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How you should measure Overall Equipment Effectively
- Jan 03, 2019 -

How you should measure Overall Equipment Effectively



There seem to be a million ways to evaluate the performance of your packaging machinery.


You can measure your packaging line efficiency, its throughput, if the equipment is operating at maximum speed, and so on. These data points give you a measure of a piece of the system but not necessarily an overall view of how effective the equipment is.


This is where Overall Equipment Effectiveness (OEE) calculations step in to provide a big-picture view of your packaging machinery performance. In today's post, we explore OEE common terms, factors that affect OEE, and walk through an example of how to calculate Overall Equipment Effectiveness.


According to PMMI's 2017 Trends in Food Processing Operations Report, 3 out of 4 companies measure OEE. For good reason: this calculation provides powerful, objective, data-driven insights into areas of opportunity to maximize packaging equipment performance.


Factors Affecting OEE

PMMI's Primary Packaging Line Playbook explains that Overall Equipment Effectiveness is a combination of three factors:


Availability - Making things at the right time (keeping the machine up and running, minimizing downtime)

Performance - Making the right thing (the right SKU at the right speed)

Quality - Making things the right way (no defects, rework, or waste)

Put simply, OEE is a measure of exactly where you can improve in your packaging line. 


OEE Terms Defined

AVAILABILITY

Equipment availability reflects the percentage of scheduled time the machine is available for operation. The measure of availability only takes into account factors that cause a packaging machine to stop running during a time that it is scheduled to be running. If planned maintenance takes place during working hours, it should be subtracted from availability. However, if planned maintenance occurs during a plant-wide shutdown, it will not factor into availability and subsequently does not affect OEE.


Factors affecting packing machine availability can include:


Operators' break times

Performing changeovers to package different products or SKUs

Planned or unplanned maintenance

Equipment failure/breakdowns

Machine set-up and adjustment


PERFORMANCE

Every piece of packaging machinery has an ideal cycle time (the time it takes to complete one finished bag). Performance is measured against that ideal cycle time. So for the calculation of OEE, performance represents the speed at which the machine is currently running as a percentage of its ideal speed.


Idle time, minor stoppages, and overall reduced operating speeds will negatively affect packing machine performance.



QUALITY

How many packages created were within specification? Ideally, the answer would be 'all of them', but invariably there may be loss due to faulty or leaky seals, improper/inaccurate fills, or issues with package contaminants. Scrap, defects, rework, and reduced yield are factors that negatively affect quality.


Quality is represented as the portion of saleable units as a percentage of total units produced.


Packaging Machine OEE Example & Calculations

AVAILABILITY

Let's say a standard shift is 8 hours (480 minutes). Operators take a 30-minute lunch and two 15 minute breaks, as well as perform a changeover that requires 30 minutes to complete. Therefore, of the entire 480-minute shift, the packaging machine is running 390 minutes or is available 82% of scheduled time.


Availability = 390 min actual runtime/ 480 min scheduled runtime =82%



PERFORMANCE

Let's also assume that the packaging equipment in the example above ideally completes 60 cycles per minute (cpm), or one bag per second. But let's say that machine cycle time has slowed and is currently operating at 50 cpm, or one bag every 1.2 seconds. Therefore, the equipment is currently running at 83% of ideal performance.


Performance = 50 actual cpm / 60 ideal cpm =83%


QUALITY

Let's say that 5050 units of 19,500 produced were out of specification and did not pass quality checks. So only 14,450 were actually saleable. Therefore, quality is at 74%.


Quality = 14,450 saleable units / 19,500 total units produced =74%


OVERALL EQUIPMENT EFFECTIVENESS

OEE is computed by multiplying availability percent by performance percent by quality percent:


Availability (82%) x Performance (83%) x Quality (74%) =50% OEE


OEE Standards & Benchmarks

According to OEE.com, the generally accepted "world-class" goals for Overall Equipment Effectiveness are as follows:

Availability: 90%

Performance: 95%

Quality: 99%

...for a total OEE of 85%

While these numbers are useful, keep in mind their context. World Class OEE was calculated related to the Japanese automotive industry in the 1970s. Today, most manufacturing companies have OEE scores closer to 60%.


OEE.com recommends not fixating on the absolute number, but instead on improving it.


Conclusions

So what exactly does this all tell us?


When looking at our example above, the equipment is 50% effective, which is not ideal but not too far off from the 60% standard. It looks like there is room for improvement in all areas. A complete process audit should be conducted, with a special focus on parts of the process that affect packaging machine availability, performance, and package quality.


We recommend addressing the following questions when performing an audit in an effort to improve Overall Equipment Effectiveness of your packaging line:


Are employees' breaks staggered to allow for constant running of the machine?

Do packaging machine operators need additional training to better recognize and proactively address minor problems?

Do you have critical spare parts on hand at all times?

Do your packaging machines feature quick, tool-free changeover?

Is there opportunity for additional automation in the system?

Can your packaging machinery accommodate multiple bag sizes and styles?

Are the machine's jaws PRODUCING IMPROPER SEALS?

Is a PREVENTIVE MAINTENANCE PROGRAM in place and are periodic service audits performed?