Club Car lowers its handicap

The golf car maker has sharpened its manufacturing game with a pull system that simplifies production as it maximizes quality.

By Gary Forger, Editorial Director -- Modern Materials Handling, 12/1/2004

The name of Club Car's new golf car is the Precedent. But when it comes to the car's manufacturing and design processes, most everything is, well, unprecedented.

To begin, both manufacturing and design started with a clean sheet of paper. The end result, according to Club Car, 'is the most dramatic transformation of the golf car since three wheels and a tiller gave way to the modern electric golf car more than 30 years ago.'

The Precedent's design has 60% fewer parts than the previous model. That, in turn, has simplified the production process and reduced the opportunity for error. In addition, productivity has improved and throughput increased. But that's just the cover of the golf ball, so to speak.

'The ultimate goal is to receive materials, move them directly to the assembly line to build cars to a customer's specifications and then ship the car to the customer the same day,' says Club Car vice president of special projects, Hank Sanders. 'Because we've revamped everything from the way the car is designed, how materials are managed, how we assemble and how we ship the product, we're close to achieving that goal.'

To make that happen, Club Car has mixed some of the most traditional materials handling systems with leading edge information systems to manage its pull system. A manufacturing execution system directs all assembly activities as well as movement of work-in-process on 60 carriers along the towline conveyor (SI Handling Systems ). RFID tracks each carrier through production.

Four over/under conveyors (Siemens Logistics & Assembly Systems ) manage work-in-process along four sub-assembly lines that feed the main line. Meanwhile there is extensive use of manipulators and other ergonomic handling equipment to ease the strain on assembly workers. The production line is in an existing building once used for warehousing.

This is the first time that Club Car has used a pull system exclusively in assembly. Pull has been used for several years on another line, but only on portions of it.

Central to the success of the pull system is the manufacturing execution system (MES). It not only tells workers what needs to be assembled on a specific vehicle, but ensures no vehicle leaves a workstation until all quality parameters are met.

When the towline pulls a carrier into one of the 36 stations on the main line, the RFID tag that identifies the carrier is read. Although the carrier id information in the tag is no more than what can be included in a simple bar code, RFID is used for a couple of reasons.

For one, the RFID tag is read automatically unlike bar codes which, at Club Car, have always required a worker to stop and manually scan the label. That simplifies data collection and removes a step from the process. In addition, RFID is considered by Club Car to be more conducive to the manufacturing environment there.

Once read, that carrier identifier is then sent to the MES which sends build instructions for that particular vehicle to a terminal at the workstation. As that is happening, a worker pushes the carrier off the towline track into the station. This disengages the carrier from the continuously moving towline chain, and ensures it will not move to the next station until reconnected to the towline.

The signal to reconnect comes to workers from the MES when two conditions are fulfilled. To begin, work done at that station must be completed to specifications monitored by the MES. In addition, the software must receive a signal from the next station in the assembly sequence that it is ready for a new carrier.

At the majority of the workstations, assembly tools are used to secure bolts and other parts. But it all has to be done to pre-set standards.

'The system allows us to ensure that every bolt is torqued to exact specifications,' says project engineer Doug Crow. The tools are equipped with special Ethernet ports that send and receive data about torque requirements and the torque actually applied during assembly.

'If the MES detects even one bad torque, it notifies the operator right away, so that he or she can make the necessary correction,' adds Crow. 'And if the error isn't corrected immediately, the MES will not allow that car to move until the correction is made. The system dramatically reduces the possibility of errors making it to the end of the assembly line.'

Similarly, the dramatic reduction in parts on each golf car has reduced the opportunity for errors in production. As Sanders points out, Club Car 'wanted to improve the quality of the product by reducing the probability of error' wherever possible.

Even the number of parts staged at the workstations has been reduced. Typically only two to four hours' worth of materials are staged.

In fact, overall component inventories at the plant are kept to a minimum. There isn't much floor space for staging materials in general. So suppliers make multiple deliveries a day. Lift trucks deliver most parts ranging from fasteners and cables to leaf springs and other large parts directly from receiving to workstations.

Four major components are built on four separate over/under sub-assembly line conveyors strategically placed along the line. Those four components are: power train, frame, gas engine, and the power module which includes the gas tank or batteries, motor and clean air system. Completed components are delivered directly to the line for assembly on the carrier.

There is also a dedicated tire handling system. This conveyor system replaces pallet delivery of tires elsewhere at Club Car. A computer-controlled system ensures that tires are inflated to the right pressure prior to delivery to the line.

Many of the parts handled at Club Car are 30 pounds or heavier. To ensure workers are not strained by handling loads that are too heavy, special balancers and manipulators, intelligent lifting devices as well as lift tables are at workstations.

Air tools are mounted on pneumatic balancers just above operators' heads, keeping the tools within easy reach. Manipulators handle a range of parts at weights from 30 to 300 pounds. The power module with batteries is one of the heaviest items handled at the plant.

The plant also has two intelligent lift devices. One handles 80 pound batteries on the power module line, and the other moves 65 pound suspensions.

In addition, 25 lift tables are used at several locations throughout the plant. The typical application is positioning containers of parts. As parts are removed from containers, the air bellows in the air table adjusts the height of the container. This eliminates the need for workers to bend or otherwise strain to get at parts lower down in the container.

By all indications, Club Car has achieved all of the key targets for the project from simplified product design to simplified and improved manufacturing.