Industrial Engineering -...

Industrial Engineering

Faculty – Ruchita Joshi

Index Unit 1

Productivity

Work Study

Unit 2 Plant layout and materials Handling

Replacement Analysis

Maintenance Management

Unit 3 Inventory Control

Quality Control

Unit 4 Industrial Ownership

Manpower Planning

Organization

Job Evaluation & Merit rating

Unit - 2

Chapter - 3

Plant layout

and

Materials Handling

Plant Location

Why study of plant location is important?

• Plant location of the plant can be constant source of higher cost, difficult marketing and transportation, dissatisfaction among the employees and customers, frequent disturbances in production, substandard quality, competitive disadvantage etc.

• Once plant is setup at a particular location, it is comparatively immobile and can be shifted later only at a considerable cost and interruption of production.

• The investment in land and buildings is quite large in case of bigger firms and economics of one location against other needs to be evaluated carefully to ensure fair return on such investment.

Plant Location contd…

Factors governing plant location

• Regional Factors: proximity to markets, proximity to sources of raw materials, availability of utilities, transport facilities, climatic condition, industrial and taxation laws, etc.

• Community factors: Availability of labor, industrial and labor attitudes, social structure, service facilities, etc.

• Site factors: Availability and cost of land, etc.

Facility Layout

Facility layout means planning:

• It is also known as Plant Layout

• A facility layout is an arrangement of everything needed for production of goods or delivery of services. A facility is an entity that facilitates the performance of any job. It may be a machine tool, a work centre, a manufacturing cell, a machine shop, a department, a warehouse, etc.

• The location of all machines, utilities, employee workstations, customer service areas, material storage areas, aisles, restrooms, lunchrooms, internal walls, offices, and computer rooms

• The flow patterns of materials and people around, into, and within buildings • infrastructure services such as the delivery of line communications, energy, and

water and the removal of waste water all make up basic utilities.

Principles of Plant Layout

The criteria which can judge whether or not plant layout is good are:

1. Principle of overall integration of factors

• A good layout is one which integrates men, materials, machines & supporting activities and others in a way that the best compromise is obtained.

• No layout can satisfy each and every principle of a good layout. Some criterion may conflict with other hence no layout is ideal. It has to integrate all factors into the best possible compromise.

2. Principle of minimum movement

• A good layout is one that permits the minimum movement between the operations. • Since straight line is the shortest distance between any two points, men and materials should be

made move along the straight path.

3. Principle of uni-directional flow

• A good layout is one that makes the material flow in only one direction that is only in forward direction towards final stage of completion without any backtracking.

• Backtracking and duplicated movements consume more time, involve unnecessary materials handling, add to cost and lead to inefficiency hence must be avoided by duplicating the necessary equipments..

Principles of Plant Layout Contd…

4. Principle of effective use of available space

• Raw materials, Work in Progress & finished goods should be piled vertically one above the another rather that being strewn on the floor.

• Area below the work tables, cupboards built in the wall are welcome since they reduce requirement of space.

5. Principle of maximum visibility

• A good layout is one that makes men, material, & machines readily observable at all times.

6. Principle of maximum accessibility

• A good layout is one that makes all servicing and maintenance points readily accessible. • Machines should be kept sufficiently apart and with reasonable clearance from the wall so that the

lubrication, adjustment & replacement of belts, removal of the parts at the time of repairs etc. can be done conveniently.

7. Principle of minimum handling

• A good layout is one that reduces the materials handling activity to its minimum. • Materials should be stored as close to the point of use as possible. • Materials should be handled in as bigger & convenient lots as possible.

Principles of Plant Layout Contd…

8. Principle of inherent safety

• A good layout is one that makes the plant safer for the workmen. • Fire protection equipments should be provided at strategic locations. • Gangways should be kept well lit. • One way traffic rule must be observed in areas of greater traffic.

9. Principle of maximum flexibility

• A good layout is one that can be altered later without much cost. • Future requirement must be taken into account while designing for the present. • Each machine should be self contained. i.e. it must have everything of its own like lubrication system,

cooling system, supplementary lighting, air system etc. • Multipurpose machines give flexibility over special purpose machines and process layout is more

flexible that product layout.

10. Principle of maximum security

• A good layout is one that safeguards the plant and machinery against fire, theft etc. without employing too many cages, doors and barriers.

