Hi all,

I've had my printer a couple of weeks, and I've been tinkering around with various settings in cura to try get the best out of it. I've got prints at 0.2 coming out nicely, but when I increase the print quality to 0.1mm layers, I'm having a problem with these unsightly tags on my prints (see attachment

Sorry if this is a noob question, but can anyone recommend which settings I should try tinkering with to get rid of these?

I'm printing with PLA and this print was done with these settings:

0.1mm layer height
print speed 30mm/s
print temp 210
bed temp 90

retraction:
30mm/s
4.5mm

advanced speed:
travel: 150mm/s
bottom layer: 15mm/s
infill: 35mm/s
top bottom: 30mm/s
outer shell: 18mm/s
inner shell: 25mm/s

cool layer time: 5sec
cool head lift enabled


many thanks in advance!

John

Hi, looks like your retraction length (4.5mm) might be too long? I'm no expert, but I've read that 0.5mm - 2mm is more suitable, depending on your extruder type (is it via bowden tube or direct?)

Thanks for the tip - I would never have thought of trying that!

I'll try dropping it down for the next print. My printer is a Chinese prusa i3 copy, looks quite similar to the geeetec i3, but it's got a different extruder - I'm not sure what kind of extruder it is (the instructions were not very helpful!), but it is direct-feed. I've attached a pic.

Yes you should definitely try a lower retraction length. Read the retraction section here (or the whole guide...) [richrap.blogspot.se]

Good luck

This is the print again, same settings, retraction distance set to 1mm, (retraction speed still at 30mm/s)



Seems to have gotten worse. I was watching it this time, and I could see the little tags building up, every time the print head passes, a bit of ooze would catch on the tag and make it longer.

I think the extruder on this cheap prusa copy must be particularly bad. I'm going to try going the other way, and increase the retraction distance *and* speed, see what happens.

onwards and upwards...

Ok! what do you mean with "cool head lift enabled"?

Edit: after googling it, this seems like it might be the culprit?

Edited 1 time(s). Last edit at 02/05/2016 03:41AM by ade2.

I'm using cura 15.04.4 as my slicing software, and it has an option to tick to raise the extuder head and pause for a while if the previous layer has been completed too quickly to cool. I've left it ticked, but I can try it unticked too.

I'm finding more and more ways of how to print badly... hopefully one day soon I'll work out how to print well!

This is the dragon printed with retraction bumped up to 5mm, at 40mm/s. A definite improvement, but still a lot of tagging.



I figured going for retraction even higher than 5mm would be a bad idea, so I'm back to square one. Having a hunt round the t'internet for any clues now...

Yes, be careful with too much retraction, as you will get melted plastic stuck further up your feed. I'd try without the cool head lift option once, as I saw several people complaining about that option producing string artefacts.

Try adjusting your temperature settings, 210 looks high to me. I print PLA at 190-200 (color dependent) on a cold bed.

On a side note, whats that paper behind you? I have thought about keeping track of all my print settings, and example prints to help me dial in settings for hard prints. Is that what you are doing?

Edited 1 time(s). Last edit at 02/05/2016 02:05PM by AudaciousTuddle.

Just had another thought, on my slicer I have some settings that let me change when and how the printer retracts the filament. You might have to play with some of those. This is my setup i used for printing a business card, I am using a greg-wades extruder, so i have a lot more room to retract, which is my retraction length is so high.

a screen shot of my slicer and of the card i printed is attached.

EDIT: I realized that i had changed the min travel for retract. that should read 1mm

Edited 1 time(s). Last edit at 02/05/2016 02:15PM by AudaciousTuddle.

Thanks for that - I'll try one at 200 with no bed heater on. I've tried 190 before, but the very thin wings started breaking up badly (see attachment) so I went back up to 210. Is there another way of stopping the thin areas breaking up at lower temperatures?

I've set my retraction distance to 5.5mm and upped the retraction speed up to 50mm/s to match per your settings, see what happens. My minimum travel before retract is currently at the default 1.5mm, so I've dropped that to 1mm to match yours too. Your business card print is very clean - if I can get my dragon to come out like that I'll be a happy man...!

The little paper chits, yes - I've printed out a load of A6 templates to write on print speed, temperatures, cooling settings etc. and final print time so I can compare the final prints with their settings. There's just so many settings to tweak, and being a noob I'm still working out what changing each one does to the print.

Right, I'll get this print going - 3hrs 53mins predicted print time on cura...

have you tried calibrating your extruder's steps per mm? it kinda looks like your under-extruding on those wings. Another problem might actually be in your slicer, not your machine. if your model has parts that are equal to or less than your nozzle diameter, then your slicer will ignore those sections and just leave them blank. you can try scaling by 1.1 and see if that makes a difference, but check your steps per mm first.

Here is a link that covers calibrating your extruder steps/mm [reprap.org]

Hmm no I've never calibrated the extruder steps per mm - I'll check out the link, thanks, see if that could be an issue.

