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Krupanidhi School of Management Module 3 (WCM)

MODULES 3 – PUSH AND PULL SYSTEMS

2 marks questions

1. Bring out the critical difference between preventive maintenance and breakdown maintenance.

Preventive Maintenance vs. Predictive Maintenance• While both preventive and predictive maintenance have the same objective of preventing any losses to the company and to keep the plant and machinery running in top condition, they differ in approach and requirements• Preventive maintenance is carried out at regular intervals whereas predictive maintenance is based upon the condition of the equipment that needs to be monitored all the time• Preventive maintenance is carried out when the machinery is in the shut down condition while predictive maintenance is done with the plant in running condition• Predictive maintenance relies heavily on information and its correct interpretation

2. Explain the term ‘preventive maintenance’. Preventive maintenance refers to set of activities that are carried out on plant and machinery before the occurrence of a failure. Preventive maintenance is necessary to protect and to prevent any degradation in the efficiency of the operating system. Preventive maintenance is characterized by periodic intervals that are predetermined and are performed with prescribed criteria so as to minimize any future failure. Preventive maintenance is very important part of maintenance in any production unit. It is not just its proper scheduling and following the procedures that are outlined but also the skills of those involved in preventive maintenance that result in a high level of maintenance. Preventive maintenance helps in avoiding failures that would cause unnecessary losses.

3. Explain 5 S housekeeping. 5 “S” is a systematic approach to good housekeeping. The concept of good housekeeping has been with Japanese for a very long time. It was only in the early 1980s that good housekeeping became a pertinent issue in Japanese industries, as companies realized its powerful contribution to productivity and quality improvement.The basis for good housekeeping in Japanese companies is a concept popularly known as 5S. This stands for five good housekeeping concepts in Japanese.

Why 5 S is required in Companies?• Workplace becomes clean and better organized,• Shopfloor and office operations become safer and easier.• Results are visible.• Employees are highly motivated

5S can be briefly described as show in the table:5 “S” Japanese English

Prof. Raghavendra A.N., BSc, MBA, UGC-NET, (PH.D) 1


1 S Seiri Sort out unnecessary items in the workplace and discard them.

2 S Seiton Arrange necessary items in good order.

3 S SeisoClean your workplace thoroughly so that there is no dust on floors, machines and equipment.

4 S SeiketsuMaintain high standards of housekeeping at workplace at all times.

5 S Shitsuke Train people to follow good housekeeping disciplines.

4. State the objectives of maintenance.The various objectives of maintenance are depicted below:

5. What is Muri and Muda?

Muda = waste (in its many forms)

Muda waste is often accompanied or caused by...

Mura = unevenness, overburden, strain

Muri = demand that exceeds process and equipment capacities.

6. What is pull vs. push system?

Push System. A "push" system is one where the manufacturer builds as many items as

possible each day, anticipating the need in the marketplace. The product is "pushed" down to


PLANT

M

AINTENANCE

Reduce Breakdowns

Reduce Downtime

Improving Equipment Efficiency

Improving Inventory Control

Implementing Cost Reduction

Maximising Production

Optimising Resources Utilisation

Optimising Useful Life of Equipment

Minimising Energy Usage

Providing Budgetary Control


the next level of manufacturing or sales, regardless of whether it is needed there or not. The

risk, therefore, is the chance that the demand will not match the manufacturer's predictions,

and an excessive inventory will have to be stored, managed, and possibly even liquidated at

some point in the future. Or on the other hand, if the inventory is not sufficient for the

demand, the manufacturer's risk includes the potential for reduced customer satisfaction

because the market wasn't properly supplied. Either way, the push system requires good

information to be reasonably effective.

Pull System. In the "pull" system, on the other hand, manufacturing is only completed when

there is a downstream need, as indicated by customer requests. In a true "pull" system, the

manufacturer doesn't have to guess how many will be needed. He only needs to react to the

demand at the time. The result is a reduction in non-value-added costs, such as inventory

management, warehousing, etc. The risks for the pull system include the possibility that,

when the item is requested, the manufacturer will not have the raw materials or the plant

capacity to produce the requested quantity in a short time.