Factors affecting Plant Layout

The factors affecting plant layout can be grouped into 8 categories:

1. Materials

• Main factors to be considered: size, shape, volume, weight, and the physical-chemical characteristics, since they influence the manufacturing methods and storage and material handling processes.

• The sequence and order of the operations will affect plant layout as well, taking into account the variety and quantity to produce.

2. Machinery

• Having information about the processes, machinery, tools and necessary equipment, as well as their use and requirements is essential to design a correct layout.

• Regarding machinery, we have to consider the type, total available for each type, as well as type and quantity of tools and equipment.

3. Labor

• Environment considerations: employees’ safety, light conditions, ventilation, temperature, noise, etc. • Process considerations: personnel qualifications, flexibility, number of workers required at a given

time as well as the type of work to be performed by them.

Factors affecting Plant Layout Contd…

4. Material Handling

• Material handling does not add value to the product; it’s just waste hence it is to be minimized as well as combined with other operations when possible, eliminating unnecessary and costly movements.

5. Waiting Time

• Objective: Continuous Material Flow through the facility, avoiding the cost of waiting time and demurrages that happen when the flow stops.

• On the other hand, the material waiting to flow through the facility not always represents a cost to avoid. As stock sometimes provides safety to protect production, improving customer service, allowing more economic batches, etc.

• It’s necessary then to consider space for the required stock at the facility when designing the layout.

• Resting time to cool down or heating up…

6. Auxiliary Services

• Support the main production activities at the plant: • Related to labor: Accessibility paths, fire protection installations, supervision, safety, etc. • Related to material: quality control. • Related to machinery: maintenance and electrical and water lines.

• The space dedicated to auxiliary services is usually considered as waste. • It’s important to have efficient services to insure that their indirect costs have been minimized.

Factors affecting Plant Layout Contd…

7. The building

• If it has been already selected, its characteristics will be a constraint at the moment of designing the layout, which is different if the building has to be built.

8. Future Changes

• It’s important to forecast the future changes to avoid having an inefficient plant layout in a short term.

• Flexibility can be reached keeping the original layout as free as possible regarding fixed characteristics, allowing the adjustment to emergencies and variations of the normal process activities.

Objectives of Facility Layout

The objectives of plant layout includes:

• Proper and efficient utilization of available floor space. • To ensure that work proceeds from one point to another point without any delay. • Provide enough production capacity. • Reduce material handling costs. • Reduce hazards to personnel. • Utilize labor efficiently. • Increase employee morale. • Reduce accidents. • Provide for volume and product flexibility. • Provide ease of supervision and control. • Provide for employee safety and health. • Allow ease of maintenance. • Allow high machine or equipment utilization. • Improve productivity.

Basic Layout Forms

The layout design generally depends on the products variety and the production volumes. There are the following type of layouts:

Product

Layouts

Fixed

Position

Layouts

Mixed Layouts Process Layouts

Quantity

Number of Different Products

• Product or Line layout • Group machines in a line to make a certain product -

Assembly Line

• Process or Functional layout • Machinery is placed according to what they do and

materials go to them.

• Fixed position or Location layout • Product stays and resources move to it.

• Hybrid, mixed or combined layout • (Variation of product layout) Machines are arranged so that

specific parts can be made in a group - then moved to next station (maybe even another plant).

• Cellular Layout

Product or Line Layout

Product Layout

• It is also called layout by sequence.

• The layout of the plant, shape and size of its buildings, location of services and storage yards, position of materials handling equipment is such that the material flows unidirectional and at steady rate.

• Special purpose machinery and equipment are employed & the equipments are duplicated, if needed, to avoid backtracking & to ensure material flow in forward direction always.

Suitability: Product layout is useful under following conditions:

1) Mass production of standardized products

2) Simple and repetitive manufacturing process

3) Operation time for different process is more or less equal

4) Reasonably stable demand for the product

5) Continuous supply of materials


Advantages: Product layout provides the following benefits:

a) Low cost of material handling, due to straight and short route and absence of backtracking

b) Smooth and uninterrupted operations

c) Continuous flow of work

d) Lesser investment in inventory and work in progress

e) Optimum use of floor space

f) Shorter processing time or quicker output

g) Less congestion of work in the process

h) Simple and effective inspection of work and simplified production control

Disadvantages: Product layout suffers from following drawbacks:

a. High initial capital investment in special purpose machine

b. Heavy overhead charges

c. Breakdown of one machine will hamper the whole production process

d. Lesser flexibility as specially laid out for particular product.

