pritika new

8/2/2019 Pritika New

1/25

Just-in-time (JIT)

Introduction:

Just-in-time (JIT)is defined in the APICS dictionary as a philosophy of

manufacturing based on planned elimination of all waste and on continuous

improvement of productivity. It also has been described as an approach with the

objective of producing the right part in the right place at the right time (in other

words, just in time).

Waste results from any activity that adds cost without adding value, such as the

unnecessary moving of materials, the accumulation of excess inventory, or the use offaulty production methods that create products requiring subsequent rework. JIT (also

known as lean production or stockless production) should improve profits and return

on investment by reducing inventory levels (increasing the inventory turnover rate),

reducing variability, improving product quality, reducing production and delivery lead

times, and reducing other costs (such as those associated with machine setup and

equipment breakdown). In a JIT system, underutilized (excess) capacity is used

instead of buffer inventories to hedge against problems that may arise.

JIT is not about automation. JIT eliminates waste by providing the environment to

perfect and simplify the processes. JIT is a collection of techniques used to improve

operations It can also be a new production system that is used to produce goods or

services.

JIT applies primarily to repetitive manufacturing processes in which the same

products and components are produced over and over again. The general idea is toestablish flow processes (even when the facility uses a jobbing or batch process

layout) by linking work centers so that there is an even, balanced flow of materials

throughout the entire production process, similar to that found in an assembly

line. To accomplish this, an attempt is made to reach the goals of driving all

inventory buffers toward zero and achieving the ideal lot size of one unit.

The basic elements of JIT were developed by Toyota in the 1950's, and became

known as the Toyota Production System (TPS). JIT was well-established in many


2/25

Japanese factories by the early 1970's. JIT began to be adopted in the U.S. in the

1980's (General Electric was an early adopter), and the JIT/lean concepts are now

widely accepted and used.

Some Key Elements of JIT

1. Stabilize and level the MPS with uniform plant loading (heijunka in Japanese):

create a uniform load on all work centers through constant daily

production(establishfreeze windows to prevent changes in the production plan for

some period of time) and mixed model assembly (produce roughly the same mix of

products each day, using a repeating sequence if several products are produced on the

same line). Meet demand fluctuations through end-item inventory rather than through

fluctuations in production level. Use of a stable production schedule also permits the

use ofback flushing to manage inventory: an end items bill of materials is

periodically exploded to calculate the usage quantities of the various components that

were used to make the item, eliminating the need to collect detailed usage information

on the shop floor.

2. Reduce or eliminate setup times: aim for single digit setup times (less than 10

minutes) or "one-touch" setup -- this can be done through better planning, process

redesign, and product redesign. A good example of the potential for improved setup

times can be found in auto racing, where a NASCAR pit crew can change all four

tires and put gas in the tank in under 20 seconds. (How long would it take you to

change just one tire on your car?) The pit crews efficiency is the result of a team

effort using specialized equipment and a coordinated, well-rehearsed process.

3. Reduce lot sizes (manufacturing and purchase): reducing setup times allows

economical production of smaller lots; close cooperation with suppliers is necessary

to achieve reductions in order lot sizes for purchased items, since this will require

more frequent deliveries.

4. Reduce lead times (production and delivery): production lead times can be

reduced by moving work stations closer together, applying group technology and


3/25

cellular manufacturing concepts, reducing queue length (reducing the number of jobs

waiting to be processed at a given machine), and improving the coordination and

cooperation between successive processes; delivery lead times can be reduced through

close cooperation with suppliers, possibly by inducing suppliers to locate closer to the

factory.

5. Preventive maintenance: use machine and worker idle time to maintain equipment

and prevent breakdowns.

6. Flexible work force: workers should be trained to operate several machines, to

perform maintenance tasks, and to perform quality inspections. In general, JIT

requires teams of competent, empowered employees who have more responsibility fortheir own work. The Toyota Production System concept of respect for people

contributes to a good relationship between workers and management.

7. Require supplier quality assurance and implement a zero defects quality

program: errors leading to defective items must be eliminated, since there are no

buffers of excess parts. A quality at the source (jidoka) program must be

implemented to give workers the personal responsibility for the quality of the work

they do, and the authority to stop production when something goes

wrong. Techniques such as "JIT lights" (to indicate line slowdowns or stoppages) and

"tally boards" (to record and analyze causes of production stoppages and slowdowns

to facilitate correcting them later) may be used.