8 Marks Questions:1. Briefly explain the concept of 5S Housekeeping. (June/July 2010)5 “S” is a systematic approach to good housekeeping. The concept of good housekeeping has been with Japanese for a very long time. It was only in the early 1980s that good housekeeping became a pertinent issue in Japanese industries, as companies realized its powerful contribution to productivity and quality improvement.5S can be briefly described as show in the table:

5 “S” Japanese English



3 S SeisoClean your workplace thoroughly so that there is no dust on floors, machines and equipment.

4 S SeiketsuMaintain high standards of housekeeping at workplace at all times.




1) SEIRI - SORT OUT THE ITEMS AND DISCARD THE UNWANTED– Make a list of all the items in the department.– The list should include raw material, wip, finished product, tools, tackles, dust

bin, facilities like chair, table, bins etc. nothing should be left unlisted.– Appropriate authority should decide which items can be disposed off and

which items need to be kept in the department.– Items marked for disposal should be disposed off in a safe manner.

2) SEITON - PLACE FOR EVERY THING– After disposing unwanted material, provide appropriate place for every item

that has to be kept in the department.– While providing the place the ergonomic factors and safety aspects have also

to be considered.– Place for movement of men and material should also be provided.– Place should be distinctly identified and marked.– Place for display of instructions, posters etc. should also be identified.

3) SEISO - CLEAN THE PLACE THOROUGHLY AND KEEP EVERY THING IN IT’S PLACE.

– Clean everything including material, floor, containers, walls, windows etc.– If necessary painting also should be done.– While painting follow color codes wherever applicable.– Insist on regular cleaning at the end of the work

4) SEIKETSU - MAINTAIN HIGH STANDARDS OF HOUSEKEEPING AT WORKPLACE AT ALL TIMES

– Ensure that people keep the items at designated place after it’s use.– If possible, design the system such that if something is missing from the place,

it is easily highlighted5) SHITSUKE - TRAIN PEOPLE TO FOLLOW GOOD HOUSEKEEPING

DISCIPLINE– Train people in 5 S, housekeeping etc.– Lead by example.– Maintain discipline in every aspect

2. What is TPM? How does it differ from other maintenance systems? What are the salient features of TPM?

Total Productive Maintenance (TPM) is a maintenance program which involves a newly defined concept for maintaining plants and equipment. The goal of the TPM program is to markedly increase production while, at the same time, increasing employee morale and job satisfaction.



TPM brings maintenance into focus as a necessary and vitally important part of the business. It is no longer regarded as a non-profit activity. Down time for maintenance is scheduled as a part of the manufacturing day and, in some cases, as an integral part of the manufacturing process. The goal is to hold emergency and unscheduled maintenance to a minimum.

The major difference between TPM and other concepts is that the operators are also made to involve in the maintenance process. The concept of "I (Production operators) Operate, You (Maintenance department) fix" is not followed.

Salient features of TPM

TPM is not a specific maintenance policy; it is a culture, a philosophy and a new attitude towards maintenance.

TPM is the involvement of operators in carrying out autonomous maintenance by participating in cleaning, lubrication, minor repair, adjustments etc.

TPM gives both the productivity index at the aggregated organization level as well as at the detailed operational unit level.

It also gives the individual productivity indices for the individual parts. It indicates the profitability of individual operational unit as well as the overall

organization, thereby giving indication as to which unit’s operation to continue and all its future investment decisions. At the same time, it clearly indicates which units is a liability and when to get out of these units.

TPM determines the profitability of individual products and the correct product mix to optimize the profit as well as optimum utilization of resources.

It provides important and vital information for strategic planning TPM shows which particular input resources are utilized inefficiently in a particular

area or for a particular product so that its efficient and effective use can be ensured. TPM integrates the entire work of planning, execution, evaluation and improvement

phases in the productivity cycle of an organization. TPM has developed individual and collective mathematical models for the

productivity indices calculation. This makes the model validation and sensitivity analysis relatively easier and precise.

3. Write short notes on Six Sigma. Six Sigma: Six Sigma is a business management strategy originally developed by Motorola. As of 2009, it enjoys widespread application in many sectors of industry, although its application is not without controversy. Six Sigma is a fact-based data driven structured methodology that is used to create breakthrough improvements in business processes with a strong focus on customer needs. It is used to solve tough business problems when the root cause of the problem or the solution is not known. Six Sigma seeks to improve the quality of process outputs by identifying and removing the causes of defects (errors) and variability in manufacturing and business processes.



