Smartrap: printing exotic filaments with Regpye's hotend
October 19, 2014 05:17PM
Hi smartrappers,
after some weeks playing with our wonderful toy I decided to share my experience about printing some of the exotic filaments that are available nowadays (and more are being invented every day: has anybody tried this or this yet?) with a Smartrap.

I previously wrote about the problems that I encountered with the standard hotend supplied with the Smartrap, although some of them came because of an improper assembly. To make a long story short, I decided to get Regpye's in the hope of having a more forgiving hotend, so I will report my printing experiences with Smartrap mounting this instead of the Huxley (that I abandoned).

This is not to say that the Huxley hotend does not allow you to print with the same materials (I failed with some of them, maybe somebody else will succeed), but I can for sure state that Regpye's hotend is indeed much more tolerant in terms of possible combinations of printing speeds and temperatures: with the majority of the materials, if you choose a temperature, you can vary the printing speed considerably without any issue, or the other way around, if you choose a printing speed you can vary considerably the temperature. So it is much easier to find good printing parameters to optimize many things at once (good layer adhesion, cleanness of the pieces, layer height, etc) without fearing clogs.

However every exotic material represents a sort of challenge, because of issues related either to the melting process or to some mechanical constraints. In the following I will report my experience about the following filaments: Colorfabb XT, Colorfabb woodFill fine, Colorfabb bronzeFill, 3DPremium soft filament, Filimprimante3d PVA and Ninjaflex.

Colorfabb XT

I can confirm all the enthusiastic comments about this filament. It is incredibly strong, almost odourless while printing, and the transparent version (now they made coloured versions too) looks like crystal.

The only problem is the need of a heated bed, so bed adhesion is very, very difficult if you have a classic Smartrap without heated bed as I have. Nevertheless, since I am too lazy to change the printing bed, I managed to make it stick a little to glass coated with PVA glue by squeezing a lot the first layer (something like 300% or 400% of the layer height, or even more) at a temperature of 240°C and at a ridiculous printing speed of 1mm/s (no mistake here). This way it sticks enough to the bed to print whatever you want, provided that you avoid any warping of the piece or the collisions with the printer head may make the piece detach from the bed while printing.

I found no problems with Regpye's hotend (using either 0.5 or 0.3 mm nozzle) even pushing it beyond the normal printing temperature. It withstood well 240°C (at least for a relatively short time of some minutes) and 220°C (for several hours). Since Regpye's hotend is very precious to me (it works great and I have only one for now) I will not dare to go beyond these temperatures for the moment.

WoodFill

The premise: results are amazing, at the touch if feels like wood (it smells like that when you print!), you can even sand it.

However this is really the most evil filament I have ever dealt with so far. It breaks so easily (handle the filament with a lot of care!), it becomes soft already at low temperatures, if you go slightly beyond its printing temperature or if you just extrude it too slowly it gets like vitrified (glossy and so viscous that it is impossible to extrude), finally it sticks to PVA glue coated bed as if it were its only raison d'être: it will never pop off even if you pray for it on bended knee.
This is actually the filament I have not been able to print with the Huxley hotend and that gave me a lot of problems even with Regpye's, because of the very frequent clogs.

In the end I discovered the simple recipe: keep the temperature not high (for me not beyond 200°C) and make sure the filament will always flow regularly and not too slowly: about (7 mm3/s) of material works for me, corresponding roughly to a flow of 2.5 mm/s of filament with diameter 1.75 mm, or to an average printing speed of 40 mm/s with a layer height of 0.25 mm and width of 300%.
Otherwise, you may foresee a clog when the extruded filament becomes glossy and slightly darker than normal.

To reduce bed adhesion, it is enough either to lower the temperature of the first layer, or to increase the printing speed or to turn on the fan. With the right combination the pieces will pop off reasonably well.

Bronzefill

Another filament with amazing properties: it shines if you polish it well enough. Not much more to say except that this is even harder to detach from the PVA glue coated bed than woodFill, if possible. For the rest, it extrudes very well (at least with a 0.5mm nozzle, I have not tried smaller ones yet but it looks like it should work).


Flexible filaments: 3DPremium soft filament, PVA and Ninjaflex

The most tricky part of using soft filaments with a Smartrap (at least with my version) is that the filament bends before entering the Bowden. In this post I described a partial fix for the problem, that makes possible at least to use them at ridiculously low printing speeds (2mm/s for the Ninjaflex because of its extreme flexibility, slightly faster with 3DPremium soft filament and PVA). The filament drive and the Bowden (that makes retraction not very effective) are the two main limiting factors. I am quite sure that printing speed can be reasonably increased with a little re-design of the filament drive, I will update this thread as soon as I manage to do it.

PVA sticks very well (meaning that it stays in place when it has to and pops off easily when you try to detach it) to the PVA glue coated glass, while with 3DPremium soft filament and Ninjaflex you have to take a bit more of care and squeeze them on the bed as described for the Colorfabb XT filament, but then they stay attached to the bed much better than the XT.