8. Small-lot (single unit) conveyance: use a control system such as akanban(card)

system (or other signaling system) to convey parts between work stations in small

quantities (ideally, one unit at a time). In its largest sense, JIT is not the same thing asa kanban system, and a kanban system is not required to implement JIT (some

companies have instituted a JIT program along with a MRP system), although JIT is

required to implement a kanban system and the two concepts are frequently equated

with one another.

Objective of JIT

1. Produce only the products the customer wants.


4/25

2. Produce products only at the rate that the customer wants them.

3. Produce with perfect quality

4. Produce with minimum lead time.

5. Produce products with only those features the customer wants.

6. Produce with no waste of labor, material or equipment every movement must

have a purpose so that there is zero idle inventory.

7. Produce with methods that allow for the development of people.

Just in time production (JIT)

Just in time is a pull system of production, so actual orders provide a signal for

when a product should be manufactured. Demand-pull enables a firm to produce only

what is required, in the correct quantity and at the correct time.

This means that stock levels of raw materials, components, work in progress and

finished goods can be kept to a minimum. This requires a carefully planned

scheduling and flow of resources through the production process. Modern

manufacturing firms use sophisticated production scheduling software to plan

production for each period of time, which includes ordering the correct stock.

Information is exchanged with suppliers and customers through EDI (Electronic Data

Interchange) to help ensure that every detail is correct.

Supplies are delivered right to the production line only when they are needed. For

example, a car manufacturing plant might receive exactly the right number and type

of tyres for one days production, and the supplier would be expected to deliver them

to the correct loading bay on the production line within a very narrow time slot.

Advantages of JIT

1. Lower stock holding means a reduction in storage space which saves rent and

insurance costs

2. As stock is only obtained when it is needed, less working capital is tied up in stock

3. There is less likelihood of stock perishing, becoming obsolete or out of date


5/25

4. Avoids the build-up of unsold finished product that can occur with sudden changes

in demand

5. Less time is spent on checking and re-working the product of others as the

emphasis is on getting the work right first time

Disadvantages of JIT

1. There is little room for mistakes as minimal stock is kept for re-working faulty

product.

2. Production is very reliant on suppliers and if stock is not delivered on time, the

whole production schedule can be delayed

3. There is no spare finished product available to meet unexpected orders, because all

product is made to meet actual ordershowever, JIT is a very responsive method of

production the purposes of:

Reducing Cost Improving Quality Improving Performance

Improving Delivery Adding Flexibility Increase innovativeness

JIT and Elimination of Waste:

JIT usually indentifies seven prominent types of waste to be eliminated:

1. Waste from Overproduction

2. Waste of waiting/idle time

3. Transportation Waste

4. Inventory Waste

5. Processing Waste

6. Waste of Motion

7. Waste from Product Defects


6/25

List of Companies that use just in time (JIT):

Harley Davidson Toyota Motor Company General Motors Ford Motor Company Manufacturing Magic Hawthorne Management Consulting Strategy Manufacturing Inc.

Benefits of JIT to the companies.

The main benefits of JIT are listed below.

1. Set up times are significantly reduced in the warehouse which will allow the

company to improve their bottom line to look more efficient and focus time spend on

other areas.

2. The flows of goods from warehouse to shelves are improved. Having employees

focused on specific areas of the system will allow them to process goods faster instead

of having them vulnerable to fatigue from doing too many jobs at once and simplifies

the tasks at hand.

3. Employees who possess multi-skills are utilised more efficiently. This will allow

companies to use workers in situations where they are needed when there is a shortage

of workers and a high demand for a particular product.

4. Better consistency of scheduling and consistency of employee work hours are

possible. This can save the company money by not having to pay workers for a job

not completed or could have them focus on other jobs around the warehouse that

would not necessarily be done on a normal day.

5. Increased emphasis on supplier relationships is achieved. No company wants a

break in their inventory system that would create a shortage of supplies while not

having inventory sit on shelves.

6. Supplies continue around the clock keeping workers productive and businesses

focused on turnover. Having management focused on meeting deadlines will make


7/25

employees work hard to meet the company goals to see benefits in terms of job

satisfaction, promotion or even higher pay.

