Rat Rig Community [Unofficial]•3mo ago

V-Core 4 300 - Do I need to work on my gantry more?

V-Core 4 300, using Beacon. I've got the range down to 0.199, and my last run for Beacon measure gantry twist showed 25.5, no compensation needed. But, as of earlier this morning, I was still having issues with my squish being inconsistent. It will be fine at the front, then grinding into the print bed at the back. I am about to run another test after messing with it for some time today to see.

32 Replies

BagellordOP•3mo ago

Okay, it claims I have low gantry twist and do not need compensation

chicken•3mo ago

It does not look like you ran z-tilt before you ran the height map. The two front corners are not aligned. I suspect your bed is even flatter. Run home, z-tilt and then redo your heightmap

BagellordOP•3mo ago

My procedure is Home All, Z tilt, Home Z, then take a mesh Is that not correct? Also, that second image is has the rear of the printer on the left and the front of the printer on the right - basically a side view, not head on

chicken•3mo ago

that is the right procedure but its hard to tell from your pictures if you are rotating the images. Can you post a new picture that is not rotated?

BagellordOP•3mo ago

What angle is best for this? I am running a mesh right now

BagellordOP•3mo ago

Here's the most recent mesh

chicken•3mo ago

its within range of being good. The thought is 0.1% of the bedsize is considered fine, so for you that would be 0.3mm. You can probably clean up that back corner but raising the foot up a turn or two then re doing z-tilt. The frames on these printers are so big they twist slightly on uneven surfaces and that can translate into your heightmap. If its low (blue) turn the screw on the foot out a turn or two and remeasure. You should see a difference. Make sure the nut on the feet is right against the frame when you are dont otherwise you can have some shaking there in your later tests. You can also try looseing the frame and adjusting it like the instructions but the feet seemed to have worked fine for me.

BagellordOP•3mo ago

I had not thought about needing to adjust the feet. I will try that. I've been messing with the gantry and pulled up on the X beam a bit, which got it down. I've just been getting some inconsistent Z with the back of the plate being closer than the front

chicken•3mo ago

klipper can deal with really messed up beds. <1mm even. The issue is the heightmap changing between the time you take it and the time you try printing. What bed temp are you trying to print at and is the printer enclosed. You really need to let printers this large warm up a little or even more if its a higher bed temp. 300mm machine will need less warm up than a 500mm machine.

chicken•3mo ago

thats what my vc4 500 looks like warmed up and it will print. Just takes time to get there unfortunately and during that time its hit or miss if it will print correctly depending on where in the bed I am printing.

BagellordOP•3mo ago

Right now I am doing PLA with a 65 degree bed, it's enclosed

chicken•3mo ago

have you tried warming up the printer for 10-20 minutes and see if the prints are good from there? I would recommend homing the printer so its at 150,150 centered and then move the Z down to like 2mm. Then preheat your bed to 65c and let it sit there for 20 minutes. I assume you have the front door off while printing PLA? If not that is something else you can try. I bet you can get your bed in that corner better with a little more work but the problem you are chasing is due to the printer warming up and flexing a little and only preheating helps that

BagellordOP•3mo ago

Usually I put the door on, and leave the top popped open I wouldn't chase it if I wasn't suspecting issues is the problem, because i'll have perfect squish at the front and then it's too close at the back, even with a mesh. So it leads me to believe something isn't flat or aligned properly

chicken•3mo ago

that might work. The other thing you can try is playing with the automatic scan compenstation. You can preheat the printer for like 45 minutes and then make a profile for 65C and save it. https://github.com/HelgeKeck/RatOS/blob/documentation_v2.1/site/docs/configuration/beacon_contact.md#5-beta-automated-beacon-scan-compensation I can find the printer.cfg config to automatically apply it if you want

GitHub

RatOS/site/docs/configuration/beacon_contact.md at documentation_v2...

The preconfigured Raspberry Pi image that makes it easy to run Klipper + Moonraker + Mainsail on your printer. - HelgeKeck/RatOS

chicken•3mo ago

yah the problem you are chasing is exactly what I chase and many others. Its all about the printer warping as it warms up

BagellordOP•3mo ago

If you can find that, that'd be great.

