Re: Simultaneity/versatility of movement

--- In CAD_CAM_EDM_DRO@y..., Bill Vance <ccq@x> wrote:

>For the part, lets say that we want to do a round conical
> version with a ramp that spirals around until it reaches the top.


>You then put the point on that opposiite corner, and placing the pen

on

> the end of the first arc, continue around and around, drawing a

spiral.

>
> Now for the questions. :-)
>
> can the xyz movements be programmed simultaneously; I.e., xyz

starting

> position, downward angle, arc point/ends, and arc direction all at

once, for

> each corner/arc, or would each move have to be individually

Arcs require a planar definition. Normally you do not program 3 axis
moves using arcs. This is primarily due to controller limitations
and in many cases because the means to develop the program is not
simple or cheap. You could use helical interpolation to develop the
arc end points with a notmal X-Y value and a changing Z. There is a
gotcha here in that many controllers *really* slow down when using
helical interpolation. It is used primarily for thread milling and
hence the Z values are sometimes interpolated to an extra decimal or
two. There may even be restrictions on maximum Z feed rates
available when helical interpolating.

However you will probably find that the Z axis in most machines is
not as strong and swift as the X & Y axes, so that if you do 3 axes
simultaneous contouring, you will be limited to the slowest one.

It is usually more efficient and faster to program a series of
waterline or planar rings (like defined with G17) with slight Z moves
in between each. The Z distance will represent the resulting scallop
height based on the size of your cutter and the problem becomes much
easier to define, program and cut. (about 30 seconds with VectorCam
to define and program).

Best Regards, Fred Smith- IMService
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