VMC ATC Cam Assembly

The ATC arm uses two signal wheels to control position sensing during the tool change:

• Left Wheel = Brake Signal Wheel
• Right Wheel = Cam Signal Wheel

Each wheel rotates past a fixed sensor block containing sensors S34 to S36. These sensors detect the arm’s position and trigger the next motion in the ATC sequence.

If the ATC arm does not reach the correct home position at the end of a tool change, or fails to travel below the spindle during tool exchange, the brake signal wheel likely needs adjustment.

Signal Wheels and Set Screws

The wheels are secured to the arm shaft by green-circled set screws (see image):

• Left screws adjust the brake signal wheel
• Right screws adjust the cam signal wheel

Adjusting Brake Timing – Brake Signal Wheel

• Loosen the left-side set screws.
• Adjust the wheel position:
  • Brake too slow → Move the brake signal wheel down to engage earlier.
  • Brake too fast → Move the brake signal wheel up to engage later.
• Use the alignment of the two blue marks as a starting point
• Retighten the screws and verify the brake engages and holds correctly at the beginning and end of the ATC arm motion.