Sometimes complex problems
demand simple solutions. Thus was the case for Ford's
production facility in Cuautitlan, Mexico. The Cuautitlan
Ford facility produces between 300,000 and 400,000 cars
and trucks each year, and has 4 different car lines,
making it one of Ford's largest non-domestic production
facilities. From basic body construction and painting, to
putting on the tires, this Mexico-based facility is involved
in a diverse range of vehicle production. Ford produces
these cars in Cuautitlan using a method of just-in -time
suppliers as well, a system where parts are supplied by vendors on an as-needed
basis. Because of this, it is crucial that inventory and tracking in the plant be precise
and closely monitored, for quality control purposes.
It's no wonder that in such a large plant, keeping track of
inventory and production automation, can be a daunting
task. Before EMS stepped in, Ford was using a manual
coding system to track the auto and truck frames as
they went through the final assembly, paint, and body
shop areas of the production line. Unfortunately, this
manual system was very ineffective due to the frequency
of error, and the costs associated with such oversights
as painting a car the wrong color. The paper identification
sheets used to track the vehicles were being lost,
switched and ruined, making quality control extremely
A system was needed for tracking that could
clearly identify where a unit was on the production line,
what had already been done to it, and what still need to be completed. In contrast to
the manual method, RFID would prove to be a very effective solution for tracking and
routing auto bodies in Fords facility, largely because of the precise accuracy, and
read write storage capacity EMS technology offers. Considering the high expenses
associated with production error, RFID also provided a cost-effective solution to
Ford's tracking and identification applications.
When Ford decided that a new system of tracking was needed, they consulted Allen
Bradley for advice. EMS was recommended first and foremost, because of their wide
range of quality RFID products as well as their excellent record of service and
application support. Ford already has a history of looking
to Escort Memory Systems for identification routing
solutions. In the past few years EMS has worked on
projects such as engineering and installing tags directly
into the bolts used to put engines together.
bolts(HMS112 L012) serve as identifiers for each engine,
and can be tracked throughout production. Recognizing
their past successes with RFID and the potential for
future improvement, Ford Cuautitlan decided to switch
from their outdated manual paper tracking system to
RFID from EMS.
With EMS technology a tag could be
secured to a vehicle skid, then custom programmed with a serial number that would
be referenced through Ford's operating system (fig 1). This serial number can
indicate what has been done to each vehicle, as well as what still needed to be
completed as it goes through the production line. Information such as the color a car
is supposed to be painted, or what interior trim is supposed to be used can be
identified by referencing this serial number programmed into the tag.
There were a number of conditions that needed to be assessed before the correct
technology could be implemented for the job in Mexico. The tags to be used in the
plant had to be able to withstand extreme temperatures, due to the fact that they
would be used in enamel paint ovens (reaching temperatures up to 220 centigrade
degrees). For such an application, EMS engineers looked to the LRP family of
products. The LRP250HT tags were chosen because of their ability to withstand high
temperature environments, such as paint ovens, as well as their memory capacity,
and read-write capabilities.
Ford was originally unsure as to how many bytes would be needed per tag to run an
effective routing system. EMS recommended the LRP250HT tag, which has a more
than sufficient 48 byte memory, as well as a transfer rate of 1200 bytes per second.
The tags are now used to reference serial numbers up to 23 digits long in Ford's
internal operating system. This is a far cry from the manual coding system, where
instructions could be lost or mixed up with other vehicles, resulting in production
error, and costly mistakes. Because each tag is fixed to the skid that carries the
vehicle it is escorting, mixing up tags is is a problem of the past.
Mounting the tags required a unique solution. By
mounting the tags directly to the metal bodies of the
vehicles, the range would be compromised, and
interference would hinder the tag's ability to function at
normal levels. The solution involved constructing a skid to
carry the auto bodies. This skid was outfitted with a
teflon mounting bracket that has a 1/2 inch non-metal
border surrounding the tags, allowing for optimal range.
The Teflon proved to be a worthy material for the
mounting brackets, and did not interfere with the range or
read/write properties of the LRP250HT tags. Ford also
engineered the skids that the tags are mounted on in a
way that allows for them to be reused after a vehicle has passed through the
production process. The tags, still encased in the Teflon bracket, are cleared of
previous information, then stored on racks. After the skid is re-attached to a new
vehicle, the tag can be written to with the new identification characteristics
appropriate for the vehicle it is escorting.
When it came time to install the antenna to read the tags, EMS decided upon the
LRP-08 antenna, which met the range specifications Ford needed. Twenty antennas,
wired using RS485 transmission protocol, were used for the application; 5 in body
production, 12 in the painting process, and 3 in the final
assembly. These antennas were set into the floor of the
production line in a nylon based, explosion-proof
enclosure. As each skid would pass over the
antenna in the conveyer belt, the contents of the tags
would be sent to the LRP820 readers. The LRP820
reader was interfaced toFord's operating system using
the Lantronix MSS100 and the EMS module, the MM80.
The 1600 tags used in the facility relay information to the
operating system, via the Lantronix unit, in the form of a
serial number, as mentioned earlier. Portions of that
number describe numerous characteristics of the car
being produced; ranging from what line of car is being put together, to what color it
will be painted. As a vehicle passes through the different stages of production
different parts of the 22-23 digit serial number are referenced, to indicate what needs
to be done in each station. This is one of the biggest benefits of RFID.
previous manual coding system required each identification sheet be manually
updated at every turn in the production line, RFID allows updates to be written to the
tag, so that it is constantly being updated without risk of operator error. This means
crucial steps aren't skipped over, or executed twice. If, for example, a vehicle gets to
the paint oven, but has not undergone the necessary modifications in final assembly,
the machine operators will be alerted that there is a problem.
Ford has found EMS products to be extremely useful and effective in this application.
Not only have they been able to establish an accurate and efficient method for routing
and identification, but they have also had the opportunity to evolve their automated
production capabilities to include the relaying of more information than thought
previously possible. Ford Cuautitlan is yet another example of how EMS is helping to
keep industry leaders all over the world, right on track.
Escort Memory Systems