Example: Wheel Rim Manufacture

Coil handling equipment – slit coils are fed into blank cutter

Blank cutter cuts pieces to exact length

Flat strip blank is rolled into a cylinder

Cylinder is flash welded

Cylinder is flared on each end to expand to outside

wheel dimensions

Wheel is roll formed though 3 or 4 successive expansions

to final wheel contour

The spider which was stamped on another line is mated with

the wheel and GMAW together

Process or Functional Layout

Process Layout

• It is also called layout by function.

• The factory is divided into process units (or departments), and within these process units all similar facilities are grouped together.

• For example, Presses, are kept at one place, milling machines are placed at another place, drilling machines are kept at same place, gear cutting machines are placed at another place and so on.

Suitability: Process layout is adopted when

1. Products are not standardized

2. Quantity produced is small

3. There are frequent changes in design and style of product

4. Job shop type of work is done

5. Machines are very expensive


T T T CG CG

T T T SG SG

M M D D D

M M D D D

Similar resources placed together


Advantages: Process layout provides the following benefits

a) Lower initial capital investment in machines and equipments. There is high degree of machine utilization, as a machine is not blocked for a single product

b) The overhead costs are relatively low

c) Change in output design and volume can be more easily adapted to the output of variety of products

d) Breakdown of one machine does not result in complete work stoppage

e) Supervision can be more effective and specialized

f) There is a greater flexibility of scope for expansion.

Disadvantages: Process layout suffers from following drawbacks

a. Material handling costs are high due to backtracking

b. More skilled labor is required resulting in higher cost.

c. Time gap or lag in production is higher

d. Work in progress inventory is high needing greater storage space

e. More frequent inspection is needed which results in costly supervision

Fixed Position or Location Layout

Fixed Position Layout of a ship

Suitability: The fixed position layout is followed in following conditions

1. Manufacture of bulky and heavy products such as locomotives, ships, boilers, generators, wagon building, aircraft manufacturing, etc.

2. Construction of building, flyovers, dams.

3. Hospital, the medicines, doctors and nurses are taken to the patient (product).


Advantages: Fixed position layout provides the following benefits

a) It saves time and cost involved on the movement of work from one workstation to another.

b) The layout is flexible as change in job design and operation sequence can be easily incorporated.

c) It is more economical when several orders in different stages of progress are being executed simultaneously.

d) Adjustments can be made to meet shortage of materials or absence of workers by changing the sequence of operations.

Disadvantages: Fixed position layout has the following drawbacks

a. Production period being very long, capital investment is very heavy

b. Very large space is required for storage of material and equipment near the product.

c. As several operations are often carried out simultaneously, there is possibility of confusion and conflicts among different workgroups.

Combined layout

• Group of equipment and workers that perform a sequence of operations over multiple units of an item or family of items.

• Actually, most manufacturing facilities use a combination of layout types.

• An example of a hybrid layout is where departments are arranged according to the types of processes but the products flow through on a product layout.

• For instance, supermarket layouts are fundamentally of a process nature, and however we find most use fixed-path material-handling devices such as roller-type conveyors both in the stockroom and at checkouts, and belt-type conveyors at the cash registers.

• Hospitals also use the basic process arrangement, although frequently patient care involves more of a fixed-position approach, in which nurses, doctors, medicines, and special equipment are brought to the patient.

Cellular layout

• Cellular manufacturing is a type of layout in which machines are grouped into what is referred to as a cell.

• Groupings are determined by the operations needed to perform work for a set of similar items, or part families that require similar processing.

• These relate to the grouping of equipment and include faster processing time, less material handling, less work-in-process inventory, and reduced setup time.

• Used when the operations system must handle a moderate variety of products in moderate volumes

Cellular layout

T T T

M

M M T

M

SG CG CG

SG

D D D

D

Resources to

produce similar

products placed

together

A cluster or cell

Material Handling

Material Handling

• Material handling is the function of moving the right material to the right place in the right time, in the right amount, in sequence, and in the right condition to minimize production cost.

