Building a CF Tube

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joeman
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Building a CF Tube

Postby joeman » Fri May 03, 2019 11:03 pm

Hi,
Thought I'd create a post of my latest project - which is a Carbon Filament winding machine (as opposed to wrapping CF fabric around a mandrel).
Ultimately, I hope to use this winder to make myself some Carbon Fiber tubes for various rocketry projects into the future, including my L3 build which I hope to start a little later this year.

Why go to all this effort? (There is a lot of mucking around to get it working properly).
Figured I'd learn quite a bit from it....and that once I sort out the engineering issues I could wind tubes fairly easily with minimal effort.

Here are a list of "mechanical" issues I've had to contend with...
* Epoxy resin /Filament interactions (not too much, not too little, but just right amount of epoxy impregnated in Filament)
* Filament tension
* Filament winding width and spacing and angles - This is a biggy. Guides help to keep the Filament running straight.

Lots of headaches and it isn't cheap stuff, so I end up winding it back on to the reel after each test...rather than cutting off and binning.


Here is a very short Youtube video of two passes at 30 degree laydown.

https://youtu.be/kHR4sF1j6xI

I use LinuxCNC on an old server with a parallel port. It is connected to the network and runs a web server, which has a small program that I connect to using my browser to generate appropriate gcode files. Lots of programming, lots of maths (vectors!!) . Using stepper motors to turn the three axis...like the ones in home 3-D printers...except larger. 3-D printer has been my friend in this side project.

Hopefully I'll have some long CF tubes to show off in a month or so.

Anyhow, if anyone would like to know more about it, ask away... :)

Cheers

Joe
L1 - Callisto (H133) - 11-Jan-2016
L2 - March Fly (1633K940) - 18-Mar-2018 - RSO

joeman
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Re: Building a CF Tube

Postby joeman » Sun May 05, 2019 6:27 pm

Did a FULL layer today - dry run at 45 degrees without any issues.

Here is a photo of how it looked at the end of winding.

IMG_8543_SML.jpg
1 SINGLE run - 45 degrees (dry-run)


The Carbon Fiber makes very nice looking patterns. VERY happy with how it looks.


Hope to do a real-run with Epoxy sometime in the next week or so - three layers, varying angles.
L1 - Callisto (H133) - 11-Jan-2016
L2 - March Fly (1633K940) - 18-Mar-2018 - RSO

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Re: Building a CF Tube

Postby SpaceManMat » Sun May 05, 2019 10:49 pm

Very cool joe. I need to get off my arse and start using my 3D printer.
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strud
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Re: Building a CF Tube

Postby strud » Mon May 06, 2019 7:49 am

Awesome work!

How much tension do you need ?

I assume the epoxy bath/applicator is a messy place....

Exciting

joeman
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Re: Building a CF Tube

Postby joeman » Tue May 07, 2019 7:17 am

Cheers!

Need about 5 N of tension. i.e. not too much. Aiming ideally for 50/50 by weight. (CF vs Epoxy)

If tension is too great, I find that when CF changes direction I can have issues with it not staying put on Mandrel. I'll probably use some Peel Ply I have here to help squeeze out excessive Epoxy.

More experimentation required.
L1 - Callisto (H133) - 11-Jan-2016
L2 - March Fly (1633K940) - 18-Mar-2018 - RSO

joeman
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Re: Building a CF Tube

Postby joeman » Thu May 30, 2019 1:47 pm

Hi
I’ve managed to make my first multi layered tube. 30,45,30 degree. Carbon fiber laid perfectly.

This is a massive step forward from previous winding.

Image

Look carefully and you can see the distinctive pattern. Did a test fit using Matt’s 75mm hardware. Was a good fit! (Thanks Matt!)

Didn’t go all to plan as you’d expect on the first multi-layer attempt.I didn’t set it to spin after finishing....so was more work to finish it. Didn’t finish as well as it should. Also, not enough excess epoxy expelled.

I’ve got some heat shrink tape and I can now mount a heat gun on the setup to help squeeze out excess epoxy evenly.


There is still much to be done before I start winding the next tube, which if satisfactory will be used for my next rocket project.

Hopefully I will have something to share soon.

Cheers!

Joe





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L1 - Callisto (H133) - 11-Jan-2016
L2 - March Fly (1633K940) - 18-Mar-2018 - RSO

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OverTheTop
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Re: Building a CF Tube

Postby OverTheTop » Thu May 30, 2019 2:13 pm

Excellent!
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strud
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Re: Building a CF Tube

Postby strud » Thu May 30, 2019 2:16 pm

Awesome job.

