Om lect 03_a(r0-aug08)_process selection_process design_mms_sies

Process Selection/ Process Design/ Process Analysis

N.K.Agarwal

Process Design

• Process design is concerned with overall sequence of operations required to achieve the product specifications

• It specifies the type of work stations, the machines and equipments necessary ad the quantities in which each is required

• Sequence of operations determined by– Nature of the product– Materials used– Quantities being produced, and– Existing physical layout of the plant

• Design of manufacturing process starts with the receipt of product specifications and ends with the final plan for the manufacturing of the product

• Steps involved in process design are– Careful review of product design and specifications to

ensure that economical manufacture is feasible– Determination of the method of manufacture that will result

in the optimum manufacturing cost– Selection or development and procurement of all machines,

tools, jigs and fixtures etc. required for manufacturing product at the required quantity level/rate of production

Process Design- Scope

– Layout of the production area and auxiliary spaces and installation of the manufacturing facilities

– Planning for and establishing the necessary control of materials, machines and manpower to ensure effective utilisation and economical; production of the product

Process Design

• Basic factors affecting the design of manufacturing process are– Volume or quantity of the product to be manufactured– The required quality of the product, and– The equipment that is available or that can be procured for

the manufacture of the product

• Major factors affecting process design decisions– Nature of product/service demand– Degree of vertical integration– product./service and volume flexibility– Degree of automation– Level of product / service quality– Degree of customer contact

Process Design- Basic Factors

• Nature of product / service demand– Production system has to be designed to produce products /

services of the kind the customer want, when they want and at a cost that allows the firm to be profitable

– Production process to have adequate capacity to produce the volume of products / services that customers want

• Degree of vertical integration– Vertical integration is the amount of production and

distribution chain, from suppliers of raw materials and components to the delivery of finished products to the customers, that is brought under the ownership of a company, whether towards the market or towards the sources of supply

Process Design- Basic Factors

• Product/Service and volume flexibility– Ability to respond fast to the customer’s needs is known as

flexibility– Product/service flexibility

• Ability of production system to change from production of one product/service to another

– Volume flexibility• Ability to quickly increase or reduce the volume of

product/service produced

• Degree of automation– Degree of automation to be adopted and integrated into the

production system is a key issue in process design, because of the high cost involved in automation and also the difficulty involved in integrating into the existing operations

Process Design- Basic Factors

• Level of product/ service quality– Mass produced products with high product quality offer a

better competitive edge to the manufacturer

• Degree of customer contact– In custom built product/services, the customer is the central

focus of the design of production processes– In case of standardised products/services, the customer’s

interaction does not affect the design of production processes in a big way

Process Design- Basic Factors

Types of Process Designs

• Basic type of production system and the finished goods inventory policy to be used must be decided at the earliest stages of process planning

• Common type of production systems are– Product- focused production system– Process-focused production system– Group- technology / cellular manufacturing system

Product Layout

• Machines arranged in a line depending upon sequence of operations

• Material moves in a line from the first machine to the finished product on the last machine.

• Investment higher as compared to process layout

BETTER SUITED FOR STANDARDISED PRODUCTS ON A MASS SCALE PRODUCTION. EX

CHEMICALS,PAPER

FINISHED GOODS

MATERIAL FLOW

RAW MATERIALS

PRODUCTION SUB-SYSTEM

RECEIVING

STORAGE

OPERATION A

OPERATION B

OPERATION C

OPERATION D

SHIPPING

EDP CONTROL SYSTEMS

INFORMATION FLOWS

CONTINUOUS FLOW PRODUCTION SYSTEM (FLOW SHOP)

Process Layout

• Grouping together of similar machines in one department

• Material moves from one group of machines to the other

• Movement over longer distance and along criss-cross paths

• May also involve part finished inventory waiting

BEST SUITED FOR INTERMITTENT TYPE OF PRODUCTION/LIGHT AND HEAVY INDUSTRIES

PRODUCTION SUB-SYSTEM

RECEIVING

STORAGE

OPERATION A OPERATION B

OPERATION COPERATION DSHIPPING

INFORMATION FLOWS

INTERMITTENT FLOW PRODUCTION SYSTEM (JOB SHOP )

WIP

WIP WIP

WIP

FINISHED GOODS

EDP CONTROL SYSTEMS

RAW MATERIALS

MATERIAL FLOW

FINISHED GOODS

Group Technology (GT)/ Cellular Manufacturing (CM) systems

• A form of production that has been developed recently

• In GT,the products or components being manufactured are placed in families or groups and separate manufacturing cells are used for manufacturing these groups– GT enables production of a wide variety of parts in small

batches to achieve economies of line-flow production without product standardisation

• CM is a subset of GT concept– A close grouping of equipments for processing a sequence

of operations in multiple units of a part or a family of parts,called manufacturing cell

– Use of cells reduces the distance moved by parts between machines

– Transportation costs reduced as parts do not have to moved in large batches

– Reduction in w-i-p inventory, and the manufacturing cycle- time or through-put time

• Most common application in automobile spare parts manufacturing

Group Technology (GT)/ Cellular Manufacturing (CM) systems

1 2

3

45

1 2 3

1 2

34

21

CELL # 3

CELL # 4

CELL # 1 CELL # 2

PRODUCTION OPERATION PRODUCT OR MATERIAL FLOW

CELLULAR MANUFACTURING LAYOUT

PART D

PART Y

PART X

PART A

PART B

3

U-Shaped Cell Layout

A

C B

D A

B C

D

C

A D

B C

D A

B

= work station

Group Technology Layout

A

C

B

D

A

B

C

D

C

A

D

B

C

D

A

B

Combined Layout

• Combination of product & process layout with an emphasis on either

• Generally adopted in industry• In fabrication plants including assembly, fabrication

tends to employ process layout while assembly areas employ product layout – Soap manufacturing industry employs product line for

manufacturing of soap, but ancillaries such as heating, manufacturing of glycerin, power house etc. Are arranged on functional basis.

