Welcome to the SeeMeCNC Community

So I'm having a multitude of extrusion issues, but until I finish troubleshooting the first group, I have to start with this:

My EZ Struder hobbed gear really bites into PLA. Like, I can consistently see gear-marks in my PLA after being pushed through the EZ struder, and there are chunks of PLA in the gear itself. I think this might be contributing to the slippage - PLA gets stuck in the gears enough where it slips, causing uneven extrusion.

Manual feed through the bowden tube is fine. Manual feed into the hotend works too. The whole thing together is a little iffy - it does seem to be binding *somewhere* but I can't track it down. Its possible that its the PEEK liner - I removed it and it looks OK, but maybe there is damage there I'm noticing. That said, feeding by hand works fine. I measured the PEEK tube at 46mm.

Manual feed with bowden hooked up at both ends is a little iffy - once extrusion begins to fail, even pushing by hand with the red lever released does not seem to work. IT's binding *somewhere* but I'm not sure where. I think maybe my bowden tube is too long, but its been fine for *months* now. I have no idea why it would suddenly start failing.

I do need to tighten down the EZ Struder gear some, but I don't think thats 100% of the problem - when turning the gear by hand, it does more or less seem to bite OK. More troubleshooting to follow.

If I re-run the PLA through, re-connect the fittings, and go, usually its fine for a few layers. But it seems to go back to slipping, and then the print goes to failure.

It does seem like there might be some binding at the push-to-fit connectors, but I can't tell what is causing it at all. They don't seem to have anything that looks like an obstruction. The PTFE tube I have is from seeMeCNC. I have another tube shipped from China to try as well.

Any ideas? I'd like to focus on the gear eating the PLA to start, while I continue to try working on other issues (loose grub screw, for example). SPot thermometer reads ~40-50C on the motor, so I don't think its hot enough to be deforming the PLA.

Using Slic3r through rep host. Kind of wonder if its the latest Slic3r build? I know that it has some volume control settings, but I have those set to match the max speed. Am going to try a print with matter control to see if that might be it.

Any thoughts? Prints look like dotted lines along perimeters, and I can see the spool failing to turn despite the print head still moving to do its thing.

Only other thing I can think of is either replacing the PEEK tube (I have some spare bowden tubing luckily), or replacing the entire hotend with an E3D to see if that removes whatever is causing the issue. And maybe shortening the bowden tube.

what do you have the hot end temp set for? it is acting like it cannot heat up the filament fast enough. if you have the temps set hot enough for pla, you need to calibrate it with a thermocouple and a multi meter, to see if your hot end is actually the temp your thermistor thinks it is.

Tom C

You may want to make sure that the fan on the Rambo is working. If the driver chip is overheating a bit it will surely cause weird problems for the stepper that you can't see. It bit me in the ass!

stonewater wrote:what do you have the hot end temp set for? it is acting like it cannot heat up the filament fast enough. if you have the temps set hot enough for pla, you need to calibrate it with a thermocouple and a multi meter, to see if your hot end is actually the temp your thermistor thinks it is.

Tom C

200C - have been printing fine at that temp for a few weeks. Was doing 210 prior without any issues. Have been using spot-thermo and temps look right so far.

Holy1 wrote:You may want to make sure that the fan on the Rambo is working. If the driver chip is overheating a bit it will surely cause weird problems for the stepper that you can't see. It bit me in the ass!

Not a bad idea - something I'll look into next.

I'm starting to think it might be the PEEK liner or something in the hotend. Manual extrusion with the hand gear takes tremendous effort - it feels like too much effort just to push the filament.

I've tightened the grub screw on the hobbed gear and swapped for a new PTFE tubing to be safe.

SO I tried one thing - extruded 50 mm of filament using Repetier Host. Put some sharpie mark on the PLA - and saw it go down...and up...and down...and up

It seems like the extruder is pushing too much filament for the hotend to handle. Its a 0.5mm hotend though - its never had this issue before.

Any ideas?

EDIT: Slic3r settings for speed:

• Perimeters: 60
• Small Perimeters: 20
• External Perimeters: 45
• Infill: 80
• SOlid Infill: 45
• Top solid infill: 45
• Support: 60
• Bridges: 60
• First layer speed: 35
• Max Print Speed: 60
• Layer Height: 0.2mm
• First Layer Height: 0.3mm
• Perimeters: 3
• SOlid Shells: 3 top/bottom

FINAL EDIT:

The issue was MOST LIKELY that at 200C, the extruder cannot apply enough pressure to keep up constant volume at higher temperatures. I need to drop speeds as temperature drops, at least for this filament. A valuable lesson - it is possible that moving to a geared extruder setup may be a significant improvement, but for now things are working just fine and my printer has been calibrated back to normal.

TL;DR: SPEED SHOULD BE DIRECTLY PROPORTIONAL TO HEAT

When it comes to replacing the PTFE tube, how sensitive is the tube to length? I thought I remember reading you need to keep the exact length of the tube. I couldn't figure out why. My tube is getting chewed up at the end entering the hot hot end, and I'm debating whether to snip off some length and keep using the same tube or replace it. can anyone shed some light on this? thanks

The length is important but does not need to be exact. Removing an inch or 2 to clean up the end will not be a problem.