JIT and TQM

7/29/2019 JIT and TQM

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JUST-IN-TIME


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Just-in-Time

a philosophy of manufacturing

based on planned elimination

of all waste and on continuous

improvement of productivity

A repetitive production systemin which the processing and

movement of materials and

goods occur just as they are

needed

JIT originated in Japan in post

WWII. Associated with Taiichi

Ohno and the Toyota

Production System

Goals:

Eliminate disruptions

Make the system

flexible Reduce setup times and

lead times

Minimize inventory

Eliminate waste


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Benefits of JIT

better quality products

quality the responsibility of every worker, not just quality controlinspectors

reduced scrap and rework

reduced cycle times

lower setup times

smoother production flow

less inventory, of raw materials, work-in-progress and finished goods

cost savings

higher productivity higher worker participation

more skilled workforce, able and wiling to switch roles

reduced space requirements

improved relationships with suppliers


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Elements of JIT

Firms reduce cost and add value to the products andservices

Benefits: lower costs, shorter lead times, better qualityand greater competitiveness

Waste Reduction

JIT partnership can exist between a firm and its most

valued supplier and allows the firm to use purchasingleverage

More frequent deliveries in smaller quantities existinginventories will be lower

Firms also develop partnership with their key customers

JIT Partnership


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Elements of JIT

Primary objective is reduce wasted movement

JIT Layout

Jumbled flows, long cycles, difficult to schedule


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Elements of JIT

Primary objective is reduce wasted movement

JIT Layout

Product focused cells, flexible equipment, high visibility, easy to schedule,

short cycles


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Elements of JIT

Inventories are costly waste. Inventory hides problems.

Reduce invty levels by reducing purchase order quantitiesand production lot sizes, finding better suppliers, automatingpurchasing process or reduce setup times

JIT Inventories


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Elements of JIT

Small batch scheduling drives down costs by reducingpurchased, WIP and finished goods inventories. It alsomakes the firm more flexible in meeting demand.

JIT Scheduling

Monday Tuesday Wednesday Thursday Friday

AAAAA BBBBB BBBBB DDDDD EEEEE

AAAAA BBBBB BBBBB CCCCC EEEEE

Monday Tuesday Wednesday Thursday Friday

AABBBB AABBBB AABBBB AABBBB AABBBB

CDEE CDEE CDEE CDEE CDEE

5 units

5 units

10 units

Weekly Production Required

Traditional Production Plan

JIT Plan with Level Scheduling

A

B

C

D

E

10 units

20 units

A level schedule is developed so that the same mix ofproducts is made every day in small quantities


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Kanban

Japanese word for card, or in JIT, signal

Uses simple visual signals to control production

Workcenter B uses parts produced by Workcenter A

How can we control the flow of materials so that B always has parts and A doesnt overproduce?

Workcenter A Workcenter B


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Kanban: Signal to Produce

When a container is opened by Workcenter B, its kanban card isremoved and sent back to Workcenter A.This is a signal to Workcenter A to produce another box of parts.


Kanban Card


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Kanban: Signal to Pull

Empty box sent back. Signal to pull another full box intoWorkcenter B.



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C

DTcontainersof#

Kanbans are used to control flow of inventory through the facility. Inventories are not

allowed to accumulate beyond the size of each container and number of containers in

the system.

To determine the number of containers for a JIT system:

Where:

D = demand rate of assembly lineT = time for a container to make an

entire circuit through the system

C = container size, in number of parts

Example:

Suppose the assembly line demand is20 parts per hour for Workcenter B,and the standard container used inthis processing area holds 5 parts. If ittakes 2 hours for a container to make acircuit from Workcenter B to the

assembly line and back again, the thenumber of containers needed in thesystem is 8.

