Printer Bed Adhesion

[Geoff]

I find no correlation between the surface I am printing on with jams.

Nozzle blockages occur (for me) for the following reasons.

1. Not printing hot enough for that filament
2. Printing too close to the print bed, stops the filament coming out - (a constant issue on my kossell due to the frame of the machine changing shape with weather and throwing my Z calibration out every now and then )
3. Clogged nozzles from foreign debris from cheap plastic, manual cleaning required.
4. The feeder gear is full of plastic shredded dust and is not gripping the filament well. A hobby knife can clean that out pretty easily.

In the case of #4, it will present the same clicking sound, but instead of it being a blockage, its more a bad feeding mechanism.

[curious aardvark]

greznel if you're scraping glue off the bed with the nozzle end - adjust your calibration. The nozzle shouldn't actually touch the print bed.

Are you calibrating before or after you apply the glue stick ?
Given the really tight tolearances 3d printers work with you should calibrate AFTER applying glue. As the layer of glue will be thick enough to effect the print.

[grezmel]

greznel if you're scraping glue off the bed with the nozzle end - adjust your calibration. The nozzle shouldn't actually touch the print bed.

Are you calibrating before or after you apply the glue stick ?
Given the really tight tolearances 3d printers work with you should calibrate AFTER applying glue. As the layer of glue will be thick enough to effect the print.

I only really put a thin layer down and have bed levelled before and after on many occasions - ive even purchase a dial guage to assist.

Im using a Bulldog extruder XL, hex hot end and 0.4mm nozzle and 1800mm/min - when I clean the nozzle it prints perfectly for a few prints, then for no apparent reason it will stop extruding correctly and clicking halfway through a print - it seems to start on infills and then a few layers up on perimeters. It happens whether I print the PLA at 190 - 200, or slightly higher at 205 - 215. When in a good mood it will print at 190 no problems.

Im wondering whether the filament is swelling in the small tube between the hex hot end fin area and the heating block and getting stuck with slight retracts during the print (retracts of 0.5mm, so nothing major). Ive got a 40 mm fan blowing through the fins and it happens with or without the fan running.

Ive also got a 60mm fan blowing directly on the to stepper drivers to keep them cool - My Stepper drivers are A4988's and I was tempted to upgrade them to some DRV8825's.

When it works Im very happy with the resulting print, but when it plays up - meh !

[wenganxiang]

I dont tend to print ABS, just PLA with bed temp of 60 deg C. I find if I dont use pritt stick it curls.

Sometimes 60 degrees is not high enough, I usually raise the temperature to 80 degrees.