Maximizing Thruput: Protect It

After the constraint has been chosen, or identified, the next step is to protect it.

But, protect it from what? What you must protect the constraint from is the effect of malfunctions on machines that are non-constraints. You see, in a close-coupled system, anytime a non-constraint shuts down it immediately shuts down the constraint. This is because the entire line is the system . All things are connected. However, the constraint can be protected.  We do this by adding buffers in places, which will allow the constraint to continue to run during a typical malfunction of a non-constraint.

When this is done effectively,  significant increases in thruput can be achieved as seen in the example above.

A buffer that is upstream of the constraint will normally be full.  This is exactly what we want. Due to the fact that the upstream machines have been uncoupled from the constraint, they can now run faster than before which means that excess product can be produced.   This is what fills the buffer.

Now, when a malfunction occurs on a non-constraint machine upstream of the buffer, the constraint can continue to run using the product out in that buffer. This allows you time to fix the problem and start the machine backup before you run out the product in the buffer. If the buffer is sized properly, the chance that the constraint will shut down due to a malfunction upstream is greatly reduced. Every time this happens you have gained more thruput.

A buffer that is downstream of the constraint will normally be empty. This is exactly what we want. Due to the fact that the downstream machines have been uncoupled from the constraint, they can now run faster than before, which means that if any excess product accumulates in the buffer it will be used up quickly.   This is what keeps the buffer empty.

Now when a malfunction occurs on a non-constraint machine downstream of the buffer, the constraint can continue to run, storing its output in the buffer. This allows you time to fix the problem and start the machine backup before you completely fill the buffer. If the buffer is sized properly, the chance that the constraint will shut down due to a malfunction downstream is greatly reduced. Every time this happens you have gained more thruput.

Check out our next post: Maximizing Thruput: Buffers!

Posted in Blog, Maximizing Thruput Series, Thruput.