85

2*20containersof#

Max inventory in this system:

8 containers x 5 = 40JIT objective: reduce inventory Reduce # of containers

Reduce setup times,

processing time, wait time or

move time


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Elements of JIT

Kaizen: comes from the Japanese words ("kai") which means "change" or "to correct"and ("zen") which means "good"

Continuously seek ways to reduce to supplierdelivery and quality problems; In production

area, improve movements problems, reducevisibility problems, equipment, reduce setup andinternal quality problems

Continuous Improvement


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Elements of JIT

The people in the organization plays a significant role inthe success of JIT

People are provided with skills, tools, time and other

necessary resources to identify problems and implementsolutions

Everyone is responsible for preventive maintenance

Role of Management:

Responsible for culture of mutual trust

Serve as coaches & facilitators Support culture with appropriate incentive system

including non-monetary

Responsible for developing workers

Provide multi-functional training

Facilitate teamwork

Workforce Commitment


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Elements of JIT

Extension of supplier partnerships and vendor-managedinventories

A suppliers employee is housed in the purchasing dept. of

the buyers organization, acting as both buyer and supplierrepresentative. He is given all the rights and duties of anemployee for the buyer firm.

Advantages:

Just-in-Time II

Buyer Supplier

Use of costless employee Improved communication with

supplier

Creates better relationship with

supplier

Security of future purchases Improved communication with buyer

Creates better relationship with buyer

Early involvement during new product

designs


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TOTAL QUALITY

MANAGEMENT


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Total Quality Management

a management approach that originated in the 1950s and

has steadily become more popular since the early 1980s

a management philosophy that seeks to integrate all

organizational functions (marketing, finance, design,

engineering, and production, customer service, etc.) to

focus on meeting customer needs and organizational

objectives

An integrated effort designed to improve quality

performance at every level of the organization.


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Quality Definition

Since TQM is all about pleasing the customer, quality isdefined as the the ability to satisfy customerexpectations

Quality is defined by the customer through his/her

satisfaction Conformance to specifications -how well the product or service

meets the targets and tolerances determined by its designers

Fitness for use - how well the product performs its intendedfunction or use

Value for price paid - consumers often use for product for serviceusefulness

Support services - how the quality of a product or service isjudged

Psychological criteria - subjective definition that focuses on thejudgmental evaluation of what constitutes product or service quality


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Elements of TQM

1. Focus on the customer

Applies to internal and external suppliers and customers

Provide high quality products and high level of customer service

TQM recognizes that a perfectly produced product has little value if

it is not what the customer wants. Therefore, we can say thatquality is customer driven.

2. Workforce involvement

Similar to JIT, commitment of employees and management iscrucial in the success


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Evolution of TQM


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W. Edwards Deming

fatherof quality control

a statistics professor at New York University in the 1940s.

After WWII he assisted many Japanese companies in

improving quality. The Japanese regarded him so highly

that in 1951 they established the Deming Prize

Demings Theory of Management

upper management must develop a commitment to quality andprovide a system to support this commitment that involves all

employees and suppliers. Deming stressed that qualityimprovements cannot happen without organizational change thatcomes from upper management.


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14 Points on Quality Managementis a set of management practices to help companies increase their quality

and productivity

1. Create constancy of purpose for improving products and services.

2. Adopt the new philosophy.

3. Cease dependence on inspection to achieve quality.

4. End the practice of awarding business on price alone; instead, minimize total cost

by working with a single supplier.

5. Improve constantly and forever every process for planning, production and service.

6. Institute training on the job.

7. Adopt and institute leadership.

8. Drive out fear.

9. Break down barriers between staff areas.

10. Eliminate slogans, exhortations and targets for the workforce.

11. Eliminate numerical quotas for the workforce and numerical goals for management.12. Remove barriers that rob people of pride of workmanship, and eliminate the annual

rating or merit system.

13. Institute a vigorous program of education and self-improvement for everyone.

14. Put everybody in the company to work accomplishing the transformation.


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Joseph M. Juran

worked in the quality program at Western Electric. He

became better known in 1951, after the publication of his

book Quality Control Handbook. In 1954 he went to Japanto work with manufacturers and teach classes on quality.

Though his philosophy is similar to Demings, there aresome differences

Whereas Deming stressed the need for an organizational

transformation, Juran believes that implementing quality

initiatives should not require such a dramatic change andthat quality management should be embedded in the

organization.


