The G98 and G99 G Codes
The G98 and G99 G Codes
Here is this program explained line by line
Z15.0 M08;
First, we bring the drill down to 15mm above the surface of the material and turn on the coolant with M08
G82 G99 Z-4.0 R1.0 P500 F50.0;
This line sets our counterbore canned cycle by using G82 and sets the movement to our hole with G99, this tells the machine that once the first hole is drilled to retract to the R1.0 value and not the Z15.0 set by the line above.
The Z-4.0 is the depth of the counterbore
The P500 value is the dwell time that is set to 500 milliseconds that will take place once the drill has reached the bottom of the hole.
F is our feed rate in mm/min.
X20.0;
This is the distance from the first hole to the second along the X axis, it is taken as an incremental move and can include a Y movement and an optional Z depth if the depth of the hole differs from the first. The G99 code is still active from the line above so the drill will retract to 1.0mm above the surface as defined by the R value.
G98 X40.0;
This line drills our third hole 40mm in the plus direction along the X axis. It retracts to Z15.0 above the surface of the part after drilling the previous hole. The G98 code tells the control that we wish to ignore the retract value of 1mm that we defined by R in our canned cycle line and to return to the Z15.0 distance. Safely above our clamp.
G99 X20.0;
The final hole is drilled 20mm in X from the last hole, the G99 code tells the machine to retract back to the R position and not the Z position.
G80;
The G80 command is the G Code we use to tell the control that the canned cycle has ended.
It is common to make the mistake of
putting the G98/G99 on the wrong line. An easy way to remember it is that we add it to the hole position after the obstacle and not on the hole position before.
Drilling problem - machine crash
Reply with Quote
Originally Posted by oldlock
