1 Introduction (1).

Process control is the coordination of machines, human labor, and the organization of work to effect the manufacture of a product. It involves the specification and monitoring of machine setups and operating parameters, formulation of rules and procedures to govern operator--machine interactions, and decisions about the utilization of, and sequencing of, operations on a line. Although the details of process control can be quite different in different industries, a common theme that emerges from its study is the evolution of manufacturing from an art to a science. Inasmuch as the long-term viability and manufacturing competence of a firm is intrinsically tied to how one manages this evolution, it is important to understand the factors that drive it.

Manufacturing technology is, in essence, the technology of process control. Because one finds in the metalworking industry a great variety of processes being practiced at any time, and because the industry is large and has a long history, it is a useful base from which to study evolving patterns of process control in the mosaic of machines, labor, and the organization of work. Because aggregate data at the level of the industry does not lend sufficient relief to the shifts in this picture, we take, as our unit of analysis, a single firm and category of products.

Within the firm we study the evolution of process control from the perspective of the work station--the locus at which technology and work come together and manufacturing takes place. Because we are interested in a particular aspect of technology and work, namely manufacturing's shift from art to science, we also examine the thinking behind the ideas that have shaped process control and the cognitive components of work.

We focus specifically on the segment of the metal fabricating industry engaged in the manufacture of firearms. A number of major manufacturing innovations have had their seeds in this industry: development of machine tools at the Woolwich Arsenal; interchangeability of parts at the Whitney and Colt factories; Taylorism at the Watertown Arsenal. Considerable scholarship has been devoted to the study of this industry, and we are also aided by the existence of a single firm, Beretta (Fabbrica D'armi Pietro Beretta Sp A), whose history includes the assimilation of each of these manufacturing innovations.

Based in the city of Gardone in what is now northern Italy, and controlled by the same family for fourteen generations since 1492, Beretta has been engaged in the manufacture of firearms for five hundred years. Whereas functionally the product has remained much the same, and manufacturing is still based on fabricating precise metal parts, the detailed processes by which it is manufactured have changed considerably over time. Thus, the firm provides as ideal a natural experiment as one could have. Although it originated none of the major metal fabricating innovations, Beretta was quick to adopt every one of them.

To illustrate how the transformation in manufacturing technology has come about, we visit the arsenals in which the various innovations originated--the Woolwich Arsenal in England and the Colt factory and Watertown Arsenal in the United States--and review the works of the originators. What these individuals thought about and did is the story of the evolution of process control in the metalworking industry.

1.1. The Case for "Epochal" Change in Manufacturing

It will become apparent as the story unfolds that process control has evolved in a succession of epochs, each characterized by a fundamental shift, or "revolution," in manufacturing technology, the organization of work, and the nature of the firm. The story is related from the perspective of the individual at a machine, where process control is effected and the changes can be seen most vividly.

Six epochs of manufacturing process control can be delineated, preceded by a pre-manufacturing epoch in which products were made but not manufactured.

(1) The Craft System (circa 1500)

(2) The invention of machine tools and the English System of Manufacture (circa 1800)

(3) Special purpose machine tools and interchangeability of components in the American System of Manufacture (circa 1830)

(4) Scientific Management and the engineering of work in the Taylor System (circa 1900)

(5) Statistical process control (SPC) in an increasingly dynamic manufacturing environment (circa 1950)

(6) Information processing and the era of Numerical Control (NC, circa 1965)

(7) Flexible manufacturing and Computer-Integrated Manufacturing (CIM/FMS, circa 1985)

The first change in the technology of manufacturing firearms came some 300 years after Beretta started making guns. It was the English System of Manufacture, which was introduced at Beretta after the Napoleonic conquest of the Venetian Republic and the establishment of a state-run arms factory near Beretta's location. Much of our understanding of how the English System changed the nature of work comes from a visit to the shop of Henry Maudslay. Sufficient records of this founder of the machine-tool industry exist to form a picture of workshops of the late 18th and early 19th centuries.

The next era, the "American System," is illuminated by a visit to the Colt Armory. It brought to a high state of refinement a system of manufacture based on the notion of interchangeability of parts and the development and use of special purpose machinery. This system was showcased at the Crystal Palace Exhibition in 1851, and within 20 years had been adopted in whole or in part by most of the armories in Europe. Beretta adopted the entire system, contracting with the American firm Pratt and Whitney to build a complete factory at its headquarters in Gardone. The third epoch was the Taylor System, which perhaps even more than the first two revolutionized manufacturing far beyond the firearms industry. Taylorism was the basis of the vast expansion in firearms and other metalworking during World War II. Because company records at Beretta are incomplete for this period, we turn to Hugh Aitken's detailed explication of the introduction of the Taylor System at the Watertown (Massachusetts) Arsenal around 1900.

The first three epochs--those characterized by the English, American, and Taylor systems of manufacturing--related to the material world of mechanization. Each saw the manufacturing world as a place of increasing efficiency and control, substitution of capital for labor, and progress through economies of scale. These objectives were obtained through an engineering focus on machines and what could be done with them. The role of labor was increasingly seen as one of adapting to the machines and the contingencies of the environment--ultimately, of being yet another machine. Concurrently, the machines themselves became more elaborate, capable of ever greater precision and control. Underlying these developments was the principle of increasing mechanical constraint.

Abbot Usher, a historian of technology, observes that

some of the impressive improvement of machines consists of

refinement of design and execution. The parts of the machine are

more and more elaborately connected so that the possibility of

any but the desired motion is progressively eliminated. As the

process of constraint becomes more complete, the machine becomes

more perfect mechanically ... The general line of advance takes the

form of substitution of the more intense for the less intense

forces, grading up through a long sequence that begins with types

of human muscular activity ... There is a steady increase in

potential (energy): we have to deal with a transition for machinery

worked at a very low potential to machinery run at very high

potential. The change in potential itself requires more and more

careful constraint of motion because these highly intense

concentrations of energy could not be applied to mechanisms until

adequate control was possible. [34, p 116]

This world of mechanization reached its zenith in the 1950s. Already one could hear rumblings of a brave new world. In 1946 Brown and Leaver laid out, in a Fortune magazine article entitled "Machines Without Men," a blueprint for a new industrial order. (2) They had made the intellectual leap from mechanization to information processing. Norbert Weiner, in his prescient analysis of the power of information processing, gave credence to Brown and Leaver's world-view. Though it would be another forty years before we would see the first automated, workerless factories, the seeds for the emergence of a new paradigm were planted.

It is appropriate that James Bright completed his landmark study, Automation and Management, in 1958, for that year marks the end of the era of mechanization. Bright observed that

the average manufacturing system of 1956 ... can be regarded as

no more than a crude assemblage of unintegrated bits of mechanism.

These mechanisms themselves may reflect the utmost in the

mechanical art of our times. Still, when collected under one roof

and directed toward a particular production end, they are anything

but a machine-like whole.

A hundred years from now the average factory of our day

may be regarded as having been no different in philosophical

concept from the factory of 1850 ... (Process) "design" has meant

the collection of equipment for a production sequence--not the

synthesis of a master machine. [8, p 16]