TPM Principles

Total Productive Maintenance (TPM) is productive maintenance undertaken by every employee through small group activities. TPM is equipment maintenance performed across the organization.

TPM maximizes the productivity of equipment by predicting and preventing unplanned downtime. TPM is one of the critical building blocks in the lean continuous improvement process, which can increase a machine’s capacity, reduce maintenance costs, eliminate overtime shifts drastically and increase productivity and profits for the company. These benefits of TPM enable lower inventory levels as no need to cover unplanned downtime.

It reduces the roles of production and maintenance by focusing on empowering operators to help maintain their equipment. The implementation of a TPM program creates a shared responsibility for equipment encouraging greater involvement by plant floor workers and can be very effective in improving productivity by increasing up time, reducing cycle times and eliminating defects.

Nine Essentials of TPM

• Self maintained work place
• Elimination of the 6 big losses
• Zero Breakdowns
• Zero Defects
• Optimal life and availability of tools
• Self-improvement
• Short production-development time and low machine life cost
• Productivity in indirect departments
• Zero Accidents

TPM focuses on employees to achieve maintenance free operations and is achieved by implementing of following three practices

• Development of TPM pillars
• Prevention of big losses
• Measuring and monitoring OEE

The traditional approach to TPM was developed in the 1960s and consists of 5S as a foundation and eight supporting activities also called as pillars.

Eight Pillars of TPM

The eight pillars of TPM consists of

• Autonomous Maintenance
• Continuous Improvement
• Planned Maintenance
• Quality Maintenance
• Materials planning, design and equipment control
• Education & Training
• Office TPM
• Safety, Hygiene and Environment Control

5S, The Foundation of TPM

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.

• SEIRI – Sort – Seiri means sorting and organizing the items as critical, important, frequently used items, or items that are not currently needed. Unwanted items can be salvaged.  Critical items should be kept for use nearby and items that are not needed in near future should be stored some place else.
• SEITON – Organize – The concept here is that “A place for everything, and everything in its place”. After usage items should be stored in their designated storage location.  To identify items easily, name plates and colored tags can be used.  Vertical racks can be used for organization.
• SEISO – Shine – Seiso involves cleaning the workplace and ensuring equipment is free of burrs, loose wires, grease, oil, waste, scrap, etc.
• SEIKETSU – Standardization – Associates decide together on standards for keeping the workplace, machines, and pathways neat and clean. These standards are implemented for whole organization and are regularly checked.
• SHITSUKE – Self Discipline – Accepting 5S as a way of life forms self-discipline among the associates. This includes wearing badges, following work procedures, punctuality, dedication to the organization, etc.

1. JISHU HOZEN PILLAR (Autonomous Maintenance)

Jishu Hozen, which means autonomous or self-maintenance, promotes development of production operators to be able to take care of small maintenance tasks, such as cleaning, inspecting, and lubricating their equipment, thus freeing the maintenance associates to spend time on more value-added activities and technical repairs.  The operators are responsible for upkeep of their equipment to prevent it from deteriorating.  Jishu Hozen (JH) has been shown to reduce oil consumption by 50% and process time by 50%.

Goals of Jishu Hozen

• Uninterrupted operation of equipment
• Flexible operators who can operate and maintain other equipment
• Elimination of defects at the source through active employee participation
• Stepwise implementation of JH activities

The effects of autonomous maintenance include

• Equipment condition is known at all times.
• Unexpected breakdowns are minimized.
• Corrosion is prevented, wear is delayed, and machine life is extended.
• Judgment of machine capability is improved.
• Parts costs are reduced.

Production Operators are expected to perform the TPM Activities of cleaning, lubrication, and inspection on a daily basis.  Make sure user follow the instructions given by the supervisor.

2.Kobetsu Kaizen or Continuous Improvement

“Kai” means change, and “Zen” means good (for the better). Kaizen is the opposite of big spectacular innovations.  Kaizen is small improvements carried out on a continual basis and involves all people in the organization.  Kaizen requires no or little investment.  The principle behind Kaizen is that a large number of small improvements are more effective in an organizational environment than a few large-scale improvements.  Systematically using various Kaizen tools in a detailed and thorough method eliminates losses.  The goal is to achieve and sustain zero loses with respect to minor stops, measurement and adjustments, defects, and unavoidable downtimes.

