Improving Inherent Reliability of a System

The inherent reliability of a system is determined by the system’s design. It means that the design of the system would determine the upper limit of reliability the system exhibits during operation. Suppose, for example, a system, with the best possible maintenance is able to achieve availability of say 90% we can say that this is the upper limit of the system’s capability that is determined by its design. A good “preventive maintenance” plan can never improve a systems inherent reliability. In other words, preventive maintenance, contrary to what many believe, cannot make a system “better”. It may, at best, only help realise the inherent reliability as determined by the physical design.

Hence the suggested process to “improve” the inherent reliability of a system, may be framed as follows: –

Understand the dynamics through tools like vibration analysis
Monitor changes and rate of change
Eliminate unnecessary maintenance tasks
Change the design of the system interactions to eliminate inherent “imperfections” and revise the maintenance plan.

In most cases, this would be the general approach.

Until we can effectively undertake some design changes (Design Out Maintenance – DOM) or take measures to eliminate inappropriate maintenance actions (Review of Equipment Maintenance – REM) it would not be possible to go beyond inherent reliability of an equipment, specially if it is undesirable in the business context. For example, a vertical pump of a power plant kept failing very frequently or had had to be stopped quite often when vibration shot beyond the trip limits. This behaviour of the system is determined by the design of the system. Unless the design (specifically the interactions between components) is corrected for improvement; the system (vertical pump) would continue to behave in that manner for all times. Likewise if the MTBF of a machine is say 90 days, it would not be possible to considerably improve the MTBF way beyond 90 days unless some undesirable interactions (which I call system “imperfections”) are corrected for improvement and a proper review of existing maintenance system is carried out. 

Such “imperfections” can be both physical and non-physical. Design features, most importantly, the interactions between physical/non-physical components are arguably the most important characteristic of a system that determine a system’s inherent reliability.

In addition, there are many physical design features that influence reliability like redundancy, component selection and the overall integration of various pieces of the system.

In the context of RCM, design extends far beyond the physical makeup of the system. There are a number of non-physical design features that can affect, sometimes profoundly, the inherent reliability of a system. Among these are operating procedures, errors in manufacturing, training and technical documentation. When a proper RCM analysis is conducted on a system or sub-system, there’s a good chance that the resulting maintenance actions will enable the system to achieve its inherent reliability as determined by its physical design features. However, if the inherent reliability is below user’s expectation or need then the design features are to be improved to achieve the desired level of inherent reliability.

Moreover, if unwarranted maintenance tasks are eliminated as it will greatly reduce the risk of suffering the Waddington Effect. There is also a good chance that if operating procedures, training, technical documentation and so forth are found to negatively impact inherent reliability, these issues will be identified and corrected. As evidenced by the Waddington Effect. In virtually every case, less than optimal, non-physical design features almost always have a negative impact on inherent reliability. Therefore, in RCM analysis a through review of existing maintenance plan (REM) along with DOM is necessary to improve inherent reliability of a system.

In brief, right amount of Condition Based Maintenance (CBM) tasks, Scheduled Inspections (which is a part of CBM activity) REM and DOM would not only help us realise the inherent reliability as determined by the physical design but also improve it, if the original inherent reliability is below business expectation.

 

Dibyendu De

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How to create an Incentive scheme to boost Self Organized Productivity?

The Issue

Creating an incentive plan or scheme in an organization is a tricky affair. Most don’t seem to get it right. As a result the desired goals are left unmet. So the top Management feels that they lost in the bargain. And surprisingly the employees also think the same that they have been unfairly treated or cheated by the scheme. Nonetheless it leaves behind a bitter taste that isolates Management from its most vital resource — the employees.

What is known or desired by Management?

However, the aims of any well-meant incentive plan is clear; some of those being —

a) Improve productivity through self organized improvement of efficiency and effectiveness of a production system.

b) Improve self managed quality as an inbuilt factor into any production system

c) Enables employees to quickly discover systemic faults in the production system and self correct those through self-initiated interactions.

What is Unknown by Management? 

a) Management does not yet have a model to work out an incentive plan/scheme that is not only systemic but also self organizing to improve the system.

b) Presently management looks at bits and pieces of data to create work wise incentive plan that is applicable to an individual or a group or a department at most. It does not know how to create an incentive plan that would map and address both interdependence of different departments and their independence too.

c) The same goes for correctly evaluating or assessing the contribution of different types and grades of employees who work in various departments.

d) Management is also unaware of the type of data to look for that would not only help them create the right type of incentive scheme but also keep the inherent dynamics of the system, where the central idea is to create a dynamic incentive plan that helps the production system to be resilient rather than a static one, which can prove to be quite anti-resilient and limiting.

What is needed? 

a) A clear understanding of the system dynamics.

b) The maximum and minimum potential of the system

c) What would be the stability zone to operate in and how to predict when instability sets in?

d) The inherent potential for the system to improve without any additional investment

e) The limit beyond which only additional investment can improve productivity.

f) The right parameters to be selected

The Resolution

The resolution to the above issue is depicted by the conceptual model as shown below:

incentive Plan
Incentive Model

Results

This model (based on science of complexity) was applied to one relatively large Indian multi-national unit and the results were the following:

1. Productivity improved by 1.75 times within 2 months of implementation of the scheme.

2. Self organized improvements took place

3. Real time communication increased between employees

4. Quality improved and sustained.

5. The improvements were self-sustaining without any other capital investment.