I have been chasing down issues with my parts not having flat bases. I though the PC shrinkage was lifting the build surface but after checking with a straight metal ruler both my plates are lower in the center in both X&Y axis. I can easily slide a piece of paper (or 2 or 3 or 4) under the ruler for a long way across the length of my build surface. Its the same with or without build plates. Bow at the middle is at least .063" or more and my ruler is a machinist scale checked with a granite surface plate so I can confirm its straight. I just put in a ticket with Bambu but curious if there is a fix where they send me a new build surface to install. One printer is only a few months old and its just as bad.
I have a few parts I sell and have been scrapping parts like mad due to flatness issues and my parts are useless now. And moving forward I cant print any more. Is there an aftermarket Mic6 build plate anywhere?
Anyone else have this issue and if so did Bambu help resolve it somehow?
While I have no solution, just out of curiosity, as there been any crashes for you? Like toolhead crashing into the build plate (whether from blobs or the nozzle itself)?
The search for the elusive flat surface continues⊠Even at this price point you are going to suffer some degree of tolerance, it will vary greatly depending on bed temperatures too. Iâm doubtful there will be a better solution in a dozen type sample if grabbed out of their spare parts bin, its typically the nature of the parts. Iâd suggest aftermarket for a better outcome or if its critical, you head upmarket and an industrial type printer.
The alternative is the old metal tape shims/stiffer plate (like a g10) and build in some sacrificial base you can âmachineâ down for squareness. In the past Iâve bothered with prior machines to get bed level and flatness to the point of madness, I had it quite good and consistent but now I just build that in and sand down the odd âperfectâ model I need.
Yeah. Not an all that uncommon problem. Your only solution is shimming. You might talk BBL in to a replacement build plate, but the next one isnât necessarily going to be much better.
I used Aluminum duct tape. One 3" square piece dead center on my platform was all it took.
Note, I clamped a dial indicator to my printhead and then dragged it around the build plate to find out where it was low/high. Mine was low almost dead center so shimming was easy. If the platform had some âwaveâ to it, I am sure Iâd have had a more challenging time of it.
I bought a Lightyear G10 bed in hopes it being 1.5mm thick would help. A magnetic shim might be a good idea. seems its dished and maybe a round shim would work. I have not seen an aftermarket plate yet, but if needed could tear mine down and design one in Solidworks, but unsure where I would get the magnetic sheet. I imagine they sell them for other machines like the voron and could make that work. But if a shim works will try that first.
So far measured right off the machine after I pulled the plate so it was still pretty hot. Also measured cold. I may attach an indicator to the printhead and run it back and forth in both axis hot and cold. But as mentioned above may just try a shim first.
Thatâs about 1.6 mm, 0.5 mm more than Iâve heard of before, and double the warp I had before Bambu sent me a replacement bed under warranty.
Submit a ticket with Bambu, include the log from a small print with auto-leveling turned on.
I didnât like the printhead holders I found for an indicator. The measurement could be affected by misalignment of the carbon rods, and extra weight of the indicator. I also did not want to risk damage to the rods. I made a small holder that could slide on a rule held perpendicular to the bed.
Nice tool. I actually never considered the x/y rods playing a part, makes a lot of sense even if its tiny. I feel like my stone age method of a rule and feeler gauge is so yesterday now lol.
Having the carbon fiber rods probably helps, as I would imagine they have a lower magnitude co-efficient of thermal expansion. Same for garolite, by the way. Youâre better off if you can avoid the problem in the first place.
@NeverDie I was thinking purely in the measuring scenario, loose bushes plus the Y-axis being metal. In this case it wouldnât be a major difference. The carbon rods would be good with the thermal changes as you mention though. All told, the Bambuâs are pretty good for hiding the bed tolerances and I for one donât miss the endless âmy bed mesh sucksâ from all and sundry (even if 98% of us donât actually need it).
This topic just had me interested as in my previous life hardcore Endering my Y-axis had the major bow in it which distracted me from the âflatishâ bed I had. Fitting up linear rails at least allowed me to concentrate on the actual bed tramming and a degree of flatness all round. @lkraus tool wouldâve been good in bypassing any gantry/axis discrepancies at the time.
Thanks for sharing that. Since youâve already done it, what is the ultimate answer on this: if you start with a perfectly flat machined aluminum plate, as you did, and then heat it up, as you are, does it stay flat? Or is it inevitably pinched by whatever its support structure is, or warped by other differences, like internal tensions in the metal or like maybe near the edges where the heat is bleeding away into the air or environment?
Iâve always wondered about that. My assumption is that you need a bigger plate than what you want as your build area, so that you stay away from the edges. But thatâs just me theorizing, and you already have done it, so youâve got solid answers.
I have the one that is layed onto the stock bed and magnetically attached. It has two pins (left and right) that go through the plate to 1) prevent the plate to go left/right and 2) prevent the flexible build plate to go right/left. The embedded magnets in the underside are strong enough to hold the flexible plate on the upper side.
Its aluminium, and it will expand in all directions if heated. The coefficient is roughly 23.5 ”m/(m * K) and dependeant on the alloy. To give an example: the build plate is 0.256m and you are heating from 20° to 100°, so the expansion is ~0.5mm in X and Y direction and 9”m in Z direction. Because the plate is not restricted in X/Y direction, it can expand without bending. The magnetic attachment is not strong enough to restrict expansion.
As you mentioned, the plate will not heat completly uniform, so it will have variations in the Z expansion. BUT at 9”m maximal expansion, you will have to measure really well, to see the difference, if the outer areas of the bed are 10° cooler than the middle.
The material is cast and machined with âExtremely low residual stressâ. Its important that it is not made from rolled aluminium sheets as the rolling is introducing internal stress you are worried about.
To answer your question, if it will stay flat: Yes.
To have a (more or less) uniform heating of the plate, I manually preheat the plate for ~10min prior to start my prints, and I do go to the edges if the part is big enough.
But with big parts and good adhesion you can have the problem that it can lift the flexible steel plate from the build plate.(Yes, happened to me). This allso can happen with the stock bed.
For that the only option would be to stick a print surface (like BuiltTak, PrintBite or others) directly onto the aluminium plate and have only one surface for all materials to print on. This can NOT be done with the stock bed. So pick your take.
In my opinion both options I mentioned are worth it, if you want to have a flat bed.
One is with stock heater, the other comes with a new heater. I dont have the latter, so cant say more about it.
A little lenghty anwer, but I hope you got your answer.
If it doesnât heat evenly, doesnât matter what itâs made from or what residual stresses there may or may not be, itâs going to warp AKA âpotato chipâ. Maybe not a lot. But because itâs basically unconstrained in Z, even though itâs not really constrained in X or Y either, it cannot possibly stay perfectly flat if the heating is uneven. The differences in thermal expansion as a function of how hot an area is will create their own stresses, and bending is the only way those forces can be relieved.
Better than the stock plate? I could easily believe that. But âperfectâ? No way. Because: physics.
Yep. I have a FLIR. Not unhappy with the flatness of my prints, so I havenât bothered to look. And I long ago got in the habit of not worrying too much about mechanical precision with my prints. I design for a larger tolerance stack-up, and I have a CNC I use to bring things in to the tolerances I need, if I need something to be really precise.
Thatâs very interesting! Do you use some kind of jig to orientate the print in 3space before cutting, or do you somehow just touch probe it to figure out exactly where it is and orientate from there?
