RE: [CAD_CAM_EDM_DRO] Air assisted ball/screw on Z axis(table hei ght) ?

Lee,

To counteract the weight of the table the machine has a pneumatic cylinder
that holds most of the weight of the table. The motor than carries the
balance of the load and has to work against the mass but not the weight
(think of it like moving a object in space, it is weightless, but still has
mass that resists movement.). So, If you turn off the motor and shut down
the air the table will start to drop as the resistance of the ballscrew
friction and the non-energized motor is not enough to hold the table up.

Tim
[Denver, CO]

> The mills that Tim & I got have a plate on the Z axis drive
> motor that says:
>
> "This Machine has an air-assisted Z axis ball screw. The knee
> clamps must
> be tightened if the air pressure is removed and the console
> turned off.
> Otherwise the knee will lower itself to its bottom-most position."
>
>
> Could anyone shed more light on this and the concept of air
> assisted ball
> screws.
>
> Thanks, Lee