Starting to have problems with my tensioner

I have printed a fair few parts. Started one tonight, failed after the 2nd layer. Re-adjusted tension, printed about 15mm and started slipping again. The tensioner system is my main design concern really. I would have thought that there were better designs by now, without making it expensive.

What's slipping? Is the the overlapped belt end in the carriage or the idler mount on the smooth rods?

Sorry, extruder tensioner. The belt system seems to be working very well.

Your filament is slipping ?
Mine did that after a few pieces, i just unmounted it, cleaned it and tuned the tension screw, now, it's good and reliable again.

Most likely, there is chewed up filament in the teeth of the hobbed insert, so it can't grip the filament. As Greg_be says, unmount it, and clean the teeth. Make sure you don't set the tensioner too tight, or it will have trouble feeding. Test it by hand. Though it is more relevant to our other printers (we need to include some information for Fisher), see the troubleshooting guide > printing problems > Poor or no extrusion.

Ian
RepRapPro tech support

Edited 7 time(s). Last edit at 08/05/2015 08:24AM by droftarts.

Yeah, you're probably right. Thanks.

documentation/troubleshooting-introduction/printing-problems/#Poor_or_no_extrusion

Ian
RepRapPro tech support

Yes the hobbed insert was all clogged. No that is not an easy service! And now to take the top off and re-jig the endstop cable for the umpteenth time...

Just solder the endstop cables.

If the hobbed insert is getting clogged it's either because it needs cleaning due to many hours of use, or because the tensioner is too tight and is biting into the filament too much, or because the material has jammed at some point and the extruder was grinding the filament rather than the motor skipping.

I doubt it's the first as you haven't had it long enough to have enough build-up from normal use. It's quite likely that the tensioner is too tight, and I guess you'll know if you've ground the filament as it'll usually mean you have to remove and discard the damaged filament.

It was probably all the problems with the G31 Z0.1 typo. Can't extrude while ploughing a furrow in the BuildTak. Cleaned it out and now trying a Minion in Velleman yellow PLA from CPC. No you can't hang a 1Kg roll on the holder on the Fisher....

How is the Velleman stuff to print with? I'm currently using some green PLA from Threedy that prints great but it's on a 1Kg roll too, and yeh, I'm going to have to come up with a better filament storage solution.
I've had quite a bit of trouble getting the white eSun stuff that the Fisher came with to print well, I find it's really susceptible to stringing and extruding inconsistently.

You're a lot pickier than I am...yes there is a lot of cobwebbing with the eSun stuff but otherwise I was very happy. I have set the extruder steps to 135.2/mm now so that will also make a difference.

Velleman stuff looks cheap and wonky, but micrometer was happy and print so far is OK, certainly for the money. Will have a better idea when it finishes. I am also using the old gcode file, didn't re-slice with latest settings yet.

I use eSun PLA most of the time in my Ormerod. It prints well at 195C first layer, 185C remaining layers. Above that causes stringing. So try a lower temperature if you are using higher, but watch out for the extruder drive skipping steps.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

135.2 steps wasn't nearly as nice surface finish. Like a vinyl record. 140 was better, but going to go back to 144.

Yeah, I was thinking of lowering the temperature. Currently on 200.

I am still getting a large wad of extra material when doing solid infill layers. Not retracting enough?

Quote
Theolodian
135.2 steps wasn't nearly as nice surface finish. Like a vinyl record. 140 was better, but going to go back to 144.

I find every roll of filament is slightly different. The easiest way to compensate is to leave the steps/mm at the value you measured when you calibrated it, and adjust the extrusion factor slider in the web interface. You can do this during printing to see what the effect is.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Erm... for the typical variation in material diameter the difference in steps per mm should be immeasurably small. The steps per mm isn't a number that should be tweaked on a whim, it can be (and should be) measured pretty accurately, pretty easily - it's a 2 minute job at most.
I dislike the idea of having to fiddle with extrusion multipliers/fudge factors. I measure the diameter of the filament when I receive it and make a profile for it, test it and perhaps tweak the filament diameter in the slicer if needed to get it bang on. If I have a roll of material that requires the steps/mm to be changed due to significant variance from 1.75mm/2.85mm or oval profile then it gets sent back or stored as scrap.

I've tried printing the eSun stuff at 190 (the original stock setting from RRP), 200 (the new stock setting from RRP), and 205 and the results are much the same. At 190 it wasn't extruding consistently and the extruder was skipping occasionally, hence why I tried the higher temperatures. That seemed to improve the flow and I didn't notice any real difference in the stringing. I'll have a look into the retract and coast settings, but my feeling is that it's just a stringy material. I keep finding long wispy string of the stuff all over my desk where I've grabbed the odd bits of ooze from the extruder post warm-up. Don't get me wrong, it's not bad stuff at all, the prints look great, it's just that the need a knife running around them to tidy them up.