Classic JIT diagram

The classic JIT diagram is as below. There the company (the boat) floats on a sea of

inventory, lurking beneath the sea are the rocks, the problems that are hidden by the

sea of inventory.

|

--|--

|

---------------

\ /

========\ Company /============ Sea of inventory

\---------/

x

xxx xxxx

xxxxx xxxxxx Rocks - the problems hidden

xxxxxxxxxxxxxxxx by the sea of inventory

If we reduce the inventory level then the rocks become exposed, as below.

|

--|--

|

--------------- x

\ / xxx xxxx

========\ Company /====xxxxx===xxxxxx========

\---------/ xxxxxxxxxxxxxxxx


8/25

Now the company can see the rocks (problems) and hopefully solve them before it

runs aground!

One plan to expose the problems is simply to:

make a large amount of finished goods stock to keep the customers supplied try running the production system with less inventory to expose problems revert to the original levels of inventory until you have had time to fix the

problems you exposed

repeat the above - hence continuous improvement

Suppliers

Suppliers can be crucial to JIT success

Supplier gets:

long-term, guaranteed, contract a good price steady demand minimal paperwork (e.g. use electronic means to order - such as email or Web

or electronic data interchange, EDI)

In return the supplier agrees to

quality components (e.g. zero defects) guaranteed delivery times a "partnership" with its customer contingency plans to cope with disruptions, common disruptions might be:

o the effect of bad weathero a truck drivers strike blocking roads/portso a flu outbreak reducing the supplier's workforce

Supplier selection criteria:

close to production plant (else potential transportation delays)


9/25

good industrial relations ("involvement", "value", "dignity", "ownership"), nostrike deals

you believe that the supplier can met their promises with respect to the list offactors given above that that they are agreeing to

With suppliers satisfying these criteria you can reduce the total number of suppliers,

indeed it seems logical so to do. If you had five suppliers meeting all these criteria

why do you need five? Obviously you might decide to have more than one supplier

for safety reasons. Even the best run supplier can suffer a factory fire or an

earthquake, but probably no more than two or three suppliers.

JIT implementation design

Based on a diagram modeled after the one used by Hewlett-Packards Boise plant to

accomplish its JIT program.

1) F Design Flow Process

F Redesign /relay out flow L Reduce lot sizes O Link operation W Balance work station capaity M Preventive maintenance S Reduce setup times

2) Q Total Quality Control

I automatice inspection M Quality measures

M Fail safe methods W Workers participations

3) S Stabilize Schedule

S Level schedule W Establish freeze window UC Under utilize capacity


10/25

4) K Kandan pull system

D Demand pull B Back flush L Reduce lot size

5) V Work with Vendors

L Reduce lead time D Frequent deliveries U Project usage requirement Q Quality expectation

6) I Further Reduce Inventory in Other Areas

S Store T Transit C Implement carrousel to reduce motion waste C Implement conveyor belts to reduce motion waste

7) P Improve Product Design

P Standare production configuration P Standardize and reduce the no. Of parts P Process design with product design Q Quality expectations

Goal of Just in Time

According to Cheng in Just-In-Time Manufacturing An Introduction, he explains

the ideas of Suzaki for the objectives of JIT. There are three main objectives:

1. Increasing the organizations ability to compete with others and remain competitive

over the long run. The competitiveness of the firms is increased by the use of JIT

manufacturing process as they can develop a more optimal process for their firms.

2. Increasing efficiency within the production process. Efficiency is obtained through

the increase of productivity and decrease of cost.

3. Reducing wasted materials, time and effort. It can help to reduce the costs.

Other short-term and long-term objectives are:


11/25

1. Identify and response to consumers needs. Customers needs and wants seem to be

the major focus for business now, this objective will help the firm on what is

demanded from customers, and what is required of production.

2. Optimal quality/cost relationship. The organization should focus on zero-defect

production process. Although it seems to be unrealistic, in the long run, it will

eliminate a huge amount of resources and effort in inspecting, reworking and the

production of defected goods.

3. Reduce unwanted wastes. Wastes that do not add value to the products itself should

be eliminated.

4. Develop a reliable relationship between the suppliers. A good and long-term

relationship between organization and its suppliers helps to manage a more efficient

process in inventory management, material management and delivery system. It will

also assure that the supply is stable and available when needed.

5. Plant design for maximizing efficiency. The design of plant is essential in terms of

manufacturing efficiency and utility of resources.

