confusing Gcode

This is Gcdoe from Fusion360

what I'm doing is simple, do a drill with T1 and it's tool offset H1, then switch to T5 and do a drill with the H5 offset.

what confuses me is that around the yellow mark, it do a change to T1 then call T5, but why? I'm using T1. And around the green mark, it do a G43 but instead of using whatever tool is set currently (T5), it set the off set to H1 (this is desired, but I don't understand what the Z0.6 before H1 does)

anyone has clue?
===============
%
(1001)
(T1 D=0.125 CR=0. TAPER=118DEG - ZMIN=-1. - DRILL)
(T5 D=0.25 CR=0. - ZMIN=-1. - FLAT END MILL)
N10 G90 G94 G17 G91.1 G61
N15 G20
N20 G53 G0 Z0.
(DRILL1)
N25 M9
N30 T1 M6
N35 T5
N40 S9170 M3
N45 G54
N50 M8
N60 G0 X0. Y0.
N65 G43 Z0.6 H1
N75 G0 Z0.2
N80 G98 G81 X0. Y0. Z-1. R0.2 F28.7
N85 G80
N90 G0 Z0.6
N100 M5
N105 G53 Z0.
(DRILL2)
N110 M9
N115 M1
N120 T5 M6
N125 T1
N130 S15000 M3
N135 G54
N140 M8
N150 G0 X0. Y0.
N155 G43 Z0.6 H5
N165 G0 Z0.2
N170 G81 X0. Y0. Z-1. R0.2 F30.
N175 G80
N180 G0 Z0.6
N190 M9
N195 G53 Z0.
N200 M30
%

Greetings,

Some Post Processors output the second "T" value for machines with tool carousels.

The logic is that while you are machining with T1, the carousel positions T5, ready for the next tool change, saving precious machine time.

Cheers,

Dave

Thanks a lot, that makes perfect sense. so what is the Z0.6 in the line N65 mean?

To expand on what Dave said, the tool isn't actually changed until after an M6 is commanded. (The T command only prepares the next tool, M6 changes it)
So the lines you have pointed out are still using tool #1. Tool #5 isn't inserted and used until line N120.

rogerxue wrote:

Thanks a lot, that makes perfect sense. so what is the Z0.6 in the line N65 mean?

That moves the Z axis to 0.6 including the tool offset amount.

cool, thanks