Page 84 - How To Implement Lean Manufacturing

Lean Manufacturing Simplified 65

thereby make the process more robust. Poka-yokes are also used in the inspection pro-
cess to achieve 100 percent inspection. There are two types of inspection poka-yokes:
those that control—that is, shut down—the process or isolate the product upon finding
a defect; and those that warn the operator via an andon.
5 Whys 5 Whys is the cornerstone of the TPS problem solving effort. The “5 Why”
technique is simple enough in concept. However, it will not work unless those using
this technique have both expertise and experience in the problem area. They must fully
understand the cause-effect relationships to utilize this seemingly simple technique.
The check on the “5 Whys” is the “Therefore” technique.
Kaizen Kaizen is the concept of improving a process by a series of small continu-
ous steps. Often times these improvements are small and hard to measure, how-
ever the accumulated effect is significant. Over the years, kaizen has evolved to
mean improvement.
CIP CIP stands for Continuous Improvement Process or Philosophy. Many can talk
about it, but few can show a process flow chart for their CIP, and even fewer can ade-
quately measure it. An example of a Continuous Improvement flow chart is shown in
Fig. 4-1. In addition, the Toyota Production System advocates the concept of yokoten,
which concerns extending the process improvements to other locations, as well as other
similar applications, as part of CIP.

The JIT Pillar
Takt Takt is the design process cycle time to match the customer’s demand, normal-
ized to your production schedule. It is the key calculation used when we synchronize
supply to the customer. Takt is calculated by dividing the available work time by the
product demand. The system is then designed to produce the product at this rate. If we
produce at a cycle time higher than takt (hence, under-produce) we will not be able to
supply the customer demand. If, however, we produce at a cycle time lower than takt
(overproduce), we will either increase inventory or idle the line to stop the overproduc-
tion. Both of these are wastes—recall that the #1 waste is the waste of overproduction.
For example, if we run our operation using two 10-hour shifts with a 30-minute lunch
break and two 15-minute breaks each shift, and run five days per week, holidays
included, and need to produce 500,000 units per year, our takt would be: {(365 – [52 × 2]) ×
(2 × [10 – 1]) × 60)}/500,000 = 0.56 minutes or about 34 seconds. That is, to stay in step
with the customer’s demand, considering our work schedule, we will need to produce
one salable unit every 34 seconds. Consequently, since there are losses, our production
cycle time will need to be shorter. For example, if OEE was 0.80, a production cycle time
of about 27 seconds (0.8 × 34 seconds) would be required.
Balanced Operations Balanced operations are a simple industrial engineering technique
to have all operation steps—of a cell, for example—operating with the same cycle time.
It is the first step in synchronizing the internal production. This technique, not unique
to Lean Manufacturing at all, is designed to avoid the waste of waiting. However, this
technique places a large emphasis on the ability to standardize operations so we can
avoid variation in the process. If any step in a process has high variation, that step will
naturally unbalance the entire line or cell.