Question

West Coast Manufacturing, Inc. offers a range of aviation services to airlines. Its primary services are repairing and overhauling planes and their interiors for its client airlines, which range in size from small regional carriers to large international carriers. As an extension to its seat repairing services, West Coast Manufacturing recently expanded into the design and assembly of airplane seats.

Since it is new to the business, a typical seat order for West Coast Manufacturing is for one plane, consisting of anywhere between 100 and 350 seats. Its more established competitors often receive seat orders for multiple planes. The process of filling each seat order is complicated by the fact that many variations of seats go into a single plane, based on how the seats are grouped together in the rows; whether the seat is an aisle seat, window seat, or middle seat; whether the seat will be placed in an exit row; and what class the seat will be placed in. There is additional variation across orders because different airlines require the use of different fabrics and cushion materials, require different types of electronics installed in the seats, and even have different dimensions of their seats.

West Coast Manufacturing's seat design and assembly business completed the upfit of its South Carolina factory a couple of months ago. The facility houses both a group of design engineers and three assembly lines. In addition to designing the seats to the airlines' specifications, the design engineers also develop detailed instructions for the assembly workers, explaining the steps to follow in assembling the seats.

Currently, each of the three assembly lines consists of 12 stations. The takt time of the assembly lines is 30 minutes. Unfortunately, as is often the case for the start-up of production operations, the assembly line is experiencing some significant challenges. For example, virtually no seats pass final inspection at the end of the line and are therefore routed to a “penalty box,” where they wait to be reworked. Regarding the quality problems, Christine Chadwick, the supervisor of the penalty box, commented:

While I haven't done a detailed analysis of why so many seats fail final inspection, my experience tells me that by far the number-one reason for the seats ending up here is because they are missing parts. Sometimes we also see seats where the parts were installed incorrectly or where a part was damaged when it was assembled.

Parts are delivered to the assembly line stations in carts. Each cart contains the parts for one seat, taken from the “supermarket.” Supermarkets are locations on the shop floor where a small amount of inventory is stored to support production activities. While the assembly worker is assembling a seat, a second cart is being filled with the parts for the next seat. Two parts pickers support each assembly line. These parts pickers travel up and down the assembly line; when they find an empty cart, they take it to the supermarket, where they pick the parts that are needed at the station.

To replenish a cart, the parts pickers refer to the laminated list of parts needed by the workstation. The parts pickers then walk around the supermarket to find the needed parts. The supermarket was designed in a U-shape to facilitate replenishing the cart with the needed parts; however, the laminated list is rarely in the order in which the parts are stored, thus requiring the parts pickers to backtrack through the supermarket. As needed parts are found, they are tossed into the cart except for smaller items like bolts and washers, which are placed in a box attached inside the cart. Immediately after taking parts from the supermarket shelves, the parts pickers scan the bar code label on the shelf with a bar code reader and enter the quantities taken in order to update the inventory level.

Each assembly line has its own dedicated supermarket. Frequently, however, parts pickers find the inventory level depleted for some parts on their list; in these cases, they go to one of the other supermarkets to find the needed parts. Each assembly line is dedicated to the seats for a specific plane order. All the parts needed for the entire seat order are delivered to the supermarket at once. Typically, it takes one to two weeks to assemble all the seats for a plane order. Occasionally, there are some bulky items that do not fit in the supermarkets; in these cases, the parts pickers must travel a couple of hundred yards to retrieve these parts from bulk storage. Bulk storage also holds the parts that arrive before they are moved to the supermarkets.

The assembly workers refer to instructions displayed on monitors at their workstation to assemble the seats. After reading the instructions and looking at the diagrams, the assembly operator roots through the cart of parts to find the next pieces to install. With the parts in hand, the operator next searches for the needed tools and then installs the parts. This process is repeated until the seat is completed, with the operation cycling between reading instructions, finding parts, and finding tools. If the work is completed in less than the 30-minute takt time, the worker can take a short break. More typical, however, are cases where the assembly workers are waiting for their carts of parts so they can begin working on the next seat.

Question 1

What types of waste are present at West Coast Manufacturing's new South Carolina facility?

Answer 1

No seats pass final inspection and have to be waited for rework, multiple order from different supermarket leads to missing parts and lack of uniformity in size and shapes, the finding tools for manufacturing also have different dimensions making all of above as waste at South Carolina manufacturing facility.