config, all the m-codes to do everything. I'm back to running Repetier server on my Banana Pro, I'll see how it goes! Hot end and heated bed all calibrated. no more bouncing bed due to the poorly tuned PID, its dialed in such that it takes ~30 seconds to settle after a 3-4 minute warm up to 90C.

So far layers are stacking up nicely and laying down nicely. I was getting symptoms of loose belts and all kinds of other things bugging me. Now its all running quite nice. DRV8825's on 32 microsteps make very little noise! I have some RAPS128 drivers coming, 128 microsteps are supposed to make it dead quiet - now to quiet down my power supply fan and I'll be happy!

[stonewater]

I am looking to build a second delta and was thinking about this combo for the controller since I have a due laying around somewhere here. are you happy with the drivers?

Tom C

[JFettig]

The drv8825 drives seem to be doing well. I should have some raps128 drives in the mailbox right now. I'll report back once they are installed, might be a few days

Looks like USPS dropped the ball, they're scheduled to be delivered today but are still in Utah

[JFettig]

I've swapped in the 3 RAPS128 drivers for X Y and Z, they sound awesome - way more industrial sounding than a high pitch squeely motor like A4988 and especially DRV8825's. They are very quiet. I also read about DRV8825's on 24v so I decided to swap out the extruder driver for a A4988. Other than adjusting my step offsets on the towers home position it was printing right away - I forgot I had to multiply it by 4 for the 128 micro steps vs 32. I'm printing with a fat nozzle right now so I can't really comment on print quality. Outside perimeters look really nice. I also have to tune retractions for the massive nozzle(.8mm)

[Jimustanguitar]

They're not high current industrial monsters, but the Silent Step Sticks that filastruder imports are pretty amazing.

I'll admit that I hooked one up and then spent a few minutes troubleshooting why my stepper wasn't moving... Well, it's silent as advertised.

My buddy put them on the XY axes of his PrusaI3, and the aquarium pump that he has cooling his print makes more noise than his steppers.

[JFettig]

Once I do something about my super loud power supply fan, I'll have a better idea how loud they really are. It seems that the only motor I can hear is my extruder motor while printing.

I need to look at my firmware, I think my rapid travels are limited by something at the moment, it doesn't appear to be going nearly as fast. I can run this printer at 500mm/s rapid speeds(4000mm/s/s accelerations) just fine but it seems like its only doing about 200-300mm/s

I've been going back and forth between Rep .91 and .92, .92 gives me a warning to turn up some step rates, .91 doesn't but I haven't gotten .92 to actually print - get a lot heater decoupled warnings. I'll have to figure out how to set up all these additional features.

[JFettig]

I did some calculations and realized that I'm maxing out around 100mm/s right now, I'm gonna have to change my microstepping to allow higher speeds. Looks like I can only get around 80,000hz out of this, reprap.org says 96khz, repetier .92 recommended 80khz. To get 500mm/s it looks like the best I can do is 32 micro steps.

[Eaglezsoar]

I have been a reader of this thread and just wanted to thank you for posting the great images and
you have done a spectacular job!