Post on 19-Jan-2015
description
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