Under Extruding Issue - Looking for Suggestions to Fix  

Re: Under Extruding Issue - Looking for Suggestions to Fix

Can't be much help considering you replaced the nozzle with a new one (I presume out of the box new). But I recently had under-extrusion I really couldn't explain and so wanted to blame a FW update. But after many attempts at cleaning the nozzle, the second cold pull fixed it. It was weird, after the first cold pull, which had the V and the 0.4mm orifice clearly defined, it'd print just fine then just stop extruding. I did a couple boils - 285 nozzle temp and extruded PLA, even pulled the nozzle and inspected it, too. Anyway - a second not-so cold pull brought up crap from where I'd expect the nozzle and heat break join is; it looked as if something was between the teflon and heat break that would occasionally jam things. Maybe a piece of debris fell down the outside of the teflon into the heat break when the extruder was busy grinding filament.

I'm wary the problem will come back and I'll need to pull the heater and heat break sometime soon to actually "fix" my printer.

Re: Under Extruding Issue - Looking for Suggestions to Fix

did you check the calibration on the extruder? roughly mark the filament 100MM from the top of the extruder. run extruder 100. and see how close it is to the top of the extruder. also does the default Gcode work? gotta figure out if its a s3d thing or not.

Re: Under Extruding Issue - Looking for Suggestions to Fix

Thanks guys. So I did an extruded test. Never tried that before and I was expecting some discrepancy, however it was 100mm right on the button. So that's good. I don't think the issue is slicer related. As I mentioned above I tried the same part with both S3D and Slic3r with similar results.

Tonight I checked the set screw for the extruder gear and that was nice and tight. Then I set the nozzle to 215°C and and with the idle gear door open I manually pushed PLA filament through the hotend. Not sure what resistance you should feel doing that but it didn't take a lot of force to do it and the filament extruded smoothly. I then raised the nozzle temp to 255° and repeated that process. It was easier to push through witht he hotter nozzle but not significantly. Again it extruded smoothly.

I then performed 3 first layer calibrations. Initially I had a z-height of -0.575 mm set. I chose -0.550, -0.500, and -.450 and looked at the small square test print at the end. All extruded fine with the -0.500 mm height looking the best. I then performed two 20 mm cube test prints from Slic3r. One with speeds set at 45 mm/s and one at 100 mm/s. Both cubes printed fine and without under extrusion. Hmmm that's good. So now I need to try the prints that were failing. I'll report back.

Re: Under Extruding Issue - Looking for Suggestions to Fix

try throwing something at it with retractions right away. I finally added a clip to my PTFE tube the last time it came loose. also I have a fan on my extruder motor, just because I felt it was getting too hot.

Re: Under Extruding Issue - Looking for Suggestions to Fix

^What part of the PFTE came loose and where is there room to add a clip?

I ran a larger print last night. Confounded things by going to a Taulman Alloy 910 because I am almost out of PLA. The 910 was not dry so got lots of pops and therefore layer adhesion was bad. However the print did complete but under extrusion was evident. The model had 4 mm retractions BTW.

I am buying some PLA and will try multiple prints with varying increases in the extrusion multiplier.

Re: Under Extruding Issue - Looking for Suggestions to Fix

My present concern is whether or not flakes of PLA are inside the teflon tube, or even outside the tube, wedging between the teflon and the stainless heat break; and occasionally were jamming the filament -- and not sliding down with it into the extruder as you'd expect. Especially after blowing out the extruder gears with canned air (lots of debris came flying out - much more than you'd ever expect). So far so good...

I've attached an image of my 1st layer call procedure. Print a large circle, adjust Z so it is filling properly and strands touching; then pull up the layer to check for strand to strand lamination and measure the printed thickness. 0.007 to 0.008 is my goal.

Re: Under Extruding Issue - Looking for Suggestions to Fix

That's a good point. I may take my E3D hot end apart and blow it out and put in a new piece of PFTE.

Your cal piece to me looks a little under extruded. My concern isn't so much the thickness of the layers but the overlap between the strands. Your picture looks similar to my first layers. I can easily pull the strands apart. This normally wasn't case because there was more material being extruded creating a larger overlap.

Re: Under Extruding Issue - Looking for Suggestions to Fix

sorry I didn't get back to you sooner, you can add a clip right under the black tab thing on top. if you print one make sure to print a small C clip works like a charm. at least have one laying around for the next time you take the hotend out.

https://www.thingiverse.com/thing:1548181

I don't think that's your issue at this point BUT worth having one ready to pop in.

Re: Under Extruding Issue - Looking for Suggestions to Fix

Have you tried printing anything off the SD card that came with the printer?

A pre-sliced gcode will price or eliminate hardware.

Re: Under Extruding Issue - Looking for Suggestions to Fix

Your cal piece to me looks a little under extruded.

The flat in my photo is - as far as I can tell - perfect. Right at or perhaps just under 0.200. Strands are firmly joined. The apparent density variation is due to the cheap filament I was using - light on pigment. It looks worse than it is.

fyi: My lower teflon seems wedged into the heat break at the bottom, and contacts the spur gears at the top. I think this is by design because I've never modified my extruder. But the discussion has me wondering if it has crept upward, and that's how crap falling down the tube began jamming.

Re: Under Extruding Issue - Looking for Suggestions to Fix

Can't be much help considering you replaced the nozzle with a new one (I presume out of the box new). But I recently had under-extrusion I really couldn't explain and so wanted to blame a FW update.

Re: Under Extruding Issue - Looking for Suggestions to Fix

I recently had under-extrusion I really couldn't explain and so wanted to blame a FW update.

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