My machine has been down for a little over a year due to relocating. My first print following startup was very under extruded. I am hoping someone has an idea about what might have changed.
Before the first PLA print:
The filament was dried at 95°F for 8 hours in a dehydrator.
The print surface was calibrated for level and extruder height.
Entered previous E-step value of 232.7.
Settings were duplicated from the last successful print.
The print was clearly under extruded so I:
Increased the temperature from 205° to 210°.
Reduced the layer height from 0.16 mm to 0.08 mm.
Slowed the print speed from 50 mm/s to 40 mm/sec
The second print was no better than the first.
Since it looked like under extrusion I decided to run the E-step test. The first run extruded 42 mm of filament rather than 100 mm.
By the 3rd run the correct E-step value to extrude 100 mm of filament was 589.
This seemed way out of line compared to the 212 value as delivered and 232.7 value I had been using. The next print came out fine.
My thought was to change the hot end to my new spare.
Changed the hot end
Re-leveled and set height
Set E-step to 232
Ran an E-step test
Again the filament used was short at 44 mm. After 3 more tests the final E-step value needed to be 575 to consume the 100 mm of filament.
Prints are coming out OK but I am concerned that I am missing something.
What would cause the E-step value to go from 232 to 589?
Why didn’t a new hothead bring that back down around 232?
Can you please post the exact G-code commands that you used for the e-steps calibration? I just want to see if something is amiss there.
Did you do the e-steps cal with a specific nozzle installed along with the hotend? If so, what nozzle? Was it new or used? Clean? Etc.
In addition, it’s possible that the extrusion motor is not getting good voltage/amperage, and so is not actually turning as it is supposed to, making the controller think it has moved much further than it actually has.
I have not seen or heard of an SM 2.0 e-steps being over 300, so I concur that yours being nearly 600 definitely points to an issue somewhere.
Thank you for the reply.
Below is the E-step code, I run it as a macro in Luban.
’
M82 ;absolute extrusion mode
M104 S200 ;Start heating extruder
M109 S200 ;Wait for extruder to reach temp before proceeding
G92 E0 ;Set position to 0
G1 F100 E100
G92 E0 ;Set position to 0
’
The nozzle was the standard 0.4 mm, used (~0.5 kg of filament)
The replacement was also the 0.4 mm nozzle provided with the machine.
I am not sure how I would go about checking the extruder head stepper motor. Does anyone know how many steps there should be for one rotation of the drive gear?
Are you still using the same firmware version that you used previously, or have you updated to the latest one? I believe some of the g-code commands changed over time (apparently SM does not use the standard Marlin firmware codes, but rather a customized version of it).
Here is the g-code that I currently use with the latest versions of firmware as of today…
G91
G1 E100 F80
It’s possible that the M82 and G92 commands you detailed are messing it up, though logically and based on SM’s current g-code layout, they should still work. You may also want to try running the cal procedure with the nozzle or hotend removed, though the hotend plug will still need to remain attached. I found this resulted in a much more accurate outcome.
Sadly, I do not know how to test the motor. Might have to get ahold of SM Support for that one, unless someone else knows how.
I started the machine with firmware Snapmaker2_V1.12.2. which was used for my last successful print.
When I saw there was a problem I updated to Snapmaker2_V1.14.3. The firmware change did not make any difference.
Using Incremental mode (G91) works equally well but still requires E=589.
I like the idea of running the E-step test with the hot end removed. It does not factor in the extrusion back pressure etc. but it will be an interesting test. I will let you know how that goes.
If all else fails I will get in touch with SM Support and let you know what I find.
I ran the E-step test again using Incremental mode and with the hotend removed/hanging.
’
M82 ;absolute extrusion mode
M104 S200 ;Start heating extruder
M109 S200 ;Wait for extruder to reach temp before proceeding
G91
G1 F100 E100
’
It advanced the filament 107 mm.
The correction becomes E=537.
Removing the hot end and eliminating the variables of the temperature, orifice and melt characteristics of the filament does not improve the situation much.
I still don’t know why the number needs to be so high, 537 vs ~232.
Sadly, I think so. Unless a more experienced user or someone who has had this level of the issue before chimes in, that may be the only remaining course of action. Wish I could help more. If you or they are able to figure it out, would love to hear back here what the solution was.