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Focused Improvement Pillar (Kobetsu Kaizen)

“Focused improvement includes all activities that maximize the overall effectiveness of equipment, processes, and plants through uncompromising elimination of losses* and improvement of performance.” (Suzuki 1994 p. 1992) The objective of Focused Improvement is for equipment to perform as well every day as it does on its best day. “The fact is machines do virtually 100 percent of the product manufacturing work. The only thing we people do, whether we’re operators, technicians, engineers, or managers, is to tend to the needs of the machines in one way or another. The better our machines run, the more productive our shop floor, andthe more successful our business.” (Leflar 2001 p. 15) The driving concept behind Focused Improvement is Zero Losses. “Maximizing equipment effectiveness requires the complete elimination of failures, defects, and other negative phenomena – in otherwords, the wastes and losses incurred in equipment operation.” (Nakajima 1988 p.xix)

Leflar identifies a critical TPM paradigm shift that is the core belief of Focused Improvement.

• 
  Old Paradigm – New equipment is the best it will ever be.
  
• New Paradigm – New equipment is the worst it will ever be.

“The more we operate and maintain a piece of equipment, the more we learn about it.We use this knowledge to continuously improve our maintenance plan and the productivity of the machine. We would only choose to replace a machine should its technology become obsolete, not because it has deteriorated into a poorly performing machine.” (Leflar 2001 p. 18) Thomas notes that Focused Improvement methodologies have led to short-term and long-term improvements in equipment capacity, equipment availability, and production cycle time. “Focused Improvement has been, and still is, the primary methodology for productivity improvement in the [Advanced Micro Devices – AMD] Fab 25.” (Thomas 2003)

Overall Equipment Effectiveness (OEE)** is the key metric of Focused Improvement.*** Focused Improvement is characterized by a drive for Zero Losses, meaning a continuous improvement effort to eliminate any effectiveness loss****. Equipment losses may be either chronic (the recurring gap between the equipment’sactual effectiveness and its optimal value) or sporadic (the sudden or unusual variation or increase in efficiency loss beyond the typical and expected range), as illustrated in Figure 7. (Tajiri and Gotoh 1992)
 

Figure 7 - Chronic versus Sporadic Losses 

Figure 8 - TPM Pyramid of Chronic Conditions shows the progression of chronic conditions to equipment failures.

Figure 8 - TPM Pyramid of Chronic Conditions

Causal factor relationships for equipment effectiveness loss are displayed in Figure 9.

The loss causal factors may be,

• 
  Single – a single causal factor for the effectiveness loss.
  
• Multiple – two or more causal factors combined result in the effectiveness loss.
  
• Complex – the interaction between two or more causal factors results inthe effectiveness loss.

Figure 9 - Effectiveness Loss Causal Factor Relationships

Focused Improvement includes three basic improvement activities. First, theequipment is restored to its optimal condition. Then equipment productivity lossmodes (causal factors) are determined and eliminated.***** The learning that takes place during restoration and loss elimination then provide the TPM program a definition ofoptimal equipment condition that will be maintained (and improved) through the life of the equipment

Equipment restoration is a critical first step in Focused Improvement, asillustrated in Figure 8. “Maintaining basic equipment conditions is a maintenance practice that is ignored in most companies today. When the maintenance group gets occupied with capacity loss breakdowns and trying to keep the equipment running properly, basic tasks like cleaning, lubricating, adjusting, and tightening are neglected.” (Wireman 1991 p. 23) Nakajima claims that equipment failure is eliminated by exposing and eliminating hidden defects (fuguai). (Nakajima 1988)

Tajiri and Gotoh concur with Nakajima and state that the critical steps to eliminate equipment restoration is to expose the hidden defects, deliberately interrupt equipment operation prior to breakdown, and to resolve minor defects promptly. (Tajiri and Gotoh 1992) Shirose notes, “the first aim of attaching importance tominor defects is to ‘cut off synergic effects do to the accumulation of minor defects’.”(Shirose 1996 p. 93) Even though a single minor defect may have a negligible impacton equipment performance, multiple minor defects may stimulate another factor, combine with another factor, or may cause chain reactions with other factors. (Shirose1996) Suehiro considers the elimination of minor defects to be one of the highest priorities of continuous improvement. “It is important to realize that even in large equipment units or large-scale production lines, overall improvement comes as an accumulation of improvements designed to eliminate slight defects. So instead of ignoring them, factories should make slight defects their primary focus.” (Suehiro1987 p. xv)

Minor or hidden defects result from a number of causal factors (Tajiri andGotoh 1992) such as:

• Physical Reasons.
  o Contamination (dust, dirt, chemical leaks, etc.).
  o Not visible to the operator.
  o Excessive safety covers.
  o Equipment not designed for ease of inspection.
  