No problems about extrusion instead, even with 0.3 mm nozzle.

Some pictures

Here are some pictures, sorry for the low quality.


From left to right: a ring made with woodFill (as it came out of the printer), the same ring made with bronzeFill (sanded a little but not polished, I do not have all the tools yet...) and a die made with woodFill (after some sanding).


Two buttons printed with woodFill: on the left a curved button after some sanding, on the right a flat button as it came out of the printer.


From left to right: Colorfabb XT, Ninjaflex and woodFill (not sanded).

So, to conclude, thanks Serge and Regpye for providing us with these extraordinary tools and happy printing to everyone!


Cristian

Edited 3 time(s). Last edit at 10/19/2014 06:17PM by cristian.
Re: Smartrap: printing exotic filaments with Regpye's hotend
October 20, 2014 06:58PM
Hey nice prints cristian!

I will have to try that trick that you did with the first layer, wouldn't a first layer raft work better then? I mean fist print a raft at high temp and high speed, and then the object. This way the object should then print OK (without a squeesed first layer)

The picture resolution doesn't really show it but the layer bonding seems very good too.

The copper fillament has a little warning about sticking to teflon so i wouldn't try that one. (unless you have a full metal hotend)

And the bamboofill thats also an interesting one!!!
Re: Smartrap: printing exotic filaments with Regpye's hotend
October 20, 2014 08:48PM
Quote
BackEMF
I will have to try that trick that you did with the first layer, wouldn't a first layer raft work better then? I mean fist print a raft at high temp and high speed, and then the object. This way the object should then print OK (without a squeesed first layer)

The problem that I found was that the filament never attached to the bed (not even for a fraction of a second) without squeezing it at very low speed (the slower you go, the better the adhesion). So I guess the same issue would come when printing the raft.

I couldn't increase the temperature too much for the first layer of the Colorfabb XT because I was already close to the rated long term working temperature of PEEK (250°C) and I didn't want to take a risk too big, although probably there is no risk at all. The PTFE sleeve may also suffer at these temperatures, even if it can easily be replaced.

About the soft filaments, I haven't tried super high temperatures (> 220°C) to make them stick to the bed, I fear a bit to get a clog by burning them in the hotend... But I always printed their first layer at temperatures higher than the rest.

Quote
BackEMF
The picture resolution doesn't really show it but the layer bonding seems very good too.

I did my best, always with some wide layer width and temperature slightly higher than strictly necessary (except for Colorfabb XT). This is needed in particular with woodFill that has poor layer bonding (and that's why the non sanded prints look quite dirty). The XT was actually below its optimal temperature, indeed the prints are very clean. However I found no issues of layer bonding with it (and it's really strong!).

Quote
BackEMF
The copper fillament has a little warning about sticking to teflon so i wouldn't try that one. (unless you have a full metal hotend)

And the bamboofill thats also an interesting one!!!

A pity for the copperFill sad smiley but I'm looking forward to reading some reviews. I also hope they will include these two filaments in the sample pack soon.
Re: Smartrap: printing exotic filaments with Regpye's hotend
October 21, 2014 04:49AM
wow ! that's impressive . I didn't see such good and detailled tests before . thank you so much Christian . ( can i link here from smartfriendz's forum too ? )

Now we all want to try those filaments.. I wanted to try wood for a long time but never had time to do.. let's try smiling smiley

I'm sure we will have better experience and less tries than you.thanks to this report


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Re: Smartrap: printing exotic filaments with Regpye's hotend
October 21, 2014 07:56AM
Silly me! angry smiley
If I only had read this tutorial before, I would have spent much less time cleaning the hotend from burned woodFill. But there are a lot of people that did my same mistake with that filament...

So it is confirmed that the clogs come from the degradation of the filament, and this depends only on temperature and time. At some point I also suspected that the nozzle was too small (0.5 in my tests) but they state that 0.4 is enough for woodFill fine. So with this information in mind maybe somebody will have more luck even with the Huxley hotend.

Quote
smartfriendz
can i link here from smartfriendz's forum too ?

Sure, Serge!

Edited 1 time(s). Last edit at 10/21/2014 08:24AM by cristian.
Re: Smartrap: printing exotic filaments with Regpye's hotend
October 21, 2014 12:33PM
Thank you for this very interesting feedback!
Re: Smartrap: printing exotic filaments with Regpye's hotend
September 07, 2015 05:45AM
A little update: here are small rings (lazily polished) made of Colorfabb's brassfill and copperfill (and bronzefill that was reviewed already) that were printed with Reg's Genie hotend without issues:



Remarkably, the copperfill filament can be difficult to print because of the friction with PTFE liners in some hotend designs. The Genie hotend has a PTFE liner but gave no problem even at low volumetric flow rates.
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