Introduction Today’s world is dominated by digital technologies, the proliferation of Internet of Things helps in improving the businesses to acquire operational data, identify opportunities
Downtime is referred to the time when the machine is not working or not available for production although the production is scheduled. This time lapse can be due to time taken for the machine setup, tool adjustments, unplanned events like machine failure, material issues, cancelled orders, shortage of workers, shortage of raw materials, emergency break took by workers, etc.,
Downtime for any industry is one of the largest sources affecting productivity. Hence, downtime has to be kept minimal to improve the efficiency of production. Few measures to minimize the downtime are equipment management, integrating sustainable maintenance, focused improvement, availability of raw materials, training the workers on machine usage, practice safety measures, etc.,
Net Runtime in manufacturing metrics terms referring the actual time a machine is running after loss period. The Net Runtime of the any machine or asset calculation based on the total running time of the machine after subtracted the schedule, availability and performance losses.
For e.g. If the scheduled time of production in 1 shift is 8 hours i.e., 480 mins, due to some reason if the machine is not working for 30 mins, then,
Net Runtime = 480 – (30 + 10 + 10)
Planned Production Time is defined as the time schedule given to the machine for production. This happens when the plant is available 24 / 7 (All Time), but still it is used for production for specific schedules (based on the shift hours or other processes).
Planned Production Time = All time – Schedule losses.
If the plant produces only good products without any scrap / defect as fast as possible with absolutely no break, then the plant is said to have Fully Productive Time reaching its peak efficiency.
All industries necessitate a highly productive system, maintenance-free machinery and skilled operators to improve business sustainability and productivity gains. Hence, industries should aim at Fully Productive Time with respect to their assets. However it required extreme process and operating business model.
The losses that occur when the plant is not scheduled for operation is called Schedule Loss. This can be due to plant shutdown, during breaks, lunch, when there are no work order or lack of raw materials availability etc.,
Scheduled loss is the critical manufacturing metrics factors that used to find the production optimization.
Note: Schedule losses is considered in TEEP calculations and not in OEE.
Performance can be defined as the speed of production to its maximum attainable speed (as mentioned in the specifications). The losses occurred due to lack of performance is called Performance Loss. Performance Loss is mainly because of
- Micro stops
- Slow Cycles
Micro stops: When the machine stops for a very short time (a minute or less) due to frequent interruptions like misalignment of machinery parts, incorrect settings, jams, miss-feeds, blocked sensors etc. is called Micro stops. Unlike downtime, micro stop is for few seconds or just for a minute.
Slow Cycles: When the machine runs slower than its actual desired speed (mentioned in the name plate) is called Slow Cycles. This may be due to performance limitations, material quality, oil leaks, age of the machine, poor maintenance etc.
Slow Cycles may lead to poor quality of production, slower production rate, wastage of resources and power etc. Hence it is important to keep these losses minimal for efficient operations.
When the product is produced but it does not meet the quality standards of production or any defects in the product, then the product will be categorized as scrap. This is a loss to the production plant because the materials used for producing and the time and energy required for producing this defective product will be a waste. Even if the defective product is reworked upon, still the time and energy required for the rework is also a waste. Hence, Quality loss should be considered a serious aspect in every manufacturing industry.
Quality Loss may be because of
- Start-up rejects
- Production rejects
Start-up rejects: When the machine starts up and till it reaches stable production, there may be few products which may not attain specific standards, the product gets rejected.
Production rejects: The defects which occur when the machine is in stable operating condition and produces some defective products. This may be because of the old machineries, wrong machine settings, poor handling of machine parts, poor quality of raw materials, unskilled labors etc.
Work order can be defined as the way work is assigned to a particular person or the machinery. Work order tells how much production needs to be done in a particular order, in specified time frame with specified quality instructions and mention the due date for completion. Work order progress tells the rate at which assigned work is progressing at any point. Advantages of work order manufacturing metrics are:
- Helps the product engineer schedule, assign and track the work progress according to the requirements given by the customer.
- Assign the raw materials required for production.
- Helps set the deadlines and plan the rate of production accordingly.
- Predict the completion date for the assigned jobs.
- Helps track the performance of the machines and improve the efficiency if required.