It uses a set of quality management methods, including statistical methods, and creates a special infrastructure of people within the organization ("Black Belts"," Green Belts", etc.) who are experts in these methods.Each Six Sigma project carried out within an organization follows a defined sequence of steps and has quantified financial targets (cost reduction or profit increase).

How six sigma works

The Six Sigma project starts in forming the Six Sigma organization. The roles and responsibilities of each member should be clearly defined. Here is a sample of defined roles and responsibilities:

Leader/Leadership Council – senior-rank management who is accountable for executing Six Sigma project within the association

Champion – performance head in-charge with directing and enlivening the Six Sigma efforts

Finance Representative – substantiate projected and concrete savings Sponsor – senior-rank management who funds the Six Sigma projects and has

directorial power to modify changes in the process Process Owner – a certified person accountable for the business course of action that

is the target of Six Sigma project Coach – gives technical help and support to the project group Team Leader – also identified as the Project Head, responsible in organizing the Six

Sigma projects from launch to finish Master Black Belt – a highly practiced Black Belt who has supervised numerous

projects and is a specialist in Six Sigma techniques and methods. Person accountable for training and mentoring Black Belts and for assisting the Six Sigma Champions and Head.

Black Belt – permanent expert who acts as a team lead on Six Sigma assignments. Usually has four to six weeks of classroom education in methods, numerical tools, and team proficiency

Green Belt – trained person who plays a part-time role on a Black Belt project team or leads less significant assignment. Usually has three weeks of classroom education in methods and basic numerical tools.

Yellow Belt – usually has one to two weeks classroom education. Devotes part-time work while doing the usual work duties

12 Marks Questions:1. What are the different types of pillars in TPM?

Total Productive Maintenance (TPM) is a maintenance program which involves a newly defined concept for maintaining plants and equipment. The goal of the TPM program is to markedly increase production while, at the same time, increasing employee morale and job satisfaction.

TPM brings maintenance into focus as a necessary and vitally important part of the business. It is no longer regarded as a non-profit activity. Down time for maintenance is scheduled as a



part of the manufacturing day and, in some cases, as an integral part of the manufacturing process. The goal is to hold emergency and unscheduled maintenance to a minimum.

8 PILLARS OF TPM

PILLAR 1 - 5S:

TPM starts with 5S. Problems cannot be clearly seen when the work place is unorganized. Cleaning and organizing the workplace helps the team to uncover problems. Making problems visible is the first step of improvement.

Japanese Term English Translation Equivalent 'S' term

Seiri Organization Sort

Seiton Tidiness Systematize

Seiso Cleaning Sweep

Seiketsu Standardization Standardize

Shitsuke Discipline Self - Discipline

SEIRI - Sort out:

This means sorting and organizing the items as critical, important, frequently used items, useless, or items that are not need as of now. Unwanted items can be salvaged. Critical items should be kept for use nearby and items that are not be used in near future, should be stored in some place. For this step, the worth of the item should be decided based on utility and not cost. As a result of this step, the search time is reduced.

SEITON - Organize:

The concept here is that "Each item has a place and only one place". The items should be placed back after usage at the same place. To identify items easily, name plates and colored tags has to be used. Vertical racks can be used for this purpose, and heavy items occupy the bottom position in the racks.

SEISO - Shine the workplace:

This involves cleaning the work place free of burrs, grease, oil, waste, scrap etc. No loosely hanging wires or oil leakage from machines.

SEIKETSU - Standardization:

Employees have to discuss together and decide on standards for keeping the work place / Machines / pathways neat and clean. These standards are implemented for whole organization and are tested / inspected randomly.



SHITSUKE - Self discipline:

Considering 5S as a way of life and bring about self-discipline among the employees of the organization. This includes wearing badges, following work procedures, punctuality, dedication to the organization etc.

PILLAR 2 - JISHU HOZEN (Autonomous maintenance):

This pillar is geared towards developing operators to be able to take care of small maintenance tasks, thus freeing up the skilled maintenance people to spend time on more value added activity and technical repairs. The operators are responsible for upkeep of their equipment to prevent it from deteriorating.

