HE280 Bed leveling. Manual tips/tricks/tweaks?

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Harblar
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HE280 Bed leveling. Manual tips/tricks/tweaks?

Postby Harblar » Thu Apr 20, 2017 1:57 pm

Ok, so I'm pretty close to having this exactly where I want to be, but I'm still missing something. Let me explain exactly where I am at first, since maybe I'm just demanding to much perfection from printer. I'm not sure where the acceptable tolerances for everything are.

I've upgraded my V2 to the new carriages, ball arms, and he 280 hotend/accelerometer. I did multiple PID autotunes and then performed numerous G29 auto calibrations (heating bed to 100 and hotend to 250 and then turning both off before running the calibration.) I've then run the Delta Calibration and have gotten in the .09 -.1 range. I've then run another G29 Calibration cycle and I am managing to get a decent first layer though, after taking the calipers to it, I find that it's not perfect. Printing a single layer test ring @.3mm layer height results in a the layer being around .45mm-.5mm at the Y tower and from .1mm-.2mm at the opposite end (between the X and Z towers).

I've gone back over and tweaked all the physical settings I can think of. I adjusted all towers to be the exact same height (baseplate to top plate) +/- .5mm. I set all endstop screws to exactly the same height and verified that all the end stop switches were at the same distance from the top plate. I then verified that all carriages were at the exact same height after homing the towers. I checked and adjusted the height of the hot plate at each screw mounting point to be as close to the same height from the top of the base plate as I could. (average difference of .1mm or less across all points) I then checked the angles on all 3 towers and found all three to be within .4 degrees of square. (though a slight warp in the build glass may account for a bit of that deviation.)

Physically speaking, are all of these measurements within acceptable tolerances? I'm pretty sure at a layer height of .3mm I shouldn't be seeing a variance of more than +/- .05mm from one side to the other. What's left to do? A manual calibration? And if so, would I need to manually recalibrate every time I perform an auto calibration?

I've got some big prints I want to start in the next few weeks and want to make sure I have as dialed in as I can so I can ensure success, since I'll be busy elsewhere while my printer is running. I also won't have the time to perform a lengthy calibration process each day, either.

Anything I'm missing?

SoWa
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Re: HE280 Bed leveling. Manual tips/tricks/tweaks?

Postby SoWa » Fri Apr 28, 2017 12:51 am

I seem to have a similar problem. I've been doing the same print over the past three weeks. It's not the same g code, but the same orientation on the bed plate. I auto probe before each print, and all the parts have a similar pattern on the first layer. Great infill on one side, poor on the other.

Could this be a problem of the glass being flat? I imagine to get down to these tolerances the surfaces would have to be ground?

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Harblar
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Re: HE280 Bed leveling. Manual tips/tricks/tweaks?

Postby Harblar » Thu May 11, 2017 11:59 am

I've been busy with work the last few weeks and haven't had any time to work on my printer, but I can say this much:

No matter what I tried the bed always appears to be high (resulting in a thinner first layer) from the X tower to the Z tower. Layer height is near perfect at the Y tower. From reading on the forums, it seems as though this is a fairly common thing with the He280 hotend and the auto leveling, but I haven't seen much on how to actually fix it. I have not done a manual calibration to try to alleviate this yet, mostly because I always had trouble with the manual calibration, hence the upgrade to the He280 for the AUTOMATIC calibration. ugh...

I finally decided to swap the hotend back to my e3d V6, so I printed out the parts necessary to combine the e3dv6 and the accelerometer board. My hope was that it would be accurate enough to get things working nicely. It would seem that not only is there a variance in the bed leveling, there is also a problems in the horizontal radius calc. Not large, but enough so that the accelerometer board wouldn't fit in the printed holder properly. The mounting holes were also slightly off. I finally said screw it and ordered the tricklaser machined parts for the upgrade. I haven't installed them yet, but this should at least assure me that I have the all the mechanicals as 100% accurate as I am physically capable of. Combined with the autolevel, the delta wizard, and topped off with a manual calibration I'm hoping I can get this thing perfected.

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Harblar
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Re: HE280 Bed leveling. Manual tips/tricks/tweaks?

Postby Harblar » Sat May 13, 2017 6:23 pm

So, I've got the e3D V6 mounted up and working fairly easy (though getting the bowden tube seated properly is a real Bear. Near impossible to reach the push fit connector once the Accelerometer board is mounted). Had a hockey puck and jam ( first ever for me) screw me up once yesterday.

Anyway... I spent probably 15-20 hours since Thursday trying to calibrate successfully and it's been an unfettered nightmare! I tried everything from auto to manual and never had any reasonable success.

Yesterday I took the heat plate off and verified the tower angles to the Wood top plate underneath the heat bed. All were similar to what I had in my first post (measured against the glass), no more than .3 degrees off from 90 on any tower, but I loosened up the T-Nuts and managed to get all the towers to less than .1 degrees of error (to the best of my measuring ability/equipment) I then checked the width of the washers under the spider plate. 4 were right at 4mm and 2 were right at 3.87. I spread the 4mm ones across from each other and put the spider plate and heatbed back on. I then made sure that the heat bed height was exactly the same at all 6 screw mounting points (13 mm +/- .01mm). I then rechecked the angles on the tower. Still within .1 degrees. I then thoroughly cleaned the glass plate and clipped it to the bed opposite each tower. I then Remeasured the angles a final time and was still less than .1 degrees off. Super! Finally I got out a dial gauge level to check the for any tilt. After sticking some folded scraps of paper under a couple of the printers feet I got the bed completely perpendicular to the center of the earth (again, to the best of my ability/equipment). I am now 100% certain I have the mechanical structure of my printer dialed in as perfect as I possibly can shy of throwing several thousand dollars worth of high precision measuring tools at it. Imagine my annoyance when none of that seemed to work!

The Calibration script by Geneb, found here:
http://forum.seemecnc.com/viewtopic.php?f=112&t=10787 runs better and quicker after my mechanical tweaking, but was now leaving a thin spot between the Y and Z towers and almost completely free floating between the X and Z towers. Manually calibrating and then running the Matter control Software calibration wizard didn't help anything (I think the software cal is broken since the 13 point pattern only tested 4! :roll: ) It was at this point I was seriously tempted to perform a Remington 12 Gauge single point Calibration. Instead I went in and started drinking beer!

Today was a different story. This morning I decided to run a cold calibration. I ran the gcode script through twice on a cold bed and hotend and then plugged all the data into the website delta calibration wizard. It took my variation down from .26 to .04! I heated things up and ran my test print and was stunned when things went much much better than they had at any point in the last two days! Still pretty thin in the YZ area along the outer edge, but noticeably better the rest of the way around! On a lark, I left things heated and then ran the calibration gcode script again. I made a couple of minor tweaks to the slicer settings (bumped the first layer height from .25 to.3 and ran the first layer extrusion to 105%) and this time the print was almost there! After checking things with my calipers I can say my first layer is now between .2mm and .35mm. I'm ready to accept that I have the extruder movement flat and am just dealing with some bed warping due to heating it to 90 degrees.

So, All that being said, would it be worth doing an additional firmware calibration to account for bed warping or would I be reopening the gates of hell in doing so? My take is that even though the first layer height varies across the print surface the top of the first layer is (or should be very close to ) level and therefore all subsequent layers will be perfectly even. Is that right? Please tell me I just about got this. I really want to start working on extruder/slicer configurations and test prints so I can get on with printing actual stuff!!! :mrgreen:


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