Exhibit $6\mathrm{.}9$: Engineers' initial design of the assembly line

ASSEMBLY LINE POSITION TASKS WORKSTATION NUMBER LABOR TIME $($SECONDS$)$

$11.$ Assemble Cover. $(78)178$

$22.$ Install LCD in cover. $(51)251+21=72$

$3.$ Prepare Base Assembly. $(21)$

$34.$ Install Main Printed Circuit Board $($M$-$PCB$)$ in Base. $(39)339+25+42=106$

$5.$ Install CPU $.(25)$

$6.$ Install Backup Batteries and Test. $(42)$

$47.$ Install Accupoint Pointing Device and Wrist Rest. $(35)435+47+23=105$

$8.$ Install Speaker and Microphone. $(47)$

$9.$ Install Auxiliary Printed Circuit Board $($A$-$PCB$)$ on M$-$PCB$.(23)$

$510.$ Prepare and Install Keyboard. $(29)529+55+10+4+7=105$

$11.$ Prepare and Install Solid$-$State Drive $($SSD$).(55)$

$12.$ Install Battery Pack. $(10)$

$13.$ Insert Memory Card. $(4)$

$14.$ Start Software Load. $(7)$

$615.$ Software Load $(120)$

$715.$ Software Load $(120)$

$815.$ Software Load $(49)$

$916.$ Test Video Display. $(60)660+60=120$

$17.$ Test Keyboard. $(60)$

$10$ Empty.

$11$ Empty.

$12$ Empty.

In words, the following is a brief description of what is done at each workstation:

Workstation $1$: The first operator lays out the major components of a computer between two white lines on the conveyor. The operator then prepares the cover for accepting the LCD screen by installing fasteners and securing a cable.

Workstation $2$: The second operator performs two different tasks. First, the LCD screen is installed in the cover. This task needs to be done after the cover is assembled $($task $1).$ A second independent task done by the operator is the preparation of the base so that the Main Printed Circuit Board $($M$-$PCB$)$ can be installed.

Workstation $3$: Here the M$-$PCB is installed in the base. After this is done, the Central Processing Unit $($CPU$)$ and backup batteries are installed and tested.

Workstation $4$: The Accupoint Pointing Device $($touchpad$)$ and wrist rest are installed, the speaker and microphone is installed, and the Auxiliary Printed Circuit Board $($A$-$PCB$)$ is installed. These are all independent tasks that can be done after the M$-$PCB is installed.

Workstation $5$: Here, tasks are performed in a sequence. First, the keyboard is installed, followed by the Solid$-$State Drive $($SSD$).$ The battery pack is then installed, followed by the memory card. The computer is then powered up and a program started that loads software that can be used to test the computer. Actually loading the software takes $289$ seconds, and this is done while the computer travels through positions $6,7,$ and $8$ on the assembly line. Computers that do not work are sent to a rework area where they are fixed. Only about $1$ percent of the computers fail to start, and these are usually quickly repaired by the supporter.

Workstation $6$: The video display and keyboard are tested in this workstation.

After assembly, the computers are moved to a separate burn$-$in area that is separate from the assembly line. Here, computers are put in racks for a $24-$hour, $25\backslash$deg C $$burn$-$in$$ of the circuit components. After burn$-$in$,$ the computer is tested again, software is installed, and the finished notebook computer is packaged and placed on pallets for shipment to Toshiba distribution centers around the world.

Tweaking the Initial Assembly$-$Line Design

From past experience, Toshihiro has found that the initial assembly$-$line design supplied by the engineers often needs to be tweaked. Consider the following questions that Toshihiro is considering:

If the line were to be redesigned to operate at the initial $253$ units per day target, assuming that no overtime will be used, what would be the maximum allowable cycle time? Develop an assembly line using the fewest possible workstations for the allowable cycle time. What would be the efficiency of the new design?

Note: Round your "Efficiency" answer to $2$ decimal places. Round down "maximum cycle time" values to the next smallest integer.$)$