Colorfabb XT-CF20 for 40h print

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rodriguejr
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Colorfabb XT-CF20 for 40h print

Postby rodriguejr » Fri Oct 06, 2017 10:13 am

Hello,

I am doing a Ducati Panigale project bike and I need to print some large parts on my Raise3D N2 Plus. I am now on my third attempt to print the Air intake (attached STL) using XT-CF20 (I have done prior prototypes using Polymaker’s PCMAX and Raise3D PLA without problems both 40h plus prints). However, with XT-CF20 I am running into trouble due to (I think) the print head hitting the model and skewing the print axis due to the accumulation of gunk on the nozzle. 20mm test print cubes print OK and so does the part for the first 8-10h. After that it is a disaster.

I have tried the following settings:

First attempt:

Print Temp: 245C
HB: 70C
Retractions as standard for PLA
First Layer: 0.15mm
Fill density: 35%
Default Printing speed: 50mm/s
With RAFT
Printing on BuildTak with very good adhesion
Z Distance to print bed 0,2mm

Result: poor layer adhesion aborted after 8h, lots of strings and gunk on the hot end

Second attempt:

Print temp: 252C
HB: 70C
Retractions as standard for PLA
Default Printing speed: 50mm/s

First Layer: 0.15mm
Fill density: 35%
Z Distance to print bed 0,2mm
With RAFT
Printing on BuildTak with very good adhesion

Print head hits print after 9h serious accumulation of gunk all over the place. lots of strings


Third attempt:

Print temp: 260C
HB: 70C
Fill density: 35%
Default Printing speed: 50mm/s
Changed Retract speed from 20mm/s to 40 mm/s as recommended by one of your users.
Z Distance to print bed 0,2mm

Result: Less gunk on the nozzle (but still quite a bit), there were some large gunk debris that formed during the night, and I assume at some point the print head hit the part and it got completely skewed. Printing in void in the morning.

In order to achieve this I need to be able to generate less gunk on the nozzle so that the chances of the print succeeding are high. Notice that the initial layers are quite good and smooth. Less strings than before.

What do I need to change?

Regards,
Jorge

Attached:
Photo of the printed part
Attachments
R6 V5.stl
(1.44 MiB) Downloaded 20 times
IMG_0456.jpg
IMG_0457.jpg

Jetguy
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Re: Colorfabb XT-CF20 for 40h print

Postby Jetguy » Fri Oct 06, 2017 2:06 pm

I know this isn't going to be super helpful but this is the little bit I know about your situation.
#1 anything carbon fiber filled is insanely abrasive and will destroy a nozzle in short order. When it does wear the nozzle, it opens up the exit to a larger diameter and can be quite dramatic. At the same time because the nozzle is a cone shape and the tip is wearing away, now your layer height is changing at the same time nozzle width is changing. I'm hoping you are running the V2H hard coated nozzles and not stock brass, but even then, I cannot stress enough how fast some filament can kill a nozzle. Also, since the V2H is a coated nozzle, it wears well right up until the coating finally gives, then the base metal is normal brass. So yes, even a V2H could fail and do so in a relatively short period of time if even the slightest defect exists in the internal coating of the nozzle.
#2 The higher the temperature of most plastics, the more stringing and threads that just build up. Plastic is polymer chain- it want's to stay connected. Retraction only works well for smaller nozzle sizes. The larger the nozzle the easier for the plastic to just basically drip out. A smaller nozzle and the combined viscosity of the plastic slows and reduces drips and stringing. So if you nozzle wears or is just anything larger than a 0.4 and you run higher temps for the material to make stronger layer bonds- the tradeoff might be more ooze and stringing.

I wish I had some miracle answer that solved your problem but I'm just trying to explain why you might have some of the problems you showed.

Jetguy
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Re: Colorfabb XT-CF20 for 40h print

Postby Jetguy » Fri Oct 06, 2017 2:14 pm

Also in an attempt to help you. I know you want the part strong. But this is also an air intake right?
So I don't think you don't need 35% infill. That's at least part of the reason this print is 40 hours.
I see you are running high number of shells and for an air tight and strong part that is exactly what I would do.

Hopefully you are running your printer in single nozzle mode with the second nozzle completely removed. That should help with nozzle strikes into printed layers.

I just think you are printing a difficult part, trying to do small layer heights (good for strength) I think you also are printing with support material (more print time and complexity) and then you are running this high temp abrasive carbon fiber filament. I think the printer is capable, of all of this, but fine tuning, experience and perfectly dialed in settings and certain optimizations may bring the success you are looking for.

Without knowing the full STL file and the overall shape, I cannot fully evaluate how much and if any support is required but that is certainly contributing to your long print time.

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Brandon
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Re: Colorfabb XT-CF20 for 40h print

Postby Brandon » Fri Oct 06, 2017 3:36 pm

Hi Jorge,

Are you running auto repair on this before printing? The file is showing it is non manifold in IdeaMaker for me.