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Joseph M. Juran

Quality Trilogy

Quality planning, necessary so that companies identify theircustomers, product requirements, and overriding business goals.

Processes should be set up to ensure that the quality standards

can be met Quality control, stresses the regular use of statistical control

methods to ensure that quality standards are met and to identify

variations from the standards

Quality improvements, the process of breaking through to

unprecedented levels of performance


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Tools of TQM

Flow Diagrams

Check Sheets

Pareto Charts Cause-and-Effect Diagrams

Statistical Process Control


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Flow Diagrams

schematic diagram of the sequence of steps involved in

an operation or process. It provides a visual tool that is

easy to use and understand.

By seeing the steps involved in an operation or process,

everyone develops a clear picture of how the operation

works and where problems could arise.


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Check Sheets

list of common defects and the number of observed

occurrences of these defects. It is a simple yet effective

fact-finding tool that allows the worker to collect specific

information regarding the defects observed.


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Pareto Charts

Pareto analysis is a technique used to identify quality problemsbased on their degree of importance. The logic behind Pareto

analysis is that only a few quality problems are important,

whereas many others are not critical.

The technique was named afterVilfredo Pareto, a nineteenth-century Italian economist who determined that only a small

percentage of people controlled most of the wealth (80-20 rule)

Pareto Chart ranks the

causes of poor quality indecreasing order based

on the percentage of

defects each has caused.


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Cause-and-Effect Diagrams

Identify potential causes for particular quality problems.They are often called fishbone or Ishikawa diagramsbecause they look like the bones of a fish.

head of the fish is the

quality problem

spine of the fish connectsthe head to the possible

cause of the problem

Kaoru Ishikawa believed that everyone in the company needed to be united witha shared vision and a common goal. He stressed that quality initiatives should be

pursued at every level of the organization and that all employees should be

involved. Dr. Ishikawa was a proponent of implementation ofquality circles,which are small teams of employees that volunteer to solve quality problems.


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Statistical Process Control

Allows firm to visually monitor process performance,

compare the performance to desired levels or standards,

and take corrective steps quickly before process

variabilities get out of control and damage products,

services and customer relationships involves inspecting a random sample of the output from a

process and deciding whether the process is producing

products with characteristics that fall within a pre-

determined range. SPC answers the question of whetherthe process is functioning properly or not.


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Sources of Variation

Naturalvariations - slight differences in materials,workers, machines, tools, and other factors. These types

of variation are unavoidable and are due to slight

differences in processing

soft drink in a grocery store, notice that no two bottles are filled toexactly the same level

Assignable variations - causes can be precisely

identified and eliminated poor quality in raw materials, an employee who needs more

training, or a machine in need of repair


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Developing Control Charts

to make sure production stays within this normal range.

We want to make sure the process is in a state of control.

Variable Control Charts-used to monitor characteristicsthat can be measured and have a continuum of values,

such as height, weight, or volume.

Example:amount of liquid in the bottles, weight of a bag of sugar

Attribute Control Charts-to monitor characteristics that

have discrete values and can be counted.


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Variable Control Charts

Mean (x-Bar) Charts used to monitor changes in the mean of a process

To construct the upper and lower control limits of the chart, we use thefollowing formulas:


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If the standard deviation of the bottling operation is 0.14 ounces, use this information to

develop control limits of three standard deviations for the bottling operation.


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Variable Control Charts

Another way to construct the control limits is to use thesample range as an estimate of the variability of the

process

A2 factor obtained from table of Constants


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The value ofA2 is obtained from Table.Forn 4, A2 .73. This leads to thefollowing limits:


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Attribute Control Charts

Control charts for attributes are used to measure quality

characteristics that are counted rather than measured.

P-charts are used to measure the proportion of items in asample that are defective.

C-charts count the actual number of defects per unit ofoutput

The primary difference between using a p-chart and a c-chart is as follows.

A p-chart is used when both the total sample size and the number of defectscan be computed.

A c-chart is used when we can compute onlythe number of defects butcannot compute the proportion that is defective.

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JIT and TQM

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