Two kinds of synchronisation
| Type | Purpose | Examples |
|---|---|---|
| Program (channel) sync | Channels wait for each other at sync points | Numbered wait M-codes (FANUC multi-path), WAITM (SINUMERIK) |
| Spindle sync | Main and sub-spindle rotate together for transfer | e.g. G114.1 on some FANUC lathes, COUPON on SINUMERIK |
Exact codes and whether they are available depend on the controller model, options and machine builder.
From CAM sync points to NC
- The programmer assigns operations to channels and adds sync points in CAM.
- The post writes one program per channel.
- At each sync point, the post outputs the matching wait code in every involved channel.
- Wait numbers are unique and increase through the program.
Example: SINUMERIK two-channel wait
; CHANNEL 1 ; CHANNEL 2
G0 X60 Z2 G0 X80 Z-50
WAITM(1,1,2) WAITM(1,1,2)
G1 Z-30 F0.2 G1 X40 F0.1
WAITM(2,1,2) WAITM(2,1,2)Pitfalls the post must avoid
- Deadlock: one channel waits for a code the other never reaches.
- Mismatched numbering: wait codes out of order between channels.
- Collisions: channels allowed to move into the same zone at the same time.
- Transfer timing: cut-off before the sub-spindle has clamped.
Verification
Multi-channel simulation with the real machine model is the only reliable way to check timing and interference before cutting.
In multi-channel machining, a missing wait code is a collision waiting to happen.
Mill-turn synchronisation
See our CNC post processor development service and multi-turret posts.