Nonmanifold.jpg


Thank you
Brandon

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walshlg
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Re: Colorfabb XT-CF20 for 40h print

Postby walshlg » Fri Oct 06, 2017 4:15 pm

you may need to insulate the hotend

rodriguejr
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Re: Colorfabb XT-CF20 for 40h print

Postby rodriguejr » Fri Oct 06, 2017 4:36 pm

Hi guys,

Thanks for your prompt replies.

@Jetguy: Thanks for your insightful comments, as always.

1) The nozzle is steel plated as recommended and I have used it just for this print. It is a 0.4mm
2) I may try the current settings for retraction with lower temperature (around 250C) with less infill (25%), higher layers. I have a Bondtech extruder, do you think I can make it go a bit faster than 50mm/s?
3) I will remove the second nozzle. I don't see any markings on the second nozzle (I run it higher than the left to avoid contact) but nevertheless I will remove it.
4) What

I have printed prototypes for this in PCMAX and PLA, both came out OK. PCMAX was kind of hard but after a couple of tweaks it worked OK.

@Brandon

Sorry. I have sent you the the STL out of Sketchup. I have executed repair in idea maker and it comes out OK.

@walshlg

How do I insulate the hot end and what is the purpose?

Regards,
Jorge

Jetguy
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Location: In a van, down by the river

Re: Colorfabb XT-CF20 for 40h print

Postby Jetguy » Fri Oct 06, 2017 5:09 pm

I sadly missed the STL in the first post and now I understand more seeing the picture and seeing what you are trying to print.
I know everybody wants to print in one piece. I get that. You think it's stronger and better.
So the problem is, that part is exactly what we call the impossible print. It's not actually impossible to print, but it violates all the rules.
There is no flat bottom on the part and has a tab sticking down. The large overhang snorkle is such a shape that it needs support.
No matter how you orient it, you are using support and anything supported is never as good as unsupported printing.

So here you are, wasting tons of carbon fiber expensive filament, already failed once because you are using huge amounts of support to print this in one piece. Flat out, it's not worth it. 40 hours? untold amounts of expensive material as waste?

The right answer is cut the part STL into much easier printable components.
There are 2 ways of really cutting that part that I see as making this much more printable and usable.
#1 would be cut the horn off and either glue it, or cut in such a way to leave a layer for easy attachment- or just redesign it.
#2 would be compromise, remove that tab on the underside and either glue it or modify it with another set of screw holes to print and attach.

Jetguy
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Location: In a van, down by the river

Re: Colorfabb XT-CF20 for 40h print

Postby Jetguy » Fri Oct 06, 2017 5:11 pm

Again, I get it that you printed it in other materials. It's not if you can print it, it's experience and understanding how and what happens with support and maximum part strength to include finish.

I want to see you print this part, but I don't want to see you keep trying and wasting material for reasons we know to fail- and in the end I want to see you learn from this and better understand how to use 3D printing as a tool in the toolbox. The better you understand how to use the tool, the more successful you will be.

Jetguy
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Re: Colorfabb XT-CF20 for 40h print

Postby Jetguy » Fri Oct 06, 2017 5:19 pm

Here is what I was getting at, I'm cutting this in Netfabb for you at a good layer where the parts can be printed with minimal or maybe even best case with no support. You print the lower half upside down flat on the build plate and the upper half as oriented.
STL cut.jpg


Now cut like this
STL cutpart1.jpg

STL cutpart2.jpg


Sorry, this is taking a bit, that STL cutting operation is taking some time on my computer which I thought was pretty fast until I tried this. I will keep trying to post the cut STL files but again, you just print them flat (have to flip the lower one 180 degress and put on the build platform) I honestly think this may be possible with zero support material.
Last edited by Jetguy on Fri Oct 06, 2017 5:34 pm, edited 1 time in total.

rodriguejr
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Re: Colorfabb XT-CF20 for 40h print

Postby rodriguejr » Fri Oct 06, 2017 5:32 pm

Hi Jetguy,

Thanks again for your help.

I think it is a good suggestion to remove the bottom bracket, I may try to find a way attach the part to the bike. I need to be a bit careful, since this thing is 150Kg/150HP and I cannot afford any loose parts or gluing stuff together.

I am giving it another try with the settings I posted. If it doesn't work I will definitely follow your suggestion of cutting the bottom.

If you have any other hints on how to improve this print they are much appreciated.

Regards,
Jorge

lami3d
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Location: Marseille - France

Re: Colorfabb XT-CF20 for 40h print

Postby lami3d » Fri Oct 06, 2017 5:40 pm

Hi,

first, you have to get a hardened nozzle (like ruby for example) to can resist to 40h print with abrasive filament.

i've also plastic sticking on the nozzle with xt-cf20 (and also XT clear), i found this : you have to break the angle by polishing it)
1458297480-post1.jpg

Results seems very good but i don't experience that.

I decrease layer height from 0.2 to 0.15 and it was better, i think 0.1mm layer height would be very good.

rodriguejr
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Re: Colorfabb XT-CF20 for 40h print

Postby rodriguejr » Fri Oct 06, 2017 5:55 pm

Hi Lami3D,

Thanks for your reply. How did you go about polishing your nozzle? Won't that remove the coating?