• The cost of MH estimates 20-25 of total manufacturing labor cost in the United States [The Material Handling Industry of America (MHIA)]

• Layout design and material handling system design are inseparable. • There is usually more than one “best” solution to the material handling system

design. • In a typical facility, material handling accounts for 25% of all employees, 55% of all

factory space, and 87% of production time. • Material handling does not add value to your product. Therefore, it must be

minimized, if not eliminated, in order to achieve significant cost savings.

Principles of Material Handling

The principles of material handling may be studied under the following head:

1. The Planning Principle

• Large-scale material handling projects usually require a team approach. • Material handling planning considers every move, every storage need, and any delay in order to

minimize production costs. • The plan should reflect the strategic objectives of the organization as well as the more immediate

needs.

2. The systems principle

• MH and storage activities should be fully integrated to form a coordinated, operational system that spans receiving, inspection, storage, production, assembly, shipping, and the handling of returns.

3. Simplification principle

• simplify handling by reducing, eliminating, or combining unnecessary movement and/or equipment. • Four questions to ask to simplify any job:

• Can this job be eliminated? • If we can’t eliminate, can we combine movements to reduce cost? (unit load concept) • If we can’t eliminate or combine, can we rearrange the operations to reduce the travel distance? • If we can’t do any of the above, can we simplify?

Principles of Material Handling contd…

4. Gravity principle

• Utilize gravity to move material whenever practical.

5. Space utilization principle

• The better we use our building cube, the less space we need to buy or rent. • Racks, mezzanines, and overhead conveyors are a few examples that promote this goal.

6. Unit load principle

• Unit loads should be appropriately sized and configured at each stage of the supply chain. • The most common unit load is the pallet

• cardboard pallets • plastic pallets • wooden pallets • steel skids

7. Automation principle

• MH operations should be mechanized and/or automated where feasible to improve operational efficiency, increase responsiveness, improve consistency and predictability, decrease operating costs.


8. Equipment selection principle

• Why? What? Where? When? How? Who? • If we answer these questions about each move, the solution will become evident.

9. The standardization principle

• standardize handling methods as well as types and sizes of handling equipment • too many sizes and brands of equipment results in higher operational cost. • A fewer sizes of carton will simplify the storage.

10. The dead weight principle

• Try to reduce the ratio of equipment weight to product weight. Don’t buy equipment that is bigger than necessary.

• Reduce tare weight and save money.

11. The maintenance principle

• Plan for preventive maintenance and scheduled repairs of all handling equipment. • Pallets and storage facilities need repair too.


12. The capacity principle

• use handling equipment to help achieve desired production capacity • i.e. material handling equipment can help to maximize production equipment utilization

Material Handling Equipments

Material handling equipment includes:

• Lifting and lowering devices: These devices are used for lifting and lowering the material in a vertical direction only. • Block and Tackle • Hand and power winches • Hoists • Elevators • Cranes

• Transporting devices: These devices are used for transporting the material in Horizontal direction. • Wheel Barrows • Hand and power trucks • Industrial narrow railways • Tractors and trailers • Aerial tram ways

Material Handling Equipments contd…

• Devices which lift and transport: These devices are used for lifting, transporting and lowering the material.

• Chutes • Spiral Rollers • Hoists with trolleys running on overhead rails • Fork lift truck • Crane trucks • Conveyors • Spiral chutes

Material Handling Equipments Lifting and lowering devices

Block and Tackle & Hoist

Block and Tackle Hoist


Hand and power winches

Hand Winch Power Winch

Material Handling Equipments Lifting and lowering devices Elevators

Traction

Elevator

Bucket

Elevator


Pillar Crane & Overhead Crane

Pillar Crane Overhead Crane


Gantry Crane & Jib Crane

Gantry Crane Jib Crane

Material Handling Equipments Transporting devices

Wheel Barrows & Hand Trucks

Hand Truck

Hand Pallet Truck

Wheel Barrow

Platform Hand Truck

Material Handling Equipments Transporting devices

Industrial narrow railways & Tractor and trailers

Industrial railways

Tractor trailer

Material Handling Equipments Lifting & Transporting devices

Chutes

Chute

Spiral Chute


Fork lift truck & Crane Truck

Fork Lift Truck

Crane Truck


Conveyors

Screw Conveyor Chain Conveyor

Roller Conveyor

Belt Conveyor Bucket Conveyor

Industrial Engineering -...

Documents

Transcript of Industrial Engineering -...