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Interesting discovery re filament thickness tolerance  

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Haku3D
(@haku3d)
Eminent Member
Interesting discovery re filament thickness tolerance

I made an interesting discovery tonight regarding filament thickness tolerance.

Some of you are probably going to say "yeah I knew about that", but I just learnt this.

I printed the gear bearing stl that came with my Mk3 using YS Filament green PLA and it took a little brute to get it spinning using a cordless drill but now it spins extremely smoothly and well.

I'd given it away so wanted another one, this time I printed it in the clear PLA I bought from Prusa and it took almost no effort to get it spinning, but it feels quite loose and sloppy, not nearly as smooth as the YS filament print, the distance between the gears is fractionally larger.

Using digital calipers I measured the clear PLA from Prusa and got consistent 1.75mm readings +/- 0.1mm, then I measured the green YS filament, almost consistent 1.8mm +/- 0.1mm readings.

That extra 0.5mm thickness made such a difference to the final print - I'm always going to remember this interesting lesson, and measure any new filaments I get. Now I'll have to make a specific PLA setting in Slic3r for the YS green PLA which says 1.8mm 🙂

Postato : 25/02/2019 5:10 am
bobstro
(@bobstro)
Illustrious Member
Re: Interesting discovery re filament thickness tolerance


[...] That extra 0.5mm thickness made such a difference to the final print - I'm always going to remember this interesting lesson, and measure any new filaments I get. Now I'll have to make a specific PLA setting in Slic3r for the YS green PLA which says 1.8mm 🙂
I followed a similar path and started to get much better and consistent results by doing a full calibration for each new filament:

  • Linear Advance calibration

  • Extrusion multiplier

  • Filament diameter

  • Temperature
  • It's a bit of work, but worth the effort for important prints. It's also made me realize settling on reputable filament brands with consistent products is important. I haven't taken it so far as creating settings for each color, but do create profiles for new materials.

    The ability to easily create independent filament profiles is one of the main reasons I shifted over to Slic3rPE as my primary slicer. It can be done with others, but tends to require a lot more duplication of settings.

    My notes and disclaimers on 3D printing

    and miscellaneous other tech projects
    He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

    Postato : 25/02/2019 5:35 am
    Haku3D
    (@haku3d)
    Eminent Member
    Topic starter answered:
    Re: Interesting discovery re filament thickness tolerance

    Thanks for the reply bobstro, thinking back on the objects I've printed with the green YS PLA it makes sense now why I sometimes had to make tiny adjustments to make a perfect fit with parts printed with other filament.

    At the beginning of this year I spent some time looking at various brands/sources/prices of filaments and quickly came to the conclusion I need 'the good stuff' with high tolerance so I can concentrate more on designing and less on fine tuning of the printer & filament, which is why I ended up buying 11 reels from Prusa and I really like the Prusament filaments for their consistency & colour.

    The green YS filament was on sale at 40% cheaper than a Prusa reel when usually it's more expensive than a Prusa reel. I had to give it a try at that price and it's doing well except for the slightly bigger diameter.

    I see now I'll have to do some calibration testing on it so the prints come out as accurate as the Prusa stuff. More interesting stuff to learn 🙂

    Postato : 25/02/2019 7:28 am
    randolph.l
    (@randolph-l)
    Honorable Member
    Re: Interesting discovery re filament thickness tolerance

    5 years ago when I started with 3d printing the difference between quality filament and the cheaper products was stark and this sort of calibration (without the added complication of LA) was not something you could bypass .

    I was printing only ABS back then, and the good stuff was just then adopting the now industry standard of ±0.05mm some of the cheap stuff varied between 1.6mm and 2mm for plastic that was sold as 1.75mm I measured with a starrett micrometer every 10cm for 2 or three meters and averaged the results but the cheap stuff varied so much from meter to meter that it was almost impossible to use; as if it got much bigger than 2.0mm it would jam in the bowden tube system and I would use a 1.9mm hole I had drilled and reamed in a plate and pull the rest of a spool that had jammed in the tube through it discarding any lengths that would not go through it.

    I would wind the useable lengths on to a spinners wool winder with the help of my then girlfriend... after that event I bought only filament that claimed to be ±0.05mm but claiming ±0.05mm was one thing and delivering on that claim back then was something else.. I just recieved a couple of kilos of Prusament Mystic Green which says it is ±0.012mm; this they back up with ID fcca302 at prusament.com. And just for fun I went over the first meter with my micrometer... i found less than 0.005 variance or double what they claim... this regularity means that with prusament I just enter 1.75 mm for the size of any of this product...

    With other companies plastic it is still important to measure and average and enter that number for that spool... I am starting to see other makers respond to prusament by stating ±0.03 or even ±0.02 as what they provide... I have found some of them to be a bit optimistic about their accuracy but they have been better than the stated industry standard of ±0.05 mm

    Postato : 25/02/2019 9:44 pm
    Martin_au
    (@martin_au)
    Reputable Member
    Re: Interesting discovery re filament thickness tolerance

    I'm just going to post this here. This is probably the fastest way to calibrate your filament extrusion multiplier to account for varying diameter filaments. https://www.thingiverse.com/thing:1622868

    Postato : 26/02/2019 12:47 am
    bhawkeye
    (@bhawkeye)
    Eminent Member
    Re: Interesting discovery re filament thickness tolerance

    Thanks for sharing that, martin. I hadn't seen that before 😀

    Postato : 26/02/2019 7:07 am
    Haku3D
    (@haku3d)
    Eminent Member
    Topic starter answered:
    Re: Interesting discovery re filament thickness tolerance

    I designed basic tolerance test objects and found if I set the green YS PLA profile in Slic3rPE to 1.83mm it fit almost as perfect as the clear PLA from Prusa, but that tolerance test link you posted is great, martin, I'll be giving that a run for sure 🙂

    randolph, interesting history, I guess waiting this long before getting into 3D printing meant I missed a lot of the teething problems regarding quality filament.
    I tried printing another of the gears in the green YS PLA from the gcode on the memory card that came with my Mk3, this time it didn't need nearly as much brute force to get the gears turning, suggesting the thickness along the entire length isn't consistent. I'll have to keep an eye on this.

    Postato : 28/02/2019 12:12 am
    randolph.l
    (@randolph-l)
    Honorable Member
    Re: Interesting discovery re filament thickness tolerance

    Ridwan, that print in place Gears Gcode is an amazing thing to print and hand to someone that does not know about 3d printing... if they understand mechanics they will be flabbergasted that such a thing is possible I was at an industrial show a few years ago and the folks at one of the $100,000 metal printers had large versions (about 500% up from the Gears Gcode I would guess) of the gears they were showing to the show attendees and even seasoned machinists were spellbound

    Postato : 28/02/2019 6:21 am
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