Business Considerations - Fundamentals of Industrial Chemistry: Pharmaceuticals, Polymers, and Business - page 64

projects and to understand the effect that delays in one piece may have on the
overall project timing. One technique to track, understand and communicate
the various aspects of a project is through the use of Gantt charts.
With any product that is sold, profitability is dependent upon costs. When
the product is a chemical, the major cost is usually the raw materials needed
to produce that chemical. Early in any project, raw material costs should be
calculated. If they are too high, the project will not be successful. Also when
a chemical is first made in larger scale, there are many factors that need to
be considered. By thinking of them in advance, there is a greater chance for
success.
This chapter tries to introduce the reader to some of these concepts. By
thinking about these things, better decisions will be made and there will be
greater productivity.

6.2 SIX SIGMA

Six Sigma is a process to improve performance. There are thick topics on the
topic and entire courses devoted to training someone on the topic so what
follows is just a brief synopsis of the technique. The name derives from the
Greek letter “ ”, or sigma, which is used as an abbreviation for standard devi-

ation. The standard deviation is the square root of the variance. If the data fits
a bell-shaped normal distribution curve, 68% of the numbers will fall within
one standard deviation of the mean, 95% within two standard deviations, and
99.7% within three standard deviations. Six Sigma has a focus on decreasing
the number of defects. A defect is anything out of specification.
Recognize that a single unit can have more than one defect. A polymer
sample might be defective (or failing a specification) in both color and in
impact. We can measure the defects per unit by dividing the number of
defects by the number of units. Imagine two processes of varying complexity.
In one process, steel rods are manufactured. The only customer specification
is that the length must be within five mm of one meter. They average one
defect per 1,000 rods. They are averaging 999 defect-free rods per 1,000. In
another process, smart phones are manufactured. For these phones, there are
25 specifications. This manufacturer also averages 1 defect per 1,000 units
(phones). However, they have noticed that a defective phone typically has
several defects. They average 999.8 defect-free phones per 1,000 phones.
Which process has better quality? They both average one defect per 1,000
units, but we can argue that the process to make the phones has better quality.
If we think about each opportunity for a defect to occur, we can measure
defects per opportunity and not per unit. In the case of the steel rods, we
would have a defect rate of one per 1,000 opportunities or 1,000 defects

σ