OEE Reports - Automated Capturing &
Recording of Availability Data
Moving Beyond Manual Data Collection
& Manual Data Compilation
Overall Equipment Effectiveness (OEE) continues to gain acceptance as an
effective method to measure production floor performance. Capturing and
recording accurate production floor information is critical for producing
reliable OEE Reports.
A number of production floors are utilizing manual methods of data collection
for producing OEE report. This approach leaves room for both inconsistencies and
inaccuracies. With manual data collection, there is usually a second step of
manually compiling the data. This is most commonly accomplished by entering in
the information into spreadsheets. This manual compilation step also leaves room
for both inconsistencies and inaccuracies.
Another disadvantage to manually collecting data for your OEE reports, like
with many maintenance and production improvement plans, is sustainability. The
more task intensive an improvement plan is, the more likely priorities will
change and the OEE initiative will fade away. With an automated data collection
system, sustainability is no longer an issue. Once in place the automated OEE
reporting stays in place and you need only act on the results.
There are cost effective automated data collection alternatives to manual
data collection that significantly improve the accuracy of OEE reports.
Automated capturing and recording of "Availability Information" will
be covered in this article. Future articles will address the automated data
collection of Performance Rate and Quality Rate.
OEE
OEE = Availability X Performance Rate X Quality Rate
Availability - Percent of scheduled
production (to measure reliability) or calendar hours 24/7/365 (to
measure equipment utilization) or equipment or line status (to measure
ability to produce), that equipment or a production line is available for
production.
Note: Measures the percent of time that the equipment can be used (usually
total hours of 24-7-365), divided by the equipment uptime (actual production).
Performance Rate - Percent of parts
produced per time frame, of maximum rate OEM rated production speed at. If OEM
specification is not available, use best known production rate or a standard
production rate can be established.
Note: Performance efficiency is the percentage of available time that the
equipment is producing product at its theoretical speed for individual
products. It measures speed losses. (i.e. inefficient batching, machine jams)
Quality Rate - Percent of good sellable
parts out of total parts produced per time frame.
Note: Determining the percent of the total output that is good. (i.e. all
products including production, engineering, rework and scrap.)
Example: 50% Availability (0.5) X 70%
Performance Rate (0.7) X 20% Quality Reject
Rate (results in 80%(0.8) acceptable) =
30%OEE (Please see www.DowntimeCentral.com/OEE_TEEP.htm
for a free online calculator to practice with.)
Defining What Is Availability
One of the first steps in initiating OEE reporting is defining the parameters
for the elements of OEE for the individual piece of equipment, production line
or the entire factory. That is clearly defining, documenting and communicating
why a piece of a piece of equipment or a production area is unavailable for
producing product.
There are three basic approaches to defining availability. The approaches are
the percent of scheduled production, calendar hours, and equipment or line
status. The schedule production approach defines availability by the production
schedule for a piece of equipment, a cell or an entire production line. The
calendar hours defines availability as the total time available to produce
product which is usually 7-24-365. The equipment or line status approach defines
availability in terms that production line or piece of equipment is in a state
to produce product. All three approaches are valid approaches. The percent of
scheduled production and calendar hours provide a broad view of availability
while the line status approach is a much more defined view.
Some examples to consider as causes for unavailability is power to piece of
equipment or does the production station have personnel in place. The above two
causes may not be enough to define the reason for unavailability. You may need
to add data inputs recording if there was materials in place or the status of
the infrastructure support (such as air pressure for air driven tools and
equipment) as monitoring points to determine if a piece of equipment, a cell
or an production line is available to produce a product. Availability must be
defined for each area or piece of equipment that will have OEE reports. In some
of the instances there will be more than one element that needs to be monitored
to determine if that piece of equipment or area is considered available.
Setting a goal of capturing availability status information with no manual
data collection or manual compilation for OEE calculations is the first step in
improving both the accuracy of OEE reports as wells as reducing the cost to
produce the reports. Start with defining what affects availability for various
areas of a production facility. Identify the specific data collection points
that will affect availability for a given area or unit of equipment. In many
cases there are data collection points already in place. For those monitoring
points, you need only to retrieve the existing data. In other instances, a data
collection monitoring device will need to be installed.
For installing new data collection points, there are available a variety of
inexpensive sensors that once installed, can capture the measurement of numerous
parameters. These sensors can detect flow rate, weight, quantity, motion
activity, phases of electrical power as wells as many other items. The sensors
usually come with normally open or normally closed switch contacts. These switch
contacts will serve as the data collection points for automated data collection.
Using sensors with switch contact outputs for most monitoring situations are
probably the easiest approach for capturing availability data. To monitor
equipment starting with power switches and other functions of equipment, it is
often the case of adding an extra set of inexpensive contacts to an existing
switch on the equipment.
There are other means to capture activity status information including
embedded equipment control software and equipment monitoring software that can
capture the parameters for availability. What must be factored into the
monitoring approach is that each monitoring point must include a time and date
stamp.
The data collected from the monitoring points must be transmitted to a
database for data retention and reporting. The database that captures and
records the status information can be a commonly available P/C database packages
such as Microsoft Access®. It is critical that all data points recorded must
include time, date and location stamps to support the development of OEE
reports. Database report writers can be used to extract the information to
produce OEE reports.
In addition to custom in house database systems, there are available
integrated data collection systems with application software packages with
complete OEE Reports. These systems and reporting can be tailored to each
individual facility's requirements.
The Wireless Connection
The implementation of the wireless LAN or other wireless technologies to
capture and transmit availability data greatly enhances the timeliness,
utilization and flexibility of the data collection system. Hard wired systems
over time, limit the functionality of a data collection system. In the past
wireless technologies did not provide the high level of reliability that is
required for factories, leaving the hard wired systems as the only alternative.
That is no longer true especially with the introduction of the wireless LAN
802.11g standard and advanced 900 MHz technology. Wireless data collection and
transmission systems provides for easy reconfigurations of changing production
floor layouts or changing production flow activity. A number of off-the-shelf
production floor wireless data collection systems are available for use on the
production floor.
Cost Justification
The implementation of an automated data collection system with an integrated
database provides immediate financial returns. The labor cost associated with
manual data collection on production lines by production personnel and the
manual compilation of the data to calculate OEE are eliminated with an automated
system. The accuracy and integrity of the source data is significant improved.
With more accurate OEE reports you will make better financially feasible
decisions that will result in even greater savings. The timeliness of the OEE
reports themselves are also significantly improved with automated data
collections. In most cases, the OEE Reports are available for review the same
date as the final element of information is captured.
About the Author: Bob Giese is
President of VersaCall Technologies Inc. which as been implementing wireless
factory floor monitoring and communications since 1995. To learn how a wireless
system would benefit your location e-mail sales@versacall.com or visit www.versacall.com.
Related Seminars:
Design
of Experiment (DOE Training) Six Sigma Training - 4 Day Workshop
Other Automated Equipment Data Collection Specialist (SCADA):
Automated
Equipment Company: California Electrical Contractor Services
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