Instructions

D) g49–Cancels any unwanted tool length compensation that may have been left
active from previous run programs
E) g90–Orders the machine to use the absolute coordinate system where the
position will always be referenced from a zero point. Again, you can zero the
axis by going to [Pop In] [Offset].
F) X0, y0, z0 is self evident. If the slides weren’t in the 0 position they would
have moved to it.
This is the basic information that all programs should start with. If I had entered a g00
command to start with (orders the machine to move to the programmed position at fastest
speed) it would be a quicker but one that can be more risky to start with. Modern CNC
machines can perform g00 moves at speeds of 1400 inches a minute (35 mpm), and
you’re making a mistake by not taking advantage of this fact, but we’re not pros at this
time and I want you to learn about feeds. Hit the [ENTER] key.
5) g02 x0 y0 z0 i-.5 j0 – This line is the code that is going to actually produce the x y
movements to create that circle we have been talking about. In this case, all the
previous commands are still in effect except the g02 is replacing the g01.
A) g02 is ordering our robot to cut a circle or start an arc with a clockwise (CW)
move. For our faithful robot to carry out this order it needs more information
or it’s going to start complaining and sending you nasty little notes and refuse
to work. Remember that the g02 will remain in effect until a g01 is called for.
B) The g02 the program needs the x, y position entered as to where this arc will
end, and since we are creating a circle it obviously will end where it started so
the present position is entered.
C) Here are a couple of new commands; i and j, and they are used to describe the
center location of our circle. These dimensions are given as the actual distance
the center is located from the present position. It is very important to
understand that our present position is not the center of this circle and only a
starting point for this circle to be created. The i represents where the center of
the circle falls on the x-axis and the j represents the y-axis.
I would also like to add at this time that the distances calculated and entered for computer
generated shapes have to be extremely accurate, and a 0.0002″ error could stop your
program from running. This doesn’t have anything to do with the accuracy you need; it
pertains to the accuracy the computer needs to calculate the many points it creates to
generate the x y movements for this one circle. This shouldn’t be any problem because of
the low cost calculators we all have today that figure things to many decimal places. Hit
[ENTER]. (This is the last time for the [ENTER] command to be instructed. From now
on you will hit [Enter] at the end of each line of code.)
6) g01 g90 x0 y0 z0 f2–I always add a line of code with a g01 or g00 and a x,y,z to
return to the home position. The “g” commands stay in effect until they are
overwritten by another g command. In this case it would have left the control in a
circle command if we didn’t add this line of code which wouldn’t be a good
practice.
38