AEV Uses Aircraft-Carrier Management techniques to Manufacture Ambulances
Reprinted with permission from Trailer & Body Builder Magazine
By John Nahas
American Emergency Vehicles (AEV), a division of the Halcore Group, is now the
third largest ambulance manufacturer in America," says Mark Van Arnam, president
and chief executive officer of AEV. The company has moved into the frontline of
supplying ambulances using rapid build-out and customer delivery schedules. As a
part of the Halcore Group, the largest ambulance manufacturing corporation in the
industry, AEV has learned to meet tight build out times by using a manufacturing
system that is similar to how an aircraft carrier readies its planes for launching.
"Our customers are in the emergency response business," says Van Arnam. "They
want to deal with a company that can respond rapidly to their needs for new
equipment"
A major factor in AEV's growth is derived from the ability to manufacture a quality
product in a shorter period, according to Van Arnam. "If the chassis and body are at
our back door and the customer has decided on the specifications, it takes seven
days for the product to go through the assembly stations. Even when adding a few
days for paint, we can turn out a vehicle in under 13 days from the time it enters the
plant."
He credits the rapid build out time directly to the company's ability to use staged
manufacturing techniques. "We use a similar system of staging our manufacturing
work that flight-deck personnel use to prepare and launch an airplane," says Van
Arnam, a veteran of the US Navy and 30-year participant of the ambulance industry.
As a carrier-based airplane moves from a lower deck storage area, it is made ready
for its flight mission in various stages. While the airplane is on the move to the flight
deck, the basic air warfare platform can be changed from a bombing mission to an
attack mission. The Navy accomplishes this by using skilled individuals and cross
training them. AEV incorporates the same philosophy for its staged manufacturing
operations.
At AEV, staged manufacturing involves moving a product through a series of
assembly stations on a timed schedule with each station adding a further level of
completion.
A central point of the staged manufacturing process is the assembly lane. The
assembly lane is the main route that a vehicle platform travels as it is manufactured
into an ambulance. Assembly stations where work is performed on the vehicle
intersect the lane. Normally, at the end of each working day, all vehicles under
construction are moved up to the next assembly station.
"Two different styles of vehicles can go down the lanes side by side," says Van
Arnam. The manufacturing flow rate is not dependent on the types of ambulances
we are building.
"We can put a type-I modular ambulance in one assembly lane, a type-II van style
ambulance in the next lane, and have them completed at the same time," says Van
Arnam. "The two major reasons are the skill level of our craftsmen and our ability to
stage each day's work on a very tight schedule.
"How we schedule the work into the assembly lanes and at each of the assembly
stations is very critical in completing our manufacturing mission,"says Van Arnam.
At each of the assembly stations, a detailed plan is given to the technician
specifically providing instructions on the build out of the vehicle. This instructional
plan is similar to plans that would be included in a model airplane kit, except that it
also includes time allotments for each procedure.
'We strive for even workloads and not to overburden one assembly lane over
another," Van Arnam says. "Nothing physically ties the various lanes together, so it
is possible that one lane would get a greater workload and have to hold vehicles
over. Our production planning is so exact because we want to avoid that issue. We
know the times that the procedures take, so we use this to design the workloads
evenly."
Assembly Station Stopovers
AEV's commitment to staged manufacturing is apparent in the design of its new
plant. "Our new facility is designed for using the staging methodology as our
procedure for manufacturing ambulances," says Van Arnam. The new facility was
architecturally planned to use staged manufacturing techniques and to have the
ability to house the nine assembly stations in a linear format.
"The nine assembly stations are designed to provide starting points for different
procedures, although the final part of an earlier procedure might be completed later
in the manufacturing process," says Randy Hanson, executive vice president of
manufacturing.
The AEV facility is designed with a coordination area as one of its assembly stations
so that chassis can be matched to bodies and placed into the assembly lanes. There
are normally three assembly lanes operating; however, AEV does have the ability to
open additional lanes as needed.
Once the chassis passes from the coordination area into the assembly area, it visits
the other eight assembly stations. They include body integration, harness
integration, electrical integration, cabinet and trim integration, upholstery
integration, quality control, detail and clean-up, and the delivery and inspection
station.
Body integration focuses on making the chassis ready to receive further building out
as an ambulance. This may encompass putting a new full length body cap on top of a
van, or combining a type-III body with the cab and chassis, explains Hanson.
"At body integration, we try to perform all the body mounting and welding
operations before the vehicles move to harness integration," says Hanson. "We will
weld structural supports inside a van body for a type-II ambulance, while we might
be integrating an ambulance body to a cutaway chassis on the other assembly lane."
