Page 226 - How To Implement Lean Manufacturing

204 Cha pte r T h i r tee n

Work Station Work in Secs Trans in Secs Total in Secs
A 46 2 48
B 39 2 41
C 44 2 46
D 43 2 45
TABLE 13-2 Gamma Line Balance Chart, New Cellular Design

Using the data from our time study, we now have:
• New station A is 12 + 11 + 10 + 13 = 46 seconds
• New station B is 9 + 7 + 13 + 10 = 39 seconds
• New station C is 12 + 12 + 12 + 8 = 44 seconds
• New station D is 8 + 9 + 13 + 13 = 43 seconds
• Flow Line E is 12 + 9 + 11 + 11 + 13 = 56 seconds, less 3 seconds from the
modifications

We will then need to look at the balance. The results are shown in Table 13-2.
In checking the balance for workstations A thru D, we find about seven seconds dif-
ference, or about 15 percent. Although we would not normally consider this good
enough, we accepted it for now. We had made so many changes we wanted to get the
cells in service and check it out. In addition, we were under severe time pressures. The
risk here is that any changes we now make in the cells will need to be done four times.
Even considering this, we were comfortable and decided to proceed with this design, in
addition, this would make for a neat transition. For example, we could reuse almost all
of the work procedures.

We Plan the Modifications and the Test Run
With this design in hand, and plans to implement these changes, Greg placed yet
another restriction on us. We would need to prove this design before he was willing to
convert the entire line. Although we were very confident, his stipulation was reason-
able, so we agreed to construct one cell (as if we had any choice at all) and direct its
product to station 17, while the original line continued to produce normally. We would
operate this cell for one or two shifts per day, measure the performance of the cell and
then proceed from there. Meanwhile, we implemented the changes on the final test.
They were simple and successful and reduced three seconds of work.
So far we have designed a cell, operating at a lower cycle time (remember that takt
is not really of interest to them, they want more, faster), and balanced so it will flow
nicely with one-piece flow. Our practical limit was the inability to add capital. Practi-
cally, this meant we wanted to increase the flow rate up to the ability of stations 17 – 21,
which was about a 12-second cycle time.

The Test Run
Over the weekend, during the construction of the first cell, we had problems. We
planned to convert the automatic conveyor to a track so the platforms could be