BagellordOP•3mo ago

Oh dear lord lol. As a test I leaned on my X gantry just a bit. This was the resulting mesh. I think that's textbook bowing

chicken•3mo ago

you put any pressure on it its going to bow. its only 2cm x 2cm and you are measuing its 100ths of a milameter so its easy to see that. under normal conditions you want have that. I would get the feet level so you start with as clean of a map as possible and then preheating the printer for a bit and you should be good. You can play with the automatic profiles as well but I think its still a work in progress. I would say it helped but didnt solve the problem for me. I am on a 500mm machine so its a 200mm longer gantry. This is a common issue with all coreXY printers. Warming up is the normal way to solve it. Some voron users have a backer on the rail to keep it from flexing. A bunch of VC3 users with had dual rails back to back with aluminum blocks between them or went over to a titanium gantry. Toro3D just released his titanium gantry for the VC4. I have one sitting in the shop I plan to install when I get my IDEX kit

BagellordOP•3mo ago

Nice.

BagellordOP•3mo ago

Oh I think I finally nailed it!

chicken•3mo ago

nice. was that the foot or playing with the frame? for the scan compensation, add this to your printer.cfg and adjust for your temps.

[gcode_macro _USER_START_PRINT_BED_MESH]
gcode:
    {% set bed_temp = params.BED_TEMP|default(printer.heater_bed.target, true)|float %}

    {% if bed_temp == 100 %}
        SET_GCODE_VARIABLE MACRO=RatOS VARIABLE=beacon_scan_compensation_profile VALUE='"ASA_ABS"'
    {% elif bed_temp == 60 %}
        SET_GCODE_VARIABLE MACRO=RatOS VARIABLE=beacon_scan_compensation_profile VALUE='"PLA"'
    {% else %}
        SET_GCODE_VARIABLE MACRO=RatOS VARIABLE=beacon_scan_compensation_profile VALUE='"Contact"'
    {% endif %}

[gcode_macro _USER_START_PRINT_BED_MESH]
gcode:
    {% set bed_temp = params.BED_TEMP|default(printer.heater_bed.target, true)|float %}

    {% if bed_temp == 100 %}
        SET_GCODE_VARIABLE MACRO=RatOS VARIABLE=beacon_scan_compensation_profile VALUE='"ASA_ABS"'
    {% elif bed_temp == 60 %}
        SET_GCODE_VARIABLE MACRO=RatOS VARIABLE=beacon_scan_compensation_profile VALUE='"PLA"'
    {% else %}
        SET_GCODE_VARIABLE MACRO=RatOS VARIABLE=beacon_scan_compensation_profile VALUE='"Contact"'
    {% endif %}

BagellordOP•3mo ago

That was gronking on the X gantry a touch. I've got to get the side panels back on and then put the printer back into its cubby hole

chicken•3mo ago

I think you need this under your [gcode_macro RatOS] in the printer.cfg as well.

variable_beacon_scan_compensation_enable: True          # Enables the beacon scan compensation

variable_beacon_scan_compensation_enable: True          # Enables the beacon scan compensation

BagellordOP•3mo ago

It sits on top of some paving stones at the bottom of my printer shelf, so I have to take it out to get the panels off

chicken•3mo ago

I would not be surprised if it changes as you move it. If it does just play with the feet. You know your frame is good enough now but it will twist as its set on not level bases and I am assuming your pavers are not 0.1mm flat 🙂

BagellordOP•3mo ago

Oh heck no. $2 pavers on top of plywood

chicken•3mo ago

I know.. being a smart ass 🙂

BagellordOP•3mo ago

I figured haha. Now I just have to summon the energy to lift this thing by myself. It's not light, I can't imagine the larger variants

chicken•3mo ago

its the size of a damn washing machine and weighs just as much

BagellordOP•3mo ago

I am running the compensation mesh now just to see how it does. I've got to go get a different cable for my chamber camera before I can button the whole thing back up Well there's still a bit of unevenness in my test squares, but it's close enough that I am doing a print using most of the bed, for a multiboard tile that I need. We'll see how that goes Print was successful. So once I get the USB camera sorted out I'll get it back together, back in place, and make sure the leveling feet have good contact and are locked in

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V-Core 4 300 - Do I need to work on my gantry more?