Regards,
Jorge

rodriguejr
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Re: Colorfabb XT-CF20 for 40h print

Postby rodriguejr » Fri Oct 06, 2017 5:58 pm

BTW here is the PCMax print (no finishing done since I need to shorten the intake a bit). Not to bad for my first print using PCMax.

Regards,
Jorge
IMG_0461.jpg
IMG_0460.jpg

lami3d
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Location: Marseille - France

Re: Colorfabb XT-CF20 for 40h print

Postby lami3d » Sat Oct 07, 2017 8:55 am

i didn't do that because i use these nozzles with abrasive material http://olssonruby.com/
I asked olssonruby if it's possible to add filet to their design but they don't do for the moment.

But it seems to work well. Maybe i 'm going to try to polish a brass nozzle when i print XT clear.

For XTCF20, i found that the phenomenon of plastic sticking to nozzle decresae when you decrease layer height (0.15 is better than 0.2 and 0.1 is better than 0.15).

EldRick
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Re: Colorfabb XT-CF20 for 40h print

Postby EldRick » Sat Oct 07, 2017 3:29 pm

This may not work well for CF XT because of the high temps, but wiping the nozzle with a bit of spray silicone on a paper towel before each print will greatly reduce plastic sticking to the nozzle.

Also, be aware that the carbon-fiber component adds almost nothing to the strength of these materials, and won't lighten the piece noticeably either. It is mostly useful for giving a rough matte finish to parts where that is desirable.

The carbon-fiber in these composite themoplastics is a small amount of extremely short fragments so they can pass thru the nozzle easily. You need long cf fibers to add any strength - think fiberglas. 20% fibers and 80% binder is not nearly enough for added strength. Also cf is almost the same density as the plastic binder so you don't save any weight.

For strength on a printable high-stress part, I'd suggest using polycarbonate instead.

rodriguejr
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Re: Colorfabb XT-CF20 for 40h print

Postby rodriguejr » Sun Oct 08, 2017 8:30 am

Hi Eldrick,

Thanks for the post. I have done a full print using PCMax and it looks solid. I have that backup plan if nothing else works. I was hoping to get the "Carbon fiber" look for the Air intake and rear parts (the rear is even bigger, so I will have to think how to cut it down).

Regards,
Jorge

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Julia Truchsess
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Re: Colorfabb XT-CF20 for 40h print

Postby Julia Truchsess » Sun Oct 08, 2017 1:42 pm

I agree with Eldrick that the CF doesn't add much strength, although it does add stiffness and has a nice matte look. For better strength and easier printing I'd recommend thicker layers. Thicker layers are stronger because each layer carries more stored heat energy as it's extruded, making stronger layer bonds. On such a large part there's no need for 150µ layers imo, you're just making life difficult for yourself. I'd go with 250 or 300µ.

Re splitting the part, yes I agree you should. Generally if you design along the same guidelines that must be observed for injection molded parts you will have good results with printed parts. And I agree you don't want to glue motorcycle parts together - design it so that it screws or bolts together.

A really good material for this application I think would be Nanodax Glass-Wool Polypropylene (GWPP):

http://haymaa.com/3d-eng/about-gwpp-filament/

Note glass wool is very different from glass fiber. GWPP is liquid-tight, has extremely strong layer bonding, does not stick to nozzles at all, and has higher temperature resistance than XT. It's not widely available yet, but they're very helpful if you send an email. Originally it was only available in white, so you'd have to paint it, but at one point they mentioned that black was coming, and I think it would be matte based on my experience with the material. It's easy to print and I don't think it's very abrasive on nozzles. It sticks well to ordinary packing tape; just put strips of tape on your build plate.

rodriguejr
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Re: Colorfabb XT-CF20 for 40h print

Postby rodriguejr » Mon Oct 09, 2017 1:48 pm

Hello Julia,

Thanks for your post.

Over the weekend I figured out new settings for XT-CF20 that now allow me to print without too much gunk on the nozzle, together with "cutting" the part to avoid the need for supports altogether. Unfortunately, overnight the throat tube got jammed by the XT-CF20 (I was a bit surprised since the temperature is now much higher) and I now need to disassemble the hot end to clear it up (the standard procedure is not working).

Regards,
Jorge

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Julia Truchsess
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Re: Colorfabb XT-CF20 for 40h print

Postby Julia Truchsess » Mon Oct 09, 2017 2:07 pm

It's natural to think that increasing temperature will cause plastic to flow better, and to some extent it's true, but higher temperature can result in more jamming with some materials, because it causes the material to swell up inside the throat tube. I don't know if it's the case for XT but it can definitely happen with PLA, especially PLA with fillers. I tried XT when it first came out years ago and had some terrible clogs; maybe they've improved it since then.

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walshlg
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Re: Colorfabb XT-CF20 for 40h print

Postby walshlg » Mon Oct 09, 2017 4:44 pm

Julia Truchsess wrote:
A really good material for this application I think would be Nanodax Glass-Wool Polypropylene (GWPP):

http://haymaa.com/3d-eng/about-gwpp-filament/



looks like not available until next spring


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