  
  
• Operator Reasons.
  o Importance of visible defects not understood.
  o Visible defects not recognized.

According to Jim Leflar (Agilent Technologies)******, “The power of that step [Focused Improvement] continues to amaze me.” (Leflar 2003) During Agilent’s equipment restoration effort hundreds of minor defects were discovered on equipment that was previously thought to be in good running order. In many cases, equipment restoration resolved chronic losses where the root cause was never identified. “Minor Defects are the root cause of many equipment failures and must be completely eliminated from all equipment. Eliminating minor defects attacks the Roseannadanna Syndrome – ‘It’s always something!’ Machines with minor defects will always find new ways to fail. (Leflar 1999 p. 6) Steinbacher and Steinbacher refer to the unrelenting pursuit of resolving small problems as ‘majoring in minors’. (Steinbacher and Steinbacher 1993) 

“Tracking OEE provides a relative monitor of equipment productivity and the impact of improvement efforts. Understanding efficiency losses drives the improvement effort.” (DiIorio and Pomorski 2003 p. 41) Typically, productivity losses are determined through analysis of equipment and production performance histories. The impact of productivity losses should be analyzed from two perspectives; 1) the frequency of loss (the number of occurrences during the timeperiod), and 2) the impact of the loss (the number lost hours, lost revenue, cost, etc.).A number of tools are commonly used to analyze productivity losses in the Focused Improvement pillar.

• Pareto Charts.
  
• 5-Why Analysis.
• 
  Fishbone Diagrams.
• 
  P-M Analysis.
  Fault Tree Analysis (FTA).
• 
  Failure Mode and Effects Analysis (FMEA).

“Companies differ in their approaches to systematic improvement, but all incorporate roughly the same basic elements: planning, implementing, and checking results.” (Productivity 1998 p. 3) Suzuki reinforces the objective of Focused Improvement to eliminate losses. “Focused Improvement includes all activities that maximize the overall effectiveness of equipment, processes, and plants through the uncompromising elimination of losses and improvement of performance.” (Suzuki1994 p. 45) Similar to Leflar, Suzuki considers the establishment of basic conditions (equipment restoration), compliance with conditions of use, the reversal of deterioration, and elimination of the environmental conditions that acceleratedeterioration to be the key elements of the Focused Improvement pillar, as presentedin Figure 10. (Suzuki 1994)

Figure 10 - The Six Zero-Breakdown Measures

It is important to note that Focused Improvement and equipment restoration is not a one-time activity. Usage results in wear and potential deterioration. “Restoring normal equipment wear is a process that continues for the entire life of the equipment.” (Wireman 1991 p. 26)

[Original: Total Productive Maintenance (TPM) Concepts and Literature Review by Thomas R. Pomorski, Principal Consulting Engineer, Brooks Automation, Inc.]

* Losses may be either a function loss (inability of an equipment to execute a required function) or a function reduction (reduced capability without complete loss of a required function). Tajiri, M. and F.Gotoh (1992). TPM Implementation - A Japanese Approach. New York, McGraw Hill.

** The basic concept of OEE and Equipment Losses will be reviewed in this paper. A more detailed discussion of OEE and other productivity metrics will be included in a subsequent paper currently in development.

*** Additional discussion of OEE calculation is included in section 2 of this paper.

**** The definition of effectiveness losses is not consistent among the Japanese authors. Nakajima originally defined six ‘Big Equipment Losses’ (Equipment Failure, Setup and Adjustment, Idling and Minor Stoppages, Reduced Speed, Defects in Process, and Reduced Yield). Nakajima, S. (1984).Introduction to TPM: Total Productive Maintenance. Cambridge, MA, Productivity Press. Suzuki suggests ‘Eight Major Plant Losses’ (Shutdown, Production Adjustment, Equipment Failure, Process Failure, Normal Production Loss, Abnormal Production Loss, Quality Defects, and Reprocessing). Suzuki, T., Ed. (1994). TPM in Process Industries. Portland, OR, Productivity Press. Shirose expanded the number of losses to sixteen to include human effectiveness losses such as Management Losses, Motion Losses, Arrangement Losses, Loss due to Lack of Automated Systems, and Monitoring and Adjustment Losses. Shirose, K. (1992). TPM for Operators. Portland, OR, Productivity Press.

***** See Suehiro, K. (1987). Eliminating Minor Stoppages on Automated Lines. Portland, OR, Productivity Press. for an excellent discussion on identifying and eliminating minor stoppage productivity losses on automated production equipment.

****** Jim Leflar uses the term ‘Precision Maintenance’ to describe his approach to TPM-oriented maintenance activity. For addition information see Leflar, J. (2001). Practical TPM. Portland, OR, Productivity Press. and Leflar, J. (2000). Achieving Precision Maintenance. 11th Total Productive Maintenance Conference and Exposition, Dallas, TX, Productivity, Inc..