Thursday 13 March 2014

Universal 3D printing filament spool standard 2014

One spool to rule them all...

Coils and coils of lovely 3D printing filament, I'm usually surrounded by them, I struggle with them and often spend time and energy mounting, clamping, switching and feeding them into to various printers.

There has to be a better way. (lets please all find a better way)

* The problem *

Every single one is different, bare coils or reels, some are even different from the same manufacturer.

Just to point out here, this is only a tiny selection of 3D printing filament reels available, these are the ones I happen to still have around me. Even the long list on of filament suppliers is a fraction of what's actually available.

Loose coils of filament are both great (no wasted spool or extra cost to ship packaging) and also the work of the devil. You usually need to cut a random shorter length of coil off, just so you can use a section of material in a sensible way, or run the risk of getting into a tangled mess of coil and printer. You then risk not having enough material to finish the print, something that seems to happen more often than I would like.

Once when trying to use a 750gram loose coil of 1.75mm material (about 300+ meters) I had a tangle so bad the extruder pulled an entire shelf down onto a laptop below, smashing it, bending rods on the printer and also messing up a very nice print. I had mounted a home made spool holder to the shelf above the printer in an attempt to use loose coiled filament. My 20 euro coil of filament cost me over 400 in damages, I didn't do that ever again.

After a lot of messing about with making my own 3DPrinted spool holders, printing other peoples, making them by hand and using various mounting systems, I resorted to using a rack as shown above. It looks ugly, the filament gets dusty and problems like tangles still happen. But as I can't find a really good solution for various printers, this is the best I have.

The closest thing we have to a 'standard' reel is based around the use of 3mm plastic welding rod/coils for automotive repair industry, these very large coils have been used with 3D printing for many years. They have a lot of benefits, but also plenty of negative aspects. Mostly being heavy and big whilst also using more than 300g of ABS to make each one.

Recycle, Recycle- 

One of the reasons I would like to see a spool standard is that I would also like to see less waste from 3D printing, and a way to recycle items like spools and packaging.

A few manufacturers like Josef Průša have already looked at cardboard, producing filament already on lightweight recyclable spools.
In this case the center mounting hole is rather large. The inner coil diameter is big enough not to cause the filament to be too tightly wound.

Dense or corrugated cardboard what would be best?

One of the very first filament orders I ever made came on cardboard spools, since then it's all been plastic of one form or another.

Lets take a look at some filament supplied on reels -

And lots of loose coils of filament too -

Make / manufacturer
Outer size diameter
Inner coil diameter
Mount hole diameter
Makerbot 1.75mm (1Kg)
Makerbot seem to have a new bigger spool? Can anyone confirm details.
Colorfabb 1.75/3mm (750g)
Now using a clear ABS reel (same dimensions)
‘Industry Standard’ 2.2Kg (1)
ABS for Up! printer
Prototype Cardboard
(not in production)
Manufacturer unknown
Taulman3D Nylon
Mini Spools
Taulman3D Nylon
Old style packets
Various reel types used by eSunPLA
mini reel
new reel? (conductive ABS)
Unknown from eBay
2.5Kg spool
2Kg spool

5Kg card spool
1Kg card Spool
Metal/Card ~800g spool
as Loose Coils

Coil 3mm filament
(100M / ~800g
Coil 1.75mm filament (100m / ~260g)
Coil 1.75mm filament (750g)
Hang on, that’s the same
Correct - It is…
Polycarbonate / also using spools now.
Unknown from eBay?
Can’t remember
Via 3Dfilaprint
Via Orbitech
Via Orbitech
Via Orbitech

(1) - These large ‘Industry Standard’ 2.2Kg spools were first used in the plastic welding industry, it's the closest thing we have to a standard.

I looks like both 30mm and 50mm mounting holes appear in many different reels, that's something 'standard'

Lots of different spools in lots of sizes - the odd looking one (middle left) is an example (one of many) of a 'home-made' spool to help make loose filament less of a pain to use.

The Question ?

Would it be possible for manufacturers to have a set filament standard for spool size, shape and mounting? Can the 3D printing community help develop that standard?
Can we make it Eco-friendly and recyclable?
Does anyone want it?
Lets find out.

Making the 'perfect' spool has a number of challenges - 
  • The inner coil diameter needs to be appropriate for the type of material and size being wound.
* Bad Spool *
3D Printing filament is not like coils of wire, don't try to cram as much as possible onto a spool.

This is 3mm semi-translucent PLA, you can clearly see the bruising of the filament as it's very tightly wound around a 50mm diameter core. The last 1/3 of the spool contents are useless due to being deformed and much too tight to feed into an extruder resulting in really nasty things like lifting the entire Z axis away from the object being printed.

This started to fail before the last 1/3 of the spool, due to pull-back and carriage lifting. Lower quality prints are also often observed during the second half of a 3mm spool this tightly wound.
  • Spool mounting diameter - Some physical resistance is good for spool mounting. Quite often a printed spool holder is used to mount the reels of filament, many different sizes force users to produce smaller diameter mounting rods in an attempt to be able to mount different types, often resulting in noise and rocking around as the spools unwind. Currently one size does not fit all.
Illustration of Inner diameter, Outer diameter and mounting.
  • Width of spool and overall outer dimension is also important, but more in deciding how much filament is required for each spool.
We have seen a trend is supplying less filament per coil over the last few years, We started at 2.3Kg reels used by the Automotive plastic welding industry, then slowly manufacturers moved to a 1Kg reel and many now supply 750g or 500g per single reel. 

Length of coil is also used by some manufacturers, often 100M of either 1.75mm or 3mm material is a 'standard' length supplied. Many manufacturers are now also offering 50M coils often targeted at retail outlets or as a way to try out new materials and colours.

