JIT Delivery only if Your Plant is Running Like a Clock
The precision you would expect from a clock is a requisite for a plant to be capable of JIT Just-In-Time deliveries to their customers.
We have talked before of the procedure to bring your factory to comply with the Takt Time required by an order. Now it is time to see why this is so important.
If you compare your plant to a clock, each one of the synchronized parts of the clock would be the workstations. The weakest link will be the limit.
Traditionally associates see some unfairness in the work load distribution, and the traditional manufacturing system is exactly that. Assignment of tasks usually takes place as the needs arise and as long as a person or area of responsibility (called department in the past), can fulfill them, they get it. This of course has each individual, machine, team, working at a different pace or rhythm.
The concept of Lean Manufacturing cannot be efficiently implemented in such environment. It is like trying to produce a symphony when each musician has a different music paper in front and is playing at a different rhythm.
Symphony vs. Arrhythmia Synchronize your Plant's Capacity, your Cycle Times, Lead Times and assure your Takt Time to satisfy your customer's needs
Think of Lean as a Symphonic Orchestra. This will be a symphony with no “solos” but everyone chronometrically synchronized to produce the perfect output. Traditional manufacturing suffers from arrhythmia. Takt time is the metronome required to put everything into synch.
All the operations performed should therefore be acutely analyzed and time-measured and documented to produce a reasonable equilibrium so they all can be performed by anyone in a timely fashion.
Here is a new discovery within:
Many people are so comfortable with their operation that their performance is excellent; the leaders enjoy that, and would keep the person in that position for all of their lifetime. It might be monotonous for those doing the job, but they rather do that than go learn new tricks somewhere else. This is a vicious circle that affects the efficiency of most manufacturing companies.
Let us see some of its inconveniences:
If one of these “specialists” does not show up for work one day, the whole operation is dramatically disrupted.
The sentiment of “the other person has it much easier than I” keeps hurting the labor relationships.
The creativity of others who could come and discover better ways of doing something stays out of the picture, and that benefit is lost.
For these and many other reasons, it is critical that you start a serious cross-training process or else you will face the consequences sooner rather than later as you evolve into Lean Manufacturing.
Timing and Balancing the Operations
Sometimes we have the tendency to call an "operation" the series of actions performed at a work-station, when in reality they usually are more than one. What the most successful implementers have discovered is that you need to dissect each of those apart.
This is done by creating in a list of each action taken in the workstation. The result will lead us to discover a few inefficiencies, for example: a person re-drilling a hole that was made in other station with a smaller diameter than needed for the new screw that was introduced in the model a year ago.
You would be amazed at the number of these types of redundancies that happen in most traditional factories and even in some “Lean.”
When you do this dissection of operations, it will be much easier to balance the workloads of the different workstations.
I recommend starting by those you have discovered are taking the longest cycle times, which turn to be the "bottlenecks." In this whole process it is necessary to listen to the associates who are doing the work. They will be able to tell what could be done before or after, that will benefit or simplify their operation. As in all these improvements, trial and error is the most economical way to go.
As you work on this “balancing” of the workloads you will be able to see that your cycle times get closer to each other. Of course the sum of all cycle times, divided by the number of workstations is going to tell you a ball-park number of seconds which define your capacity to run products within that minimal takt time.