Bed crashes in lowest position

Bambu Lab X1 Series
1

For some reason when I print something large and it completes the bed lowers to its lowest position but it does not appear that it knows when to stop and it just grinds and sounds like the printer is going to break. I rush to power it off and then when I power it back on I have to raise the bed manually to about half way up in order to be able to successfully home the printer. What could be wrong and is anyone else having this issue?

1 Like
2

I have not seen it where it gets the “grinding” noise at the end of a print. The end gcode for this is:

{if (max_layer_z + 100.0) < 250}
    G1 Z{max_layer_z + 100.0} F600
    G1 Z{max_layer_z +98.0}
{else}
    G1 Z250 F600
    G1 Z248
{endif}

If the maximum print height is less than 150, it will lower the bed about 100mm, otherwise it will go to 2mm up from the bottom.

What everyone DOES see, though, is if the bed ends up close to the bottom and you start a new print, it pushes the bed lower and makes that hideous sound. The printer really should keep track of where the bed is between prints, or use the current sensing it has for X and Y to know when to stop for Z.

The sound is (mostly) harmless, but it’s not a good look.

5 Likes
3

I’ve had that happen to me, as well as when I start a new print and the “Z” drops too much, hear the grinding then goes back up for homing.

1 Like
5

This happens when you start a new print after a large print.
After a large print the bed will drive to the bottom, if you start a new print it is in the start gcode to lower the bed again before moving the head.

6

Thank you everyone, it is good to know that I am not the only one experiencing this. It is highly concerning when it happens as I know that sound cannot be good.

1 Like
7

Bump!

This still appears to be an issue 10 months later on P1S :neutral_face: - I get grinding and cracking noises, sounds like something is going to break.

Surely this can be resolved with firmware update.

8

I have had this issue since I got my P1S. Sound is very bad. But it happened about 6-8 times but printer still functions.

9

Happened to me and I almost shat me pantaloons. Right after a large, mask Print.

1 Like
10

So I’m getting what you are getting. I see constant posts about the bed crashing noise occuring when starting a new print after a large print, but I’m getting the noise at the end of printing moderate to large prints. The machine didn’t always do this and even though multiple people are saying it won’t hurt the machine, it is still very jarring, loud, and (in my opinion) not acceptable.

Using the touch screen to move the bed down can reproduce this as well. It finally figures out it can’t move anymore after hitting down over and over (while making said crashing/grinding noise a few times in the process).

I’ve looked and looked and I couldn’t find any attempt to fix this (except for fixing the bed position before the next print for the other issue). I’m really hoping @BambuLab or @SupportAssistant gets eyes on this because I’m not the only one experiencing this.

I wish I can pinpoint when this started, but it feels rather recent, perhaps somewhere around the 01.08.05.00 firmware (and similar BambuStudio release).

I think this is the code that is part of the process, but it might be beyond gcode.

M400 ; wait all motion done
M17 S
M17 Z0.4 ; lower z motor current to reduce impact if there is something in the bottom
{if (max_layer_z + 100.0) < 250}
    G1 Z{max_layer_z + 100.0} F600
    G1 Z{max_layer_z +98.0}
{else}
    G1 Z250 F600
    G1 Z248
{endif}
M400 P100
M17 R ; restore z current
11

FYI I did find this post from @JonRaymond

This quote in particular is interesting:

Ideally it would be done in the machine limit perimeters but there isn’t away currently to access or adjust them.