Engineering Manufacturing Concepts
From wsuwiki
Kaizen
By E. F. Pierce
Implementation at Boeing
1999 was a big year for Boeing. In more relative terms it was a year of downsizing, not the standard employee style downsizing Boeing is known for, but the downsizing of production lines. 1999 was the year that Boeing began implementing the fundaments of Kaizen into its 737 production line. Prior to its implementation, it took 28 days to make one 737. Now it takes less than 11, and this number is going down.
The lean system isn’t just about making things go faster though, that’s just the result of improvements made in other areas. Prior to this change, airplane fuselages were arranged in the factory in a herringbone pattern, 29 planes, each in a station having certain work performed. When a plane was ready to move to another station, work stopped so the line could be reshuffled. Boeing lost 7.5 workdays every month due to the necessity of moving this line. Excess parts were stored in the building (sometimes the parking lot as well!) in some cases for many months due to the magnitude of the excess. Part of the introduction of lean was the closing of two 737 production lines, the advent of a moving line, and adaptation of a just-in-time part ordering system. The line has changed form 29, rather stationary airplanes in various states of assembly, to 11 stations, each with a certain job performed. The in-progress aircraft are highly mobile; in progress craft are either located on rollers or, in the case of the main line, on a magnetic track where the planes are oriented nose to tail. The first four stations are prior to the main moving line; these stations accept the fuselage as it comes in from the delivery train from Wichita where the tubes are assembled. Ancillaries are added here, prior to entering the main line where the wings are attached and the plane is installed to the magnetic track which traverses the factory at an ever-increasing rate of 1.4 planes per day. Prior to the in progress airplanes move into the next station, a forecasted event, and the parts needed for that station are ordered from a local supplier, a local Boeing factory working at the same rate as parts are needed in the 737 line.
The closing of the second line allowed for lower overhead costs, reduction of stored parts, introduction of a just in time parts cue. According to “Boeing Frontiers,” the company’s on-line magazine, “To date, the 737 program has shaved its flow time by 30 percent, reduced its crane moves 39 percent, lowered its inventory levels 42 percent, and reduced its needed floor space by 216,000 square feet. The tooling and equipment necessary to support assembly has been reduced by a factor of 12 to 1 in most cases and work in process (WIP) has been cut from 14 to 5 airplanes.” Figures 1 and 2 depict the assembly line at the Renton, Washington 737 assembly plant.
Kaizen
Kaizen is a Japanese word that literally means continuous improvement. Continuous improvement is at the heart of any lean manufacturing enterprise and is oftentimes not best viewed with Boeings 737 factory on Lake Washington. Continuous improvement can be better view perhaps at a small parts production facility, another leg in the extended-enterprise that adds value to a Boeing airplane.
Prior to “going lean” an operation to make a small part would perhaps make them in batches of hundreds to thousands, implying that the mean production time per part would be small, inventory on hand would be large (facilitating storage), production tools would be large and expensive, and errors would be confined to large batches. Improving this operation via a lean system would involve utilizing a just-in-time methodology to guide the production of the part so as stores would only contain just what is needed, machinery size and cost could be limited to just what is necessary to produce the part when it is needed, sand errors in manufacture creating the need for re-work or scrapping would be minimized to one part versus an entire batch. Just-in-time is one of the two pillars that support the concept of a lean production system. The time to produce a part will increase, but the cost-benefit of such an increase in production time is overshadowed by the increase in efficiency and lowering of cost by utilization of such a smaller process. The time to produce a part, called Takt time, is one of the sub groups in the just-in-time group. Takt time for a part to be produced is established from the total time it takes to make an assembly and is closely monitored so as to maintain product flow as well as decrease Takt time.
Small production scale also allows for more innovation by those in charge of production, the worker. The worker involved in this production can easily pinpoint flaws in the undertaking of the manufacture and improve on them. One of the items in the lean canon is the placement of power to innovate in the hands of those who the innovation will help. This is not to say that they are the only ones that have a say in it, however. In the Toyota production system, as at others who subscribe to Kaizen, such as Genie Industries and Boeing, a worker experiencing a deficit in production is encouraged to stop production and signal for help. This is second pillar of the lean production system and is known as Jidoka. Instigating this stopping of production by an Andon, or visual cue, halts production and calls for management on the floor, who will help a worker isolate production problems where they begin, solving them there, and increase the value added by a process. Jidoka seeks build quality into a production process, separate man from machine using intelligent automation. This is typically accomplished by implementing low-cost automation, error-proofing, equipment upgrades and reliability improvement.
The Lean Academy
During the summer of 2005 I interned with the Boeing company in their Liaison engineering division. During this internship I was subjected to Boeing’s “Lean Manufacturing Academy,” a one-week course in lean manufacturing designed to orient employees to the successful manufacturing scheme. The class consisted of a several guest lecturers and teachers, along with several hands on simulations devoted to honing the basics of lean in the minds of the students. The most notable of these was of course the “Circuit Board Factory” simulation. This excruciatingly frustrating, day-long, simulation had students in groups of 8 assembling working circuit boards. An assembly line, or factory, was developed at the beginning of the day and modified as necessary as the day progressed. The circuit boards came in three different models with 8-15 pieces each; they were assembled according to orders posted by teachers posing as customers. Each completed circuit board was delivered to the customer who would inspect it for form and function. Early on, most boards were rejected by customers for either of the two reasons, generally due to the latter, however. It was possible to resubmit if the condition of the board was rectified, and the customer would provide feedback, but only in a yes/no binary fashion. Between manufacturing runs, of which there were three throughout the day, the factory was modified with instructor help so as to be more lean, and hence more successful. The “customers,” who were purposefully hard on the manufacturing workers, insisted on the cheapest and the best, a goal that was achieved by the end of the day through implementation of the canons of Kaizen. At the end of the simulation, after the third and last simulation, accepted models generally rose by about 60% over the first run.
Reorganization
Lean has it’s cost though; this last experience was easily the most frustrating thing I experienced while at Boeing. Reorganization of an existing factory I am sure is well modeled in this simulation. Building a lean system from the ground up is one thing, but changing an existing system is a pain and can be very expensive. Boeing has yet to update it’s 777/747 final assembly line in Everett to this system, however most of the feeder lines for these planes come out of the same buildings as those for the 737 and are quite efficient and Kaizen adherent. This is elementary to the lean system; the feeder lines must first be compliant to the end goal, the main line can only be made so once the feeders are suitably adapted. Genie industries have as well not fully reorganized to a completely lean system. Of their two factories in Washington, only a small portion of one is fully lean. Like Boeing, this is attributed to the high cost of reorganization of an existing and fully operational manufacturing line to that of a new one that will have it’s own snags and time consuming manufacturing shutdowns as the new system is brought into full operation. In both of these cases though, it is only a matter of time.