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Voron 0.1 LGX Lite Y Axis Offset


BrandonManz
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I recently decided to upgrade my V0.1 extruder to the LGX Lite, but I've run into a strange issue.
I purchased the Bondtech mini after upgrade kit (https://www.bondtech.se/product/mini-after-lgx-lite-upgrade-kit-for-voron-v0/), but upon installation, I noticed that the hotend (Phaetus Dragon HF) positioning leaves the nozzle approx. 6mm further back than the original mini afterburner. Whenever I home the y axis, the nozzle sits behind the bed, and the nozzle cannot reach the front of the bed.
I've tried to think of/find solutions for the issue, but all I can think of is changing the bed mounting system. Is this a common issue to have with the lgx lite and/or am I missing something? 

67891413209__8FA81666-6CA9-4A14-B115-4E4D0EC7B36F.jpeg

67891474647__EC64180B-8AC2-460D-9F96-10BCC548DEA3.jpeg

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Since the V0 homes to the maximum position you can simply increase the y maximum offset in the printer.cfg. So let's say the current maximum is 123mm then make it roughly 129mm and then the nozzle will be able to reach the front of the bed. Sorry out in the car at the moment so can't remember the exact parameter, but it relates to the y maximum position. 

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The settings you want to adjust are the position_endstop and position_max in the section covering your y stepper (e.g. [stepper_y]). Basically, increase those values by your additional 6mm and you'll have readjusted the (y) zero point back to the front of the bed.

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@smirkOkay, so I've already tried making adjustments to the position_enstop and position_max settings, however, the problem seems to be that the gantry moves to the end of the y axis rails before the nozzle reaches the front of the bed. Also, when the printhead comes all the way forward, it is just about flush with the front of the printer. 

Pic for reference (excuse the wires lol):

image.thumb.jpeg.3f34e4c307ec33d8b8fcdafbc1e4370e.jpeg

Edited by BrandonManz
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The picture is useful, worth a thousand words s they say 🙂. I'm as stumped as you as. The hotend might be large enough to poke out the front of the printer,but it shouldn't be the limiting factor in the travel along the y-axis, that should be the the carriages on the rails themselves hitting the physical rail stops. In that 3rd picture the x gantry looks all the way up to the (red) y-axis end-stops. The only time I had an issue with the x-gantry not travelling the full length of the y-axis (basically stopping a few mm early) was, as it turned out, I'd somehow managed to get a loose screw drop into the top slot of the extrusion holding the y-axis rails. It was just enough to stop the gantry moving to completely to the front of the bed. It was a black screw in a black extrusion, took me ages to see it but as I say by the look of you picture the gantry has travelled the full length of the y-rail and hit the (red) rail-blocker thingy.

I presume the new print head works in all other respects (i.e. prints, just not to the full scope of the bed)? When I'm back home, I'll look at my v0.1 and you picture see if that helps me trying to visualise the issue. I don't think the stock voron bed is very adjustable in the y-direction. The kirigami  bed I've got is the Mk3 (?) which has got slots instead of mounting holes so apparently you can adjust the bed physically in the y-direction. I'll check and see if that feature was in response to a specific issue (e.g. the LGX Lite Hotend really needs some physical bed adjustment)?! Sorry, I'm clutching at straws there.

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I am as stumped as @smirk as I have the LGX lite mod on my Voron 0 and have not experienced any such issues. Is the hotted fitted in the correct orientation? As a trial I flipped my hotted and there is a 5mm difference in the position of the nozzle relative to Y. Just a thought.

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Make sure it's a version-3 Kirigami bed as that's the ones with the slots,which apparently are there to help with sherpa mini hotends (which I presume means they must displace things too much).

How does the x-carriage mount from  the Bondtech kit compare with your former stock x-carriage mount (and motor-frame), in terms of dimensions? How do the hot-end cowls compare? The 6mm just strikes me as to significant to be accounted for by natural variations in printing/mounting so it's either got to be something mechanical (your rails have slipped out of alignment - absolutely daft, as I can't actually think of a credible example/reason) or Bondtech have sent you the wrong mounting kit (!?!, "Sorry sir, we sent you the extra fat one"). Both options I'd say are daft/straw-clutching but clearly there is something as there's a large 6mm discrepancy.

Personally, I'd probably strip it all back and start a step by step comparison with the stock head (and Phaetus hot-end). Build them up slowly until I got a clue as to which bit was knocking it out of whack. I know that's not as neat or easy as it sounds in my head (and I'm not explaining it well) as the hotend is an integrated affair but at least I could see if the x-carriage mount was sticking too far forward, and then perhaps dry fit the cowling (without the phaetus) and see if the mounting holes (for the phaetus) are too far forward. Again, sorry, if you've already tried all of that, but I guess on the positive that'll give you a good idea which part/area needs to be modded to move things into alignment.

One thing, niggling at the back of my head (related to the size, 6mm) if you manage to move the nozzle, forward enough to reach to front of the bed then won't it be  right on the edge at the back (reducing wiggle room) which then might cause a challenge for homing, as the nozzle might be homing right over the bed?

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I'm in the middle of putting in an LGX Lite myself but I had to redesign the carriage for a mgn9 and work got crazy so it's stull just a pile of parts.  I think you have too many spacers on yours, maybe try removing the bondtech back plate, the printed part should replace that, and also that grey spacer between the motor and the carriage.  That should help with straightening up in the vertical direction as it looks a bit angled in the pics.

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On 7/9/2022 at 9:49 AM, BrandonManz said:

unfortunately, the hotend is already oriented to have the nozzle on the front end. I've considered getting a kirigami bed for another 3mm or so of wiggle room. I might also consider modding the x carriage mount to have the hotend mounted further forward. 

@BrandonManz Went through my LGX mini install and remembered I printed off the new mounts for the bed as well. Did you use the original Voron repository mounts or those in the file from the Olof LGX mini mod?

It is under the heading: 

 

 

at:

https://www.bondtech.se/2021/12/27/voron-v0-1-toolhead-setup-for-lgx-lite/#tab_z-axis-bed-adjustable-y-offset

 

 

  • Z-axis Bed Adjustable Y offset set – to allow the print bed to move back and forth from -1 up to +3.5 mm.

 

Edited by mvdveer
Spelling, added clarification
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