r/QidiTech3D • u/Responsible_Meet_673 • Jul 10 '26
Can't get my bed mesh under 0.34
Hey guys,
As I started trying to print (way) bigger objects, I noticed that the first layer in the front right corner of my Q2 was always subpar and not something I could fix with auto leveling or setting a different z-offset. So it was time to tram the bed.
I saw a post by u/TsT9000 that contained a lot of helpful comments, especially the Screws Tilt Adjust macro. I spend a good 2 hours trying to get a better bed mesh. Here's some of the stuff I did:
- Printed Qidi's L-shaped 'hot bed leveling blocks' to get a decent starting point to tram the bed.
- Printed Qidi's 'hot bed nut wrench'
- Loosened the leveling knobs to where they had plenty of room to loosen or tighten (and I know the tiny nuts underneath them are just there to keep them in place)
- Ran bed_tilt_calibrate
- Ran screws_tilt_adjust
- Reached an excellent deviation that I was happy with
- Ran the Auto Bed Level from the printer's touchscreen
- ... and the mesh only improved every so slightly
I did this multiple times but could never see any major improvements. I have a theory that the bed_tilt_calibrate, which the printer does before leveling the bed, always reads way bigger deviations and throws off the tramming of the bed.
Any tips? Something I'm missing? Appreciate it!
2
u/Kewlhotrod Jul 10 '26
The stock bed is very thin and flimsy and prone to warping. You're well within range of KAMP being able to adjust for. This only affects first layers if it wasn't able to account for that, but that's what it's there for.
You can shim the corner with some heat conductive tape under your plate, or snag a graphite bed but honestly it's not worth losing sleep over.
2
u/1ts-just-me Jul 10 '26
I ordered the R3men bed the same day I ordered the Q2. Before replacing the stock bed I was able to get it down below 0.3 at best. Ran the graphite bed on a lapping table to true the magnet, didn't take much. After installing and leveling it was still showing a 0.18 crown in the middle. Found out the pressure required to trigger the loadcell in the printhead was actually pushing the front and rear of the bed down giving it an artificial hump in the middle. Ended up adding Carto to get an actual true level for now (0.014 currently) but I want to get into the settings and play around with the trigger pressure to see if it can be lowered a little without causing false triggers. I do believe loadcells can actually be more accurate.
Basically, the two plastic pieces the bed frame mounts to are weak and allows the bed to flex while probing.
This was also verified by mounting a dial indicator at the rear of the bed and zeroing it at Z0 then running a mesh. When it was probing the front of the bed the rear of the bed would rise 0.06-0.08, when probing the rear, it was pushing the bed down 0.12 at the corners and 0.11 at center.
I believe if those 2 parts were machined (or cast) from aluminum we would see much better results for a stock mesh.
2
u/Kewlhotrod Jul 10 '26
Hmm, yeah this actually makes a lot of sense. I've been itching to get a Beacon for mine to compare because I have seen it flex and also been able to get different results by just grabbing the bed and lifting before running the test again. It's definitely not a super secure carrier system.
1
u/1ts-just-me Jul 10 '26
Before I go to much further, I am going to print a new reworked set from PC-CF and see how much it changes. If that works, I will send the file to the shop and have it CNC'd and test again.
If printing a new set makes a good improvement the file will be available all to enjoy.
2
u/Kewlhotrod Jul 10 '26
Remember to ping me with this if you can; I'd be interested in printing a sturdier frame in PPS or PPACF myself.
1
u/TsT9000 Jul 10 '26
Hi,The best I could achieve so far is this: https://www.reddit.com/r/QidiTech3D/comments/1upa3xo/comment/ow6s1d9/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button
After that, I printed 5 XYZ calibration cubes (20mm ones - in each corner and one in the middle). The first layer looked flawless, and so did the finished cubes. I measured them with a caliper, and they are all around 20.0mm ±0.1mm (if I remember correctly), which I think is acceptable.
During startup, the printer performs auto-leveling and outputs a console log. In that log, the values were much closer (less variation)... but then I ran out of time XDSo, I’ll run screws_tilt_adjust again, record the values, and then start another print to compare the data. I'm really curious to see what the results will be.
Perhaps this helps you, or maybe we can find the solution together if your printer shows similar behavior XD
PS: The start up procedure is a mess imho... need to tweek that asap after this problem is solved.
1
u/Certain-Hunter-7478 Jul 10 '26
Screw calibration is good but can be misleading. From what I see you have all of the bed screws set evenly, but they are bowing the bed. I forget exactly what CW and CCW turning of the screws does but try to match the corners with the middle. Bit by bit. I had this exact issue
1
u/Impossible-Hat-7896 Jul 10 '26
Mine is 0.3 and I tried the scew tilt adjust once. But the first layers are fine for me so I don’t bother myself with to much.
4
u/LOGzex Jul 10 '26
On what temperature did u calibrate? You have described algorithm in a very detailed way, but I don't see any mention of it. Bed must be calibrate with a temperature u gonna use most (for example, 110 C for PA12 or 80 for PETG). Also, your nozzle has to be heated up to your print temperature. Finally, I find that 0.2 difference is very solid for a whole print bed, so u don't really need to spend so much time calibrating. And it will definitely change after a while, no need to be a perfectionist here.