Lowering manufacturing cycle times is a continuous challenge.

Reducing machine cycle time helps to increase production throughput and profits.

Cycle time depends on many factors including conveyors, process times, vision, clamps, tooling, operators, and robots. This presents techniques to reduce robot cycle time.

1. Cells with multiple robots must be sequenced properly to optimize cycle time.

   Restructuring interference zones reduces the amount of time the robots need to wait for each other.

   Robot A starts the cycle inside the interference zone while Robot B starts outside the interference zone. Then Robot A moves clear of the zone and Robot B finishes inside the zone.

   When sequenced correctly, the wait time for both robots' interference zone is minimized.

2. Rounding corners during the robot's movement will lower cycle time.

   Rounding corners means that, while moving, the robot does not reach the exact programmed point, but starts to move to the next point a certain distance before the programmed point.

   This reduces the robot deceleration between points and creates a rounded path.

   By reducing the deceleration times, the robot's overall path will be faster and cycle time lower. Use higher cornering values when the robot is moving between fixtures and use lower values when the robot is moving within the fixture.

3. When Fanuc position registers are used to offset positions, the look-ahead execution feature will be disabled automatically.

   This means that all moves that use offsets are executed as fine points regardless of the continuous settings in the program.

   To prevent this problem, use “lock preg” before the moves and “unlock preg” when the moves are complete.

   While the position registers are locked, the look-ahead execution will be enabled, and the robot path will round corners like regular positions.

4. Use the correct speed for the distance between points.

   Every time the robot moves from point to point, the robot accelerates to the programmed speed and then decelerates when the robot approaches the end point.

   If the programmed speed is too high, the robot will accelerate, but not reach the programmed speed, and will rapidly decelerate.

   The robot path is more efficient if the robot can accelerate, move along the path at the programmed speed, then decelerate smoothly.

5. Use the signals ‘open clamps early' and ‘request tool reposition' correctly to reduce the process time.

   Requesting a clamp reposition while the robot is moving and before it is required allows the clamp to open/close before the robot reaches it.

   This reduces the time the robot needs to stop and wait for the clamp reposition.

   ‘Open clamps early' signal allows the tooling clamps to open as soon as the robot is clear of the opening clamps.

   This will allow the clamps to open while the robot is moving instead of waiting until the robot reaches home.

6. Executing large angle wrist movements properly increases the efficiency of robot paths.

   Reduce large wrist (J4-J6) movements by eliminating positions where the wrist flips.

   Use long distance moves involving the major axis (J1-J3) to change wrist orientations.

   This will allow the wrist to change gradually during the major axis move.

7. For Kuka KRC 1 and 2 robots, adjust the system variable “filter” to change the fine point settling time.

   The settling time is the length of time that the robot waits after completing a fine move to execute the next command.

   Decreasing the settling time reduces the time it takes the robot to move from one fine point to another fine point.