Lecture 1 and 2

Lecture 1
Process Planning and Cost Estimation
MECX42 (Credit-03)
Dr Serajul Haque

MODULE I INTRODUCTION 9
Types of production- Standardization, Simplification- Production design and selection-
Process planning, selection and analysis- steps involved in manual experience based
planning and computer aided process planning- Retrieval, generative-Selection of
processes analysis-Break-even analysis
MODULE II WORK STUDY AND ERGONOMICS 8
Method study, Definition- Objectives-Motion economy- Principles-Tools and
Techniques – Applications- Work measurements- Purpose, Use, Procedure, tools and
techniques, standard time- Ergonomics- Principles and applications.
MODULE III ESTIMATION AND COSTING 8
Importance and aims of cost estimation –Functions of estimation –costing –
Importance and aims of costing- Difference between costing and estimation -
importance of realistic estimates- Estimation procedure.

MODULE IV ELEMENTS OF COST 7
Introduction-Material cost- Determination of material cost, Labor cost - Determination of
Direct Labor cost-Expenses- Cost of Product(Ladder of cost)-Illustrative examples, Analysis
of overhead expenses-Factory expenses - Depreciation-Causes of depreciation- Methods of
depreciation- Administrative expenses- selling and distributing expenses- allocation of
overhead expenses.
MODULE V ESTIMATION OF MACHINE TIME AND COST 6
Estimation of machining time for machining operations involved in lathe, drilling, and
milling and grinding – Estimation of machining cost
MODULE VI COST ESTIMATION IN FORMING, CASTING
AND WELDING SHOP
7
Product cost Estimation: Estimation in forging shop-Losses in forging-Forging cost-
Illustrative examples. Estimation in foundry shop-Estimation of pattern cost and casting
cost- Illustrative examples. Estimation in welding shop-Gas cutting- Electric welding-
illustrative examples
Total
Hours

PROCESS PLANNING
Process planning : It may be defined as the determination of the processes and the sequence of
operations required to make the product.
It consists of devising, selecting and specifying processes, machine tools and other equipment to
transform the raw material into finished product as per the specifications called for by the
drawings.
(5 M’s)
The purpose of process planning is to determine and describe the best process for each job so
that:
(i) Specific requirements are established for which machines, tools and other equipment can
be designed or purchased.
(ii) The efforts of all engaged in manufacturing are co-ordinated.
(iii) A plan is made to show the best way to use the existing or proposed facilities.

Objectives of Process Planning

STEPS INVOLVED IN PROCESS
PLANNING
The steps involved in process planning are :
(i) The finished product is analyzed so that its sub-assemblies
and individual components are identified from manufacturing
point of view.
(ii) Prepare a Bill Of Materials [BOM] for all components of
the product which forms a basis for purchase of raw materials.
(iii) Decide which parts are to be manufactured in the plant
and which parts are to be purchased from the market
depending upon the facilities available in the plant, i.e.,
decision with regard to “make” or “buy” to be taken.

(iv) Choose the appropriate blank size i.e., raw material size and select
the most economical process to be followed to manufacture
components of the product. This is done by comparing the various
possible methods of obtaining the final product.
The basic factors of volume to be produced, i.e., production quantity,
required quality of the product and the capabilities of the equipment
available are carefully considered in this step.
(v) Decide the sequence of operations to be performed on each
component in the process selected.
(vi) Each operation is assigned to the type and size of machine or work
station that will perform the job most economically.

(vii) Depending upon the accuracies called for by the
drawings, determine the machine tools to do the operations.
(viii) Determine the need for any special equipment like jigs,
fixtures, cutting tools etc.,
(ix) Determine the inspection stages and instruments required
and the need for designing any inspection devices (say gauges,
etc.).
(x) Estimate the standard time for performing the job.

(xi) Determine the type of labour (skilled, semi-
skilled or unskilled) required to do the job.
• Process planning has been traditionally carried
out by methods engineers, manufacturing
engineers, industrial engineers or by process
planners.

1. Product Analysis
• Marketing Aspect
• Product Characteristics
• Economical Analysis
• Production Aspect

MARKETING ASPECT
• Sales and Marketing is a key function whose participation is often
hard to enlist.
• Sales and Marketing are critical functions in this process, since they
provide the starting point of the planning and scheduling
process -- the forecasts and customer order demands
• They are also vital from the viewpoint of providing the proper
customer perspective whenever changes need to be made to plans
and schedules based on mismatches of resources to customer
demands.
• A marketing analysis is done to determine size, the nature of the
customer and possible trend.

