Transcript Eng. Nkumbwa, R. L. Copperbelt University School of Technology 2010- Zambia

Eng. Nkumbwa, R. L.
Copperbelt University
School of Technology
2010- Zambia
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Principles of Manufacturing Technology
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What is Manufacturing Technology or
Manufacturing Engineering Systems
Manufacturing is the use of machines, tools and
labor to make things for use or sale.
The term may refer to a range of human activity,
from handicraft to high tech, but is most commonly
applied to industrial production, in which raw
materials are transformed into finished goods on a
large scale.
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Principles of
Manufacturing Technology
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Such finished goods may be used for
manufacturing other, more complex
products, such as:
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Household appliances
Automobiles
Other products sold to wholesalers, who in turn
sell them to retailers, who then sell them to end
users - the "consumers".
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Understanding Manufacturing Systems
Engineering
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Modern manufacturing includes all intermediate
processes required for the production and
integration of a product's components.
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Some industries, such as
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semiconductor electronics
and steel manufacturers
use the term fabrication instead.
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Understanding Manufacturing Systems
Engineering
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The manufacturing sector is closely connected
with engineering and industrial design or
industrial engineering.
Examples of major manufacturers include:
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North America include:
 General Motors Corporation,
 General Electric,
 Pfizer.
 Examples in Europe include :
– Volkswagen Group,
– Siemens, and Michelin.
– Examples in Asia include
 Toyota, Samsung, and Bridgestone.
 Example in Zambia include:
 ZamSugar, ZamBrew, Lafarge, Zambezi, Trade kings, Uniliver, TAP,
Kafue Steel, Amanita, Zambeef, Parmalat, Milling Co., Plastic Co. ,
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Indeni, Scaw, etc
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Economics of Manufacturing
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According to some economists,
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manufacturing is a wealth-producing sector
of an economy,
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whereas a service sector tends to be wealthconsuming.
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Economics of Manufacturing
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Manufacturing is a huge component of the
modern economy.
Everything from knitting to oil extraction to
steel production falls under the description of
manufacturing.
The concept of manufacturing rests upon the
idea of transforming raw materials, either
organic or inorganic, into products that are
usable by society.
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Manufacturing Categories
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Chemical industry
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Construction
Electronics
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Semiconductor
Engineering
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Pharmaceutical
Biotechnology
Emerging technologies
Nanotechnology
Synthetic biology, Bioengineering
Energy industry
Food and Beverage
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Agribusiness
Brewing industry
Food processing
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Manufacturing Categories
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Industrial design
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Metalworking
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Interchangeable parts
Smith
Machinist
Machine tools
Cutting tools (metalworking)
Free machining
Tool and die maker
Global steel industry trends
Steel production
Metalcasting
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Manufacturing Categories
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Plastics
Telecommunications
Textile manufacturing
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Transportation
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Clothing industry
Sailmaker
Tentmaking
Aerospace manufacturing
Automotive industry
Bus manufacturing
Tire manufacturing
LETS JUST SAY ANYTHING THAT IS NOT NATURAL
IS MANUFACTURING
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So, What is Manufacturing?
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According to Webster's,
Manufacturing is the making of goods or
wares by manual labor or by machinery,
especially on a large scale, from raw
materials or unfinished materials.
It is the making of a finished product or
goods.
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Manufacturing Methods
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There are different manufacturing methods
namely:
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Batch Production
Job Production
Continuous Production
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Batch Production
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Batch production is the manufacturing technique of
creating a group of components at a
workstation before moving the group to the next
step in production.
Batch production is common in bakeries and in the
manufacture of sports shoes, pharmaceutical
ingredients (APIs), inks, paints and adhesives.
In the manufacture of inks and paints, a technique
called a colour-run is used.
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Batch Production
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A colour-run is where one manufactures the
lightest colour first, such as light yellow
followed by the next increasingly darker
colour such as orange, then red and so on
until reaching black and then starts over
again.
This minimizes the cleanup and reconfiguring
of the machinery between each batch.
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Job Production
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Job production, sometimes called jobbing, involves
producing a one-off product for a specific customer.
Job production is most often associated with small firms
(making railings for a specific house, building/repairing a
computer for a specific customer, making flower
arrangements for a specific wedding etc.) but large firms
use job production too.
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Continuous Production
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Continuous production is a method used to manufacture,
produce, or process materials without interruption.
This process is followed in most oil and gas industries and
petrochemical plant and in other industries such as the float
glass industry, where glass of different thickness is processed
in a continuous manner.
Once the molten glass flows out of the furnace, machines
work on the glass from either side and either compress or
expand it.
