3DE - 3D Printed Carbon Wrapped e-bike frame

Chambers

Chambers

100 W
Joined
Nov 11, 2011
Messages
298
Location
Brisbane
So while I slowly save money for my other project https://endless-sphere.com/forums/viewtopic.php?f=28&t=106672 I have been thinking about designing a 3D printed carbon wrapped frame.

The idea being that it would be 3D printable on a standard ender 3 style printer and build-able with some fairly basic tools, I have an idea for a simple drive using the BHT/GNG/LMX/LR style motor but I haven't modeled it yet -

If this all works out the way I hope I plan on releasing an opensource parametric model so if someone else wanted to build one they could tailor it to their size/motor choice etc... But that's a long way down the track...

A few pics of some early prototyping of the down tube top tube interface below... Feel free to tell me how terrible this idea is - but I'll probably try it anyway :lol:
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Answers to a few questions before they come up -

Why 3D printed - 3D printing is fairly accessible to most people these days and allows complex shapes to be designed and built repeatably.

Why not 3D print a split-mold - I could and still might go that route but if only making 1 it seems like a lot of extra effort and material.

I'll add some others as I think of them...
 
Super cool! Any chance you could print most of it in "vase mode" aka single perimeter, and then go for carbon lasagna? Perhaps fiber glass could be a place to experiment!
 
LewTwo said:
I am subscribing to this thread.
I am interested to see how this works out for you.
Click to expand...

Thanks it will be a fun experiment either way I think

Grantmac said:
You could do inflatable molds for the straight sections and save a bunch of print time.
Click to expand...
interesting idea, do you mean in conjunction with a clam shell mold?

cheapcookie said:
Super cool! Any chance you could print most of it in "vase mode" aka single perimeter, and then go for carbon lasagna? Perhaps fiber glass could be a place to experiment!
Click to expand...
Thanks, i think vase mode would be possible but might be a bit more delicate to put together? I have a fiber glass repair kit somewhere in my shed so I will use that for some initial tests
 
OK so maybe not SUPER simple :D Here's the rough design so far for Revision 1, This design uses the same motor and battery combo from my other bike (link in first post) so that I can interchange parts for testing. 3DE 1_LI.jpg
It differs from my other frame in that it will be using a more standard rocker arm style rear suspension, The motor mounting area will probably be made from laser cut aluminium with a layer of fiberglass in between to avoid galvanic corrosion
 
Chambers said:
Grantmac said:
Molds for the intersections and inflatable sections for the connecting areas.
Click to expand...

Ok I get it, but I have no idea how to make an inflatable mold :lol:
Click to expand...

Sections of inner tubes or similar.

HOWEVER on second thought I think it would be easier to just use off the shelf rectangular carbon tubes and then do custom molds for the intersections.
 
HOWEVER on second thought I think it would be easier to just use off the shelf rectangular carbon tubes and then do custom molds for the intersections.
Click to expand...
Yeah I thought about that too - problem is your limited by the tubes available etc..
 
Enough printed to do a bit of a test - Not the greatest fiber-glassing but it will do for a first test lay up
 

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LewTwo said:
My Stupid question: How does one determine how many layers may be required?

I an not a big fan of "proof by failure at speed"
Click to expand...
Haha yeah good question - and the only real answer is 'it depends' i.e. what type of fabric is being used in what area etc.

I'm not going to pretend I'm any kind of expert on the subject though, any good composite vendor has a material properties section and that's where I will start - there are also lots of good youtube videos on the subject.
I plan on figuring out what is necessary then adding more than that for piece of minds sake. I'll post my findings here as I go for others reference.

I find that I need to just start somewhere or I end up never starting.
 
Chambers said:
LewTwo said:
My Stupid question: How does one determine how many layers may be required?

I an not a big fan of "proof by failure at speed"
Click to expand...
Haha yeah good question - and the only real answer is 'it depends' i.e. what type of fabric is being used in what area etc.

I'm not going to pretend I'm any kind of expert on the subject though, any good composite vendor has a material properties section and that's where I will start - there are also lots of good youtube videos on the subject.
I plan on figuring out what is necessary then adding more than that for piece of minds sake. I'll post my findings here as I go for others reference.

I find that I need to just start somewhere or I end up never starting.
Click to expand...
Do not forget the resin component as well. Polyester has more give (i.e not as prone to fracture) but epoxy has more strength (not as prone to stretch).

I am looking forward to your research results. I have a design in mind (much more utilitarian). Carbon fiber or fiber glass might be a practical construction method ... as I have not room, or adequate power, (or money) for proper metal working equipment (i.e. welder, torch, ect).
 
This should work fine. If the first version needs some upgrades in one spot or another, that's just the normal development process.

A while back, there was a post about using abandoned foam. The builder used stiff hard foam insulation, carved it into the frame shape, inserted tubing for the head-tube and bottom bracket, "brazing" drop-outs, then overlaid it with carbon fiber cloth.

He mentioned that the foam could be dissolved with a solvent, but it didn't hurt anything to just leave it in. All of the stresses were carried by the hard shell. This is a brilliant use of 3D printing, and assembling many small pieces is a process that only needs to hold the shape for the fiberglass or carbon fiber to be applied.
 
