CAM G Code issue

[hato54]

I start with a Face milling but the Face mill will first go to Z0, then travel to the start point.

Then it goes to Z15 (Clearence), then Z5 (Feed) and last Z-0.5 (the milling level) which is ok.

Why will it start Z0, it should be Z15 (Clearence)before it travels to start point?

I must done some wrong????

Need help.

(1001)
(TEST1)
(T3 D=52. CR=0. - ZMIN=-0.5 - FACE MILL)
(T7 D=6. CR=0. - ZMIN=-15.5 - FLAT END MILL)
(T8 D=5. CR=0. TAPER=118DEG - ZMIN=-17.5 - DRILL)
G90 G94 G91.1 G40 G49 G17
G21
G28 G91 Z0.
G90

(FACE1)
M5
M9
T3 M6
S1000 M3
G54
M8
G0 X103.8 Y-36.106
G43 Z15. H3
Z5.
G1 Z4.7 F300.
G18 G3 X98.6 Z-0.5 R5.2
G1 X70.
X0. F1000............

Best regards

Håkan

[HughesTooling]

I think this might be set in the post-processor, what post are you using.

Mark.

[HughesTooling]

Looking at your code a bit more the G91 sets incremental mode so the z0 should not do anything.

Mark.

[Anonymous]

Have you tried running it yet, or are you just reading your gcode?

G28 is an interesting function that I've never used before. http://www.cnccookbook.com/CCCNCGCodeG28ReturntoReference.htm

I don't know why your machine would go to Z0 when it's calling a Z0 move using relative coordinates (G91).

[hato54]

I test the code without starting the machine (using Mach 3) and it really moves the spindle to Z0.

/Håkan

[hato54]

I will go to my shop and test it in the real world and see what happens...

[HughesTooling · Accepted solution]

G28 is listed as return to home for Mach3, so is your machine fitted with limit switches. I think Mach3 has machine coordinates and part coordinates it should be going to the machine home.

Mark

[Anonymous]

It is but I believe if you feed it a coordinate it goes to that location before returning to home, but in this case the coordinate is a relative Z0 so I'm not sure why it's moving anywhere other than machine home. Perhaps his machine home on Z is 0 and low on the Z travel. I always setup my machines so the top of Z travel is 0 and the rest is negative to avoid these sorts of mistakes.

[hato54]

Now a made the final test on the machine.

First I pushed the button "Ref all home" and then I jogged X, Y in the center of my vise and Z down and zero.

Then I started the machine...

It works just as You say Mark, the machine return to Z home, not Z0.

When a tested the code in the Mach 3 software (no machine was connected to this laptop) the Z moved to the Z0.

I think I have to simulate a "Ref all home" if I should make a "software" milling.

Thank You all for helping me

Best regards

/Håkan