Kobetsu Kaizen uses a special event approach that focuses on improvements associated with machines and is linked to the application of TPM.  Kobetsu Kaizen begins with an up-front planning activity that focuses its application where it will have the greatest effect within a business and defines a project that analyses machine operations information, uncovers waste,

uses a form of root cause analysis (e.g., the 5 Why approach) to discover the causes of waste, applies tools to remove waste, and measures results.

The objective of TPM is maximization of equipment effectiveness.  TPM maximizes machine utilization, not merely machine availability.  As one of the pillars of TPM activities, Kaizen activities promote efficient equipment and proper utilization of manpower, materials, and energy by eliminating major losses.  Examples of Kobetsu Kaizen includes

• Relocating gauges and grease fittings for easier access.
• Making shields that minimize contamination.
• Centralizing lubrication points.
• Making debris collection accessible.

3.Planned Maintenance

The goal of planned maintenance is to have trouble-free machines and equipment that produce defect-free products for total customer satisfaction. Planned Maintenance achieves and sustains availability of machines at an optimum maintenance cost, reduces spares inventory, and improves reliability and maintainability of machines.

With Planned Maintenance the associates’ efforts evolve from a reactive approach to a proactive method and trained maintenance staff helps train the operators to better maintain their equipment.

Steps in Planned Maintenance (PM) include

• Evaluate and record present equipment status.
• Restore deterioration and improve weaknesses.
• Build information management system.
• Prepare time-based data system, select equipment, parts, and team, and make plan.
• Prepare predictive maintenance system by introducing equipment diagnostic techniques.
• Evaluate planned maintenance.

4. Hinshitsu Hozen or Quality Maintenance (QM)

Quality Maintenance (QM) targets customer satisfaction through defect free manufacturing of the highest quality products. The focus is on eliminating non-conformances in a systematic manner. Through QM we gain an understanding of what parts of the equipment affect product quality, eliminate quality concerns, and then move to potential quality concerns. The transition is from reactive to proactive (From Quality Control to Quality Assurance).

QM activities control equipment conditions to prevent quality defects, based on the concept of maintaining perfect equipment to maintain perfect quality of products. These conditions are checked and measured in time series to verify that measured values are within standard values to prevent defects. The transition of measured values is trended to predict possibilities of defects occurring and to take countermeasures before defects occur.

QM activities to support Quality Assurance through defect free conditions and control of equipment.  The focus is on effective implementation of operator quality assurance and detection and segregation of defects at the source.   Opportunities for designing Poka-Yoke (foolproof system) are investigated and implemented as practicable.

5. Materials planning, design and equipment control

It directs practical knowledge and understanding of manufacturing equipment gained through TPM towards improving the design of new equipment. The new equipment reaches planned performance levels much faster due to fewer startup issues. Maintenance is simpler and more robust due to practical review and employee involvement prior to installation.

6. Education & Training

The goal of training is to have multi-skilled revitalized employees whose morale is high and who are eager to come to work and perform all required functions effectively and independently. The focus is on achieving and sustaining zero losses due to lack of knowledge / skills / techniques. Ideally, we would create a factory full of experts.

Operators must upgrade their skills through education and training. It is not sufficient for operators to learn how to do something; they should also learn why they are doing it and when it should be done. Through experience operators gain “know-how” to address a specific problem, but they do so without knowing the root cause of the problem and when and why they should be doing it. Hence it becomes necessary to train operators on knowing why. This will enable the operators to maintain their own machines, understand why failures occur, and suggest ways of avoiding the failures occurring again.