I'm anxiously waiting for continuous carbon filament printing capabilities to come to DIY priced printers. They are currently able to produce parts with greater strength to weight than aluminum, but start at I believe $5k minimum.
Certainly in my lifespan I can foresee printing an entire bicycle frame at home.


Out of curiosity what are you using for a powerplant?
 
LewTwo said:
Chambers said:
LewTwo said:
My Stupid question: How does one determine how many layers may be required?

I an not a big fan of "proof by failure at speed"
Click to expand...
Haha yeah good question - and the only real answer is 'it depends' i.e. what type of fabric is being used in what area etc.

I'm not going to pretend I'm any kind of expert on the subject though, any good composite vendor has a material properties section and that's where I will start - there are also lots of good youtube videos on the subject.
I plan on figuring out what is necessary then adding more than that for piece of minds sake. I'll post my findings here as I go for others reference.

I find that I need to just start somewhere or I end up never starting.
Click to expand...
Do not forget the resin component as well. Polyester has more give (i.e not as prone to fracture) but epoxy has more strength (not as prone to stretch).

I am looking forward to your research results. I have a design in mind (much more utilitarian). Carbon fiber or fiber glass might be a practical construction method ... as I have not room, or adequate power, (or money) for proper metal working equipment (i.e. welder, torch, ect).
Click to expand...
Funnily enough I have all of that metal working equipment (used to do it for a living) and I love it but it's alot of work - especially to make more than one of something exactly the same. Do-able just lots of work.... I like the idea of 3d printing even though it takes a lot of time the machine is doing most of the work while you're doing other things.
 
spinningmagnets said:
This should work fine. If the first version needs some upgrades in one spot or another, that's just the normal development process.

A while back, there was a post about using abandoned foam. The builder used stiff hard foam insulation, carved it into the frame shape, inserted tubing for the head-tube and bottom bracket, "brazing" drop-outs, then overlaid it with carbon fiber cloth.

He mentioned that the foam could be dissolved with a solvent, but it didn't hurt anything to just leave it in. All of the stresses were carried by the hard shell. This is a brilliant use of 3D printing, and assembling many small pieces is a process that only needs to hold the shape for the fiberglass or carbon fiber to be applied.
Click to expand...
Thanks SM yes I think there is some real potential here. If someone really wanted to remove the print they could print with PVA and wash it out in water there is an artical from stratisys about it - though I'm not sure on it's availability for household 3d printers
 
Grantmac said:
I'm anxiously waiting for continuous carbon filament printing capabilities to come to DIY priced printers. They are currently able to produce parts with greater strength to weight than aluminum, but start at I believe $5k minimum.
Certainly in my lifespan I can foresee printing an entire bicycle frame at home.


Out of curiosity what are you using for a powerplant?
Click to expand...

Those commercial machines are pretty cool, one day I'm sure they'll be accessible but I think it's a long time before they are ender 3 price.

V1 pictured above is designed around using the parts from my other build (link in the first post) - Cyclone coaxial motor, I have a drive in mind that I haven't designed yet that will be cheaper and close to equal in performance for V2
 
What kind of plastic are you using?
Vase mode singlewall prints in large size are prone to warping heavily, especially if you use ABS.
Epoxy does not adhere to plastics, unless they have high load of GF/CF or somehow treated (like flame treatment) for better adhesion. You'll get a lot of crackles and pops when riding as interior plastic will delaminate from the shell.. don't ask me how I know :p.
If printing something like GF nylon, it is really strong in direction of the layers and adheres to epoxy very strongly - so it can be relied upon to be somewhat 'structural'.

However, unless your goal is to have 'flowing/organic' shapes, buying chinese carbon tubing from Ali and using lugs vaccum formed over a 3d printed mandrel to glue them together seems like a better idea. That's what I'm doing right now.

xh8WKKOh.jpg


Btw, you can have *too much* vaccum it seems, even using a hand pump, compromising strength. There is an easycomposite video where they explained 'ghetto vaccum bagging' using storage bags, and noted that you can pull too much.
 
BalorNG said:
What kind of plastic are you using?
Vase mode singlewall prints in large size are prone to warping heavily, especially if you use ABS.
Epoxy does not adhere to plastics, unless they have high load of GF/CF or somehow treated (like flame treatment) for better adhesion. You'll get a lot of crackles and pops when riding as interior plastic will delaminate from the shell.. don't ask me how I know :p.
If printing something like GF nylon, it is really strong in direction of the layers and adheres to epoxy very strongly - so it can be relied upon to be somewhat 'structural'.

However, unless your goal is to have 'flowing/organic' shapes, buying chinese carbon tubing from Ali and using lugs vaccum formed over a 3d printed mandrel to glue them together seems like a better idea. That's what I'm doing right now.

xh8WKKOh.jpg


Btw, you can have *too much* vaccum it seems, even using a hand pump, compromising strength. There is an easycomposite video where they explained 'ghetto vaccum bagging' using storage bags, and noted that you can pull too much.
Click to expand...
I plan to fully encapsulate the plastic, I'm using PLA for this initial proof of concept and the fibreglass seemed to bond very well - if this doesn't work out I'll proba ly explore PVA filament and dissolve it out with water after molding. Cheers
 
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