Classification of Manufacturing Processes

1. 1.1.3. Classification of Manufacturing Processes
Bearing in mind diversity of human activities in various domains of industry, it is useful to realise
that a classification of manufacturing processes depends on its purpose. For example, if a scientist
intends to analyse interaction between the basic disciplines and manufacturing applications, a
probably useful classification would group processes into:
- Chemical industry
- Bioengineering (Biotechnology)
- Nanotechnology
- Electronics
- Construction, etc.
Material scientists would tend to classify manufacture based on the processed material, e.g.
processing of
- metallics
- polymers
- ceramics
- glasses
- composites
- biomaterials (woodworking).
Departing from the concerns about the human-tool-product interaction, one can distinguish manually
operated and semi/fully -automated systems with fixed or variable routing, etc.
Thus, differing classifications of manufacturing processes are published, and in this section, several
additional options will be introduced, with presenting one that is deemed to outline substantial
characteristics, along with emphasising educational aspects, as a bottom line.
Some authors attempted to distinguish processes based on whether we treat the workpiece by
- addition of material
- subtraction (removal, waste) of material
- equibalance of material.
Moreover, there are classifications based on some organisational and logistic aspects such as
- Lean manufacture
- Flexible manufacture
- Just in Time manufacturing
- Agile manufacturing
- Bulk processes
Further approach follows highlighting other specificities of the process, by distinguishing
- Computer-integrated manufacturing
- Celular manufacturing.
From the point of view of system organisation with an emphasis on the final product, some authors
distinguish
(i) Discrete manufacturing, (e.g. production of toys, computers, cars). In discrete manufacturing a
number of separate operations is involved, independent in a sense that these operations can be
separated arbitrarily in time and space (location)
(ii) Continuous (”Process”) manufacturing (e.g. production of bread, paper, steel rolling).
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2. Official institutions frequently provide lists of the observed manufacturing systems. The American
Bureau of Labor Statistics classifies manufacturing into hundreds of subfields and sub-subfields.
It is, however, useful to note difference in concepts of “industry” and “manufacturing process”.
Industry is a cluster of systems commercially organised for making and providing of goods and
providing services on a large scale. Hence, we have education industry, entertainment industry, food
and beverage industry, industry providing medical services, manufacturing industry etc.
Manufacturing (system) process is an organised activity that realises, on a commercial base, making
chemophysical materialised products in a diverse range of quantities (including single products).
For the purpose of this discourse it is useful to observe classification of manufacturing industry
into PRIMARY, SECONDARY (intermediate) and TERTIARY (final) manufacturing industry.
Primary manufacturing industry may be divided into several categories:
1. Genetic Industry, including the processing of raw biological materials that may be augmented by human
intervention (e.g. agriculture, forestry, however its products are made of genic materials.
2. Extractive Industry, including the production of other (non-biological) categories of exhaustible raw
materials e.g. mining, quarrying, and the extraction of minerals that cannot be augmented through cultivation.
3. Extractive Industry, including processing fossil fuels (formed in the geological past from the remains of
living organisms.)
Tertiary (final) manufacturing industry covers a very broad range of fabricating activities, with the common
denominator of bringing the quality of materials to a level needed in final consumption. Examples include the
automotive, aerospace, furniture, clothing or food industries. It can be stated that final industry has the highest
variety and the broadest range of product quality specifications, when compared with the other two general
categories.
Secondary (intermediate) manufacturing industry links these primary and final industries by improving the
quality of the products of the primary industry so they become more suitable as input materials needed for
final production. Products of secondary industries are typically made on a very large scale whether in the form
of batch, serial or continuous manufacturing. Moreover, there is an incentive to make these intermediate
products useable for a wide range of differing applications.
Bearing in mind that this publication covers only selected intermediate processes for fabricating solid semi-
final products based primarily on non-genetic materials, the following classification focuses on the differences
between the characteristics of manufacturing processes themselves:
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3. According to the above Figure, manufacturing processes are classified based on the used techniques:
a) Processes based on fluidity and solidification of materials (eg. casting white iron in sand molds)
b) Processes based on plastic flow in solid state and accompanying elastic reactions (e.g. forging)
c) Processes based on joining of solid components (eg arc welding)
d) Processes based on cutting (e.g. drilling)
e) Processes based on altering solid microstructure (e.g. normalising heat treatment)
f) Combined processes, where the hybrid techniques combine the above categories (e.g. sintering).
It is certainly interesting to consider what it is that is common to all manufacturing?
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4. In addition, if we limit ourselves to non-genic solid products, we can observe that the dimensions of
manufactured products range between nm and km
Reasons for the above distribution have to do with the scale of human dimensions relative to natural
phenomena in our ambient.
In conclusion, it is important to realise that any classification makes sense in the context of the
relevant agenda of concern. Of course, some classifications serve better to the intended purpose then
other, and perhaps, an example of poorly designed classification can serve well as an anti-model:
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