7. Office TPM Pillar

Office TPM should be started after activating f our other pillars of TPM (Jishu Hozen, Kobetsu Kaizen, Quality Maintenance, and Planned Maintenance). 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

• Processing loss
• Cost loss in areas like procurement, accounts, marketing and sales
• Communication loss
• Idle loss
• Set-up loss
• Accuracy loss
• Office equipment breakdown
• Communication channel breakdown, telephone and fax lines
• Time spent on retrieval of information
• Unavailability of correct on-line stock status
• Customer complaints due to logistics
• Expenses on emergency dispatches/purchases

Improving the office efficiency by eliminating the above-listed losses helps in achieving Total Productive Maintenance.

8. Safety, Health and Environment

The target of the Safety, Health & Environment is

• Zero accidents,
• Zero health damage, and
• Zero fires.

The focus is on creating a safe workplace and surrounding areas that are not damaged by our process or procedures. Autonomous Maintenance is daily preventive maintenance (cleaning, inspection, lubrication and re-tightening) performed by the equipment operator. This pillar plays an active role in each of the other pillars on a regular basis.  The major categories of Maintenance includes

• Breakdown Maintenance (BM) is when we wait for equipment to fail and then repair it. For example, some electronic equipment is simply replaced when it fails.
• Preventive Maintenance is periodic maintenance that retains the condition of equipment and prevents failure through the prevention of deterioration, periodic inspection, and equipment condition diagnosis. PM includes daily cleaning, inspection, lubrication and tightening. Preventive Maintenance is further divided into Periodic Maintenance and Predictive Maintenance. Periodic Maintenance is time-based, which involves periodically inspecting, servicing, and cleaning equipment and replacing parts to prevent problems.
• Predictive Maintenance is condition-based, which involves predicting service life of important parts based upon inspection or diagnosis, to use the parts to the limit of their service life.
• Corrective Maintenance improves equipment and its components so that preventive maintenance can be performed reliably. Equipment with a design weakness is redesigned with corrective maintenance to improve reliability or maintainability.
• Maintenance Prevention deals with improving the design of new equipment. Current machine data (information leading to failure prevention, easier maintenance, prevention of defects, safety, and ease of manufacturing) are studied and designs are incorporated in new equipment.

OEE (Overall Equipment Effectiveness)

It is a metric that identifies the percentage of planned production time that is truly productive. It was developed to support TPM initiatives by accurately tracking progress towards achieving “perfect production”.

• An OEE score of 100% is perfect production.
• An OEE score of 85% is world class for discrete manufacturers.
• An OEE score of 60% is fairly typical for discrete manufacturers.
• An OEE score of 40% is not uncommon for manufacturers without TPM and/or lean programs.

OEE consists of three underlying components, each of which maps to one of the TPM goals set out at the beginning of this topic, and each of which takes into account a different type of productivity loss.

Component	TPM Goal	Type of Productivity Loss
Availability	No Breakdowns	Availability takes into account Down Time Loss, which includes all events that stop planned production for an appreciable length of time (typically several minutes or longer).
Performance	No Small Stops or Slow Running	Performance takes into account Speed Loss, which includes all factors that cause production to operate at less than the maximum possible speed when running.
Quality	No Defects	Quality takes into account Quality Loss, which factors out manufactured pieces that do not meet quality standards, including pieces that require rework.
OEE	Perfect Production	OEE takes into account all losses (Down Time Loss, Speed Loss, and Quality Loss), resulting in a measure of truly productive manufacturing time.

OEE is tightly coupled to the TPM goals of No Breakdowns (measured by Availability), No Small Stops or Slow Running (measured by Performance), and No Defects (measured by Quality). It is extremely important to measure OEE in order to expose and quantify productivity losses, and in order to measure and track improvements resulting from TPM initiatives.

OEE calculation is based on the three OEE Factors: Availability, Performance, and Quality. Here’s how each of these factors is calculated.

Availability – Availability takes into account Down Time Loss, and is calculated as:

Availability = Operating Time / Planned Production Time

Performance – Performance takes into account Speed Loss, and is calculated as:

Performance = Ideal Cycle Time / (Operating Time / Total Pieces)

Ideal Cycle Time is the minimum cycle time that process can be expected to achieve in optimal circumstances. It is sometimes called Design Cycle Time, Theoretical Cycle Time or Nameplate Capacity. Since Run Rate is the reciprocal of Cycle Time, Performance can also be calculated as

Performance = (Total Pieces / Operating Time) / Ideal Run Rate

Performance is capped at 100%, to ensure that if an error is made in specifying the Ideal Cycle Time or Ideal Run Rate the effect on OEE will be limited.

