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Wednesday, October 24, 2012

Review : printing with wood filament

Printing with wood filament : a short review 

Twisted Gear Lamp by BenitoSanduchi, printed with Cura at 80mm/s, 0.2mm layers, Ultimaker

You may like to read also my post on wood shades though temperature changes.

What is a "wood filament"?

I bought an early batch directly from a small producer in Germany. The full reference was LAYWOO-D3 LOT F0142. It was not cheap, but it even got more expensive because everyone wanted some!

How it is made sounds trivial: just a mix of saw dust and plastic... But shaping this mix into a nice filament must be tricky otherwise all the major producers would have produced it before and would be already be selling kilometers of it...

There was no choice on the color yet.

What strikes me first is the surface, which is extremely rough compared to the other filament kinds. I think there is still air in this filament... The overall stiffness is much lower than PLA, and you almost feel like you could bend it without breaking it (even though it still breaks nicely with a sharp movement and pliers). Later, I had serious issues with the filament for some time which lost all of its flexibility, but the issue is gone thanks to a air dryer.

Unusual deep marks left by my hobbed bolt (with a medium tension on the feeder)

The filament diameter is not very constant, but it is not worse than the two kind of PLA filament I had. From 3.0 to 3.1 mm, which is totally fine for me. I never had any grinding issue (during the first week of the filament). Some people however report serious issues and varying diameters (read on from this post for example). Note that my bowden tube is non standard, and its inner diameter is 4mm (OD 6mm). This proved to help a lot obviously.

Printing wood (how weird does it sound!)


On my first print, I thought I was under extruding a bit because I heard bubbles popping out of the nozzle while printing, and the thin walls where not that smooth. I still should try with higher feed rate just to check how it behaves and if the result is smoother.

However the macros for horizontal filling (picture on the right) seems to tell it is pretty well tuned. See how the successive pass really fit each other better than with PLA (my nozzle is 0.4mm). Well, it may not be better, but since the material is rough, it really looks like it is.

The layers are harder to see than with PLA. At 0.1 height, it makes walls almost invisible. But much more interestingly to me, the horizontal filling is much nicer than with PLA.

Also, the extruding temperature really seems unimportant, really not like PLA. You just can set almost anything and it prints nicely, but you will get different colors. For this, you need to insert specific g-code manually in the generated file or use my forthcoming Cura/Skeinforge plugin.

Also, it looks instantly "dry" out of the nozzle. So much that I may significantly reduce the minimum time between layers so it prints faster. It really does not look like it is melting the previous layer top when the heads moves over (looks like wet cardboard more than plastic to me). However the layers still stick nicely to each other; may be because of the texture more than because they get welded ?

With surprise, I realized I could bend the following object where I could not with PLA. Hence, I suspect that this material will not stand the same amount of stress as with PLA nor ABS. It actually looks like something between cardboard and a springy MDF (it gets a bit stiffer with time, not much imho). The printed object also really can be painted, much more than with PLA or ABS.
It really gives a fine result, but not for all uses.

Printed at 222°, 60mm/s, 100% fill. The resulting object is quite elastic.

Printing at 80mm/s, I could probably go much faster

A closeup HD video that show the nice "thick" paths

Tips and issues with wooden filament

I would not leave the filament heating for long in the nozzle as it becomes really brown (and somehow crusty), so there may be a risk to obstruct the nozzle (update: good prediction since it just occurred to someone!). So I purge the head manually with regular PLA when a print is done (which now appear to me very "chemical/industrial" compared to the wood filament).

Purging : from much heated wood to pink PLA. Disgusting but safer.

I had no grinding at all when I checked carefully the feeder marks on the filament. May be that was thanks to my bowden tube replacement, or to my own feeder, or both. Actually, even though the filament surface is rough, since the material is smooth I can move it in the bowden tube as easily as with PLA (if not more).

Also make sure to keep it in a sealed bag and somewhere it will not degrade as mine did :(

Conclusion


As a final note, I think this material really rocks for artists and designers, and even though I am not an artist, I think I will always have a spool of wooden filament nearby :)

Check also how you can get different shades of brown (gradients) by varying the extruding temperature during print.

And then, now, I want to go and invest a bit in making my own filament. Winter is coming and I will have a pile of wood dust, together with a pile of broken PLA things. By the way, it even smells like a biscuit :p






This could be my new business card, but the clean up is more difficult than with PLA




About Me

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If you know me and you cannot tell exactly what my real job is, then you probably found the right Jeremie. Check zax.fr for some pointers.

I am self-employed and I help start-ups, research centers, small companies with their needs related to computers, maths and mechatronics. If you have a project and know what "R&D" is, then you already caught my interest ;)