That's all quite a challenge for a standard spool, but if we were flexible on the width and possibly had two outer dimensions it would be possible to make a standard more people could easily use and manufacturers could implement. Just as important is the ability to design them into new and existing 3D printers.
  • Print material - to some degree defines the minimum internal coil size. 1.75mm material can be wound in a tighter coil and materials like Taulman Nylon or Recreus FilaFlex are both so flexible they can be wound very tightly with minimal impact on the ability to print with them.

  • Nylon's, flexible and PET materials also have a tendency to try and unwind from their coils so a bigger inner coil diameter could also help them be less likely to loop and get tangled.
Cost - 

Another major factor will be cost of the spool and any packaging. reducing weight is good for shipping costs and making it from materials that can be easily recycled really needs to be a major goal.
Plastic spools used today cost under $1 and in reality customers are not likely to pay a great deal more for a standard spool? but how much and can a robust spool made from materials like strong cardboard be viable?

Ideas - spark more ideas - 

We now have dimensional information above on some of the types of spools and coils available, and to get the ball rolling here are some simple ideas for filament spools I have been thinking about.

We can see that many reels already have a 50mm mounting hole diameter, so this looks like a reasonable starting point, Both the Ultimaker and Makerbot Replicator use a 50mm spool mount.

The inner inner diameter, bigger is better, but you need to allow enough room for filament without also having a very large outer diameter. A size of around 120mm for the internal seems to work well for most types of plastics and filled materials in both 3mm and 1.75mm sizes.

A diameter of 220mm for the outer will allow for a typical quantity of filament depending on the width of the spool, 75mm shown here.

Cardboard spool concept, 1Kg spool or 3 x 250g based on the same specification of mounting hole and overall size.

The plastic dust cover/case is an item I would also like to see available (or 3D printed) - make it easy to mount on / in a 3D printer and refill with the recyclable cardboard filament spools.

How you can help - 

If you want to get involved (and please do), a discussion thread on the RepRap Forum is started here.

  • Start discussions wherever you want, and spread the word, lets make something happen.
  • Ask your filament supplier if they can support the standard, if they say no, ask them why and let people know the reasons.
  • If you manufacture a 3D printer, what do you require from a filament spool?
  • Sketch or design something, say what would work for you and your 3D printer, what's not working now and how you solve it (or not).

The 3D Printing Association is providing support for this project and also looking for feedback and ideas to help with this campaign, both from filament manufacturers and everyone in the community.

Filament manufacturers response - 

I have contacted a number of manufacturers to suggest the idea of a universal or standard filament spool - designed by feedback from the community, all the responses have been very positive, with many immediately supporting the idea and wanting to help make sure it's viable for them and their customers.

Individual manufacturers (both filament and 3D printer) can submit feedback and ideas directly and I hope more will also get involved and see if this can result in something good and useful for all.

Thanks for reading.



  1. This is a great idea Rich! Only last night I was trying to untangle at 750g roll of 1.75mm PLA after it tied a knot around itself! It would be great to be able to purchase filament and simply locate it on the printer, feed it into the extruder and away you go.

    I’ve been using a company for a couple of years who supply the material in loose coils; in general I have no problems as I’ve made myself an adjustable spool which caters for the variation in loose coil inner diameter. I’ve noticed that some loose coils are zip tied together to hold its shape – I find these ones tend to tangle much less than the non zip tied coils. Either way this isn’t a great solution because I can never quite trust that the filament will tangle itself during an unattended print. Nothing worse than coming back to a 10 hour long print only to find its been skywriting for 9.5 hours!!

    I think the concept of a cardboard spool is a great idea and I was given the choice to spend a little more money I would buy a spooled coil over a loose coil every time.

    Also on a slightly different note, reding your blog I agree that filament suppliers seem to be offering less per coil. For someone like me who only prints in one colour at a time I find it quite tiresome as the coils (especially 1.75mm) do not last long enough. Minor quibble though!

    Thanks for getting the ball rolling Rich. I’ll watch the progress with a keen interest and I’ll do what I can to help along the way.

  2. Not to divert from the spool discussion, but are there existing solutions/hacks/etc to detect when filament stops feeding into the extruder? Having something in place to determine if the filament is "stuck" and can alert you or stop a print might be quite useful, and prevent the falling of shelves/spools/etc onto your printer.

  3. Glad to see someone is working on this cause it is something that has been annoying me for a while.
    I recently Picked up a few empty spools for mig welding wire from work and intent on spooling my faberdashery filament onto them as the coil diameter is quite big. But it is time consuming and stressful winding filament onto spools, Up to now I have often just been risking using them as loose coils which often ends up in tears!

  4. Good to see you working on this rich. i had to stop using bagged filament after loosing it while coiling 100M it onto a spool. I even made a spool holder which would work with cardboard, plastic etc. Other thing to mention on the industry standard spool. i think colorfabb making there spools now clear is a great help also from a selling point you will order before you run out which will only help filament suppliers with sales.

  5. I make my own spools now - I use a 2" PVC pipe connector, and print 2 nearly 8" diameter ends to glue onto the 2" pipe connector which is pretty darn standard. The ends have 1" holes in them which turn well and smoothly on a 3/4" PVC or metal pipe. I drill one small hole in the PVC for starting the filament wind. Works really well. Right now I glue both ends but I'm thinking about a removable end (2 or 3 bolts) to accommodate loose spools.

    I do NOT recommend using cardboard sides unless they are treated with an epoxy or something to make them rigid. When exposed to heat, cardboard sides often spread, and the filament falls down into the gap and jams. After 5 or 6 repeated jams on different spools, I now respool onto my spools before printing.

    @raster, I'm thinking along the same lines. A microswitch on the filament feed path so when there's no filament, it causes the printer to pause (and probably retract and lift as well) until you can reload it.


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