The time occupied by the item within the cell is known as the throughput time, the time
spent in adding value to the item is known as the cycle time. In functional machine layouts
there is a considerable difference between these two values, however, in work cells the
difference is minor.
The cycle time is governed by the slowest operation within the cell. This does not necessarily
mean the slowest machine.
Now consider the operation times for each activity within the die casting cell.
|Casting ------------------------||60 seconds
|Separation -------------------||2 seconds
|Machining face -------------||15 seconds
|Drilling and tapping -------||20 seconds
|Inspection --------------------||10 seconds
The robot servicing this cell has to perform all of the transfer operations within the cycle time
of the die casting machine will have to wait until the robot is free before the unloading can
continue. This will result in underutilisation of the machine and possibly some process
problems could arise. It is necessary to remember that other processes must be
accommodated within the 60 second process time of the die casting machine. The available
time for work transfer can be worked out by taking the difference between the cycle time of
the die casting machine and the sum of the cycle times of the other processes.
Available time for robot is: 60 - (2 + 15 + 20) = 23 seconds
The inspection operation will be carried out using a vision system at the dispatch magazine.
This means that components need only be placed in the inspection machine, removal and
palletisation will be carried out by the inspection machine.
Your task is to design the robot cell complete with all machines required for the product. You
will need to select a robot capable of the task and finally to write the robot cycle for the
You will need some more information on the robot, firstly the robot will be required to have a
capability of turning through a 270 degree arc, it should be able to extend and contract its arm
and also move vertically.