Controlling the speed of rotation of those machines and
varying them in numbers produces a glass ribbon of varying
width and thickness.
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Cell Production
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Cell production involves both machines and human workers.
In conventional production, products were manufactured in
separate areas (each with a responsibility for a different part of
the manufacturing process) and many workers would work on
their own, as on a production line.
In cell production, or cellular manufacturing workers are
organized into multi-skilled teams.
Each team is responsible for a particular part of the production
process including quality control and health and safety.
Each work cell is made up of one team who deliver finished
items on to the next cell in the production process.
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Mass Production
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Mass production (also called flow
production, repetitive flow production, series
production, or serial production) is the production of
large amounts of standardized products, including and
especially on assembly lines. i.e. Elsweedy in Ndola.
The concepts of mass production are applied to various
kinds of products, from fluids and particulates handled in
bulk (such as food, fuel, chemicals, and mined minerals)
to discrete solid parts (such as fasteners) to assemblies
of such parts (such as household appliances and
automobiles).
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Lean Production
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Lean Production, which is often known simply as "Lean", is a
production practice that considers the expenditure of resources for
any goal other than the creation of value for the end customer to
be wasteful, and thus a target for elimination.
Working from the perspective of the customer who consumes a
product or service, "value" is defined as any action or process that
a customer would be willing to pay for.
Basically, lean is centered around preserving value with less work.
Lean manufacturing is a generic process management philosophy
derived mostly from the Toyota Production System (TPS) (hence
the term Toyotism is also prevalent) and identified as "Lean" only
in the 1990s.
It is renowned for its focus on reduction of the original
Toyota seven wastes to improve overall customer value, but there
are varying perspectives on how this is best achieved.
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Agile Production
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For the past ten years a quality revolution has arose because
now, the marketplace has become global.
A sophisticated and aware customer base has grown because of
the increase of service industries where the customer plays a
direct role in the delivery process.
No longer can companies assume they can put out products to
customers at the manufacturers schedule and quality levels.
Many companies have realized this. Many have researched for
was to make positive changes, which will permit them to identify,
and quickly respond to the customer likes and complaints.
At the same time, these changes must allow the manufacture the
ability to get their products quickly to market.
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Agile Production
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This is known as Agile Manufacturing.
Agility means to have the ability to change quickly.
The development of manufacturing support technology,
which permits marketers, designers, and production
personnel the ability to share a common database of
parts and products, is one contributing factor a
manufacturer must have in order to become an agile
manufacturer.
Goldman et al. (1995) suggest that Agility has four
underlying components: deliver value to the customer;
be ready for change; value human knowledge and skills;
form virtual partnerships.
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Industrial Engineering
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Industrial engineering is a branch of engineering concerned
with the development, improvement, implementation and
evaluation of integrated systems of people, money,
knowledge, information, equipment, energy, material and
process.
It also deals with designing new prototypes to help save
money and make the prototype better.
Industrial engineering draws upon the principles and methods
of engineering analysis and synthesis, as well as
mathematical, physical and social sciences together with the
principles and methods of engineering analysis and design to
specify, predict, and evaluate the results to be obtained from
such systems.
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Understanding Product Design
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For any organization to deliver the required
service or product to the market, they must
first understand the customer requirements
and design the product that meets the stated
and implied needs.
All things on this plant that are not natural
where once designed and manufactured.
Below is an illustration of the design process.
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Recognition of Need
Definition of Problem or Need
Problem Synthesis
Analysis & Optimisation
Evaluation
Presentation
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Waterfall Product Development
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Use of Concurrent Engineering
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After identifying the requirements for the New Product, a
design will be developed for the required product.
However, just having the details of the design alone is not
enough to deliver the product to the consumer, so we need
Manufacturing information which will suggest the processes
required to make the product.
Therefore, Product Design and Product Manufacturing
Process should be done at the same time or in parallel.
Concurrent Engineering is a work methodology based on
the parallelization of tasks (ie. performing tasks concurrently).
It refers to an approach used in product development in
which functions of design engineering, manufacturing
engineering and other functions are integrated to reduce the
elapsed time required to bring a new product to the market.
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New Product Analysis
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Everyday we use thousands of different products,
from telephones to bikes and drinks cans to
washing machines and microwaves.
But have you ever thought about how they work or
the way they are made?
Every product is designed in a particular way product analysis enables us to understand the
important materials, processing, economic and a
esthetic decisions which are required before any
product can be manufactured.
An understanding of these decisions can help us in
designing and making for ourselves.
