I’ve been running into a (somewhat common) problem of the build plate lifting in the corners. I also noticed the front corners were much more prone to lifting than the rear. So, I decided to check the magnetic sheet field strength on the printer plate.
I used two approaches; I used Magnetic Flux Film (4" x 4") to identify the problem areas and I used a steel washer and spring scale to measure the pull force.
Magnetic Flux Film
Spring Scales
On my printer, this Magnetic Field Viewing Film offered a good indication of areas with diminished field strength. Just lay the film on the magnetic sheet and look for anomalies in the field pattern. I put a glass sheet on top of the film to make sure there is consistent contact between the two. There are 5 photos below showing the center and 4 corners. You can see how the flux lines are distorted in different areas of the bed. The degree of distortion indicates the loss of field strength.
Then I measured the pull force on different areas of the magnetic sheet. I used a fender washer (1 5/8 OD, 3/8 ID) with a string hot glued to the center and spring scales to measure the force (in grams) to pull the washer off the sheet. See photos and results.
So it looks like it’s time to replace the magnetic sheet. Bambu sells replacement sheets for $15. Replacing the sheet looks straightforward provided the adhesive layer comes off with the sheet vs having to be scrapped off the heat plate.
My wife could see the problem straight away, your Feng Shui needs realignment Turn your printer 30deg right and use the bigger poop chute…
Thats quite a variation, have you tested another machine/brand to see if this is a general result of heat and/or layout? I’m not up on magnet theory, but does location to other metals around influence this over time (then I see the back near the z rod is high meh). Am intrigued and watching for the update when you install a new magnet sheet.
*Here we are thinking all these bed adhesion issues was due to the lack of Dawn plate washing. PS. that stray bit of filament is triggering lol.
I don’t have another printer that uses a magnetic plate. Just a FLSun that uses a glass bed.
Most (90%) of my prints stay in the center 2/3 thirds of the plate. In that area the field strength still looks good. I don’t run high temp materials, just PLA, PETG and TPU. So I wouldn’t think heat caused the problem.
I thought the metal frame under the aluminum plate might be an issue. But parts of the frame are also located where the field strength is strong.
I have the mag sheet on order. But I may go one step further and try to address my warped bed too. I’m thinking of gluing a 3.3mm borosilicate glass plate to the aluminum plate then mounting the mag sheet on top of that. The down side is it will add about 500 grams to the print plate assembly. So I may not do it.
I’d love to have an old school glass plate for memories For now I’ve got a thick G10 lightyear plate that hasn’t lifted yet (ABS/ASA/PA). It is an interesting pick up anyhow and looking forward to what comes of it.
Ah - the magnetic field is to hold the build plate to the printer bed. The cleaning steps are to have the models stick to the build plate. It’s two different things.
We’ve seen people post here about models shrinking during printing but with strong adhesion to the build plate it actually lifts the build plate off the bed. Low magnetic force could be why they were able to curl the build plate.
I have 3 lightyear g10 plates and absolutely love them. There have been some recent reports of poor customer service and orders not shipping - but I never had an issue with support, and my first plate that had a surface failure was replaced by the company quickly. All 3 of my plates have slightly different manufacturing characteristics as their designs changed, but I print like 90%+ of the time on these. Being so thick and ridged it would take a lot to warp this plate off the bed. It also has a much stronger magnetic attraction to the bed than the slim spring steel plates so it take more effort to remove in general.
I’ve put many hours on the Pro plate from last year, its got a couple of defect spots (age related) but overall happy with the quality. My initial experience with the company was a little disconcerting, they went dark the moment my payment was sent but they did send the plate (I ordered from Australia). I’ve seen the quality issues around the place but as usual its the internet and stories of woe get more attention
Agreed. I jump to my Lightyear plate when I need to print in the far corners of the bed. Its added stiffness does the job. I’ve also been happy with the adhesion.
But I also like the flexibility of using other plates for different surface finishes and rapid prototyping. They all have their pluses and minuses.
There will be a counterpoint to that, though. I cringe when removing a build plate with something big where I have to pull away from the magnetic force over the whole build plate at the same time.
It ends up being a lot of force that could impact the bed lift mechanism. I don’t know how much margin we have so that’s why I cringe and try to ease the plate off as best I can.
Very interesting, I never gave any thought about possible decay of the magnetic field. Have not had any issues with the plate lifting of the bed as of yet. I ll be ordering the viewing film so I have a reference if any such problems would arise over time.
Please update us when you have changed the magnetic sheet, I m very curious to see the results!
I’d steer away from supporting that sham of a “Business”. Taken 3 months to receive a product with 0 response to numerous support messages and emails I gave up. One day it randomly showed up…
You can see by the reviews this is a normal instance, plus the plates are garbage and overpriced.
I already had a magnetic field visualizer sheet and finally got around to checking my print bed in a November ‘23 X1-C. Turns out for magnetic field uniformity I’m golden. Hopefully enough margins to figure out which corners but I took photos of the four corners and the center. I slid the sheet around just to check the full plate and mine is all like these shots. No blems or issues.
Turn your printer 30deg right and use the bigger poop chute…
For now I’ve got a thick G10 lightyear plate that hasn’t lifted yet (ABS/ASA/PA). It is an interesting pick up anyhow and looking forward to what comes of it.
