Re: [CAD_CAM_EDM_DRO] Re: Cncpro/Gcode

tauseef wrote:

> Hi everyone!
> I have some questions on CNCpro and G-codes. If anyone can help that
> would be great!
>
> 1) What is F5-F8 I01-I04 for?

Fxxx normally specifies feed rate, in IPM or mm/Min.

> 2) It has "V" (varibable) but I am not sure how to us this?
> 3) It has L (loop g-code) but I am unsure how to put this
> into a line, can anyone please provide me with an example?

The L word is used in traditional G-code as an optional specifier
for such things as alternate coordinate systems, length offset
selection, etc.

> 4) what is E-stop for? (emergency stop??)

Yes. usually there is a hardware component that watches for fault
conditions from various units like servo amps and spindle drives,
and manual emergency buttons, and also watches for an emergency
alarm from the CNC control. If there is an emergency (servo
runaway, spindle crash, etc.) it shuts off power to the axis drives
and stops the spindle, coolant, etc.

> 5) How and why do you use subroutines?

These could be useful if you had a number of similar features on
a part (or a pallet of identical parts). You would write the G-code
to do one, and then offset the coordinate system for each feature
or part, and run the subroutine to machine that part.

> 6) why would you use tool "length" compensation?

If you need to change tools to complete a part, you don't want to
have to measure the Z=0 offset every time you change the tool.
Of course, if you use collets and Jacobs chucks, you DO have
to measure every time. But, with tool holders, the end mill, drill,
etc. can be repeatably inserted into the spindle, and the CNC
control can keep the length of the tool in its tool table. When you
switch tools, you don't have to adjust for the different lengths
in the program, the length correction is computed from the length
stored in the tool table.

> 7)how do you use machine offset coordinates?

There are a number of ways to use this. The generic part offset is
set to X=0 Y=0 at the lower left corner, for instance, and then all
coordinates are the same as you would measure from that corner
with a caliper. But, you might have a fixture with a known offset
from a nice corner on the fixture to a hard to measure feature on
the part. Instead of having to make difficult alignment to that difficult
feature, you use an edge finder on the edges of the fixture, and then
enter to offset that is built into the fixture. Another use of the
multiple offsets is to machine several parts that are mounted to
a multi-part fixture with the same program. the program only
knows coordinates base on the part, but a different work offset is
programmed for the reference location of each part.

> 8)do I generally want to keep <V> const. contour off or on?

This is specific to the CNC control. If you have any cuts that
consist of many short line segments, then you probably want this
on. I'm guessing from the name that this allows the machine to move
smoothly from one line segment to the next, as long as they are
nearly in the same direction.

Jon