PLA extrusion

Tim said it best... the BIGGEST issue with PLA extrusion is prebaking it. After that the next big hurdle is proper cooling and spooling to maintain size. Ian has the spooling pretty much sorted (watching my beta spooler go at it right now) and there is some work being done on a water cooling solution (rather messy but cheap and works until better parts arrive)

Personally I have destroyed one of the newer motors working with pla... PLA sucks up heat insanely. I honestly feel that we need a larger melt zone (longer heater) to properly work with pla. After toasting the motor i added another heater to it and put a new motor on and i havent had any real issues since. Anyone using a single motor i highly suggest at least 4 hours baking at 200F and then immediate transfer to the hopper, which i suggest covering with saran wrap immediately. Anything not put straight into the hopper needs to be placed in an air tight container with dessicants or it will be useless for filament extrusion in about 30 minutes unless you live in a desert or other low humidity area.

Thankfully where the printers are extruding at least 40F above the filament makers the humidity isnt half as big of a headache once the filament is made. I have a spool that has been sitting with full air flow for two weeks now and still prints with no issues, but if i was to grind it up to make more filament i would HAVE to rebake it first.

Hope this helps anyone that is ripping their hair out over pla.

AND LET YOUR SYSTEM GET UP TO TEMP AND SIT THERE FOR AT LEAST 15 MINUTES (i normally do 30) THIS ENSURES ANY MOISTURE/RESIN INSIDE THE TUBE HAS MOISTURE BAKED OUT AND BECOME FULLY MELTED!!!

He probably stalled the motor and wasn't around to power it off. PLA is decentl tolerant of humidity during printing, but not during extrusion.

I was running with way too much pressure testing different extrusion temps due to moisture. Didn't follow my own rule and used pellets I baked the night before.. Prolly just came off track/broke a gear inside the box, easy fix. Tim was correct about my unclear statement on extrusion. When using the filament the higher temps we print with remove most issues with moisture and isn't a concern. Its only when making filament its an issue. Jesse no one has per say mastered pla Yet we are all still looking for the best method. I'm about to begin some experiments involving pla 160 temps PTFE tubes and water. Once I get a stable reliable method down I'll post here.

Can you post a picture of your water cooling setup?

Also post a picture of the PTFE tube.  I couldn't get that to work with ABS.  Apparently ABS doesn't have much friction when liquid, and not much when solid, but is more sticky when soft and rubbery.  Trying to guide it through a tube to protect it during the transition from rubbery to solid always resulted in jams, or extremely slow extrusion if it made it out the other end at all.

PLA has a much sharper transition between liquid and solid, so maybe that approach will work.

i will gladly upload some pictures after work (4pm est). Why anyone wants to see a picture of ptfe tubing rigged in is beyond me... anyone can do that just drill your hole out by 1/64 of an inch and only go in a 1/32 of an inch (but ill still share that as well). Pla doesn't seem to have much issue with sticking, but then i also lubed up the tube just to be safe and i run a small amount of lubricant through my machine with my pellets as well (have had zero noticeable difference extruding and printing this way with either abs or pla, better tolerances resulting from less drag and snag, though if you use too much or the wrong kind of lubricant it will mess the filaments up). ABS i haven't tried with a tube as i already have tolerances as low as i think possible without getting a better caliper and making unnecessary changes (.01-.02 is plenty good in my opinion)  I mistyped earlier my current pla variances are .1 not .01. Water cooling i will not be uploading pictures of as it is rigged up and still a work in progress (im using an old car fuel pump and a horribly rapidly thrown together plexi box and fish tank tubing for crying out loud). Once i get it to work reliably and not look like something a kindergartner assembled ill be happy to share that as well. The new gears i made were done with the customizable gears on thingiverse, i wont upload pics of those either because ive only been using them for about 8 hours of extrusion and don't want to be responsible for anyone that doesn't read and research carefully and fries out their motor due to bad gear ratios trying to increase speeds. Again PLEASE unless you have alot of money to play with DONT try any of this yet unless your confident you know what your doing.

I am also using much lower temps 138-140C. At 160 the pla would be so running it would basically flow like water coming out of the nozzle.

Got stuck working a double but had pictures of the gears on my phone, quick web upload and post until i get out of here. (being management sucks somedays)

Small gear stripped entirely.

large gear missing teeth, and the teeth from the small gear in the bottom of the gear casing.

another view of the large gear and small gear teeth

Tim Yes i prebake. the variance issue i have with pla is i am testing extrsusion straight down rather then off of a table or other surface, my non test unit is extruding between .04 and .06. The gear issue i think was caused by a combination of issues, 1. I was only running at 140 2. Not Thinking I used pla that i had baked the night before without re-baking it  3. I had this shaft locked to the motor with a gator grip.
Slippage was not going to happen so the teeth gave, honestly i would have expected the motor to burn out before the teeth giving especially with only having about 50 hours on this motor. I have a few different high torque motors that i ordered (including a few that match the ones shipped) intended for testing increasing speed after i was happy with the rest of the setup. Moore's law i suppose, What you dont plan for happens. Go figure.

Tim... I wouldnt say they hold up exactly.... but then i havent gone up to 100% infill yet. at 30% a gear lasts 1-3 hours before giving out. at 50% 3-5. Think i need to see how long a copy of the originals would work, which means taking apart another motor to scan.