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Getting Started
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The first task in product analysis is to become familiar
with the product! What does it do? How does it do it?
What does it look like?
All these questions, and more, need to be asked before a
product can be analysed.
As well as considering the obvious mechanical (and
possibly electrical) requirements, it is also important to
consider the ergonomics, how the design has been
made user-friendly and anymarketing issues - these all
have an impact on the later design decisions.
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Let's take the example of a bike
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What is the function of a bicycle?
How does the function depend on the type of
bike (e.g. racing, or about-town, or child's bike)?
How is it made to be easily maintained?
What should it cost?
What should it look like (colours etc.)?
How has it been made comfortable to ride?
How do the mechanical bits work and interact?
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Systems and Components
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There are 2 main types of product - those
that only have one component (e.g. a
spatula) and those that have lots of
components (e.g. a bike). Products with lots
of components we call systems. For
example:
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System Components
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Product
Components
Bike
Frame, wheels, pedals, forks, etc.
Drill
Case, chuck, drill bit, motor, etc.
Multi-gym
Seat, weights, frame, wire,
handles, etc.
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Product Analysis
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In product analysis, we start by considering
the whole system. But, to understand why
various materials and processes are used,
we usually need to 'pull it apart' and think
about each component as well.
We can now analyse the function in more
detail and draft a design specification.
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Some important design questions
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To build a design specification, consider
questions like the following:
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What are the requirements on each part (electrical,
mechanical, aesthetic, ergonomic, etc)?
What is the function of each component, and how do
they work?
What is each part made of and why?
How many of each part are going to be made?
What manufacturing methods were used to make
each part and why ?
Are there alternative materials or designs in use and
can you propose improvements?
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Design Questions
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These are only general questions, to act as a guide - you
will need to think of the appropriate questions for the
products and components you have to analyse. For a
drinks container, a design specification would look
something like:
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provide a leak free environment for storing liquid
comply with food standards and protect the liquid from health hazards
for fizzy drinks, withstand internal pressurisation and prevent escape
of bubbles
provide an aesthetically pleasing view or image of the product
if possible create a brand identity
be easy to open
be easy to store and transport
be cheap to produce for volumes of 10,000+
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Choosing the Right Materials
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Given the specification of the requirements
on each part, we can identify the material
properties which will be important - for
example:
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Choosing the Right Materials
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Requirement
Material Property
must conduct electricity
electrical conductivity
must support loads without breaking
strength
cannot be too expensive
cost per kg
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Material Selection
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One way of selecting the best materials would be to look
up values for the important properties in tables. But this is
time-consuming, and a designer may miss materials
which they simply forgot to consider.
A better way is to plot 2 material properties on a graph,
so that no materials are overlooked - this kind of graph is
called a materials selection chart (these are covered in
another part of the tutorial).
Once the materials have been chosen, the next step is
normally to think about the processing options.
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Choosing the Right Process
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It is all very well to choose the perfect material, but somehow we
have to make something out of it as well! An important part of
understanding a product is to consider how it was made - in
other words what manufacturing processes were used and why.
There are 2 important stages to selecting a suitable process:
– Technical performance: can we make this product with the
material and can we make it well?
– Economics: if we can make it, can we make it cheaply
enough?
Process selection can be quite an involved problem - we deal
with one way of approaching it in another part of the tutorial.
So, now we know why the product is designed a particular way,
why particular materials are used and why the particular
manufacturing processes have been chosen.
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Is there anything else to know?
Wrap Up…
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Product analysis can seem to follow a fixed
pattern:
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Think about the design from an ergonomic and
functional viewpoint.
Decide on the materials to fulfil the performance
requirements.
Choose a suitable process that is also economic.
Whilst this approach will often work, design is
really holistic - everything matters at once - so be
careful to always think of the 'bigger
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Example Analysis
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Is the product performance driven or cost driven?
This makes a big difference when we choose materials.
In a performance product, like a tennis racquet, cost is one of
the last factors that needs to be considered.
In a non-performance product, like a drinks bottle, cost is of
primary importance - most materials will provide sufficient
performance (e.g. although polymers aren't strong, they are
strong enough).
Although we usually choose the material first, sometimes it is
the shape (and hence process) which is more limiting.
With window frames, for example, we need long thin shaped
sections - only extrusion will do and so only soft metals or
polymers can be used (or wood as it grows like that!).
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Choosing between Different Materials
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There are three main things to think about when choosing
materials (in order of importance):
– Will they meet the performance requirements?
– Will they be easy to process?
– Do they have the right 'aesthetic' properties?