Edited 1 time(s). Last edit at 08/05/2015 06:12PM by bluesign2k.

Quote
bluesign2k
Erm... for the typical variation in material diameter the difference in steps per mm should be immeasurably small. The steps per mm isn't a number that should be tweaked on a whim, it can be (and should be) measured pretty accurately, pretty easily - it's a 2 minute job at most.
I dislike the idea of having to fiddle with extrusion multipliers/fudge factors. I measure the diameter of the filament when I receive it and make a profile for it, test it and perhaps tweak the filament diameter in the slicer if needed to get it bang on. If I have a roll of material that requires the steps/mm to be changed due to significant variance from 1.75mm/2.85mm or oval profile then it gets sent back or stored as scrap.

Sorry if I didn't make myself clear. It's not that the filament diameter varies much, it's that different types of filament seem to need different extrusion factors even if you have calibrated the extruder steps/mm accurately and you enter the measured filament diameter exactly in the slicer. The theoretical value just doesn't work, it typically results in over extrusion. I suspect this is because the extruded filament doesn't end up with the ideal square section that the slicer assumes, instead the sides bulge a little.

Edited 1 time(s). Last edit at 08/05/2015 06:38PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Hmm, interesting. Personally, I've never had that issue. If anything I've only had slight under-extrusion that is usually due to the material preferring not to spread sideways but compress slightly instead and the expand once the head has moved away. This results in the extruded bead being slightly less wide than expected and the layer being slightly thicker. Mind you, these were not standard materials.

I wonder whether filaments that require you to tweak extrusion factors are simply not of a circular cross-section. I've seen some crazily oval filaments in the past... they just don't get near the printer. I see no reason why you shouldn't get the expected output if the steps/mm is correct, you know the filament diameter and the flow rates aren't wild. Are they just particularly liquid materials that compress in the head and experience some form of die swell on exit?
I also wonder how much of a difference it makes that I usually manually set the extrusion width rather than letting the slicer calculate a value? I recall that Slic3r in particular used to throw out some very suspect extrusion widths if left on auto.

Easiest way for me to test the printing results was to try the same gcode file with different steps/mm. The Velleman doesn't have a nice a surface finish as the eSun at any setting I tried, but it's cheap and otherwise printed fine so that's fine by me. 135 steps/mm was noticeably worse. 140 and 144 looked the same. 144 was really hard to get off the bed, broke the part. So after calibrating my extruder steps/mm properly I will know where to start with the extrusion factor.

I would prefer more extrusion on outlines and a LOT less on solid infill including the base layers.

I tried 200 deg for the first layer and 195 from layer 2 (on Velleman yellow PLA). Ended up with half a Minion. When it got to the part where it travels over open space it stopped extruding. Was fine until then.

Oh, and the initial problem where it stopped extruding during the print was actually a problem with the STL model. It wasn't even trying to print there. Ooops.

Curse you stringiverse!

Edited 1 time(s). Last edit at 08/06/2015 03:55PM by Theolodian.

With a pine green eSun, I print all the spool at 195 first 189 others.
Only one clogged nozzle during the all spool, probably because Z was to close to the bed

I just did the test on my extruder after cleaning out the hobbed insert again (really needs to be easier to take apart and threads on motor are going to go). 100mm extrusion command gave 106.Xmm of filament at 144 steps/mm, so 135-136 steps/mm is the theoretical setting. However I expect that I will have to set the extrusion factor to at least 103%.

Before changing your extrusion factor, have you measured the filament diameter (an average over say, a 1 m length) and updated your slicer settings? If you're underextruding then it's likely that your material is thinner than what you have set in the slicer.

I meant in terms of I wasn't happy with printing results at 136 before. Did the RRP robot.g at 136 earlier and it was fine, so probably need to start over with S3D settings now. I will reconfirm filament diameter too.

This Velleman red PLA is 1.79 to 1.81mm, so 6% bigger. On top of the 6% over on the steps...

Wow! That's awful stuff! I'be never come across 1.75 filament that measures ove 1.76, usually if anything, its under sized.

Yeah it's pretty poor. Was still surprised at how far off it was. Good and cheap for making colourful trinkets for the kids. 24 quid for a Kilo including VAT and delivery.

Try Threedy filament. Its £18 per Kg for PLA or ABS. Maybe I'm a little biassed as I know the guys, but I certainly find that their PLA prints better than the eSun stuff, and I've seen plenty of stuff printed with their ABS that looks just fine.