| The idea of quality assurance and quality
guarantee goes back to cultural prehistory. This chapter will, however, put
the emphasis on quality management in the 20th century.
Until the beginning of the 20th century, in industrial
production, the individual manufacturing steps for preparing a product - as
was the case in the factories prior to the industrial revolution - were
substantially the responsibility of a worker, who thus could also check the
quality of his own work.
The increased demand of goods of any type at the beginning
of the 20th century required a different strategy of production. To increase
the production output of the factories, groups of workers became specialized
in individual manufacturing steps under the direction of a foreman. The
quality checks were carried out by the foreman, who was responsible for the
quality of the work carried out under his supervision.
Approximately around the time of the First World War, the
first full time quality checkers were employed. Based on ideas by the
engineer Frederick W. Taylor and the concept by Henry Ford for the
production of the "T" model (Tin Lizzie), the manufacturing processes were
divided into individual steps, which were then carried out by the most
suitable workers. This work organization referred to as functional master
principle had the effect that in the conveyor belt production especially
unskilled workers were used, who were not capable of carrying out the
testing of the high-tech products. This resulted in the formation of quality
testing departments, which were exclusively responsible for monitoring the
quality of the products.
As late as the 1950's, Taylor's work organization approach
was still widely accepted. With the onset of mass production, it became
clear that a 100% check of the manufactured products was too expensive. It
was replaced by a partial control on the basis of statistical methods, in
order to improve the performance and throughput of the testing departments.
The required statistical know-how was already available at the beginning of
the 20th century, but was not used in industry until around 1930. In 1924
methods for the continuous process monitoring and evaluation on statistical
basis ("control charts", statistical process control) were developed.
In the 1960s and 1970s, the increasing complexity of the
products and manufacturing processes led to increased integration of quality
management in the product development and manufacturing processes. The
objective of these efforts was to eliminate errors not at the place where
they were discovered but where they occurred, because the later an error is
discovered, the higher the costs of error elimination. Compared with this,
pure control measures are pushed to the background.
The main changes in the area of quality management that
have occurred over the last 20 years can be summarized by three main points:
- Carrying out quality tests as early as possible, with
the aim of avoiding rejects and reworking of product units that do not
conform with quality from the outset.
- Increased use of statistical methods as early as during
quality planning (DoE methods - Design of Experiments - statistical
experiment planning)
- Increased automation of quality management and
introduction of computer-assisted measurement and evaluation techniques
The ideal objective of the future is "mastered
production", in which no rejects whatsoever are produced. To this end,
quality assurance measures must be applied to all areas of the company and
also to all stages of the product formation. The suppliers must be included
in such a strategy as well. These efforts aimed at achieving a zero error
production are expressed by quality philosophies such as Total Quality
Management (TQM), Total Quality Control (TQC) and Company-Wide Quality
Control (CWQC) whose implementation is presently being started.
Under the TQM aspect, continuous improvement of quality is
a task that the management board must define and be responsible for as the
company objective. This makes quality a strategic company objective. The aim
of the quality policy of a company is to give quality, as an important
parameter of success in the company, its due significance.
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