Re: [CAD_CAM_EDM_DRO] ball screw vs lead crew

On Thu, 22 Apr 2004 13:02:09 -0700 (PDT), you wrote:

>Hi,
>I have few questions to ask the group for help. Why do we only use ball screws for X and Y axis and for Z we use lead screw? Are there ways that we can use ball screws for all three axis? I have read many threads at Cnczone.com on this subject but I still need help. Could some one help me? Thanks

One reason may be just the cost. Another reason may be that since
ball screws are so efficient, pushing on the table will move the whole
assembly. Unless the head is rather precisely balanced, without
sufficient friction, the whole thing will come crashing down when
power is removed. This, I imagine, is Not Good (tm).....

The friction on an acme screw, while it does require a heavier motor
to move the head (even if balanced) will prevent the tools from going
walkies....

Harvey