francfalco 37 Posted August 7, 2015 in Under-extrusion - Is your Bowden tube 'really' clean? (edited) Hi all, I, like most people on here have had and the occasional 'unexplained' under-extrusion issue - one minute printing fine and then the next, thin layers, gaps and weak extrusion. Interestingly for me, i was printing Ninjaflex over the weekend and i had an issue with under-extrusion. Nozzle was clean and extruder tension was fine. But then i noticed in the Bowden tube a 'hair' of previous filament stuck in the tube - almost invisible, but had been left behind from the previous 'change filament'. I had to disconnect the tube at both end and run a piece of filament through and then i noticed the 'hair' bundling up into a mini birds nest as i pushed it through and out of the tube. A quick lube with some Olive oil and the Ninjaflex slid through the tube with ease. I know this won't be a 'fix all' solution, but something to check if you don't already? NOTE: don't be tempted to blow through the tube to clear it, it'll only leave behind moisture which will make filament stick like crazy - ask me how i know... Cheers Edited August 7, 2015 by Guest Share this post Link to post Share on other sites
Dim3nsioneer 356 Posted August 7, 2015 in Under-extrusion - Is your Bowden tube 'really' clean? This fine strains occur when you take out the filament HOT. That's why I always take it out with a cold pull. To clean the Bowden tube I can recommend to use a piece of pipe cleaning wire which can be pushed through the tube by a piece of filament. Share this post Link to post Share on other sites
francfalco 37 Posted August 8, 2015 in Under-extrusion - Is your Bowden tube 'really' clean? Interesting. So what is the procedure to change filament with a 'cold pull'? I just follow the 'change material' sequence on the front panel and as you say, the filament is rewound hot from the nozzle often leaving behind fine strands. Share this post Link to post Share on other sites
Dim3nsioneer 356 Posted August 8, 2015 in Under-extrusion - Is your Bowden tube 'really' clean? This is what I do (with PLA): - heat the nozzle up to 200°C - open Robert's feeder - push a bit of filament manually through the nozzle - let the nozzle cool down to x (x=90°C on my UMO, 80°C on my UM2 with the original heater block, 70°C on my UM2 with the Olsson Block) - pull the filament out (requires some force) - use the 'insert filament' option in the advanced menu to insert new filament Share this post Link to post Share on other sites
