Re: 4-Axis CAM suggestions?

--- In CAD_CAM_EDM_DRO@y..., "Roger Swift" <vrsculptor@h...> wrote:

> I've been fairly successful doing 3-axis machining (Rhino > STL >

STLWorks (demo) > CNCPro >Gecko 340) on my converted Tree Journeyman.
So far I've just been playing but I want to add a 4th axis to machine
some irregular shapes.

The resulting G-code still only drives 3 axis, one of which is
rotary. This seems like a waste and a loss of capabilities when
CNCPro (and EMC) is ready and willing to drive all 4 axis.

>
> Do I have this right? Do any of you have any suggestions for

There are not many parts that you cannot machine with 3 axes linear
or 2 linear and 1 rotary. In the commercial world, those few parts
usually come under close scrutiny for redesign as the cost of more
axes goes up geometrically. Much of the equipment is one-off, there
are a lot of variations in the way the various axes are implemented
and even though there are standards, it seems that no two machines
are alike. Commercial post processors can be a significant part of
the cost of a Cad-Cam package and its not like taking a Fadal or Haas
and making a tweak or two.

I will illustrate some of the variations that I have stumbled across:

1) What is the rotary called? ABC-U-W something else?
2) Can it be programmed in absolute or does it require incremental?
3) Does it have to be rewound past 360 degrees, past 7200 degrees,
ever?
4) What direction is plus and which minus.
5) Is there a maximum angle of rotation?
6) How many decimals are required? mixed, 4 for linear 3 for rotary,
something else?

The list of variations is quite long.

Best Regards,

Fred Smith
IMService