Simplify3D User Forum

I have used Simplify3D in lieu of Bambu Studio with my X1-Carbon since the day I got it. I have also heard this noise for just as long. I finally asked a friend about it, which has multiple X1-Cs and he said he has never heard it. Last night I fired up Bambu Studio, sliced a model and sent it to the printer wirelessly and it didn't happen. Either it has something to do with printing from a microSD (which I highly doubt), something is just wrong with my hardware, or there is something wrong with the start code that comes out of Simplify3D for this printer. Can anyone assist me? I did just send this problem to Bambu Lab as well.

https://d.pr/v/2fiuzk

We have a X1C in our office that we use almost constantly with S3D. Have never heard a noise like you described.

Have you already tried going to Help > Configuration Assistant, and re-downloading the profile that we provide for the machine?

3DPrintNut wrote: ↑Thu Apr 27, 2023 1:32 pm https://d.pr/v/2fiuzk

I hear this on the start of the print after machine is turned on (I think it is not every start, only after poweron) during homing, I assumed they use homing without limit switches (detecting motor stall) and that they configured motor current bit high so the motors are audible while homing... I might be wrong I have only one x1-c so no clue what's "normal" ... I have more issues with the "ding" that is heard when the shoot is opened

I re-installed it within the last month on a different PC. Do you think something has changed since then? Thanks for letting me know that is not normal.

sorry to take slightly off topic. My P1P and others according to BL's forums are making that exact same noise during the print start up routine now for about a couple weeks or so. However that's from prints coming out of BS and not S3D related at all, it's Bambu's code or something. People are speculating one and in some cases multiple axii are maxing out at the very beginning of the dance and poops it does before a print. Think I read somewhere someone suggested Prusa owners should be used to it but never owned one so no idea there.

My ticket is still in progress and for some reason I can't copy the text to paste it here, but here was their last reply.

Interesting. I wonder why we don't hear it on our machine. Perhaps it only affects certain firmware versions or certain types of prints?

Can't really see it in the video, but is the print bed in a very low position, i..e. the last print has been quite tall ?This would explain the noise since the first move will lower the bed beyond the last position and stepper motors are skipping then

I just started back with S3D (thanks for the new updates) because I wanted to try it with my Bambu. The Bambu X1C has had no issues with Bambu Studio or Orcaslicer.

Yet, starting today with S3D I have had this same BRRRRRRTTTT issue and came to check on the forum. I was glad to see others with this issue as well.

I assure you it is a real issue, because after an hour of messing around, I solved it. Then I intentionally made it happen again, then I solved it again.

The issue is caused by the end g-code in S3D. It sends the bed too low. Here is the line:
G1 Z256 F1200

This is not the issue exactly, because the print ends fine. The issue is STARTING the next print.

On startup of a new print, the Bambu moves the Z-axis down. It can’t do that with the bed at Z256, so it stalls out the Z-steppers. BRRRRTT!

I checked the ending gcode code on the Bambu Studio app and guess where it sends the bed? It depends on your print height. It may just send the bed halfway or it may send it to the bottom of the printer.

The difference is where that bottom is. The bottom used by BambuStudio is coded in 2 lines:
G1 Z250 F600
G1 Z248

So, to replicate, make a print using the stock Z256 ending code. Then start a new print. BRRRTT!

To solve it, make a print using the corrected Z248 ending code above. Then start a new print. The bed now drops in silence during startup.

Repeat as need to cause and solve the issue.

I have confirmed this info by watching the bed at the end and beginning of many prints and also by lightly touching each leadscrew, bed, or hotend as needed during the BRRRRTTT!! to find the problem. It is 100% caused by the Z axis moving too low at the end of the previous print and stalling when the new print starts and the bed does its little “drop dance” after bed heatup. The BRRRTT!! occurs at around G28 in the startup process after starting from a bed that is set too low by the previous print’s ending gcode.

So, just make that change and get back to printing.

S3D team might want to take a look at that issue and fix/improve it in the update. Maybe take a look at the Bambu Studio ending g-code as well. I also tested prints using the full Bambu Studio ending code copied and used as the ending gcode in S3D and it works fine with the AMS filament change commented out so it behaves as the S3D code does by not unloading the filament at the end of the print. That is how I first found that the endings were messing up the beginnings!

I am using the newest printer (a week old), updated firmware, and latest software.

You’re welcome!

@willnewton

Thanks for the information. This is what I ment in my reply above concerning the position of the bed at the end of a print sessions. Bambu actually confirms that this noise is no harm to the printer, as the motors are only skipping, But it does sound weird.