Policy:

1. Uninterrupted operation of equipments.2. Flexible operators to operate and maintain other equipments.3. Eliminating the defects at source through active employee participation.4. Stepwise implementation of JH activities.

JISHU HOZEN Targets:

1. Prevent the occurrence of 1A / 1B because of JH.2. Reduce oil consumption by 50%3. Reduce process time by 50%4. Increase use of JH by 50%

Steps in JISHU HOZEN:

1. Preparation of employees.2. Initial cleanup of machines.3. Take counter measures4. Fix tentative JH standards5. General inspection6. Autonomous inspection7. Standardization and8. Autonomous management.

PILLAR 3 - KAIZEN:

"Kai" means change, and "Zen" means good (for the better). Basically kaizen is for small improvements, but carried out on a continual basis and involve all people in the organization. Kaizen is opposite to big spectacular innovations. Kaizen requires no or little investment. The principle behind is that "a very large number of small improvements are more effective in an organizational environment than a few improvements of large value. This pillar is aimed at



reducing losses in the workplace that affect our efficiencies. By using a detailed and thorough procedure we eliminate losses in a systematic method using various Kaizen tools. These activities are not limited to production areas and can be implemented in administrative areas as well.

Kaizen Policy:

1. Practice concepts of zero losses in every sphere of activity.2. relentless pursuit to achieve cost reduction targets in all resources3. Relentless pursuit to improve over all plant equipment effectiveness.4. Extensive use of PM analysis as a tool for eliminating losses.5. Focus of easy handling of operators.

Kaizen Target:

Achieve and sustain zero loses with respect to minor stops, measurement and adjustments, defects and unavoidable downtimes. It also aims to achieve 30% manufacturing cost reduction.

Tools used in Kaizen:

1. PM analysis2. Why - Why analysis3. Summary of losses4. Kaizen register5. Kaizen summary sheet.

PILLAR 4 - PLANNED MAINTENANCE:

It is aimed to have trouble free machines and equipments producing defect free products for total customer satisfaction. This breaks maintenance down into 4 "families" or groups:

1. Preventive Maintenance2. Breakdown Maintenance3. Corrective Maintenance4. Improvement Maintenance

PILLAR 5 - QUALITY MAINTENANCE:

It is aimed towards customer delight through highest quality through defect free manufacturing. Focus is on eliminating non-conformances in a systematic manner, much like Focused Improvement. We gain understanding of what parts of the equipment affect product quality and begin to eliminate current quality concerns, and then move to potential quality concerns. Transition is from reactive to proactive (Quality Control to Quality Assurance).



QM activities are to set equipment conditions that preclude quality defects, based on the basic concept of maintaining perfect equipment to maintain perfect quality of products. The condition is checked and measured in time series to verify that measure values are within standard values to prevent defects. The transition of measured values is watched to predict possibilities of defects occurring and to take counter measures before hand.

PILLAR 6 - TRAINING:

It is aimed to have multi-skilled revitalized employees whose morale is high and who has eager to come to work and perform all required functions effectively and independently. Education is given to operators to upgrade their skill. It is not sufficient know only "Know-How" by they should also learn "Know-why". By experience they gain, "Know-How" to overcome a problem and what to be done. This they do without knowing the root cause of the problem and why they are doing so. Hence it become necessary to train them on knowing "Know-why". The employees should be trained to achieve the four phases of skill. The goal is to create a factory full of experts.

Policy:

1. Focus on improvement of knowledge, skills and techniques.2. Creating a training environment for self learning based on felt needs.3. Training curriculum / tools /assessment etc conductive to employee revitalization4. Training to remove employee fatigue and make work enjoyable.

Target:

1. Achieve and sustain downtime due to want men at zero on critical machines.2. Achieve and sustain zero losses due to lack of knowledge / skills / techniques3. Aim for 100 % participation in suggestion scheme.