6. Adopt the work ethnic of Japanese workers for continuous improvement. Commit a

long-term continuous improvement throughout the organization. It will help the

organization to remain competitive in the long run.

Limitation of Just in Time

Regardless of the great benefits of JIT, it has its limitation, JIT has the following

major limitations:

1. Culture Differences The organizational cultures vary from firm to firm. There are

some cultures that tie to JIT success but it is difficult for an organization to change its

cultures within a short time.

Traditional Approach The traditional approach in manufacturing is to store up a

large amount of inventory in the means of backing up during bad time. Those


12/25

companies rely on safety stocks may have a problem with the use of JIT.

Difference in implementation of JIT Because JIT was originally established in

Japanese, it is somehow different for implementing in western countries. The benefits

may vary.

Loss of individual autonomy This is mainly due to the shorter cycle times which

adds pressures and stress on the workers.

Loss of team autonomy This is the result of decreasing buffer inventories which lead

to a lower flexibility of the workers to solve problem individually.

Loss of method autonomy It means the workers must act some way when problems

occur, this does not allow them to have their own method to solve a problem.

JIT success is varied from industry to industry Some industries are benefit more

from JIT while others do not.

Resistance to change JIT involves a change throughout the whole organization, but

human nature resists to change. The most common resistance are emotional resistance

and rational resistance. Emotional resistance are those psychological feeling which

hinder performance such as anxiety. Rational resistance is the deficient of the needed

information for the workers to perform the job well.

Relationship between management and employees is important A mutual trust must

be built between management and employees in order to have effective decision

making.

Employee commitment Employees must commit to JIT, to enhance the quality as

their ultimate goal, and to see JIT as a way to compete rather than method used by

managers to increase their workload.

Production level JIT works best for medium to high range of production volume.

Employee skill JIT requires workers to be multi-skilled and flexible to change.


13/25

Compensation Compensation should be set on time-based wages. This allow the

workers to concentrate on building what the customers wants.

Effect of Just In Time

Effect of Just-In-Time Purchasing Relationships on Organizational Design,

Purchasing Department Configuration, and Firm Performance

Just-in-time purchasing requires close relationship and co-operation on product

development and specification(product and information flow). It also involves joint

product design, extensive verification of supplier quality and shared production plan.

Three questions are addressed in this articles:

1. Is JIT purchasing associated with overall organizational design?

2. Is JIT purchasing associated with the configuration of purchasing?

3. Is JIT purchasing associated with performance?

To answer these questions, we have to first look at the factors that related to each of

the question. In consideration of overall organizational design, four different aspects

are discussed: formalization, decentralization, integration and specialization.

Formalization refers to formal internal performance control, formal benchmark

control and the strategic formalization of the purchasing function. It is found that themore JIT purchasing, the more internal and benchmark control are implemented. The

reasons for that are 1) JIT represents the exact process management, so more

performance information is needed to ensure that the remaining inventory meets the

specification. 2) JIT provides feedback which are essential to the succeed of JIT

implementation. And also, with the increase of JIT purchasing, a written statement of

shared vision(goal) of the firm is needed.


14/25

Decentralization consists of line-operating decision and scheduling. JIT purchasing is

related to decentralized decision-making because a higher employees involvment will

result in higher performance. JIT purchasing is positively related to line-operating and

negatively related to scheduling.

Integration is the lateral communication. While there are more JIT purchasing, it is

very important to have a stable and good communication among departments within a

firm. Thus, JIT is positively related to integration.

Specialization focuses on division of labor. As more JIT purchasing, more labor is

needed to perform a faster production schedule. So, it is positively related to JIT. It is

very obvious that JIT purchasing is associated with overall organizational design.

To address the second question, we have to look into two aspects. They are the

number of layers for the purchasing function and the span of control of the senior

purchasing executive. The authors found out that JIT purchasing is negatively related

to the number of layers for the purchasing function and positively related to the senior

purchasing executives span of control.

For the third question - Is JIT purchasing associated with performance? JIT is

expected to be related with efficiency, financial performance and market performance.

And it is found out that JIT is negatively related to weeks of inbound inventory,

positively related to financial performance and market performance.

From this study, two managerial implications can be drawn. First, implementing JIT

exchange with suppliers. The relationship between buyer and seller is now toward

relational exchange as the JIT purchasing is more frequently used. Second, JIT

purchasing correlates with performance.

