Reliability management means defining reliability specifications at an early stage in the product development process and monitoring their development in sense of reliability growth throughout the entire product development process. But reliability management does not stop after the start of production. Even during field operation, modern methods of field data evaluation and pattern recognition procedures are used to carry out passive market observation on the one hand and to generate important input for new development projects on the other.
It is important that reliability flows into the corporate culture and is not a one-off event. An organisational and procedural anchoring in the company is therefore indispensable. Numerous standards and guidelines, such as VDI 4004, DIN 60300 or VDA 3.1 and 3.2, deal with the subject of reliability and are mastered by our experts.
As already mentioned, reliability management can be divided into a preventive and a reactive area. Both of these branches are intertwined, exchange information in the ideal case and ensure an integrated approach to reliability management. Preventive and reactive reliability management are described in more detail below.
Figure: reliability management
Preventive Reliability Management:
Preventive reliability management deals with questions of reliability during the product development process (PDP) to identify potential and errors as early as possible and to remedy these cost-efficiently. The goal is to design a highly reliable and safe product that is characterised by minimum failures in the field and consequently low guarantee and warranty costs. Furthermore, reliability growth should also be ensured.
The following steps should be dealt with in preventive reliability management:
- Reliability requirements and goals (empirical values, competition data, normative requirements, customer requirements, etc.)
- Reliability specifications (incl. test and inspection planning, specifications for suppliers)
- Reliability prediction and assessment (incl. development tests, system models)
- Reliability verification (prototype test)
- Reliability testing (pre-series test)
- • Record of ACTUAL reliability (production tests, field data analysis > reactive methods)
The following figure shows an integrated reliability process, the likes of which has already been implemented by IQZ staff for well-known companies.
Figure: Integrated reliability process
We apply the following methods in preventive reliability management:
FMEA, FMECA, RBD, FTA, Markov models, WeiBayes, MTTF/MTBF, Success-Run, Sudden Death, EOL test, shirring method, load derivations, reliability partitioning, simulation, mathematical optimization, reliability block diagrams/redundancy analysis, safety verification, risk assessment
Reactive Reliability Management:
Reactive reliability management relates to all phases of the product life cycle following delivery of the product to the customer. Thereby it is attempted to make statements on the reliability of the corresponding products on the basis of real field data. Methods also exist that can be used to determine key errors from data. These should always precede a reliability analysis of field data to focus the later analytical work on critical problem cases. This means that financial as well as personnel capacities are not spread evenly over all products according to scattergun approach but can be deployed selectively.
The results from field data analyses – e.g. from a reliability forecast – are ideal to support preventive reliability management. Reliability requirements and thus goals can be formulated with these, amongst other things, and these constitute an important basis for the development process. Field data analyses remain a suitable aid in guarantee and warranty management. They can be used to forecast guarantee costs, estimate the risks of extended warranties or verify recall campaigns. In addition, field data analyses supply decision-making aids when calculating the replacement demand for series or final stockpiling. Thus, they are an important part of obsolescence and spare parts management.
Figure: Field load as a function of vehicle series over driving performance