I’m running PLA @ 215 (tried up to 225, down to 195) on a heated bed, both with and without a cooling fan on the part. Printer is Davinci 2.0 running Repetier.
I keep getting half prints. The quality of the part that does print looks great, but just can’t get a full part anymore. The printer goes through the motion, but the plastic doesn’t extrude after a certain point (different heights each time). This plastic has given me a bigger headache than the previous one I used. I’ve only gotten a handful of successful prints off of it. (I only print small items.)
@Neil_Darlow
You are probably right, but I would be careful with the 100% cooling. Depending on the type of fan, one could cool the nozzle down to a temp that is not enough to melt the PLA.
I know, because I’ve been there, done that, etc.
I’ve got the fan always blowing the heat break.
Tried running 185C and up. It doesn’t extrude at all until 195, but it curls out. 205 is the lowest temp I can get it to come out straight & steady.
I ran the filament back 10 clicks, then forward again and it extrudes. Not sure what that means. — Spoke too soon. Extruded just a little bit before jamming. Guess heat creep sounds right.
UPDATE: Checked out the filament I pulled out after each failure and discovered they all had been whittled away by the drive gear. Not sure what’s causing it, but may try to change the extrusion multiplier (filament diameter is set on the high end of measurements, which should cause under extrusion if anything I think).
New question: what factors lead to filament not feeding smoothly? My “atomic pulls” are not showing anything unusual (debris, etc) and I’m just about done printing the model with my other PLA (different supplier), and it is working really well through the exact same setup.
Grinding of the filament usually accompanies a jam.
To avoid jams you need a decent flow rate for your material. This is sometimes difficult for small objects where the advice is to print multiples or use a layer cooling fan.
@Rien_Stouten I think it is well-known that layer cooling fans should not cool the hotend either by careful design of ducting or by insulating the hotend itself. Both are common techniques. The use of 100% layer cooling permits higher print speed and thus flow rate which is beneficial in these cases.
Still sounds like heat creep. The time delay, the stripping at the drive gear, the somewhat varied points of failure…
Anything you can do to produce less waste heat is likely to help. A quick hack might be to place some cardboard on the print bed out of the way of the print head. Not elegant, but might get you through a pinch. What’s your bed temperature?
I see the daVinci 2.0 is listed as printing ABS, but doesn’t mention PLA. You might need to consider a different extruder, as heat creep is a common problem that affects PLA, but doesn’t really affect ABS as much.
Heated the extruder to 220C and manually pushed my 2 filaments through. There is a noticeable difference in how fast they flow, so I’ll try a slower print speed tomorrow.
Unless slower printing allows you to drop the temperatures, it will likely make the heat migration worse. The only case in which slower prints will help, is where the extruder is still able to push filament even as the cold end of the extruder warms up. My bet is it will fail at a lower layer height when printing at a lower speed.
Thanks for the feedback. It’s actually the DaVinci 2.0A which does PLA, but not well. The extruder isn’t a great design, but it does work with one brand of PLA.
I’ve run bed temps of 50-70C. Actually, this PLA isn’t sticking even at 70C. I have been using some glue like I did before I hacked the printer.
I’ve got some heat tape (forgot what it’s actually called). I can wrap the nozzle to help hold the heat in. I’ll also do some more research on print speeds. I’m also starting to wonder if this may be mislabeled as PLA. The smell is not so strong as my other PLA, which is a very strong sweet smell.
Bed temperature sounds like your culprit then. Have you tried 3M blue painters tape? You might have more luck with lower bed temperatures on that stuff. But, I’ll admit, I have very few hours logged printing PLA
Well, it will reduce the effectiveness of your heat break fan. If the air it’s using to cool your extruder break is too warm, then you’ll see jams exactly like this. 60 degrees is plenty warm enough to jam your extruder. I’d bet money that your problem is caused by the increased bed temperature.
Had been running with door (and lid) open. This time turned on the a/c and fan running, no bed heat. Same result. Even tried 2nd extruder and reset to default speeds, no luck either. I think heat creep does make sense still, just not sure how to resolve it. Will try low temps again.
You’re jamming up your filament inside your hotend due to heat creep. Not enough cooling on your heat sink. The filament is starting to bulge and no longer able to push through.
You heated your hotend to 220c and there was a noticeable difference on flow rates between the 2 filaments when you manually pushed them through. Honestly, that doesn’t sound like heat creep, that sounds like one of the materials may be ABS. Heat creep won’t affect you while you’re quickly pushing filament through, as your transition zone stays small. The filament that is harder to push, when you bend it, does it snap?
I’ll give it a try at 185C and let you know how it goes!