F.P.

F.P.

G.C.

G.C.

G.C.

H.T.

H.T.

G.G.

G.G.

RAW MATERIAL

RAW MATERIAL

PR

OC

ES

S L

AY

OU

T

FINISHED PRODUCTS (GEARS)

F.P. = FORGING PRESS G.C. = GEAR CUTTING

H.T. = HEAT TREATMENT FURNACE G.G. = GEAR GRINDING MACHINE

COMBINATION LAYOUT OR HYBRID LAYOUT FOR GEAR MANUFACTURING

PRODUCT LAYOUT

Process Technology• Refers to the equipment, people and systems used to

produce a firm’s products and services• Five types of process technologies are

– Job shop technology• Suitable for a variety of custom-designed products in

small volume– Batch technology

• Suitable for a variety of products in varying volumes– Assembly line technology

• Suitable for a narrow range of standardised products in high volumes

– Continuous flow technology• Suitable for producing a continuous flow of products like

chemical plants, oil refineries– Project technology

• Suitable for producing products that are tailor made to the unique requirements of each customer

Process Technology Life Cycle

• Manufacturing cost per unit decreases in mature products over a period of time

• Life cycle starts from the stage of ‘start up’ and ends in the stage of ‘decline’

• Manufacturing process undergo a change from job shop through batch production, assembly line production and continuous flow production

• Output volumes ,rates of process innovation and degree of automation also changes from the first stage to the last stage– Low at start-up and high during maturity stage

INT

RO

DU

CT

ION

GR

OW

TH

MA

TU

RIT

Y

DE

CL

INE

PROCESS FOCUSSED,TO ORDER, JOB SHOP

PROCESS FOCUSSED,TO ORDER, BATCH

PRODUCT FOCUSSED,TO STOCK, BATCH

PRODUCT FOCUSSED, TO STOCK, CONTINUOUS

STAGES OF DEVELOPMENT

SA

LE

S V

OL

UM

E

PRODUCT LIFE CYCLE AND PRODUCTIVE SYSTEM TYPES

Job shop

BatchAssembly line

Continuous flow

Time

The Process Life Cycle

Man

ufa

ctu

rin

g

cost

/un

it

Process Selection/ Process Design

• Process design is concerned with overall sequence of operations required to achieve the product specifications

• Selection of appropriate process technology affects the economics of operation and hence needs to be done considering various associated aspects

References

• Production & Operations Management: Aswathappa / Bhat

• Production and Operations Management: Chunnawalla/Patel

• Modern Production / Operations Management: Buffa / Sarin

• Operations Management: R.G.Schroeder

Thank You

LOW VOL-LOW STANDARDISATION, ONE OF A KIND

LOW VOL-MULTIPLE PRODUCTS

HIGHER VOL-FEW MAJOR PRODUCTS

HIGHER VOL-HIGH STANDARDISATION,COMMODITY PRODUCTS

JOB SHOP

JOB SHOP- BATCH PROCESS

ASSEMBLY LINE

CONTINUOUS /FLOW SHOP

PRODUCT CYCLE

PR

OC

ES

S L

INE

PRODUCT- PROCESS MATRIX

NONE

NONE

Process alternatives- Decision

• Depends upon various factors– Batch size and Product variety– Capital requirement– Economic analysis

• Batch size and Product variety– For a single product having a large demand– Product focused organisation dedicated to the single product– Gives low production cost per unit– System very inflexible

• Equipments specialised to the product and employees specifically trained make it impossible to change the system to produce any other product

• Product-focused batch system appropriate when number of product design increases and batch size of the products decrease– System relatively inflexible but possible with some difficulty

to change the equipments and employees for other products

• Job shop producing unique products in batches of a single item appropriate for production of many one-of-a kind products– System has highest flexibility

• Cellular manufacturing of some of the production parts within a job shop becomes appropriate when the number products decreases and batch size of products increases as compared to the previous case

Process alternatives- Decision

• Capital requirements – Capital required for the production system depends upon on

the type of production processing organisation– Requirement maximum for product focused, dedicated

systems and diminishes for product focused batch systems and cellular systems

– Requirement minimum for process focused job shop production systems

• Economic analysis of Production process– As fixed and variable costs tend to differ from one form of

production process to another, economic analysis used for comparing alternative processing plans for the production of products

– Cost function of processing alternatives, the concept of operating leverage, break-even analysis and financial analysis are important aspects of economic analysis

Process alternatives- Decision

Process Design/Selection

• Process selection is a major strategic decision as it involves allocation of resources of a long nature

• The transformation process is expected to generate an output desired by the market and should be done in the most cost efficient way

• Process selection has a business dimension– To get into the market and stay there, and once this is done – To win orders