Printer keeps stopping mid-print

[Mike_Francies]

Hi, I am getting really frustrated as my printer, an Openbeam Kossel Pro, keeps stopping mid-print and reporting 'too long extrusion prevented'. What does this mean and how can I prevent it? The end of the printlog is below.

RECEIVED: ok
SENT: G1 X-15.762 Y2.100 E8.2870
RECEIVED: ok
SENT: G1 X-15.156 Y3.150 E8.3251
RECEIVED: ok
SENT: G1 X-15.762 Y4.200 E8.3632
RECEIVED: ok
SENT: G1 X-15.156 Y5.250 E8.4013
RECEIVED: ok
SENT: G1 X-15.762 Y6.300 E8.4394
RECEIVED: ok
SENT: G1 X-15.156 Y7.350 E8.4775
RECEIVED: ok
SENT: G1 X-15.398 Y7.769 E8.4927
RECEIVED: ok
SENT: G1 X-15.552 Y7.489 E8.5028
RECEIVED: ok
SENT: G1 X-16.293 Y5.701 E8.5636
RECEIVED: ok
SENT: G1 X-16.829 Y3.841 E8.6245
RECEIVED: echo: too long extrusion prevented
too long extrusion prevented
RECEIVED: Vx_max: open
RECEIVED: y_max: open
RECEIVED: z_min: TRIGGERED
RECEIVED: z_max: open
RECEIVED: ok
SENT: M105
SENT: G1 X-17.090 Y2.301 E8.6736
WARNING: Firmware unresponsive. Attempting to force continue...
SENT: M105
Total build time: 14.42 minutes

I would really appreciate any help, thanks.

[JoeJ]

It's a firmware warning, so once it's triggered printing stops indefinitely until you reset it. I've seen that error mentioned a few times, but it was always with older firmwares that I believe had a bug where that warning would be triggered even during normal operation. I thought it had been fixed now, but maybe not.

Anyways, here's some relevant code from the firmware for when this warning is given

Code: Select all

    #ifdef PREVENT_LENGTHY_EXTRUDE
    if(labs(target[E_AXIS]-position[E_AXIS])>axis_steps_per_unit[E_AXIS]*EXTRUDE_MAXLENGTH)
    {
      position[E_AXIS]=target[E_AXIS]; //behave as if the move really took place, but ignore E part
      SERIAL_ECHO_START;
      SERIAL_ECHOLNPGM(MSG_ERR_LONG_EXTRUDE_STOP);
    }
    #endif

It is intended to prevent extremely long E-axis moves, but clearly it isn't working properly since the 2 commands on either side of that warning had extremely small E-axis distances. So if I were you, I would just go disable it. It's controlled in your Configuration.h file. Here's an excerpt from the default Marlin config file starting at line 220

Code: Select all

#define PREVENT_LENGTHY_EXTRUDE

#define EXTRUDE_MINTEMP 170
#define EXTRUDE_MAXLENGTH (X_MAX_LENGTH+Y_MAX_LENGTH) //prevent extrusion of very large distances.

So either comment out the line that says "#define PREVENT_LENGTHY_EXTRUDE" by adding a "//" before it, or make the EXTRUDE_MAXLENGTH value much larger. You may also want to check that your X_MAX_LENGTH and Y_MAX_LENGTH values were set correctly, since the default value for EXTRUDE_MAXLENGTH uses the sum of those two parameters. So if they weren't set correctly, that could also have been the root cause for why you were seeing this warning during normal operation.

[Mike_Francies]

Hi Joe,

Thanks for the reply. I think the problem is now sorted but it was not necessarily the 'PREVENT_LENGTHY_EXTRUDE' issue. I still need to do another test to find out because I commented out the line you suggested so to make doubly sure, I need to reverse that and try again.

Previous to the error log I submitted here, I did have two or three different errors that resulted in the same, lost communication. This led me to suspect the USB cable/connectors. For some reason I had swapped the physical USB port on the laptop and thought nothing more of it until I tried to re-load the firmware and I kept getting an error when uploading. I swapped the cable back to the original port and the re-load went fine as did the print.

It would appear that there is an intermittent problem or spurious signal on one of my USB ports on the computer. I hope this is the case as it was becoming really annoying and I don't want it to rear its ugly head again. I'm 95% confident.

Thanks again for your input.