Palletizing queue



I am using works process for plalletizing process. The robot is fixed to generic gantry which moves up-down and right-left. The robot makes the palletizing from 4 different conveyors. However, the problem is the palletizing is done automatically and not according to the queues of the products on the conveyors which makes problems that make the robot not reach all the process even though it makes high utilization.

I want to make the palletizing based on the longest queue.

Plus, how to control the gantry speed? It moves very slow. I tried to reduce the stroke but still it moves slowly.

You can see the attached image of the layout.