06 managing production operations - singar

7/30/2019 06 Managing Production Operations - Singar

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Managing Production Operations

Assuring Product Quality

Quality is described as fitness for use or customersatisfaction. It is divided into three categories.

Quality of Design: Measures the extent to which fitnessfor use is incorporated into the product design throughthe specification of proper materials, tolerances andother precautions.

Quality of Conformance: Also known as quality ofproduction, measures how well the quality specified inthe design is realized in manufacture and delivered tothe customer.

Quality of Use: Measures how the product is applied oremployed and what that does to its properties.


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Quality Costs

An important step in getting management

support for improving quality is documenting the

total cost of poor quality and of quality control

efforts.

ASQC has established four categories of costs tohelp in this analysis:

Prevention Costs: Incurred in advance of

manufacture to prevent failures, such as qualityplanning, training, data analysis, reporting,

process control and motivation programs.


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Appraisal Costs: Include the costs of inspection of

incoming parts & materials, inspection & test of product

in process & as a finished product, and maintenance of

test equipment.

Internal Failure Costs: Those that would not appear if

there were no defects in the product before shipment to

the customer. They include scrap, rework, downtime andyield losses caused by defects, cost of material review

and disposition of defectives.

External Failure Costs: Caused by defects found after the

customer receives the product. These include the costs

of investigating & adjusting complaints, the costs of

replacing defective product returned by the customer,

price reductions and warranty charges.


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Increasing Quality of Conformance

Effect of Quality Improvement on Quality Costs

Total Quality cost

Failure

cost

Appraisal

cost

Prevention

cost

Qua

lityCosts


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Statistics of Quality

Statistics consists of gathering, organizing, analysis anduse of data.

Statistical methods are used to evaluate the quality

characteristics of the process / product.

Two Types of statistical methods are used in qualitycontrol. They are:

Variables method involve measuring the quality

characteristic on a sample of the item being controlled. Attributes method involve counting as defective those

items that do not fall within a stated specification.


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Process Control Chart

Upper Controllimit

Central line

Lower Control

limit

1 2 3 4 5 6 7 8 9

Sample number

Samplem

ean


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Inspection & Sampling

Inspection is carried out to determine whether the

product meets the specifications set for it.

This is done by sampling lots (batches) of product and

accepting or rejecting the lot depending on the number

of defectives in the sample.

Example:

Take a random sample of 125 items from the lot.

Accept the lot if it contains no more than 3 defective

items.

Reject the lot if it contains 4 or more defective items,

then either 100% inspect it or return it to the producer

as unsatisfactory.


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Taguchi Loss Factor

Loss ($)

LSL T USL


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Total Quality Management

The criteria focuses on two goals: Delivering ever improving value to customers.

Continuously improving overall organizational

performance.

TQM is deployed in categories such as manufacturing,

service, small business, education & health care.

Productivity: It is defined as the output produced per

unit of resources applied. A simple measure might beunits of production per labor hour.


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Work Measurement

Work measurement is the art and science of determining

reasonable and fair times for performing various worktasks. These are called time standards.

A time standard is the time required for a qualified

employee working at a normal pace under capable

supervision experiencing normal fatigue and delay to do

a defined amount of work of specific quality when

following the prescribed method.

It is a measure of how long the task should take. Time standards are usually set on a per piece basis.

These are divided into informal time standards and

engineered time standards.


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Informal Time Standards

Methods for developing informal time standards include educatedguesses, use of historical data, timing one cycle of a task and work

sampling.

This is less accurate and inexpensive.

Engineered Time Standard

Engineered Time Standard are precise and accurate, expensivealso.

Each portion of the work measured is observed closely toeliminate unnecessary motion to improve work place arrangement

and to institute better work methods where possible. Allowances like personal time, recovery from fatigue and

unavoidable delays are included here.

These are developed by stopwatch time study, predeterminedtime systems and standard data.


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Maintenance & Facilities Engineering

Scope of MaintenanceThe following are the primary functions of themaintenance activity:

1. Maintenance of existing plant equipment.

2. Maintenance of existing plant buildings and grounds.

3. Equipment inspection and lubrication.

4. Utilities generation and distribution.

5. Alterations to existing equipment and buildings.

6. New installations of equipment and buildings.


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List of maintenance concerns in a plant:

Roofing

Flooring

Refrigeration

Air conditioning, heating & ventilation

Special purpose rooms and their environment

Electric circuit protection Utilities

Transportation equipment

Materials handing systems

Elevators Painting

Corrosion protection

Pest control

Lubrication of machine tools


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Types of Maintenance

Corrective Maintenance: Simply repair and work,

when an equipment breaks down.

Preventive Maintenance: Establishment of most

cost effective schedule for inspection, lubrication

and identification & replacements of worn parts.

Predictive Maintenance: Involves the use of

sensitive instruments like vibration analyzers,

optical tooling, audio & resistance gages to

predict trouble or any other critical issues that

may occur.


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Some Maintenance Management

Considerations

Size of Maintenance Staff

Work Orders

Work Scheduling

Repair Parts Inventory.


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Total Productive Maintenance

An integrated, top down, system oriented, life cycle approach tomaintenance, with the objective of maximizing productivity.

Promotes the overall effectiveness and efficiency of equipment inthe factory.

Establishes a complete preventive maintenance program forfactory equipment based on life cycle criteria.

Is implemented on a team basis involving various departments to

include engineering, production operations and maintenance. Involves every employee in the company, from the top

management to the workers on the shop floor. Even equipmentoperators are responsible for maintenance of the equipment theyoperate.

Is based on the promotion of preventive maintenance throughmotivational management.

The objective of TPM is to eliminate equipment breakdowns,speed losses, minor stoppages and so on. It promotes defect freeproduction, just in time (JIT) production and automation. TPM

includes continuous improvement in maintenance.


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Human Resource Management

Recruitment and Employment

Equal Employment Opportunity

Industrial Relations

Compensation

Education and Training

Health and Safety

Employee Benefits


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Purchasing & Materials Management

Recognition of need

Description of requirement

Selection of possible sources of supply

Determination of price and availability

Placement of the order

Follow up and expediting of the order

Verification of the invoice

Processing of discrepancies and rejections

Closing of completed orders

Maintenance of records and files

06 managing production operations - singar

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