Re: Z axis drive

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Anders Wallin
<anders.wallin@h...> wrote:

>
> >
> >
> >Gerry,
> >Nice conversion! Do you feel the counter weight system was

required?

> >Just curious as I have an RF45 clone comming soon and will be

doing a

> >CNC conversion.
> >Thanks!
> >Bob
> >
> >
> In my experience, when moving the whole milling head, it's

definitely

> required (unless ofcourse you use a very powerful Z-motor).
> The Z-axis is now the most easily moving axis on my machine.
> The counterweight does add to the intertia of the system, so max
> acceleration is basically divided by two, but otherwise there are

no

> problems. most commercial vmc's that I've seen construction

pictures of

> use the same solution.
> See http://www.anderswallin.net/2004/11/cnc-milling-of-mdf-

plug/

> for my BF20 size mill conversion.
>
> AW
>

All the commercial VMCs I've worked on use hydraulic or pneumatic
counterbalencing on the Z axis, usually hydraulic and with the
cylinder in a 2:1 compound arangment with chains like on a forklift.
Reduces the inertia problem since the counterballance is some chain
and a piston as opposed to a giant weight.

Pete C.