The most important resource in any manufacturing plant is time. It is one resource that cannot be bought and you only get a certain amount every day. Therefore, the wise use of time is critical. Machines cannot operate 100% of the time. When a ma-chine is not in operation producing product we say that machine is incurring down-time. Some downtime is positive and some is negative. Downtime must be scheduled to maintain and clean machines to keep them operating at peak efficiency. We call this planned downtime. It is placed in the production schedule and everyone prepares for planned downtime by having everything ready to make the best use of the time while the machine is down. The amount of planned downtime should be as little as possible, but as much as needed. If enough planned downtime is not included in the schedule, the machine will start shutting down unexpectedly.
The negative downtime is called unplanned downtime. Unplanned downtime is any stoppage of the machine that is not in the production schedule. Examples are electrical or mechanical breakdowns, power outages, lack of raw materials, operator errors, and quality problems. The goal for any manufacturing facility should be zero percent unplanned downtime. However, this goal cannot be achieved unless all employees realize the importance of preventing unplanned downtime.
Employees cannot concentrate on reducing unplanned downtime unless all downtime is measured and analyzed. The best method for measuring is to have the machines automatically record downtime into a computerized database program. Once the downtime is captured, the operators can explain the causes and plans can be formulated to eliminate those causes. Constantly being on the look out for impending downtime will go a long way to reducing it. The keys to this are constant patrolling of the production equipment and a good preventative maintenance program.