"Harness integration is where a larger electrical wiring system is introduced to the
vehicle platform," says Hanson. "Everything is built upon the foundation of this
electrical harness."
The AEV plant contains specialized paint and finish equipment needed to complete
the manufacturing of an ambulance. Vehicles are never exposed to the outside
elements while under-going paint and finish. This paint booth is equipped with full
drying capabilities and has an automated paint proportioning system.
Integrating the harness into the vehicle is a demanding task. However, some feel
that the van style ambulance is actually easier to manufacture than type-I or typeIII styles because the wiring is located within the shell of the vehicle.
Located at the assembly stations are floor level exhaust vents that tie into a central
piping system to exhaust the fumes.
Each harness is manufactured specifically for the vehicle platform that it's going to
be installed in, incorporating all of the connective needs of the emergency and
medical equipment that will be added by the customer.
"Electrical integration starts the processes of adding more componentry to the
vehicle platform," says Hanson. More circuits are placed between the circuit boards
and readied for stringing through the cabinets for outlets and further equipment
connections.
Installation of cabinetry and wall plate mounting for electrical connections is started
in the trim assembly station. This is where the interior starts to look like an
ambulance and not just a bunch of wires hanging from different locations, explains
Hanson.
Seat coverings are added and floor covering is installed at the upholstery assembly
tation. Between trim and upholstery, a lot of the medical items and hardware needed
for the ambulance functions are added to the vehicle.
After all of these assembly stations are visited, the vehicle goes to a quality control
assembly station.
"There are five quality control inspectors who work up and down the assembly lanes
and who also provide inspections for the vehicle at this assembly station," says
Hanson.
"This is a very detailed and documented inspection area," says Vern Madewell,
engineering and quality control manager. "We would rather a unit or some part of it
fail during inspection than in the Reld. If we see something that isn't fitting correctly
let's say a cabinet that is hard to open or shut-it gets our attention immediately."
Paint and Finish
After a unit passes this station, it is taken off the assembly lane and placed in paint
and finish area for scheduling into the paint process. When the paint finish is
completed, the unit returns to the assembly lane where it is staged at the detail and
clean-up station.
The last and final stop is at the delivery-inspection assembly station for a complete
check of the vehicle's mechanical aspects, the electronic communications
componentry, the interior and exterior finish, the medical equipment, and many
other subsystems of the manufactured ambulance.
"Paint is not considered one of the assembly stops because we do our own
scheduling," says Terry Roberts, paint and finish manager. AEVs new facility has a
section where the vehicles ready for paint and finish work can be queued separately
from the assembly stations.
Although the paint facility itself is large, it is still combined under one roof with the
main plant. "We've built enough room into the plant so that a vehicle never has to be
exposed to the elements," says Roberts.
The paint booth is 16' tall x 16' wide x 40' long and is equipped with spray guns that
incorporate an Akzo Nobel, Mix it-2 proportioning system. "Something we do
differently is to have a maintenance crew work throughout the plant at night," says
Roberts. During that time, the crew cleans the booth, replaces the floor filters daily,
recoats the booth with Booth Coat solution on a weekly basis, and replaces the top
filters monthly. These maintenance items insure a quality finish.
"We do our own painting prep-work, and we also do a quality control check after the
paint finish is applied," says Roberts. "All of this is handled in such a short time
frame because the parts, and even any nameplates or insignia attachments, are
delivered to the paint area in kit form before work starts on that vehicle."
Kit Form
Another important factor to insure a consistent manufacturing flow rate is the work
done before a vehicle ever enters the assembly lanes. "We do all our engineering
and design, and we create a list of all the materials required to build out the vehicle
before it ever hits our back door," says Hanson. "We don't want a vehicle locked in
at an assembly station waiting on a needed part or cabinet assembly."
Before a chassis enters the plant, there is a complete set of build-out plans and a
detailed schedule of materials needed to complete the manufacturing process. "In
one microcosm of activity, we first check to ensure that all parts are available in our
plant, so that we can then put them into the assembly kits as the vehicles travel into
the different staging areas.
"To maintain the product flow rate throughout the different stages of assembly, each
staging has to be specifically detailed down to the smallest assembly procedure,"
says Hanson. "Our historical information allows us to get a good idea on breaking
down the staging points but then we also build in learning-curve time if this is a new
procedure for that craftsman."
Parts kits are provided at each assembly station with the needed parts for each
day's scheduled assembly procedures. "This keeps the manufacturing flow rate
moving at the planned work-flow pace," says Hanson.
"Several materials specialists make a detailed schedule of standard and optional
parts for each assembly station," says Hanson. When the plant facility was planned,
a room was designed for the assembly of the parts kits. The materials specialists pull
the parts from storage areas and organize them into individual plastic bins that are
made for each vehicle for its next day's assembly stopover.
