Lecture Material on Workshop Technology and Practice
CHAPTER 1
GENERAL INTRODUCTION
1.1 Introduction
Workshop practice is a very vast one and it is very difficult for anyone to claim a mastery over it. It
provides the basic working knowledge of the production and properties of different materials used in
the industry. It also explains the use of different tools, equipment, machinery and techniques of
manufacturing, which ultimately facilitate shaping of these materials into various usable forms.
1.2 Basic Definitions
1.2.1 Workshop
It is a room or building in which machines are made or repaired. In other words, workshop supports the
mandate of providing services in the maintenance, repair, installation, modification, design and
manufacturing of equipment.
1.2.2 Technology
It is the practical use of human knowledge and skills to turn natural items into useful products for the
benefit of mankind. It comes from the Greek word tecknos, which means "art". It concerns itself with
making something useful. Technology is involved in all the products, inventions, and discoveries made
by people. Anything created by nature is not technology e.g. sand, water, trees, and rocks.
1.2.3 Workshop Technology
It is the practice of technology whereby the workshop serves as its environment.
1.2.4 Workshop Practice
It is all practical and mental activities undertaken in the workshop for the creation of new technology
using resources, or effecting the repair and maintenance of machines and / or tools.
Resources create new technology. The resources of technology are the following:
• People
• Knowledge
• Creativity
• Skill
• Tools and machines
• Capital
• Time
• Materials
• Energy
University of Mines and Technology , Tarkwa Page 1 of 85 Lecturer: Dr J. C. Attachie
,Lecture Material on Workshop Technology and Practice
1.2.5 People
They are the creators of technology. They are the end users of the products of technology. People are
involved in technology. They make things happen.
1.2.6 Knowledge
It is wisdom, information, learning, scholarship and understanding. Knowledge gives you the power,
but creativity gives you direction.
1.2.7 Creativity
It is your ability to use your imagination to develop new approaches. You use your creative energies
to develop experimental solutions to solve problems.
1.2.8 Skill
It is the combination of knowledge and practice. It allows people to perform activities well.
1.2.9 Tools
They are any hand or machine - operated device employed in engineering, manufacturing, building
construction, woodworking and metalwork to cut or shape metal or wood products or parts. Commonly
used hand tools are: Screwdrivers, hammers, wrenches/spanners, saws, drill, pliers, staplers, spirit
levels, calipers etc.
Machine or power-operated tools are: Lathes, dies, presses, equipment used for boring, milling and
welding. Tools generally increase one's ability to do work.
1.2.10 Hand Tool
It is non-electrically powered manually (hand-) operated simple tool used in the workshop to perform
different engineering and non-engineering works and repairs in order to achieve a desired output.
1.2.11 Machines
They are tools with a power system that takes advantage of certain scientific laws and makes tools
work better.
Technology involves processes and systems.
1.2.12 Process
It is the conversion of ideas or activities through the use of machines, resources and labour into useful
products.
1.2.13 System
It is a group of parts working together to achieve a goal. It is essentially an organised or established
way to doing something through objects or ideas that work together to complete a task.
University of Mines and Technology , Tarkwa Page 2 of 85 Lecturer: Dr J. C. Attachie
,Lecture Material on Workshop Technology and Practice
1.2.14 Automated System
It is any system in which machines control machines.
1.2.15 Feedback
It is that part of a system that measures and controls the outcome of the system. Addition of feedback
to an open-loop system results in a closed-loop system. Feedback provides a constant flow of
information about the quality of product of a process. A sample feedback system is shown in Fig. 1.1.
The open-loop system has no way of measuring or controlling its product. They cannot shut
themselves down at the appropriate time. Examples could be bathtub, kerosene heater, stove etc.
Compare
Input Process Output
and Adjust
Feedback
Fig. 1.1 A Feedback System
University of Mines and Technology , Tarkwa Page 3 of 85 Lecturer: Dr J. C. Attachie
, Lecture Material on Workshop Technology and Practice
CHAPTER 2
ELECTRICAL MATERIALS AND CABLES
2.1 Classification
Electrical Materials
Magnetic Constructional
Conductors Semiconductors Insulators
Materials Materials
E.g. Copper Silicon Mica Iron Concrete
.
Aluminium Germanium Paper Cobalt
Tellurium Rubber Nickel
Silicon-glass
Fig. 2.1 Classification of Electrical Materials
2.2 Conductors
A conductor is a material of negligible resistance that allows the free passage of an electric current
along it, e.g. copper, aluminium etc. Other conductors of electricity apart from metals are:
• Liquid: Water
• Gases: Neon
2.2.1 Copper
Pure annealed copper is used for the winding of electrical machines. High purity copper is obtained by
electrolytic refining. Traces (0.1%) of iron, silicon or phosphorous seriously reduce the conductivity of
copper. The conductivity of copper is also decreased when it is hard drawn into wires for use in
machines. Annealing is therefore necessary before the material can be used in machines
Hard drawn copper because of its increased mechanical strength compared with annealed copper is
used for conductors in low voltage overhead distribution lines. Long span lines of thin cross section
require conductors of higher mechanical strength. This is achieved by adding a small percentage of
cadmium to copper. Cadmium increases the mechanical strength of copper without affecting its
conductivity adversely. The usual addition of cadmium are between 0.8% and 1%.
Copper conductors having a steel core are also employed for long span transmission lines, where a
combination of high conductivity, small sag and minimum cross section are desired. In such
conductors, an insulating tape over the wire has to be provided in order to prevent the corrosive action
of steel on copper.
