Stringy print after few layers.

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starburstquicks
Posts: 5
Joined: Wed Jun 11, 2014 12:56 pm

Stringy print after few layers.

Post by starburstquicks »

For the last month - I've been racking my brain how to make my print finish 100%. Luckily I've had the chance to learn tons about slicing settings, and troubleshooting the mechanical parts. Anyways...

First few layers print amazing. Either first 1-10 layers print beautifully, but part way through... the extrusion becomes stringy and lacking a full volume. I have tried 90-100% fill density setting in a few different patterns, playing with temperatures (typically printing at 215-220), extrusion speeds, perimeter/fill speeds (down to 20-30mm/min).

What could it be? If my first many layers are doing well, and then it seems to be lacking the ability to extrude full amount half way through. If I "pause" the print and then extrude 5mm, it usually comes out fine.

Anyways - here is an example where it got stringy even on the first layer on some of the perimeters.
stringy print.jpg

seaton
Posts: 291
Joined: Tue May 14, 2013 9:04 am
Location: Bunbury, Western Australia
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Post by seaton »

I've seen similar problem, not on first layer though, but would happen at other layers, on two other new V3 Felix printer recently bought by two friends of mine in our local maker group, after recommended by myself :). I went through the calibration procedure on the printer with extruders, stepper motor current level etc with them and similar results, ended up trying different slicer (simplify3D) and all problems resolved.

So have you made sure that your thin wall is correctly calibrated? is the filament feeding through without slipping (i.e. hold the filament and with the heated extruder, command 50mm to go through and try and hold the filament, does it stall? If so then adjust the tension on feed pulley and check stepper motor current settings, and if after this then try another slicer, doesn't have to be simplify, but try the free version of Kisslicer and see if it makes a difference.

Stephen...
Stephen...

Felix 2.0 -> Felix 3.0 dual
Simplify3D Slicer, Kisslicer
Have you added your Felix to the Map? http://goo.gl/maps/HajnZ

http://blog.strobotics.com.au

starburstquicks
Posts: 5
Joined: Wed Jun 11, 2014 12:56 pm

Post by starburstquicks »

Thanks Stephen.

What is the thin wall? Otherwise, yes I have done everything I can think of and that I see on blog posts. The extruder is callibrated (i.e. 50mm on the program is 50mm in real life). The diameter of the filament has been measured at 1.75mm with low +/- values. The tensioner on the feed pulley is good. No stalls, no slipping. I tried slic3r, in fact that is basically the main slicer I use now. But I most certainly would be happy to try simplify3D and/or kisslicer.

I get the feeling that there must be either a clog in the extruder that isn't coming out (I pull the filament out at 1000mm/min when the print begins to fail like the manual says to try to declog it). And/Or the Slicing settings need tweaking. However I feel like for a month now I've tried every combination of slicer settings. So frustrating. The first month I had it though... it printed beautifully, so I know it is possible.

frankjoke
Posts: 150
Joined: Sat Dec 28, 2013 6:07 pm

Post by frankjoke »

Had same with some PLA which worked nicely the first half of the roll but then made problems.

Anyhow, what I do always if a feed problem appears is to remove the hot end, clean the inside and wheel (there is always a lot of dust there), unscrew hotend parts and look if there is some material in there to clean and then build it back again, heat it up and drill with 0.3 0r 0.35mm drill (with a handhold drill holder) into the tip to clean it up.

This helped so far.

p.s.: I changed the teflon tubes to 3mm ones because the material flow is easier in there, especially with material from end of roll which is actually pretty bended and caused sometimes that the extruder cut into material too much when retracting often.

seaton
Posts: 291
Joined: Tue May 14, 2013 9:04 am
Location: Bunbury, Western Australia
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Post by seaton »

starburstquicks wrote:Thanks Stephen.