"All of those parts kits are organized the day before they are needed and then
delivered to the appropriate assembly station the night before their use," says
Hanson. "The parts are ready for our craftsmen to use as soon as they begin that
day's assembly procedures. Not having a needed part at the plant is one issue, but
we don't want craftsmen chasing parts to complete their work.
"Substantial amounts of coordination and preparation go into a day's assembly work
at each station," says Hanson, "but this planning maintains a consistent
manufacturing flow rate that probably can't be beaten in the ambulance
manufacturing industry."
Vendor Supplied Subassembly
"We look at the dedicated resources that we can put into building a component, the
quality level of the finished product, and if we want to supply the continued research
and development investment into making the in-house product better as newer
technologies become available," says Van Arnam. "Because of this thought process,
we have made some decisions that might differ from some other ambulance
manufacturers," Van Arnam says. "We believe these decisions allow AEV to operate
at a higher quality margin." A component that AEV sources from an outside vendor is
the modular ambulance bodies for the type I and type III ambulance. AEV's internal
study showed that a vendor who can provide the latest computer and engineering
stress analysis should build the skeletal aluminum frame. AEV also wanted a vendor
that would put the research and development dollars into reviewing newer and
possibly more effective ways of building bodies with aluminum and lighter-weight
materials. "When we looked around at manufacturers of aluminum bodies, we soon
found that Mickey Body Company in the neighboring town of High Point, North
Carolina, had a level of aluminum construction expertise that couldn't be exceeded
elsewhere," says Van Arnam. "We formed a partnership with Mickey to design and
build the ambulance body that is used exclusively for the AEV product. "Mickey can
perform 3D modeling of our ambulance bodies," says Van Arnam. "This type of
analysis, along with Mickey's ability to perform finite element analysis (FEA), allows
AEV to provide some things that aren't common in the ambulance manufacturing
business. This is helpful for Europe where FEA is required or in building military
ambulances." The partnership with Mickey also allows for more customer-oriented
customization of both the interior and exterior of the body. '"We can add items to a
body or build custom aluminum compartments on a rapid-request basis, and know
that its done correctly," says Van Arnam.
In-House Manufacturing
At first glance, the AEV factory might appear to have several nonrelated
manufacturing operations housed under one roof. In separate areas apart from the
main assembly floor,facilities are used to manufacture electrical harnesses, light and
sound control boxes, cabinets, seating, and window/doorframes.
Along with the assembly plans used to build the ambulance, there are detailed plans
made for each part that will be manufactured in-house for that ambulance. "Our
shops know what components are needed to build out the ambulances that are
ordered," says Van Arnam. "The managers of those shops work with our parts
manager to insure that we have the right items to keep the workflow moving."
Detailed schematics of the electrical wiring harness and circuit boards are prepared
and sent to the electrical wiring shop. "If wires are not cut to the correct lengths or
not included in the harness, that can slow the progress of the assembly," says Van
Arnam.
AEV manufactures each harness to meet the customer's chassis and electrical
specifications. "Everything that is added to the lighting, radio, and medical
equipment plan must have a power source and a connecting point," says Van Arnam.
"We build the harness and circuit boards realizing the rigors of the ambulance
business and maintaining zero tolerance for electrical connection problems."
The harnesses are constructed using several 15' x 25' pegboards that can be set up
in pattern jigs to manufacture different wiring harness models. The computer
schematic used to set up the jig provides for wire gauge, color, and numbering on
the wire. Any deviation from this plan requires that the engineering group be
notified so that a new schematic can be produced. The schematics are eventually
incorporated into the owner's manual for that particular ambulance.
"If a customer needs a new harness for a five year-old ambulance, we can build one
in one day," says Van Arnam. "All we need is a VIN number and we will have the
exact computer information of how we manufactured the last one. We just plug the
needed connector points into the board, and it will take a few hours to build the new
harness."
Another substantial component of an ambulance is the emergency lighting and
approach warning system. Greater demands are being placed on ambulance
manufacturers to incorporate more accident scene lighting, audible warning
equipment, and approach lighting.
"Early emergency equipment had a siren and a few extra lights to warn of the
ambulance's approach," says Van Arnam. "Today, an emergency vehicle
manufacturer is confronted by a greater selection of equipment that a customer
might want Wire harness jigs are used to manufacture complicated wiring harnesses
which connect to emergency sound and lighting equipment, medical equipment, and
handle all of the standard vehicle's electrical needs on the vehicle. This makes
having clear and ergonomically designed in-cab control panels for these devices very
important."
