Harley-Davidson''s Engine Remanufacturing Program owes its existence to the nearly 1 million 1340 Evolution engines sold between 1984 and 1999, their loyal owners, and Lean assembly practices. The company launched a pilot operation in 1998 to meet customer needs, and it remains a profitable niche business segment for the company.
"We knew the twin cam engine was coming around the corner," says Glen Senger, a senior manufacturing engineer at Harley-Davidson. "We didn''t want all the people who owned Evolutions to feel the motor company was turning their back on them. So this was our way of saying ''we''re here to support this product.''"
Owners bring their bikes to authorized Harley-Davidson dealerships, where mechanics remove and place the engines in containers and ship them to the Milwaukee facility. The engines are dismantled, all paint is stripped off, and components are inspected. Then the heads, cylinders and flywheels are remanufactured to original factory specs. Reusable parts are machined, cylinders are rebored and rehoned, while heads get new seats and guides, etc. All parts are set to exact tolerances and passed through rigid specification checks. If they make the cut, they go on.
The engines are reassembled with new components, including rocker boxes, gear covers, valve trains, fasteners, gaskets, and bearings, usually using new crankcases as well, since the used crankcases seldom meet specs. Each engine is hot tested to Harley-Davidson standards. Engines that pass muster receive a one-year unlimited mileage factory warranty. After a final round of cleaning and polishing, engines are packed for shipping. Current output is 5-6 engines per day, and there is additional capacity if needed.
Harley-Davidson incorporates automation and manual labor in this cellular assembly operation. The line relies on automation to ensure proper torque on fasteners, proper machining on critical dimensions, assembly of critical components such as bearings, part and engine ID, and final testing. Lean machinery and manual assembly can be integrated by balancing setup, machine run, and labor time. Four employees are on the assembly line and 10 are involved in machining. The assembly employees rotate through all the functions and those in machining rotate through other machining positions so they are all cross-functionally trained.
Since the line builds per customer order, "we have created a one for one relationship," notes work group advisor Starr Rudolf. "Each order is taken to final assembly; consumption of the parts needed for that order triggers the machinist or the supplier to fill the demand as it is consumed. We have a 3-day internal turnaround, so we know that the parts need to be back at the line for assembly into a remanufactured engine within 3 days to maintain that turnaround. Based on historical usages, we have set minimum inventory requirements on all parts, which determines where to place the ''fill trigger.''"
The major challenge facing the implementation of Lean at the remanufacturing facility has been the "justification of new, highly flexible equipment based on the low volume and high product mix," Rudolf tells IEN. How can this dilemma be addressed? "Find alternate methods to accomplish the same job or bring in more work into the area. Currently we are working on both solutions."
What''s the latest thinking in the facility''s lean strategy? "Gain flexibility at final assembly by commonizing the assembly process," comments Rudolf. "To accomplish this feat, we need to maximize the space and presentation of parts at the line, place all model-specific information at the hands of the assemblers, and create a system that will allow the highest quality assurance."
Harley-Davidson is trying to innovate in other ways as well. "Cellular assembly can lead the cell designer(s) to a paradigm of high volume and low product mix through setup reductions and process improvements," Rudolf explains. "We have tried to avoid this paradigm by asking the question, ''What else do we want to (or have to) build or remanufacture across this cell?'' This may require a change in how you view a cell. It may require two cells that are conjoined at one point in the process, then divided at another point."
Photographs courtesy of Harley-Davidson Photography & Imaging. Copyright Harley-Davidson.