I'm new to CNC machining and just recently converted a G0759 mill to CNC using Hoss designs and recommendations. All appears to be working well but I just ran into the following problem with peck drilling cycles.
I generated a fairly simple G Code file via CamBam and when I tried to machine the part I ran into problems with the peck drill cycle. Specifically, the first hole or drill cycle is the problem, all holes following are fine. The first hole cycle appears to jump high speed down about .25 inches at the end of each peck. The drill lowers at the correct feed rate of 5.0. The drill then appears to drill down .125” as expected but then the drill goes high speed down another .25” and then retracts out of the hole high speed to where it started. For some reason MACH, or maybe my controller board AKZ250 is adding the additional .25” high speed plunge at the end of each peck.
Strangely, the second peck drilled hole in the G file works properly. I’ve even ended the drill cycle and started a new one in the G Code and it also works fine, just the first hole of the first peck drill cycle in the G Code file behaves this way.
Below is a simple code snipet that demonstrates the problem on MY system which is running MACH3 Version R3.043.066 on Windows 7 and talking to a AKZ250 USB interface controller.
Any help or advice appreciated.
G20 G90 G91.1 G64 G40
G0 Z0.125
M3 S2200
G0 X-0.613
G98
(the following peck cycle exhibits the problem)
G83 X-0.613 Y0.0 Z-0.6 Q0.125 R0.125 F5.0
(the following peck cycle works properly)
G83 X0.613 Z-0.6
G80
G98
(the following two peck cycle work properly)
G83 X-0.613 Y0.0 Z-0.6 Q0.125 R0.125 F5.0
G83 X0.613 Z-0.6
G80
G0 Z0.125
M5
M30