We deal with the processing aspects of materials in a different
part of this course.
For now it is sufficient to note that experienced designers aim
to make the decisions for materials and processes separately
together to get the best out of selection.
The choice of materials for only aesthetic reasons is not that
common, but it can be important: e.g. for artists.
However, the kind of information needed is difficult to obtain
and we won't deal with this issue further here.
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Material Selection
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Most products need to satisfy
some performance targets, which we determine by
considering the design specification e.g. they must be
cheap, or stiff, or strong, or light, or perhaps all of these
things...
Each of these performance requirements will influence
which materials we should choose - if our product needs
to be light we wouldn't choose lead and if it was to be
stiff we wouldn't choose rubber!
So what approach do we use to select materials?
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Using Material Selection Charts
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So what we need is data for lots of material
properties and for lots of materials.
This information normally comes as tables of data
and it can be a time-consuming process to sort
through them.
And what if we have 2 requirements - e.g. our
material must be light and stiff - how can we trade-off
these 2 needs?
The answer to both these problems is to
use material selection charts.
Here is a materials selection chart for 2 common
properties: Young's modulus (which describes how
stiff a material is) and density.
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Using Material Selection Charts
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On these charts, materials of each class (e.g. metals, polymers) form
'clusters' or 'bubbles' that are marked by the shaded regions.
We can see immediately that:
– metals are the heaviest materials,
– foams are the lightest materials,
– ceramics are the stiffest materials.
But we could have found that out from tables given a bit of time, although
by covering many materials at a glance, competing materials can be
quickly identified.
Where selection charts are really useful is in showing the tradeoff between 2 properties, because the charts plot combinations of
properties.
For instance if we want a light and stiff material we need to choose
materials near the top left corner of the chart - so composites look good.
Note that the chart has logarithmic scales - each division is a multiple of
10; material properties often cover such huge ranges that log scales are
essential.
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Using Material Selection Charts
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To find the best materials we need to use the Young's
modulus - density chart from amongst the available
charts. The charts can be annotated to help reveal the
'best' materials, by placing a suitable selection box to
show only stiff and light materials.
What can we conclude?
The values of Young's modulus for polymers are low, so
most polymers are unlikely to be useful for stiffnesslimited designs.
Cambridge Engineering Selector (CES) is the Software
used for Material Selection developed by Prof. Ashby.
Other material property selection charts include:
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Wrap Up
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By considering 2 (or more) charts, the properties needed to
satisfy the main design requirements can be quickly assessed.
The charts can be used to identify the best classes of
materials, and then to look in more detail within these classes.
There are many other factors still to be considered, particularly
manufacturing methods. The selection made from the charts
should be left quite broad to keep enough options open.
A good way to approach the problem is to use the charts to
eliminate materials which will definitely not be good enough,
rather than to try and identify the single best material too soon
in the design process.
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How is a processing route chosen?
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The selection of a suitable process to manufacture a
component is not a straightforward matter.
There are many factors which need to be considered, for
example: size of component, material to be processed
and tolerance on dimensions.
Whilst all processes have slightly different capabilities,
there is also a large overlap - for many components there
are a large number of processes which would do the job
okay. So, where do we start?
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Material Compatibility
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In product analysis (and a lot of design work), the
material to be processed is often known before the
process to be used has been decided.
This makes life a little easier as the first thing we
can do now is check what processes can be used
for our chosen material - i.e. which are compatible.
For convenience, processes can be split up into:
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Metal shaping: e.g. forging, rolling, casting
Polymer shaping: e.g. blow moulding, vacuum forming
Composite forming: e.g. hand lay-up
Ceramic processing: e.g. sintering
Machining: e.g. grinding, drilling
Joining: e.g. soldering, gluing, welding
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Material-Process Compatibility Table
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We can then use a material-process
compatibility table to determine which
processes are suitable for manufacture.
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+ : routine
? : difficult
X : unsuitable
Polymer
Shaping
Machining
Joining
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Polymer
extrusion
Compression
moulding
Injection
moulding
Blow moulding
Milling
Grinding
Drilling
Cutting
Fasteners
Solder / braze
Welding
Adhesives
Polymer
Wood
ABS
(thermoplastic)
UF
(thermoset)
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Pine
+
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+
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+
Process Compatibility Table
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These tables show whether a particular
material-process combination is routine,
difficult or unsuitable.
Using this table we can usually narrow down
our choice of processing options, but how
can we go further?
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Comparing the costs of processing routes
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There are many costs involved in the making and selling of a product,
these include:
– Research
– Advertising
– Packaging
– Distribution
– Manufacturing
For different products, the importance of each contribution will vary.
