Maintenance Strategy Based on Reliability Analysis and FMEA: A Case Study for Hydraulic Cylinders of Traditional Excavators with ERRS

Table 2

Suggested ranking system for the occurrence of failure modes [37].

Rank ()	Comment	Failure frequency
10	Extremely high	≥0.2
9	Very high	≥0.1
8	Repeated failures	≥0.05
7	High	≥0.03
6	Moderately high	≥0.02
5	Moderate	≥0.01
4	Relatively low	≥0.005
3	Low	≥0.001
2	Remote	≥0.0005
1	Nearly impossible	≥0.0001