i’m getting strange blobs on some of my bigger prints (see pictures attached). the massive layer shift in the print is caused by the blob blocking the nozzle i think, so please ignore it by now.
Any idea what may cause these blobs?
Printer: Original Prusa Mk3
Filament: Prusa PLA grey
Slicer: Prusa Control, default Settings for Prusa PLA
Thanks for your help!
Could be a lot of things. Over-extrusion, not enough retraction, temperature too high.
Also, I wouldnt expect a blob to cause a layer shift, that sounds more like your motors current is set to low or your belts are slipping.
Test your extrusion rate. Make sure that if you tell it to extrude 100mm it is extruding 100mm. Then printing some calibration cubes and other test prints. Measure the dimensions to ensure that you are able to print accurately and that you are handling bridging and travel correctly.
The problem with trying to diagnose issues with a large irregular shaped print is that it is hard to tell what is intentional and what is due to printing problems. For example, I’m not sure what you are trying to print and how much of the irregularity in your groves is intentional.
Update your firmware
Run PID
You also look to be running your printer too hot
@Ralph_Schaffner thanks for your reply. The blob i photographed is not intentional.
The blob caused the belt to slip by colliding with the nozzle, causing the layer shift. thats well understood. My question was, what can cause the blob, and how can i fix it?
@Gary_Tolley_Grogyan firmware is the current version.
what is PID? the printer runs on default settings.
PID is the algorithm by which the heaters maintain a precise temperature.
If you are seeing temperature changes of at least 1 deg C, then you might need to rerun the PID calibration routine
@Gary_Tolley_Grogyan thanks, but maybe it sounds dumb to you, but your explanation doesn’t help me at all, because you don’t mention how to do it. is it a program? how do i do it?
There should be a menu option on your printers display.
Otherwise plug in pc and send gcode command M303 E1 S200 C8
M301 Pnnn Innn Dnnn
M500 stores the values into EEPROM
@Gary_Tolley_Grogyan thanks, it was helpful. how do i resd the current settings of the printer? so that i can check if there is an deviation?
I believe that it is gcode command M501
@Gary_Tolley_Grogyan ok, so i’ll set this settings per M301 before every print, to see if it fixes the issue. if it fixess it i’ll save it per M500. would this be correct?
Nope, settings are stored in EEPROM, no need to reenter them once they are stored
M301 stores the values into RAM, so when you power cycle, they will be lost. Hence storing them EEPROM via M500
so my approach would be correct. Thanks@Gary_Tolley_Grogyan
@Christian_Schulz I didn’t think the blob was intentional. If ever I encountered a large blob in my printing, usually the object to being printed would get dislodged because the force of the motors would overcome the adhesion of the object to the bed. If your print head is bouncing off a blob then either your belts are to loose or the motors are not getting enough current.
Personally, I don’t think you have a pid tuning issue but if you don’t know how to tune your printer, I would check out this website page
https://reprap.org/wiki/PID_Tuning
Zooming in on the images you posted, I would definitely say you are over extruding.
The blobbing and stringing are most likely due to printing at too high of a temperature.
You never gave any information about your printer type, the plastic you are printing or the temperatures you are printing at so noone is going to be able to give you any specific pointers, just general advice.
@Ralph_Schaffner on my initial post i posted all informations available to me.
@Christian_Schulz sorry, I’m replying from my phone and didnt remember you mentioning the printer type and that you are using pla. I only remembered that you didn’t mention your temperature settings even after mentioning to you that you are probably printing at too high a temperature.
The PID calibration is in the calibration menu towards the bottom on a Prusa i3…
