Re: Climb Milling

--- In CAD_CAM_EDM_DRO@y..., ron ginger <ronginger@r...> wrote:

> Sure, the program can cause the motor to backup to the right
> mathematical spot, but while its doing that compensation the table

is

> quite free to get grabbed by the tool.

Ron I think you have mixed up the purpose for backlash compensation.
1) Climb milling should never be done with acme lead screws, it is
dangerous. It is also unrelated to backlash compensation in software.
2)Ball screws with more than .001 backlash are probably not correctly
adjusted, or are worn out. With or without software compensation,
table jerk with ball screws is probably caused by the saddle sliding
from improperly adjusted gibs or worn ways(side flex or side slop).

>
> A great bit of proof why Ive always maintained software compensaton

for

> backlash is bogus.

2) Backlash compensation or other kinds of machine error correcting
in software will place the tool in a more accurate position, which
means that you can make a part with tighter tolerances with a less
accurate and less expensive machine. Usually this results in the
ability to accurately and reliably machine to tolerances 1/2 as wide
or 1/3 as wide. If you can hold +/- .003 without error compensation,
with it you can probably hold +/-.001 to +/-.0015. A fantastic
improvement in real capability with just a software cost, not the 2-3
times the machine cost that it would cost you to do it with a more
accurate milling machine and tooling.

Aside from the "supposed" improvements in surfaces from climb
milling, the real reason to use climb milling is for roughing, not
finishing. It takes approximately 1/3 the horsepower to climb mill
as compared to conventional mill the same material. This applies to
the spindle motor and the axis drive motors. This is one reason that
coolant becomes mandatory with CNC machining of metals. The amount of
cutting is dramatically greater and the heat build up in the material
and the chip, can become catastrophic if not constantly doused with
coolant.

Best Regards,

Fred Smith
IMService