There are several importance tools for total quality management control:

1. relations diagram

2. Affinity diagram

3. Systematic diagram ( Tree diagram)


15/25

4. Matrix diagram

5. Matrix data analysis

6. Process derision program chart

7. Arrow diagram

From seven tools, it help Japanese product quality to meet following total quality

management: The ability to eliminate defective products

The ability to improve productivity

The ability to complete tasks on time

The ability to increase product value-driven

The ability to completely eliminate waste

The ability to reduce lead time and inventory cost

Just in Time Inventory and Productive Management

Introduction:

Generally speaking, most of the company and factories must manage the inventory

material efficiently and effectively. Therefore, reducing levels of inventory stock in

company and factory is an internal and external matter. In terms of supply and

demands management, the Just-In-Time (Inventory Management) are linked

strategically and operationally. Take Japan for an example. Japan has encouraged the

adoption of just-in-time methods and quality management methods. That is the reason

why Japan can do a good job on economic performance. As to Technological

advances, it also play an important role on inventory management.

Essential Aspects inventory Management influence on Just in Time

Lessons have been learnt from Japanese methods where substantial efficiencies are

gained from frequent deliveries of small quantities to meet immediate demands. This


16/25

compares with methods of stock control such as the economic inventory management

approach.

Reduction inventory in supply chains

Reduce transit time

Reduce manufacture cost

Increase management efficiency and effective

Reliable delivery

Short distances between client and server

Consistent quality so that server performance and throughput is unaffected

Just in Time-----Manufacturing

(1) Introduction

Just in Time---manufacturing is a systems method to develop and operate a factory

system. It is mainly basis on the total Decrease of waste. As you know, many people

think JIT is not a new knowledge field. As a matter of fact, it has been part and plays

an important role of the Japanese manufacturing industry adopted method for a long

time . It requires all the materials such as equipment, human resources, and

management skills are made available only in the amount required and at the time

required to do the job. It is based on producing only the necessary units in the

necessary quantities at the necessary time by bringing production rates exactly in linewith market demand. Generally speaking, JIT means making what the market wants.

JIT has been found to be so effective that it increases productivity, work performance

and product quality. Whats even more, it plays a vital role to increase productivity

and decrease the total cost of manufacturing production.

(2) Planning for JIT


17/25

Since each manufacturing process is different, it is up to the individual company to

determine the degree of appropriateness and the final application of JIT. However, it

is very important to define the plan and objectives before setting up a JIT

manufacturing system. It is impossible to establish a new JIT system that can be used

successfully without change. Therefore, we should take serious consideration to make

a plan for Just-In-Time, which will benefit to our factory performance.

3) Defining the Planning

JIT manufacturing system requires an understanding of the objectives of JIT, and

objectives of the JIT system. After the objectives are set up for the manufacturing, the

process of planning becomes one of determining what is required to meet thoseobjectives. The goal of a JIT approach is to develop a system that allows a factory to

have only the materials equipment and people by hand required doing the some plan.

T o achieve this goal, we should have equipped with at least five fundamental plan:

a) Integrating and optimizing every step of the manufacturing process

b) Reducing manufacturing cost

c) Producing product on demand

d) Developing manufacturing flexibility

e) Produce quality product to maintain commitments and links made between

Customers and Suppliers

We also should keep in mind that achieving these obtaining targets do not

automatically make a company a JIT manufacturer. On the contrary, it will lead to

achieve even one of these objectives will prevent a manufacturer from establishing a

successful JIT system. According to Common Wealth on May, 1996 report, it said

that A company cannot decide to implement JIT; they must earn the right to use JIT

by revising their quality for system."

(4) Reducing Manufacturing Cost


18/25

If we can design products that it will speed up and decrease manufacturing processes.

Gradually, it will helps us to reduce the cost of manufacturing and building the

product to specifications benefit. One aspect in designing products for manufacture

ability is the need to set up a good boss and employee relationship. At least, this is to

cultivate and procure the resources of the production experts, and the line employees

to develop cost saving solutions. Participatory quality programs utilize employee

knowledge about their job functions and review the department performance. It will,

finally, encourage with rewards for suggested total cost saving.

