mounting linear guideways on carbon fiber structure

General Composites Discussions Engineering Talk
#1

Hi,
I want to make a linear slide using carbon fiber for the base and sled as opposed to the more traditional aluminum.

Normally, there will be a reference surface precision ground into the aluminum which the guide ways are pressed up against using tapered gibs.

This serves the purpose of straightening the guide ways and resisting lateral forces.

My current plan is to mold a similar ledge in a CF plate and use washers or a plate with threaded holes on the backside to spread out the force of the guide way and gib bolts.

My question are:

  1. How strong will a 2~3mm ledge be?
    Seems like this ledge will be prone to delamination. Will the rail pushing up against this ledge be considered localized force?

  2. What would be the ideal (or realistically doable) fiber orientation be for this ledge?
    UD with the fibers parallel to the guide way? UD with fibers perpendicular? Plain weave with fibers at 45 degrees?

  3. What kind of metal should I use for the washers if I factor in bond strength and the ability to spread out the pressure of the bolts?

  4. Will 6mm holes spaced 30mm apart create a fault line in the CF plate and dramatically weaken the structure?

Last but not least… Got a better idea?

Any thought, comments, or feedback would be appreciated.

#2

I’m sorry I can’t help much but I would use cloth with fibers running at a 45. I love the idea and question because I have a similar problem on a project of mine. Are you making a cnc router? Why carbon?

#3

Hi Oneturboneed,
Yes, I’m making a Z axis ram for my mill. Reduced weight, more rigidity, and possibly more vibration absorbtion.

What are you building?

#4

I’m Building a 5.5 x 12 x 3.5 foot cnc 5 axis router. Wow I never thought about using carbon to reduce vibes and even maybe a little weight. I think I’m gonna try and make another z out of carbon just to see what it does. Thanks for the idea.
I don’t think you will have to worry about delamination of the carbon on the rails as long as you dont use a compression type insert. Referring back to the original post.