MARKETING ASPECT
QUESTIONNAIRES
1. Whether the proposed product offers the functions
that are desirable and acceptable to the customer?
2. Is it within buying capacity?
3. Does it satisfy the buying preferences?
4.Is the product already existing?
5. If it entirely new product about which the customer is
unaware?
6.What will be the expected demand for product both
long term and short term?
7.What are the factors influencing the demand?
8. Who are the competitors?

Product Characteristics/ Finished Parts
Requirements
1. Functional Aspects: How the product functions?
e.g; Washing machine, Objective to wash cloths.
How washing is carried out, whether rinsing and
drying both be done in machine, based on that
automatic or manual supervision.
Trends of Functional Versatility, means increase
the range of application. eg; with mixer, grander
and juicer is also their.
Hand tool polisher, cutter and driller attachment
can also be applied.

2. Operational Aspect: Easy to handle and simple to
operate.
Versatility means different attachment can be used easily,
change over time multi purpose.
Easy accessibility
3. Durability : It defines quality and reliability of product.
Durability refers to length of active life of the product
under given working conditions.

4. Aesthetic Aspect:
“அவர் பார்ப்பது விற்கிறது”
“Avar pārppatu viṟkiṟatu”
Aesthetic aspect refers to the final shape and appearance
around the basic skeleton which are required for
performance of intended functions.
Aesthetics make the product attractive and induce in the
customer a willingness to possess.
Aesthetic can be improve by symmetry, balance, contrast,
continuity and proportion.

Production Aspect
(i) In this consequence Design for Manufacturing (DFM) concept is important.
DFM means the design for ease of manufacturing of components of a product.
DFM describes the process of designing or engineering a product in order to facilitate
the manufacturing process in order to reduce its manufacturing costs.
DFM will allow potential problems to be fixed in the design phase which is the least
expensive place to address them. Other factors may affect the manufacturability
such as the type of raw material, the form of the raw material, dimensional
tolerances, and secondary processing such as finishing.
(ii) Specialization : One of the important characteristics of manufacturing today is
that of specialization. Some manufacturers concentrate on producing a single
item, and others restrict production to a line of related products. The result of
such specialization is usually lowered cost of production and improved quality.
• Specialization also means the division of work or effort, and this occurs at the
operator (worker) level and at the management level.

• At the worker level there are those who work on jobs requiring a great skill, such
as machinists, tool and die makers and welders, such craftsmen become high
skilled specialists. Other workers do semi-skilled jobs. Both skilled and unskilled
operators keep our mass-production and assembly lines running day after day.
Although such specialization has elements of monotony and inflexibility, it results
in high volume production at low cost.
• Specialization of effort also operates at the management level. Management
effort, generally, is divided into various special functions such as design,
engineering, sales and finance and so on as the business grows in size and
complexity.
• Within any one specialization there will be further specialization or sub-
specialization. Engineering, for example will have its specialists in mechanical
electrical and automobile work.
• Considering this machines are also designed for special purposes (SPM: Special
Purpose Machines as opposed to GPM: General Purpose Machines) which will
complete one specific operation as efficiently as possible on one type of
component. This ensures a high degree of uniformity of work turned out. i.e.,
consistency in the quality of work.

• iii. Simplification : The concepts of
specialization, standardization and
simplification (known as three S’s) are closely
inter-related and lead to inter-changeability in
manufacturing.
• Simplification is the process of reducing the
variety of products manufactured (also known
as variety reduction).

(iv)Standardization : Results in overall cost reduction and
economy in purchasing and manufacturing.
• In this respect designs plays an important role in ensuring
that there is standardization amongst all the assemblies
and sub-assemblies and various components of the
products manufactured.
• Standardization promotes interchangeability :
Interchangeability, or interchangeable manufacture,
means that any standardized part produced can be
interchanged such that any component will assemble
equally well with any mating part without any fitting being
necessary. The parts produced must be as near identical as
possible, and standardization of all dimensions, tolerances
fits and other part features ensure this.

Standards are available to the engineer covering a
wide variety of features such as
(i) Dimensions, tolerances, and fits,
(ii) Material specifications and properties; raw
material sizes,
(iii) Machines, tools, gauges, instruments,
(iv) Methods of assessing and inspecting parts, sub-
assemblies, assemblies and products; and
(v) Installation and commissioning of equipment
and machinery,

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