(5) Manufacturing Flexibility

According to China time report on August 1996. "Manufacturing flexibility is theability to start new projects or the rate at which the production mix can be adjusted to

meet customer demand." Planning for manufacturing flexibility requires the

understanding of the elements in the manufacturing process and understanding

elements in the process that restrict flexibility and improving on these areas. The

unique feature of Just-In-Time is the modification from between pull and push

systems. The main idea behind these approaches are that "work should not be pushed

on to the next worker until that worker is ready for it." (Hauser, J.R.) As a result,

manufacturing flexibility requires production managers to consider the some

important factors, such as supplier lead time, production process time, process setup

time and so forth.

6) Keep in touch between customers and suppliers

For factory main commitment to achieving the internal structures, both customer and

supplier are also playing a vital role to support JIT manufacturing. Because it is theprimary requirement for developing the JIT system, each other can establish trust and

honest between the supplier and the customer which is a must, since every Just-in-

Time operation depends on it. Supposed, finally, it leads to failure to keep the

commitments each other. Finally, it will be result to a serious form of breakdown

manufacturing systems. Therefore, we should pay attention to this kind of serious call.

Never be ignorant of this commitment. If we can make use of Just-In-Time

(manufacturing approaches), it, eventually, will attain those goal, which are the

fundamental concept of producing product only as needed or on demand.


19/25

Example:

Toyota manufacturing processes route the product around the plant to various work

centers where work is staged to be processed. Implementing manufacturing cells

typically increases net income dramatically and reduces cycle time over 50%. The

cost of design and implementation is usually recovered within the first year from

inventory savings. In this paper, we present the benefits of bringing the processes to

the product and discuss the value of simulation as a tool to design and predict cell

performance prior to implementation; therefore, reducing financial and technical risk

to the company.

On September 10, 1997, Mr. Hoskins presented on "Improve Profits and ReduceCycle Time with Manufacturing Cells and Simulation" for the National Technology

University series on Kanban just-In-Time Manufacturing of this series. On October 27

- 28, 1996 Jerry Hoskins, President presented a paper titled "Developing a Lean

Implementation Roadmap" at the SME Kanban Manufacturing Conference in

Dearborn, Michigan. The intent of this paper is to provide information to companies

on where to start with a Kanban implementation based on where one is currently

manufacturing operation. His theory help our many manufactures implement all the

elements of Kanban Manufacturing directed at elimination of manufacturing waste as

defined by the Toyota Production System. These systems are more flexible,

responsive, and profitable than traditional manufacturing systems. And, its theory also

help our many participate determine where best to start with a Kanban

implementation which usually involves an assessment of current operations. Once

plan is developed we design the system to be implemented which may involve layout,

cells, JIT, process technology, and process simulation.

Elements of Just in Time

According to Cheng, the basic elements of JIT manufacturing are:

People Involvement

Plants

System


20/25

People Involvement

Maintaining a good support and agreement from people involved in production. This

is not only reduce the time and effort in implementation of JIT, but also minimize the

chance of creating implementation problem. (Cheng, 6) The attempt to maximize

peoples involvement may carry through the introduction of quality circle and total

involvement concept. (Cheng, 7)

Manufacturers can gain support from 4 sources.

1. Stockholders and owners of the company - should maintain a good long-term

relationship among them.

2. Labor organization - all labors should be well-informed about the goals of JIT, this

is crucial in gaining support from the them.

3. Management support - support from all level of management. The ideas of

continuous improvement should spread all over the factory, managers and all shop-

floor labor.

4. Government support - government can show their support by extending tax and

other financial help. This can enhance the motivation, and also help in financing the

implementation of JIT.

Plants

Certain requirements are needed to implement JIT, there are:

1. Plant layout - the plant layout is mainly focus on maximizing working flexibility. It

requires the use of "multi-function workers".

2. Demand pull production - it means to produce when the order is received. This can

manage the quantity and time more appropriately.

3. Kanban - a Japanese term for card or tag. Special inventory and process


21/25

information are written on the card. This helps tying and linking the process more

efficiently.

4. Self-inspection - it is carried out by the workers at catch mistakes immediately.

5. Continuous improvement - this concept should be adopted by every members in the

organization in order to carry out JIT. This is the most important concept of JIT. This

can allow an organization to improve its productivity, service, operation and even

customer satisfaction in an on-going basis.

