CONTROLLED AUTOMATION, INC.

BEAMLINE

CONVEYOR POSITIONING

The conveyors are controlled by AC or DC servo motors/controllers or DC motors and DC regen controllers. The conveyors will accelerate up to speed and then decelerate to a stop for an operation (punch, mark, stencil, etc.). The conveyors should accelerate and decelerate smoothly and stop at the final position without backing up (overshoot). The machine is set up to accelerate/decelerate lighter weight material faster and the heavier weight material slower. The top speed of the conveyors will also be faster for the lighter material than for the heavier material. Once the positioning constants for the conveyors are setup by Controlled Automation employees during the initial startup, they rarely need to be changed. If conveyor positioning problems arise, they are usually gradual and mechanical related. When conveyor positioning problems exist, length measurement accuracy suffers.

COMMON PROBLEMS

Loose chains, bad bearings, warped rollers, grooved rollers, and improper setting of or bad holddown/sideclamp assemblies can all cause conveyor positioning problems.

Loose chains cause positioning problems during acceleration, deceleration, and final positioning of the material. Loose chains cause the conveyor motors to turn without the conveyor rolls (material) moving immediately, or the conveyor motors to stop while the material is still moving.

Bad bearings can cause the same symptoms as the loose chains. They can also overload the conveyor motors causing the controller to fault, the conveyors to move and position slowly, and/or the motor to burn out.

Warped rollers will cause problems during the final positioning of the material. The motors and conveyors will stop at the correct position, but when the conveyor motor controller is disabled for a punch operation, the material may roll forward or reverse slightly.

Grooved rollers are an indication that the conveyor rolls are turning while the material is not moving, usually with lighter material. Possible reason are: holddown air pressure too low, holddown wheels bad, sideclamp air pressure too high, sideclamp rollers not horizontal (tilted), sideclamp rollers locked up (not turning), or the conveyors not aligned correctly (material binding).