My nozzle diameter is 0.4mm - the dragon prints fine with the temperature at 210, I don't know if that makes any difference?

Sadly on my last print I came back to this mess...



my bed adhesion obviously isn't so good on a cold bed (I'm using kapton tape) - gonna try it again with a 70 degree bed, at least then I can see how it prints with a 200 degree head.

Second time lucky.....!

Edited 1 time(s). Last edit at 02/06/2016 01:27PM by johngill1971.

Your almost definitly under extruding. One of the effects is that is causes first layer not to adhere as well since it is not putting down enough plastic.

Just had a look at that link about the extruder steps per mm calibration, thanks for that. Bit stumped on that. I've found a machine setting in cura called "e steps per 1mm filament" which obviously is what I need to set - it's currently set to 0, which I gather means "use the firmware default value". My printer has the GT2560 control board, but I don't know how to quiz the firmware to get it to tell me what its current esteps is set to. Bit more googling required methinks...

Did your controller come with the firmware on it? Or did you have to use the arduino IDE to upload it? If you have the files you can look in the config.h file, inside that file there are a bunch of different variables that you can set, including the extruder steps per mm. I know in the Repitier (what I use) you can also set it using the LCD screen.

Edited 1 time(s). Last edit at 02/06/2016 05:36PM by AudaciousTuddle.

The controller board came with the firmware pre-installed so I've not uploaded anything. I've been rooting round on the internet to find out how to interrogate the firmware on the board. I think I've found it - buried deep within the onboard lcd menu system, there is an esteps setting.

I tried using cura's flow % compensation set to 120% to address the under-extrusion problem. I started printing, and the extruder was clunking away quite badly at 20mm/s print speed, so I dropped it to 15mm/s and it clunked only a couple of times on the first few layers, so I left it running overnight.

Found this in the morning:



*sigh*

I assume this means it's still underextruding. I started another print with the same settings, but increased the temp by 5 degrees to 200. It's halfway through now. Once it's done I'm going to have a rummage through the on-screen lcd menu to find the esteps setting. I think I really need to get that sorted before any further experimentation.

The esteps is definitly what your looking for. But you can actually tell if it's calibrated or not without that. The easiest way I know is to measure 60mm of filiment op from the extruder and mark it with tape or something. then manually have it extrude 50mm, measure the distance you have left, if it's not 10mm then BAM! You know what your problem is.

I highly recommend a pair of calipers for This, Harbor Freight sells a digital pair for like $5 that won't last forever, but will be more than adequate for this.

I've calibrated my extruder. Marked 100mm and told it to extrude 100mm. And it had, pretty much, bang on extruded 100mm.

But I've noticed something else that I think could be the problem, and it's the extruder clunking. Using the on-board lcd control of the printer, I pre-heated the nozzle to the default setting of 185 degrees. And then used the on-board lcd control again to extrude the 100mm, and it extruded perfectly, no clunking. I set the print temp to 185 in cura, and started a new print at my usual 20mm/s, and clunk-clunk-clunk, the extruder was slipping and not extruding properly.

Thinking it was trying to force through too much filament, I even tried slowing down the print speed to 5mm/s (!!!) and still the extruder was clunking, and it was barely depositing anything on the build plate at all. Something weird going on for sure, any ideas anyone?

Maybe the temp is dropping while printing. Or you could be too close to the bed. When you are manually extruding I am assuming you are above the bed.

---

Newbie with Folgertech 2020 i3.

Well I'm glad your firmware is all correct. That makes things much easier on you. Have you tried adjusting the trim-pots on your stepper drivers?

This thread has a great detailed description of how to do it. [forums.reprap.org]

Edited 1 time(s). Last edit at 02/07/2016 12:44PM by AudaciousTuddle.

msaeger, yes, I'd not checked the bed alignment for a few prints, and it had drifted which is why it wasn't extruding the first layer properly. Thanks for that.

audacioustuddle, thanks for the trim-pots advice, I'll go check that out too.

Thanks for your patience - this learning curve is a tad steeper than I'd expected!!

Any progress?

feels like one step forward two steps back at the moment...

After investigating the trim pots, I found some really odd stuff going on. According to the webpage above (thanks for the link) the output voltage from the trimpot should be about 0.5V. It was actually set at 0.82V, so I brought it down to 0.5V and tried another test print. But the misfeed clunking from the extruder stepper motor just got worse. Also strangely, the stepper motor was barely warm to the touch. I whacked it back up to 0.82V, and it only gets mildly warm when extruding, so I thought I'd try cranking it up to 1V just to see what happens. From what I've read on the other threads, it seems 1V should be way too high, yet the stepper motor was still only mildly warm when printing, but the clunking didn't seem to be any better than what it was like at 0.82V, so I put it back down to 0.82V. (any ideas what could be going on with this??)

I've guessed I must have an under-tensioned extruder. I put up another thread about that, and it looks like I'll be buying a new extruder - one which actually has a tensioner on it. I'm learning why my 3D printer was so cheap now...

thanks for all your help so far!