System

This refers to the technology and process that combines the different processes and

activities together. Two major types are MRP (Material Requirement Planning) and

MRP II (Manufacturing Resource Planning). (Cheng, 8)

MRP is a computer-based, bottom-up manufacturing approach. This involves two

plans, production plan and master production schedule. Production plan involves the

management and planning of resources through the available capacity. Master

production schedule involves what products to be produced in what time. (Cheng, 8)

MRP II is mainly involved the management or planning of financial resources in

order to carry out the operation.

The above three factors formed the element of JIT.

JIT approaches

Three main approaches are possible:

1. Reducing manufacturing and administrative cycle times

2. Reducing all waste

3. Reducing the pulled flow breakdowns

Cycle time reduction


22/25

The cycle time represents the time between the customer demand and its final

delivery:

1. Manufacturing cycle time includes the machining, transportation, inspection and

warehousing. Classical tools are used to reduce these cycle times such as SMED,

TPM, 5S

2. Administrative cycles are less visible since they more occur in the background.

They include order entries, purchase entries & follow-up, payments, credit notes

Depending on industries, there can be up to 90% waiting time and 10% value added

time!

Waste reduction

The wastes encompass all operations not having any value added on a given product.

Shigeo Shingo from Toyota has classified them among 7 root causes:

1. Over-production: to be sure to get the right component quantity, we produce

more!

2. Queues or Waiting time: Products dont move as produced to early

3. Transports: No value added and can be expensive (e.g. factory transfer,)

4. Processes: If not well adapted to the operation to perform, there can be a waste of

time

5. Movements: Useless movements in a shopfloor or around a line.

6. Non-Quality: Defective products are pure financial loss!

7. Inventory: Overstocking is usually seen when disruptions occurred during the

manufacturing cycle, when a machine is down too often for instance or when

absenteeism is always over predicted.

Japanese people use to say that the inventories are made to tackle unsolved problemsin order to maintain the throughput rate.

So the method consists in reducing slowly the inventories in order to continuously

solve the issues causing problems:


23/25

Flow breakdowns

This approach consists in identifying all the flow breakdown causes in order to

eliminate them.

The main objective is to maintain a high throughputs rate in order to quickly assemble

or produce the products to get faster sales revenues.

The causes could be classified as following:

Random breakdowns:

o Waiting timeso Missing part or componento Machine breakdowno Absenteeism

o Rework


24/25

o Waiting for decision (after inspection) Operation breakdowns:

o Inspectiono Transit (between shopfloors or to warehouse)o Handling / Warehousing

JIT change management scope

The JIT is a full process that impacting all factory main functions, from sales to

purchasing troughout the supply chain:

Sales: From maximizing turnover at all cost to maximizing margins. Salespeople should change their habits to avoid big ordering waves disturbing the

manufacturing line, by smoothing orders through the year and get yearly

discount instead of individual order discounts. New metrics for sales

performance are hence required.

Suppliers: There are fewer suppliers but they are considered as partners with

long term contracts in order to get a stable supply plan and reduce the

shortage. Hence long term forecasts are issued so that they can plan

accordingly. Supplier Schedules are used, replacing traditional purchase

orders, and reception inspection is skipped or simplified for selected suppliers

allowing direct delivery to the manufacturing line.

Distribution: It can represent up to 40% of the cost paid by the customer.

Distribution is optimized by increasing delivery frequencies to reduce

inventory levels and reducing the number of warehouses.


25/25

Engineering: Products are standardized in order to reduce the number of

components and lower the safety stocks. Then products are simplified as much

as possible: less bill of material levels, simpler routings, fewer operations but

productivity should increase by reducing the value added times.

Manufacturing lines: Machines are grouped by products family not by their

functions anymore. The raw material and components are stored on the line

itself, replacing a central warehouse (and high inventory). Preventive

maintenance is done to reduce the number of machine breakdowns, flexibility

and reduced exchange die are searched, non-quality is avoided and machining

setup is simplified.

Human Resources: The workforce is back in the middle of the productionprocess. Continuous improvement is performed at all levels every day. The

work environment is optimized, less noisy, clean and safety is improved.

Workers are taking decisions over the lines in order to improve the

manufacturing layout and the line efficiency. Performance is now measured

accordingly: team performance instead of individual, manufacturing schedule

adherence per product rather than total quantity produced of all items,

Conclusion:

The JIT is rather a philosophy or a concept than a simple method. All departments are

involved to change from traditional manufacturing to lean production. It is a long

process that needs to be followed over a decade to get fruitful results

pritika new

Documents