PILLAR 7 - OFFICE TPM:

Office TPM should be started after activating four other pillars of TPM (JH, KK, QM, and PM). Office TPM must be followed to improve productivity, efficiency in the administrative functions and identify and eliminate losses. This includes analyzing processes and procedures towards increased office automation. Office TPM addresses twelve major losses. They are

1. Processing loss2. Cost loss including in areas such as procurement, accounts, marketing, sales leading to

high inventories3. Communication loss4. Idle loss5. Set-up loss6. Accuracy loss7. Office equipment breakdown



8. Communication channel breakdown, telephone and fax lines9. Time spent on retrieval of information10. Non availability of correct on line stock status11. Customer complaints due to logistics12. Expenses on emergency dispatches/purchases

PILLAR 8 - SAFETY, HEALTH AND ENVIRONMENT:

Target:

1. Zero accident,2. Zero health damage3. Zero fires.

In this area focus is on to create a safe workplace and a surrounding area that is not damaged by our process or procedures. This pillar will play an active role in each of the other pillars on a regular basis. A committee is constituted for this pillar which comprises representative of officers as well as workers. The committee is headed by Senior vice President (Technical). Utmost importance to Safety is given in the plant. Manager (Safety) is looking after functions related to safety. To create awareness among employees various competitions like safety slogans, Quiz, Drama, Posters, etc. related to safety can be organized at regular intervals.

2. What is waste management? Discuss the seven wastes. Waste or muda is anything that does not have value or does not add value. Waste is something the customer will not pay for.

The seven types of waste are:

1. Waste from overproduction

2. Waste from waiting times

3. Waste from transportation and handling

4. Waste related to useless and excess inventories

5. Waste in production process

6. Useless motions

7. Waste from scrap and defects

Waste from overproduction

It may sound surprising, but many companies are producing more than necessary because they lose parts, products, material! Without order, care and discipline in storage, inventories



will fill all available space. Temporary storing a batch in a non defined / dedicated area is risky, as someone could move the batch without care or notice. In such a case, it is likely to lose its track, all ending in a waste of raw material, energy and man power.

It may lead to a double waste if the lost batch requires to produce a new one be delivered!

Eliminating the wasted space and valuable surface by excess inventories and overproduction is another potential improvement.

Waste from waiting times

Waiting is a consequence of poor synchronization between process stages or bad preparation. Waiting for parts, material, tools, instructions, etc, can be caused by a lack of rules about storage places, when people have to search everywhere.

Are the items you are waiting for really necessary? If they're not, if they do not add value to the job or the product, it it wise to try to eliminate them or at least reduce the wait time and storage distances.

Waste from transportation and handling

The necessity to move and transport can be caused by the previously mentioned wastes. All transportations may not be eliminated, but they have to be kept to the very minimum.

Looking for a pallet truck to move crates or pallets is a common occupation in the workshops. People most often claim for more trucks, but a proper set of rules, parking areas and discipline to bring them back after use is enough to solve availability problems.

Waste related to useless and excess inventories

"Useless"! The name itself gives the solution. In the 5S way, anything that is useless is to be eliminated. In case of inventories, the gain is the value of the goods stored and the regained spaces, which must be dedicated preferably to value creating activities.

Paper documents and their numerous copies, catalogues and calendars of previous years, files and data, dry and worn out pens and pencils... all excess inventories!

Waste in production process

Procedures and work guides which are not constantly updated are likely to let useless operations be performed in the process. Sorting and ordering applies also in the sequences of the process and the related documents.

This type of waste is also common in administration processes and office work. Old rules still remain even if the causes of their creation disappeared a while ago. As long as nobody will update the set of rules, everyone will carry on, sticking to the olds with application and discipline(!!).



Useless motions

Ergonomics of the work place is certainly the most popular and "visible" application of the 5S. The layout and display of the area will follow the 5S logic, favoring availability of necessary items, distance of reach, and ease for tending...

Among useless motions, do not forget the walks to search for missing items, data, instructions, complementary information...