University of Mines and Technology , Tarkwa Page 4 of 85 Lecturer: Dr J. C. Attachie
CHAPTER 1
GENERAL INTRODUCTION
1.1 Introduction
Workshop practice is a very vast one and it is very difficult for anyone to claim a mastery over it. It
provides the basic working knowledge of the production and properties of different materials used in
the industry. It also explains the use of different tools, equipment, machinery and techniques of
manufacturing, which ultimately facilitate shaping of these materials into various usable forms.
1.2 Basic Definitions
1.2.1 Workshop
It is a room or building in which machines are made or repaired. In other words, workshop supports the
mandate of providing services in the maintenance, repair, installation, modification, design and
manufacturing of equipment.
1.2.2 Technology
It is the practical use of human knowledge and skills to turn natural items into useful products for the
benefit of mankind. It comes from the Greek word tecknos, which means "art". It concerns itself with
making something useful. Technology is involved in all the products, inventions, and discoveries made
by people. Anything created by nature is not technology e.g. sand, water, trees, and rocks.
1.2.3 Workshop Technology
It is the practice of technology whereby the workshop serves as its environment.
1.2.4 Workshop Practice
It is all practical and mental activities undertaken in the workshop for the creation of new technology
using resources, or effecting the repair and maintenance of machines and / or tools.
Resources create new technology. The resources of technology are the following:
• People
• Knowledge
• Creativity
• Skill
• Tools and machines
• Capital
• Time
• Materials
• Energy
University of Mines and Technology , Tarkwa Page 1 of 85 Lecturer: Dr J. C. Attachie
,Lecture Material on Workshop Technology and Practice
1.2.5 People
They are the creators of technology. They are the end users of the products of technology. People are
involved in technology. They make things happen.
1.2.6 Knowledge
It is wisdom, information, learning, scholarship and understanding. Knowledge gives you the power,
but creativity gives you direction.
1.2.7 Creativity
It is your ability to use your imagination to develop new approaches. You use your creative energies
to develop experimental solutions to solve problems.
1.2.8 Skill
It is the combination of knowledge and practice. It allows people to perform activities well.
1.2.9 Tools
They are any hand or machine - operated device employed in engineering, manufacturing, building
construction, woodworking and metalwork to cut or shape metal or wood products or parts. Commonly
used hand tools are: Screwdrivers, hammers, wrenches/spanners, saws, drill, pliers, staplers, spirit
levels, calipers etc.
Machine or power-operated tools are: Lathes, dies, presses, equipment used for boring, milling and
welding. Tools generally increase one's ability to do work.
1.2.10 Hand Tool
It is non-electrically powered manually (hand-) operated simple tool used in the workshop to perform
different engineering and non-engineering works and repairs in order to achieve a desired output.
1.2.11 Machines
They are tools with a power system that takes advantage of certain scientific laws and makes tools
work better.
Technology involves processes and systems.
1.2.12 Process
It is the conversion of ideas or activities through the use of machines, resources and labour into useful
products.
1.2.13 System
It is a group of parts working together to achieve a goal. It is essentially an organised or established
way to doing something through objects or ideas that work together to complete a task.
University of Mines and Technology , Tarkwa Page 2 of 85 Lecturer: Dr J. C. Attachie
,Lecture Material on Workshop Technology and Practice
1.2.14 Automated System
It is any system in which machines control machines.
1.2.15 Feedback
It is that part of a system that measures and controls the outcome of the system. Addition of feedback
to an open-loop system results in a closed-loop system. Feedback provides a constant flow of
information about the quality of product of a process. A sample feedback system is shown in Fig. 1.1.
The open-loop system has no way of measuring or controlling its product. They cannot shut
themselves down at the appropriate time. Examples could be bathtub, kerosene heater, stove etc.
Compare
Input Process Output
and Adjust
Feedback
Fig. 1.1 A Feedback System
University of Mines and Technology , Tarkwa Page 3 of 85 Lecturer: Dr J. C. Attachie
, Lecture Material on Workshop Technology and Practice
CHAPTER 2
ELECTRICAL MATERIALS AND CABLES
2.1 Classification
Electrical Materials
Magnetic Constructional
Conductors Semiconductors Insulators
Materials Materials
E.g. Copper Silicon Mica Iron Concrete
.
Aluminium Germanium Paper Cobalt
Tellurium Rubber Nickel
Silicon-glass
Fig. 2.1 Classification of Electrical Materials
2.2 Conductors
A conductor is a material of negligible resistance that allows the free passage of an electric current
along it, e.g. copper, aluminium etc. Other conductors of electricity apart from metals are:
• Liquid: Water
• Gases: Neon
2.2.1 Copper
Pure annealed copper is used for the winding of electrical machines. High purity copper is obtained by
electrolytic refining. Traces (0.1%) of iron, silicon or phosphorous seriously reduce the conductivity of
copper. The conductivity of copper is also decreased when it is hard drawn into wires for use in
machines. Annealing is therefore necessary before the material can be used in machines
Hard drawn copper because of its increased mechanical strength compared with annealed copper is
used for conductors in low voltage overhead distribution lines. Long span lines of thin cross section
require conductors of higher mechanical strength. This is achieved by adding a small percentage of
cadmium to copper. Cadmium increases the mechanical strength of copper without affecting its
conductivity adversely. The usual addition of cadmium are between 0.8% and 1%.
Copper conductors having a steel core are also employed for long span transmission lines, where a
combination of high conductivity, small sag and minimum cross section are desired. In such
conductors, an insulating tape over the wire has to be provided in order to prevent the corrosive action
of steel on copper.
University of Mines and Technology , Tarkwa Page 4 of 85 Lecturer: Dr J. C. Attachie