Quality – Quality takes into account Quality Loss, and is calculated as:

Quality = Good Pieces / Total Pieces

OEE – OEE takes into account all three OEE Factors, and is calculated as

OEE = Availability x Performance x Quality

It is very important to recognize that improving OEE is not the only objective. As an example, following data for two production shifts may result in higher performance of the second shift than the first due to higher OEE very few companies, however, would want to trade a 5.0% increase in Availability for a 3.5% decline in Quality

OEE Factor	Shift 1	Shift 2
Availability	90.0%	95.0%
Performance	95.0%	95.0%
Quality	99.5%	96.0%
OEE	85.1%	86.6%

OEE provide the user with three numbers, which are all useful individually as situation changes from day to day. And it helps user visualize performance in simple terms – a very practical simplification. An example for OEE calculation is listed for better illustration

OEEE Example

The table below contains hypothetical shift data, to be used for a complete OEE calculation, starting with the calculation of the OEE Factors of Availability, Performance, and Quality. Note that the same units of measurement (in this case minutes and pieces) are consistently used throughout the calculations.

Item	Data
Shift Length	8 hours = 480 min.
Short Breaks	2 @ 15 min. = 30 min.
Meal Break	1 @ 30 min. = 30 min.
Down Time	47 minutes
Ideal Run Rate	60 pieces per minute
Total Pieces	19,271 pieces
Reject Pieces	423 pieces

Planned Production Time = Shift Length – Breaks = 480 – 60 = 420 minutes

Operating Time = Planned Production Time – Down Time   = 420 – 47 = 373 minutes

Good Pieces = Total Pieces – Reject Pieces  = 19,271 – 423  = 18,848 pieces

Availability = Operating Time / Planned Production Time = 373 minutes / 420 minutes

= 0.8881 or 88.81%

Performance   = (Total Pieces / Operating Time) / Ideal Run Rate

= (19,271 pieces / 373 minutes) / 60 pieces per minute

= 0.8611 or 86.11%

Quality            = Good Pieces / Total Pieces  = 18,848 / 19,271 pieces = 0.9780 or 97.80%

OEE    = Availability x Performance x Quality = 0.8881 x 0.8611 x 0.9780 = 0.7479 or 74.79%

The Six Big Losses

OEE loss categories (Down Time Loss, Speed Loss, and Quality Loss) can be further broken down into what is commonly referred to as the Six Big Losses – the most common causes of lost productivity in manufacturing. The Six Big Losses are extremely important because they are nearly universal in application for discrete manufacturing, and they provide a great starting framework for thinking about, identifying, and attacking waste (i.e. productivity loss).

Big Losses	OEE Category	Examples	Comments
Breakdowns	Down Time Loss	Tooling Failure   Unplanned Maintenance Overheated Bearing Motor Failure	There is flexibility on where to set the threshold between a Breakdown (Down Time Loss) and a Small Stop (Speed Loss).
Setup and Adjustments	Down Time Loss	Setup/Changeover   Material Shortage Operator Shortage Major Adjustment Warm-Up Time	This loss is often addressed through setup time reduction programs such as SMED (Single-Minute Exchange of Die).
Small Stops	Speed Loss	Component Jam   Minor Adjustment Sensor Blocked Delivery Blocked Cleaning/Checking	Typically only includes stops that are less than five minutes and that do not require maintenance personnel.
Slow Running	Speed Loss	Incorrect Setting   Equipment Wear Alignment Problem	Anything that keeps the equipment from running at its theoretical maximum speed.
Startup Defects	Quality Loss	Scrap   Rework	Rejects during warm-up, startup or other early production.
Production Defects	Quality Loss	Scrap   Rework	Rejects during steady-state production.