Note that the cost is not the same as the price - the difference is the
manufacturer's profit!
Here we are only interested in the manufacturing cost - the other costs
are not likely to be affected much by our choice of process.
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Manufacturing Costs
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So how can we go about estimating how
much it might cost to make a product?
The easiest way is to notice that the basic
manufacturing cost has 3 main elements:
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Material Costs
Start-Up Cost
Running Cost
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Material cost
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The material cost per component depends
on the size of the component.
We may assume that (for a given
component) the same amount of material is
used for all processes:
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Material cost per part = constant
(same value for all processes)
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Manufacturing Costs=Constant
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Startup cost
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All new products have one-off startup costs,
such as special tools or moulds which have
to be made.
This cost only occurs once, so it is shared
between all the total number of components
made - the 'batch size':
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Startup cost per part = one-off cost ÷ batch
size
(gets less for bigger batches and is different for
each process)
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Start-Up Cost
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Running cost
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Many manufacturing costs will be charged at an
hourly rate, such as energy and manpower.
In addition the capital cost of the machine must be
"written off" over several years, which can also be
regarded as an hourly cost - the same would apply if
instead a machine was rented.
The share of this hourly running cost per part
depends on how many parts are made per hour, the
production rate:
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Running cost per part = hourly cost ÷ production rate
(constant, but different for each process)
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Running Costs
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Total Manufacturing Cost
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The total cost is the sum of these 3 cost
elements.
These are;
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Material Costs
Start-Up Costs
Running Costs
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Case Example: Aero Engine
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Aero-Engine Analysis
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Hotter,
Stiffer,
Stronger,
Lighter…
Where does the aero-engine go next?
Use the chart below to help you select the
appropriate material for each component
of the Jet Engine.
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Sustainable Design or Eco-Design and
Eco-Manufacturing or Green Mfg.
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Sustainable design (also called environmental design,
environmentally sustainable design, environmentallyconscious design, green design etc) is the philosophy of
designing physical objects, the built environment and
services to comply with the principles of economic, social,
and ecological sustainability.
The intention of sustainable design is to "eliminate
negative environmental impact completely through skillful,
sensitive design“.
Manifestations of sustainable designs require no nonrenewable resources, impact on the environment
minimally, and relate people with the natural environment.
Eng. Nkumbwa
Design for Environment (DfE)
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Design for Environment (DfE) is a general concept that
refers to a variety of design approaches that attempt to
reduce the overall environmental impact of a product,
process or service, where environmental impacts are
considered across its life cycle.
There are three main concepts that fall under the Design
for Environment umbrella:
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Design for environmental processing and manufacturing: This
ensures that raw material [Resource extraction|extraction] (mining,
drilling, etc.), processing (processing reusable materials, metal
melting, etc.), manufacturing are done using materials and processes
which are not dangerous to the environment or the employees working
on said processes. This includes the minimization of waste and
hazardous by-products, air pollution, energy expenditure, among
others.
Eng. Nkumbwa
Design for Environment (DfE)
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Design for environmental packaging: This ensures that the materials used
in packaging are environmentally friendly, which can be achieved through
the reuse of shipping products, elimination of unnecessary paper and
packaging products, efficient use of materials and space, use of
[Recycling|recycled] and/or recycleable materials.
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Design for disposal or reuse: The [End-of-life (product)|end-of-life] of a
product is very important, because some products emit dangerous chemicals
into the air, ground and water after they are disposed of in a landfill.
Planning for the reuse or refurbishing of a product will change the types of
materials that would be used, how they could later be disassembled and
reused, and the environmental impacts such materials have.
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Definition:
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Design For Environment (DFE) is the idea of implementing certain aspects of
environmentally friendly design to create a sustainable product . Although
there is no actual DFE certification, following the Design For Environment
guidelines helps to minimize waste and pollution, and saves money that is
typically spent on product reprocessing.
Eng. Nkumbwa
Global Competitiveness
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Competitiveness is a comparative concept of the ability
and performance of a firm, sub-sector or country to sell
and supply goods and/or services in a global market.
Although widely used in economics and business
management, the usefulness of the concept, particularly
in the context of Manufacturing Systems is critical.
The term may also be applied to markets, where it is
used to refer to the extent to which the market
structure may be regarded as perfectly competitive.
This usage has nothing to do with the extent to which
individual firms are "competitive'.
Read more about Manufacturing Competitiveness in
Zambia
Eng. Nkumbwa
Wrap Up
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Any worries this far??
Eng. Nkumbwa