What is the thin wall? Otherwise, yes I have done everything I can think of and that I see on blog posts. The extruder is callibrated (i.e. 50mm on the program is 50mm in real life). The diameter of the filament has been measured at 1.75mm with low +/- values. The tensioner on the feed pulley is good. No stalls, no slipping. I tried slic3r, in fact that is basically the main slicer I use now. But I most certainly would be happy to try simplify3D and/or kisslicer.
do a search for thin wall calibration, basically it calibrates the extruder output, i.e. if the nozzle diameter is 0.35 what is the width of the extruder filament? by doing a thin wall calibration then this values is calibrated to a know value for the slicer, so by the end of it your filament should be extruding at 0.35mm I calibrate mine to 0.41, which is whats calculated automatically for my slicer.
I get the feeling that there must be either a clog in the extruder that isn't coming out (I pull the filament out at 1000mm/min when the print begins to fail like the manual says to try to declog it). And/Or the Slicing settings need tweaking. However I feel like for a month now I've tried every combination of slicer settings. So frustrating. The first month I had it though... it printed beautifully, so I know it is possible.
Thats also a possibility and you will need to carefully clean the nozzle. But if you want accurate prints you will need to perform the thin wall calibration at some pint in time
Stephen...

Felix 2.0 -> Felix 3.0 dual
Simplify3D Slicer, Kisslicer
Have you added your Felix to the Map? http://goo.gl/maps/HajnZ

http://blog.strobotics.com.au

cbensch
Posts: 54
Joined: Fri Jan 24, 2014 9:52 pm
Location: Simsbury, Connecticut US

Post by cbensch »

If I may - a few thoughts here:

1) You're printing much too hot. Don't worry, I did the same thing myself and was amazed when I dropped my temps way down. I put my first layer down at 225 C so it's good and gooey and has great adhesion to the bed. My subsequent layers immediately drop down to 185 C. But 5 degrees C makes a huge difference with some PLA brands. Start at 180 and if it's having trouble extruding increase the temp by 5 degrees. IMPORTANT: most PLA filament degrades rapidly when subjected to temperatures of 220C and above. It literally turns rock hard in your extruder. My first layer, at higher temps, are OK. But the filament I discuss below in #2 simply rots in my extruder at 220C. I got one nasty burn when my extruder was jammed with the stuff and I went to go clean it out with a .3mm drill bit. It exploded molten filament onto my hand. Left me a nice blister.
2) I bought some Makerbot filament thinking it would be the bomb. It turns out the Chinese stuff I got on eBay puts it to shame. Ironically, I needed to reduce my extrusion multiplier for the Chinese stuff and increase it for the Makerbot filament yet they are both within .1mm in diameter. But the Makerbot always came out stringy and with obvious overlaps. My Slic3r profiles were a match except for my multiplier. My point is, you might have better luck with different filament.
3) Strings are also caused by Z lift (or drop). A lot of people experiment with dropping the bed between layers. Bad idea. Retracting the filament between layers is a very good idea. I have great results at 1mm retraction, but terrible results with as little as .1mm in either direction +/- from 1mm.
4) If the print gets goopy on upper layers it may also be caused by your speed. Delicate (small) prints mean a slower speed but slower speeds mean the filament hasn't had a chance to cool between layers yet. The extruder keeps it constantly molten. Some people experiment with putting a large room fan facing the print for higher layers. I've had great results with this very idea. But two things to keep in mind. You'll increase the chances for warping by cooling it quickly. Keep your heat bed at 55C during the entire print and use a glass sheet for improved results. Second, be sure the fan isn't sending cold air into the corrugated vents of the bed. use your hand to be sure the air is directed towards the print and even towards the extruder only if you can pin it down that closely. I designed a computer fan holder for the side of my 2.0 that works well and the fan is fixed so I don't have to worry about a big fan in the room to bump into after "calibrating" the direction of the air.

cbensch
Posts: 54
Joined: Fri Jan 24, 2014 9:52 pm
Location: Simsbury, Connecticut US

Post by cbensch »

Here, I get amazing results with these settings using Slic3r. I had to go through 3 spools of testing prints to get here unfortunately. But even the smallest perimeters (.5mm) and even minute 3D extruded texts 9also .5mm) come out beautifully. If you don't get the same results then it's simply the difference in filament.

Make sure your Z calibration is spot on. The aluminum bed has warped twice on me and I now use a 3/16ths" piece of window glass on my heat bed with a single piece of blue tape on the bed following the x-axis to make up the low point. Adhesion with the glass is crazy good. I put a piece of computer paper under the extruder and drop it down to home. The paper should be hard to pull out but not impossible. Disable the motor in Repetier Host and manually drag the y-axis and x-axis to different parts of the bed. it should be the same all around. This will give a great .3mm first layer.
Attachments
Speed.jpg
Skirt and Brim.jpg
General.jpg
Filament.jpg
Extruder.jpg
Cooling.jpg
Advanced.jpg
Infill.jpg
Layers and Perimeters.jpg

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