atomickidstudios wrote:Experiencing a very odd phenomenon, which I have not been able to isolate. It became very pronounced when printing a brim on a model today. During printing, it will consistently jerk / recoil the bed away from the print head during part of the layer causing a very wide blob to form. This gets compounded as each loop is made. When the next layer is applied these built up blobs now cause the print head to skip causing even more of a mess.
I've check the movement of the carriage manually after homing all axis, and nothing mechanically is causing the bump, e.g. a part of the carriage or side pulley mechanisms hitting. Adjustments in flow rate, diameter, etc... didn't seem to have an effect.
I was trying to see if there was some sort of forced retraction of the bed between the end of one outline and the start of a next, but I don't see anything like that. I also removed the brim and just did a 2 online skirt away from the model to clean the head. The problem persists, but doesn't cause as much of an issue because I'm not layering those "blobs" up to the edge of the model.
Lastly, tried printing in another part of my bed by moving the model. It's base is essentially an "X" at 120mm (sq). ... so I can't move it too much around, but the problem persisted.
If you have dual nozzles, you might try removing the one not-in-use. if it is hitting part of your print, it will lift the head as it goes by creating a blob. It may create another blob as the unused nozzle hits the new blob too.
If it is a first-layer phenomenon, you may also try adding .05-.10 mm of Z offset. It COULD be "blobbing" because of too much backpressure in your hot-end.
As always, let us know your printer type/material and other relevant stats for better help...