Materials and Manufacturing: Study Material with Solved Assignments

This study material covers topics such as joints, surface processes, material properties, and manufacturing processes. It also provides information on the best material choices for engineering projects. The document includes solved assignments and essays on various topics related to Materials and Manufacturing.

MATERIALS AND MANUFACTURING.
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Manufacturing Questions
Question 1
Example of a joint Category of a joint
A threaded joint
A brazing joint
Question 2
1 Soldering Materials selection and specific reasons
Copper and Silver based alloys
Silver-based alloys have always been
preferred for the process of soldering in

various applications. This is because its
figurative value is almost competing
with that of gold. Silver alloys are very
much compatible with most of the metal
components. Its application is limited to
these areas where the temperature is not
expected to go higher than 900 degrees.
They provide proper strength and
compatibility.
2 Friction Welding In most of the cases, the preferred
material for such joining is alloys of
aluminum. These alloys are used more
due to their workability which is
relatively superior and less affordable in
terms of cost. In cases where proper
friction welding with superior
weldability and good strength are
required, stainless steel and aluminum
material may be used.

Question 3
Surface Processes
Component of engineering Surface process
In this particular component, the
surface finishing process used is
called electroless plating. The
reduction agent that replaces
electricity has been used in place to
induce fabric or polymer material.
The type of surface finish that has
been illustrated here is called
painting by the use of electricity. It
is commonly called electropainting.
It has basically been used to achieve
surface decoration and anti-
corrosion properties (Berto and
Lazzarin 2014).
Question 4
Advantages of using surface finishing process on the material components
I. Some of the surface finishing processes enhance the aesthetic value of the component
like painting for decoration.

II. The wear resistance of the component is improved
III. In the case of the metals, proper surface finishing enhances torque tolerance of the
components.
IV. The process of vulcanization is enhanced that is improved ability to bond with rubber in
the case of metal surface finish.
V. Surface finishing allows for the solderability of the material component.
Question 5
Shaping Process and advantages
Die Casting Die casting is basically a process of metal
casting that involves forcing a molten metal
which is under pressure into a mold cavity.
Advantages
 This process allows for the production
of very complex shapes that have closer
tolerances as compared with other
processes of mass production.
 Also, it produces parts or components
that are very durable, having a feeling
of quality and dimensionally stable.
Injection Moulding Injection molding refers to a process of
manufacturing that is used for the fabrication

of the items from the plastics toys and trinkets.
The molten plastic material is introduced into
the mold of the recommended shape and size.
Advantages
 It is the quickest way of producing
more components of similar parts
 It allows for design freedom and also
very cost effective.
Extrusion In this particular process, a raw material that is
basically thermoplastic material is fed by
gravity from a hopper that is mounted from the
top into the extruders’ barrel. Additives can
then be added. Although this particular process
is almost similar to injection molding, there is
a slight difference in that it is normally
continual.
Advantages
 It is normally preferred for mass
production of the components
 It is cheaper/Cot effective.
Question 6
Material choice and processes

Process Advantages Disadvantages
Continuous Melting Process
This involves feeding of raw
material from the beginning
and receiving the molten
product from the end.
 It is conducive for the
process of production.
 It is very high
throughout
 It allows or limited
modification on the
product
 It does not support
small scale production.
Question 7
What an engineer should consider when selecting a manufacturing process
I. Cost of manufacturing
II. The desired surface finishes of the product
III. Capabilities of manufacturing techniques
IV. The flexibility of the process
V. Environmental Sustainability of the process.
Material Questions
Question 1
Structure of the atom

