Problem- Eccentric :confused:

[cb4]

It's probably been done before but I can't find anything on the web so here goes.

If we take two eccentric circles and rotate them we are able to reach everywhere. Thereby doing away with a lot of axles, linear bearings and lead screws. Basically it's an overarm router with an off centre turning table, as the circle turns it passes every point the arm can reach.

The circles are rotated by normal gears and motors hidden from view





The orange things are IPE80 beams supporting the collar for my large bearings



this allows the axis bearing the Z axis to rotate



The bed also rotates, It's supported by again two large bearings and a lot of little ones that keep it balanced



So there we have it full range of the cirkel



All we need are a few beefy bearings & gears which are cheap one less stepper motor and a whole lot of math which is free but causes headache

So... has anybody else tried controlling this and is it silliness or is it a good idea.

Kind Regs

Wouter Warnaar

[mactec54]

Hi cb4

A Great idea, But as you say will be a headache to do the programing, you also know anything is possable today

[Al_The_Man]

Are you wanting to do this purely mechanical? or do you intend to have some kind of processed control with feedback and require a key-input/display?
I am not fully clear on the objective, but I would look at a Galil card with gearing or electronic cam feature, the legacy cards can be obtained cheaply and would have ample power.
See the Galil site for animated examples.
Al.

[cb4]

It was supposed to be a cnc machine

The site you mentioned is full of nice calculations, thanks.

[cb4]

sorry last nights reply was rather late and obscure.

It must be able to mill aluminium and wood although more would be nice.

So far it's just a thought about a cheaper way to built a machine, I'm not made of money so doing away with a lot of expensive components while retaining the function was the idea.

A friend of mine remarked that it would be cheaper just to buy a pin router, my objection has always been that the work area is to small.

A set-up like this however would increase the work area to an acceptable level and allow me the precision and sturdiness of a well built router.

The design holds only lead screws and linear bearings on the Z-axis

In comparison to a conventional large gantry router it has one less stepper.

[LeeWay]

I can see a couple issues that may pop up. It would be difficult to put long pieces in place. Difficult to get things squared up to start with. Might be okay for things like coinage or things where you must mill all of the material and then cut a profile.

Not as handy when you need to retain an existing edge.

A three axis machine is incredibly simple in the way it operates. Basic gcode can be done by hand fairly easy for less complex parts. I don't think your concept will be anything near that easy to code. Depending on your skill level though, it might be worth the challenge.
I would only build a concept machine such as yours for the challenge and not to try and save money.
It would be cool to see it in action though. Not trying to deter you at all. Just my initial observations. I say go for it.