Re: [CAD_CAM_EDM_DRO] Re: Backlash effect on Part accuracy

shadi_salhab_78 wrote:

>
> Hi Jon,
>
> What is climb mill and what is it's advantage?
>
> Thanks.

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Hello Shadi_Salhab,

Climb milling refers to a particular direction in which the milling
takes place. Assuming that your spindle rotates clockwise, as most do,
then milling the outer wall of a pocket in a clockwise direction would
be "conventional milling" while milling the same wall in a
counterclockwise direction would be "climb milling".

Conventional milling is recommended for most operations because it is
predictable and stable and the safer of the two methods.

Climb milling produces a much nicer surface but has a tendancy to grab
and pull the part into the endmill bit. This can result in chatter
(excessive vibration of the part) if there is sufficient backlash. It
can also jerk a part out of a vise if the part is not firmly secured.
Been there...done that.

I usually hog out most of a pocket with deep cuts, within the limits of
my little Sherline CNC mill, using conventional milling. Then, to make
it pretty, I may skim off the last 0.010 inches of wall using climb
milling. I often skim off zero with climb milling and just let the bit
scrape the debris off the wall.

Tom Hubin
thubin@...