Figure 1: Structure of the atom (Shackelford, Han and Kwon 2016).
Question 2
Type of bond Description
Covalent Bonding In this bonding, there is actually sharing of the
valent electrons. In most of the cases, the
resultant product of the bonding is called a
molecule especially if the individual elements
are not of the same element (Bauer et al 2013).
Each pair is expected to contribute to the
electron that will be shared.
Ionic Bonding This is another type of bonding which results
in the formation of the compounds. In this type

of bonding, there is normally complete transfer
of the valent electron by just one of the
individual element (Hutchings and Shipway
2017). The compound formed is called an ionic
compound.
Question 3
Groups of Polymers and their descriptions
Type Description
Natural polymers These are polymers that exist naturally. They
are found from plants and animals. These are
basically made of cellulose, proteins, resin,
cellulose, and rubber among others
(Shackelford, Han, and Kwon 2016) .Sisal
ropes are the best examples.
Semi-synthetic polymers These are derivatives of cellulose like cellulose
acetate, cellulose nitrate.
Synthetic Polymers A variety of the polymers in this group are
made from plastics. These plastics are

commonly known as polythene products. Some
of the common examples include nylon 6,6 and
also synthetic rubber(Askeland and Wright
2013).
Question 4
Material Properties
Property Group Material Property
General properties In general, material properties range from
being solid, liquid and gases. These properties
are connected with the state of the material that
are sometimes influenced by the temperature
variation (Jahan, Edwards and Bahraminasab
2016).
These materials can be measured in terms of
the forces inserted by them in weight expressed
in Newton. Gases and liquids can have their
quantities expressed in terms of volume in
cubic meters.
Mechanical properties The physical properties range from stiffness,
strength, hardness among others. Each physical
property can be expressed in different units
depending on the parameters that are involved.
Resistance to deformation which is strength

may be expressed as N/mm2 (Jeon et al. 2015).
Chemical properties The chemical properties of the materials
directly relate to its environmental substances
(El-Eskandarany 2013). The corrosive
properties of liquid/gases rely on the PH value
as expressed on the PH scale.
Question 5
Component Alloy Reason/main property
Cobalt alloys It has higher
resistance to the
crevice, galvanic
corrosion, pitting,
corrosion fatigue
among others.

The best material to
be used here is
Magnesium alloy
Its tensile strength
and elongation in the
arm of the wheel and
even in the rim of the
wheel is normally
220MPa.
Gold alloyed with
copper, silver or
platinum
It does not cause skin
irritation, the material
is workable and
finally has a fine look
and feel.
Steel and its alloys The material is
flexible and also
durable. This makes it
a perfect material in
the manufacturing of
car since it will bend
instead of breaking.

Question 6
Properties of Ceramics
1. Ceramics have good frictional properties
2. They have high hardness
3. Ceramics possess a low thermal conductivity
4. They are non-magnetic
5. They have high strength
References
Askeland, D.R. and Wright, W.J., 2013. Essentials of materials science & engineering. Cengage
Learning.
Bauer, S., Schmuki, P., Von Der Mark, K. and Park, J., 2013. Engineering biocompatible implant
surfaces: Part I: Materials and surfaces. Progress in Materials Science, 58(3), pp.261-326.

Berto, F. and Lazzarin, P., 2014. Recent developments in brittle and quasi-brittle failure
assessment of engineering materials by means of local approaches. Materials Science and
Engineering: R: Reports, 75, pp.1-48.
El-Eskandarany, M.S., 2013. Mechanical alloying: For fabrication of advanced engineering
materials. Univ. Press of Mississippi.
Hutchings, I. and Shipway, P., 2017. Tribology: friction and wear of engineering materials.
Butterworth-Heinemann.
Jahan, A., Edwards, K.L. and Bahraminasab, M., 2016. Multi-criteria decision analysis for
supporting the selection of engineering materials in product design. Butterworth-Heinemann.
Jeon, N.J., Noh, J.H., Yang, W.S., Kim, Y.C., Ryu, S., Seo, J. and Seok, S.I., 2015.
Compositional engineering of perovskite materials for high-performance solar
cells. Nature, 517(7535), p.476.
Shackelford, J.F., Han, Y.H., Kim, S. and Kwon, S.H., 2016. CRC materials science and
engineering handbook. CRC press.