I have a serious problem with blobs due to the printer halting for a few seconds every now and then. I know that this is an issue that already affects many people and is not (exclusively) caused by octoprint itself. However there are a few things I don't understand - maybe someone familiar with these issues could help me clear things up.
First, here's my setup:
- Raspberry 3 B & Wanhao Duplicator i3 v2.1
- Raspberry 3B+ (octoprint freshly installed with no plugins) & Wanhao Duplicator D9 MK2
- Both are running the latest stable release and are connected with 115200 baud
- I prefer quality over speed, so I usually print at around 30mm/s and 100µm
I never had these kind of issues on Setup #1 although the (slightly slower) RPI also acts as a webcam server (RPi_cam_control - I don't use octoprint webcam support) and runs a CPU-demanding sensor-readout-and-plotting program.
On setup #2 though, there's lots of blobs on my prints with the printer stalling up to 5 sec. CPU-wise there's nothing to complain; it's mostly in the one-digit % area with no notable deviations when the printer pauses.
This even happens when I print the same .stl files with almost the same gcode. However it doesn't seem to happen on very simple files < ~2MB. Most of the time I'm printing gcodes of ~ 10-50MB in size.
So I guess the serial interface somehow is the bottleneck. This is really strange because the D9 is the more modern printer. On the other hand it's CPU seems slower (just judging by their clock speed). The old printer features an ATMEGA1284 (20MHz) while the newer one is driven by the ATMEGA2560 (16MHz).
Workaround for me is to print everything from SD.
Unfortunately I control the printer mostly remote. So uploading a file to SD card takes ~ 1hr/10MB; so I have to have the uploading PC connected to octoprint for 5 hours in case of a 50MB file - when connection drops, I have to start over again.
Is there a way to first upload the file to the octoprint server and afterwards copy it from there to the printers SD card? Uploading to the server just takes a few seconds; so this would make the process much less painful.
Any other suggestions concerning my actual problem? Printing everything from SD can't be a long-term solution. Do I have to upgrade to a more modern mainboard? If yes - which one is recommended and works flawless with octoprint?