Waste from scrap and defects

Number of defects and quality problems can be directly linked to the work place state:

Assembly mistakes (parts mismatch) due to jammed work table with parts from different models / series

Forgotten parts in assembly, the parts could not be seen in the mess on the table Scratches on parts by scrap form the work table (burrs, dirt, parts...) Spoiled parts, useless because dirty, scratched... Assembly mistake by not following the right sequence

3. Explain the concept of lean manufacturing.

Lean Manufacturing is a systematic methodology that identifies and eliminates all types of

waste or non-value-added activities; not only in production or manufacturing operations, but

in the service industry as well. Whether you are manufacturing a product or providing a

service, there are components that are considered “waste”. Lean concepts are purely about

creating more value for customers by eliminating activities that are considered waste. Any

activity or process that consumes resources, adds cost or time without creating value becomes

the target for elimination.

Lean focuses on the “big picture” or improvements in the entire business process as opposed

to incremental improvements. It is the business process system that can significantly improve

a company’s profitability.

Lean concepts improve operating performance by focusing on the continuous flow of

products, materials or services through the value stream. To achieve this, the various forms of

waste must be identified and eliminated. Waste can include any activity, step or process that

does not add value for the customer. Lean Manufacturing, sometimes also referred to as the

Toyota Production System, is about the systematic elimination of waste.

LEAN Manufacturing Concepts

• 5S



• Kaizen

• Value Stream Mapping

• Quick Changeover/SMED

• JIT/Kanban

• Poka Yoke & Mistake Profing

• Total Productive Maintenance

5SThe basis for good housekeeping in Japanese companies is a concept popularly known as 5S.

This stands for five good housekeeping concepts in Japanese.

5 “S” Japanese English



3 S SeisoClean your workplace thoroughly so that there is no dust on

floors, machines and equipment.

4 S SeiketsuMaintain high standards of housekeeping at workplace at all

times.


Kaizen

"Kai" means change, and "Zen" means good (for the better). Basically kaizen is for small

improvements, but carried out on a continual basis and involve all people in the organization.

Kaizen is opposite to big spectacular innovations. Kaizen requires no or little investment. The

principle behind is that "a very large number of small improvements are more effective in an

organizational environment than a few improvements of large value.

Value stream mapping

It is often part of a kaizen event. In its true form the value stream map documents all parts of

the manufacturing process from the time the order is taken until it is delivered to the customer

Quick Changeover or SMED (Single Minute Exchange of Dies)

SMED efforts attempt to reduce the number of steps and the time it takes to perform each

during a change in the manufacturing process.



JIT/Kanban

The concept originated in Japan and adopted by many companies in India. As a concept, JIT

means materials arrive on time and no inventories are held at any time either in raw materials,

WIP or finished goods. Materials are pulled in to the system. JIT system ensures great

efficiency in production. Monden (1981) defines JIT as a production system to produce the

kind of units, at the time needed and in the quantities needed.

One of the most important tools in a pull system is kanban. Based on a proven Japanese

model, kanban is a visual approach to production control, using simple tools like returnable

containers, cards, or even empty spaces to “pull” products from “producing” workstations or

suppliers toward “consuming” workstations or businesses. In this context, “a kanban” is a

sign or visual aid indicating that a work center has finished a process, requires work, or needs

more materials. Kanban enable work centers to track supplier or customer needs and respond

quickly and appropriately.

Pokayoke and mistake proofing

Poka Yoke is a quality management concept developed by a Matsushita manufacturing

engineer named Shigeo Shingo to prevent human errors from occurring in the production

line. Poka yoke (pronounced “poh-kah yoh-kay”) comes from two Japanese words –

“yokeru” which means “to avoid”, and “poka” which means “inadvertent errors.” Thus, poka

yoke more or less translates to “avoiding inadvertent errors”.

The main objective of poke yoke is to achieve zero defects. In fact, it is just one of the many

components of Shingo’s Zero Quality Control (ZQC) system, the goal of which is to

eliminate defective products.

A quality concept to manufacture ZERO defects & elimination of waste associated with

defects is known as zero defect quality. The goal of ZDQ is zero! Make certain that the

required conditions are in place and controlled to make acceptable product 100% of the time.

ZDQ functions by combining four elementary components:

1. Point of Origin Inspection

2. 100 % Audit Checks

3. Immediate Feedback

4. Poka-Yoke

Total Productive Maintenance (TPM)



TPM is a support function promoting high machine time availability and effectiveness. As

companies increase the use of LEAN techniques wasted steps are eliminated in the

manufacturing process to provide more time processing material and making products

customers want.


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