What epoxy are you using?

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Re: Building a CF Tube

Postby joeman » Thu May 30, 2019 4:40 pm

Hi,
I'm using West Systems, though I'm considering using Renlam K3600 because it is less viscous.

The West Systems epoxy really hugs on to the roller and the CF tow, even with the doctor blade and high tension rubber band.

Cheers!

Joe
L1 - Callisto (H133) - 11-Jan-2016
L2 - March Fly (1633K940) - 18-Mar-2018 - RSO

drew
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Re: Building a CF Tube

Postby drew » Fri May 31, 2019 10:36 am

[quote="joeman"I use LinuxCNC on an old server with a parallel port.[/quote]

I can't put to words how much I enjoy the above sentence Joe. You're leveraging a parallel port in 2019!?!?! That's just plain awesome. Image

You're doing some great work, thanks for sharing and keep us up to date on your progress.

And yes, I recommend you switching to Renlam/Araldite K3600 for your epoxy system. Everything about it is wholly superior when compared to Wests in this use case.

drew
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AMRS Records Committee Chairman
Max Alt AGL - 26,850ft - L935 - THUNDA 2019
Max V - 3,004 ft/s, ~Mach 2.67 - L935 - THUNDA 2019

joeman
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Re: Building a CF Tube

Postby joeman » Thu Jun 13, 2019 2:37 pm

Thanks Drew!!

Thanks for coming and saying hi at Thunda

Yes, I remember using parallel port for some other project 20+ years ago!! Here I go again.

Regarding # of layers of CF, I’ve got some Finite Element analysis software... trying to ascertain the best configuration... angles and # of layers. I know it has to be balanced and symmetric..... basically I’m trying to ascertain the loads that I would expect at MaxQ. Fun stuff, but takes time to get something realistic.


Always learning!


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L1 - Callisto (H133) - 11-Jan-2016
L2 - March Fly (1633K940) - 18-Mar-2018 - RSO

joeman
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Re: Building a CF Tube

Postby joeman » Thu Jul 18, 2019 5:12 pm

Well I’ve spent about two months getting my head around FEA and I think I finally have a model of 3” tube with M3700 with various masses and forces you would expect at burnout....lift at nose cone, lift at fins, drag, etc

The result is that with 4 layers (each layer containing fiber in both directions, the failure index is really low.... about 0.005. If I play with laminate thickness (because I have had to guess it a bit), it creeps up to 0.01.
All acceptable.


Using 45,30,30,45 degrees. Changing to something like 40,20,20,40 doesn’t make much difference. The wonder had do lower angles, but I feel more comfortable with higher angles.


So tomorrow, time permitting I’m going to see if I can roll a 1.8m long 3” tube.

Cheers
Joe



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L1 - Callisto (H133) - 11-Jan-2016
L2 - March Fly (1633K940) - 18-Mar-2018 - RSO

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OverTheTop
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Re: Building a CF Tube

Postby OverTheTop » Thu Jul 18, 2019 6:30 pm

Nice work on this! 8)
TRA #13430
L3
"Everybody's simulation model is guilty until proven innocent" (Thomas H. Lawrence 1994)

drew
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Re: Building a CF Tube

Postby drew » Fri Jul 19, 2019 11:41 am

Great work Joe. I'm very keen to see you final weights for a given slice of airframe.
Andrew Hamilton
AMRS 28 L3
AMRS Records Committee Chairman
Max Alt AGL - 26,850ft - L935 - THUNDA 2019
Max V - 3,004 ft/s, ~Mach 2.67 - L935 - THUNDA 2019

joeman
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Re: Building a CF Tube

Postby joeman » Fri Jul 19, 2019 4:46 pm

Thanks guys.

I shouldn’t be so surprised, but I finished the wind!


Had almost one screwup with wires... (don’t ask). Fortunately it paused about a second later. (I have a pause between layers). Fixed it up and resumed it.

A few surprises...
* did take longer than expected ... a lot longer. Screwup in calcs....but not critical
* it was epoxy hungry.... even with renlam
* I think the app made it do about 5 too many passes per layer. Not serious but must be something wrong in code.

I have managed to put heat shrink tape on this time and a heat gun to help the cure and squeeze excess epoxy out.

I’m pretty sure it will be an improvement on last one.... and possibly usable for my next build - L3 build.


Image

Next step is dry ice tomorrow to remove it from mandrel.

Cheers

Joe



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L1 - Callisto (H133) - 11-Jan-2016
L2 - March Fly (1633K940) - 18-Mar-2018 - RSO


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