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AEV Uses Aircraft-Carrier Management Techniques to Manufacture Ambulances

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, and 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 work loads 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 work load 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 cut-a-way 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." 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 process 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 station. 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 field. 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. AEV's 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, MixIt-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 workflow 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 it's 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 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 in-house 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 US," 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 cabinet makers 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 ten 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 emphasis 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 ten-hour days, but we get more productivity during those ten hours than if we used a regularly scheduled day and didn't use staged manufacturing practices."

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