Overview of time management methods
In operational practice, the REFA and/or MTM methods are normally used for ascertaining standard times. In general, there are two ways of ascertaining standard times:
- Recording actual times (e.g. REFA)
- Setting target times using times predetermined by systems (e.g. MTM)
In recording actual times, the REFA approach is the dominant method:
- In order to ascertain the standard time, the work process has to be observed and measured and the degree of performance has to be evaluated.
- In practice, evaluating the degree of performance is problematic.
MTM is the system most often used for predetermined times.
- With the basic MTM procedure, the analytical effort is relatively high.
- MTM is often used in large series and mass production with lower cycle times.
However, the actual need of companies goes beyond pure ascertainment of predetermined times.
The ascertainment of predetermined times should always be associated with the optimisation of work processes; specific potentials for improvement have to be recognised. At the same time, there has to be a reasonable relationship between effort and use. For this reason, a suitable methodology has to be capable of covering various precision levels.
It was for this purpose that ROM®, the ROI operation sequence method, was developed.
Features of ROM®
ROM® - The ROI operation sequence method
- is a system of predetermined times that works with time classes and thus achieves high analytical efficiency.
- makes it possible to derive essential indications for configuring work methods and work stations.
- has basic data and index times in scheduled timetables for all assembly processes.
- has a uniform performance level and does not require any evaluation of the degree of performance.
- is used for the analysis and assessment of all work processes that can be fully influenced by people.
- enables the assessment and evaluation of alternative methods in advance.
- can be used in the planning and optimisation phase to ascertain best practice assembly times.
- delivers requirements to logistics derived from the work station configuration.
- where needed, works with parts lists and work plans and on this basis enables the determination of plan times.
- is easy to learn, simple to use, and modifiable to meet specific circumstances.
The rationale behind ROM®
The rationale behind ROM® is based on the assessment of standard operation sequences. ROM® was developed by ROI on the basis of the fact that more than 85% of all work processes that can be influenced by people consist of five basic movements.