Max force exceeded

[calley]

Been running the mod for a couple of days and so far everything works pretty well. Though, I still have a lot to learn about this printer.

However, I get this error occasionally and I cant find any mention of it in the config or docs:

Transition to shutdown state: flashforge_loadcell: Max force exceeded. Last weight was: 1180g

I've eve caused this error a few times by poking at a part or pressing on the bed too hard while printing. But now I'm getting it during prints too. Last time seemed to be near a curling overhang, so I'm guessing that caused the change in load cell reading.

I see it listed in the config as a tempreture sensor, but no details on the settings...
[temperature_sensor Load_Cell]

And I noticed LOAD_CELL_TARE but it just references FLASHFORGE_LOAD_CELL_TARE and I haven't found much on it. Seems to be run by BED_MESH_PROFILE and AUTO_BED_LEVEL so I assume its getting run before I print.

In the logs, it only seems to reference any readings as a temperature
Load_Cell: temp=400.0 TVOC_Value: temp=0.0

Not that experienced at reading the finer details in a klipper.log but the previous temperature values dont seem to correlate to the value in grams in the error. But I may not be looking at it right.

When it crashed with Last weigh was: 1180g the temp value was 400
But another Last weight was: 960g the previous temp showed -20

Any pointers on where to dig for more info?

Let me know if I can provide any more pertinent info, klipper logs etc...

[xblax]

Thanks for reporting this @calley
The default max force in the firmware is 900g, I also found that this is a bit too sensitive (for example if I clean the bed while it's heating up for a print).

I did not notice that it happens during regular print, but it makes sense that this could happen on curled overhangs.

To mitigate the issue you can set the max force in printer.base.cfg like this:

[temperature_sensor Load_Cell]
sensor_type: flashforge_loadcell
max_force: 2000

I will probably include a higher default value for the next release.

[calley]

Added that to my .cfg so hopefully that helps.

Where can I find more on how to read/calibrate that value?

Seems to be all over the place sometimes.

[loss-and-quick]

g992/flashforge-ad5m-5mpro-research#27 (comment)

[loss-and-quick]

It is better to do like that:

FLASHFORGE_LOAD_CELL_SET_MAX_FORCE FORCE=2000 ACTION="pause"

TEMPERATURE_WAIT SENSOR=heater_bed MINIMUM={bed_temp-5}  ; wait for bed

FLASHFORGE_LOAD_CELL_SET_MAX_FORCE RESET=1

[H4NNE5]

Holà,
Warming up this thread again, having had the same issue recently and implementing @loss-and-quick 's additional code.
I recently had a load cell shutdown (1512g exceeding 1500g limit).
I also wondered about the Tare command, which is only called in the bed leveling macros but not in "START_PRINT".
So I added it there right after "FLASHFORGE_LOAD_CELL_SET_MAX_FORCE RESET=1".

What are your thoughts about Tare-ing?

[raistlin7447]

I just now also got the max force exceeded error. I was doing a manual multi-filament print. Never had this issue before that. So perhaps related to that?

[iRomanyshyn]

Hi @xblax, first of all, I would like to say a big THANK YOU for your work. I prefer using this project over another from russians. I prefer not to use the russian software, as it's a big risk.

And yes, while I'm printing the full plate of cylindrical objects, the MCU often shuts down. That's a bad default behavior. I'm going to experiment with it to make it capable of printing such objects, while still maintaining safeguards against accidents.

[loss-and-quick]

I prefer not to use the russian software, as it's a big risk.

It's very funny to hear that — even if there's something there, it's better than leaking data to your own overseers.

Also, the project source code is available; look if you're so worried about being watched by the Illuminati.

[iRomanyshyn]

It's very funny to hear that — even if there's something there, it's better than leaking data to your own overseers.

I mentioned it because software trust and supply-chain security matter, especially in embedded and infrastructure-related systems. That’s a perfectly valid concern today.

For example, Entware itself has raised concerns before regarding hosting and project transparency. And yes, people living under authoritarian governments often have a very different view of privacy, telemetry, and state surveillance. That’s not “Illuminati paranoia”, it’s just reality.

Anyway, this is getting off-topic.

The actual issue is that the MCU shutdown protection seems too aggressive for certain print patterns, for example dense full-bed cylindrical prints. It would be useful to make this behavior user-configurable instead of immediately triggering a full shutdown.