Bed is not stable

Hello well,

Well, it seems my saga with SnapMaker A250 continues. After it went to an official reseller center to repair all my problems, it seems I had two defective rails (one changed by myself and another changed by the reseller). One thing that bothers me, and I can’t figure out if it’s supposed or not to happen, my bed seems to go “up/down” each time the bed moves. I have other printers and the bed is steady like a rock.

I uploaded a small video where you can check this. If you take a closer look to the bedfront , you can notice when the the bed comes to front, it seems the front goes up. The same happens when going back, it seems it down’s in the front.

Link: Multimédia1.mp4 - Google Drive

Is this normal? If not, how can I solve it? The maching came properly assembled from the reseller shop this time.

Note: Needed to add in GDrive since couldn’t upload files here.

The carriage inside your linear rails are loose. Here is snapmakers guide on how to fix this:

I performed this fix myself about a month ago as my bed also wobbled (but not as bad as yours), likely due to drilling holes at too high a feed speed when CNCing. Its a fairly quick fix but does require partial dis-assembly of the machine. After doing the fix my bed is rock solid.

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The bed on these machines will never be rock-solid without a rebuild that involves adding parts. The bed is mounted on tiny plates ~40 mm wide and the bed extends ~120 mm past that in each direction, a 3:1 torque arm for force on the bearings. That’s a fundamental design flaw.

Tightening the bearings would certainly be useful as an amelioration. In the video, it looks like there’s a cable rubbing on the rear side of the table, causing it to move. It’s also going to cause the cables to fail. Dress the cables to stay out of the way.

The cables aren’t rubbing into anything. The only free to move cable is the bed one.
Despite that, I will try to check both things to solve this mistery. This obviously will affect my print quality.