AEV's answer to this market demand was to incorporate the manufacturing of switch
panels and consoles into its repertoire as subassembly operations.
"We manufacture the in-cab panel devices because we can design them to fit
ergonomically, and we have control over the back side connections," says Van
Arnam. "We can design the cab for the driver to have control over the radio and the
warning systems and not be bothered with redundant controls or a rocker switch
that just covers up a hole in a prefabricated panel."
AEV performs the plastic engraving for the cover plates inhouse after the customer's
light and audible warning system has been designed. The plastic plate, switch covers,
and metal housing unit go together and form a subassembly that will be stored in a
labeled parts kit, ready for delivery to the appropriate assembly station.
"When people first look inside an ambulance, they are surprised by the amount of
cabinet space," says Van Arnam. "Cabinet fit becomes a big issue. Because of this,
we have a dedicated area within the plant that manufactures all of our interior
cabinets.
"Most of our customers want the interior space to be designed to their
specifications," says Van Arnam. "They have a certain pattern that works well for
their emergency equipment and medical protocol, and that's the interior
configuration they want"
AEV is able to quickly meet the needs of its customers by manufacturing all the
interior cabinetry. Each ambulance has a cabinetry plan that is sent to the cabinet
shop. From there, the cabinetmakers proceed with the design and layout of all the
cabinets.
"We cut all the wood product and begin cabinet construction for that specific
ambulance in advance of the chassis' arrival at our facility," says Van Arnam. "By the
time the chassis hits our facility, we usually have the complete interior cabinet space
manufactured and laminated and ready for installation into the vehicle."
Along with the cabinetry, the seat shop also manufactures all of the vinyl seating
areas. "We have numerous color and material choices for the customer to specify,"
says Van Arnam. Once that covering is chosen, we will construct the interior seating
surfaces to customer specifications.
"As you know, North Carolina is the furniture manufacturing capital of the U.S.,"
says Van Arnam. "We are fortunate that we are headquartered in an area that has a
great depth of furniture and cabinet manufacturing expertise.
"By having our cabinetmakers and our electrical harness people working on the
project before the chassis hits our facility, we shorten the build-out time that our
customer has to wait."
Requiring Assembly Depth
Both Van Arnam and Jeff Dreyer, production manager, credit the skilled assemblers
with keeping the assembly lanes moving without a "push-pull" effect.
"AEV gives a lot of latitude to the assemblers in how they handle the building time
once a vehicle is at their assembly station," says Dreyer. "Everyone on the floor
handles that responsibility very well, even if they have to stay late to finish a
procedure before that vehicle moves to the next assembly station."
AEV doesn't employ craftsmen based upon one specific skill. "In a staged
manufacturing environment, we are buying ten hours of labor a day, and we buy it
from very skilled individuals who can perform many different assembly skills," says
Van Arnam.
"An assembler upstream might be called on to finish the installation of an electrical
subassembly after the vehicle has left the electrical integration assembly station,"
says Van Arnam. "Because we are not waiting for the electrical assembler to walk
over from another building or to finish another job, we cut down on a tremendous
amount of wasted time."
AEV invests heavily in training its production craftsmen in new skills and techniques
for building ambulances. Based in the picturesque town of Jefferson, North Carolina,
AEV has been able to build a loyal workforce that enjoys the Appalachian Mountain
lifestyle. "We actually have a waiting list of potential candidates that want to work
for us and live in this area," says Van Arnam. "Because of this, we look at the town
of Jefferson as a contributing partner in bringing quality employment candidates to
our doors."
The plant's operational hours are also tailored for the workforce. "Many of our
craftsmen have small farms or grow Christmas trees," says Van Arnam. "We operate
the factory for 10 hours a day, and everyone gets Fridays off.
"We just don't have the workforce turnover that some manufacturers face," says
Van Arnam. "Our craftsmen like living in this area. That's important because we look
at training our craftsmen as an investment. We can see real returns from that
training by looking at the varied skills they have and the contribution that those
skills make to our system of staged manufacturing."
Custom Design
In 1996, AEV moved into its new plant facility. "The manufacturing facility is 73,000
sq. ft. and was constructed at a cost in excess of $2.5 million," Van Arnam says. It
was specifically designed to house our operation. I can't emphasize enough the
value of having the plant designed specifically for the job that we are doing.
"We believe our system turns out a better product in a shorter period of time than
many other manufacturing systems," says Van Arnam. 'We are able to perform the
work of a full 40-hour week in four days. Yes, we work 10-hour days, but we get
more productivity during those 10 hours than if we used a regularly scheduled day
and didn't use staged manufacturing practices."