Time Measurement chart
Methods-Time Measurement (MTM) is a predetermined motion time system that is used primarily in industrial settings to analyze the methods used to perform any manual operation or task and, as a product of that analysis, set the standard time in which a worker should complete that task.
The basic MTM data was developed by H.B. Maynard, JL Schwab and GJ Stegemerten of the Methods Engineering Council during a consultancy assignment at the Westinghouse Brake and Signal Corporation, USA in the 1940s. This data and the application rules for the MTM system were refined, extended, defined, industrially tested and documented as a result of further work in later years.
In 1948, Maynard, Stegemerten and Schwab published the book “Methods-Time Measurement” giving full details of the development of the MTM system and its application rules. The use of MTM spread, firstly in the USA and then to other industrialised countries. In 1951 the USA / Canada MTM Association for Standards and Research was formed by MTM Users. The system originators then assigned the MTM copyrights to the MTM Association.
Other national MTM Associations were founded and, at a meeting in Paris in 1957, it was decided to form an International MTM Directorate (IMD) to co-ordinate the work of National Associations. National MTM Association members of IMD now hold the MTM copyrights for their territorial areas.
Other MTM based systems have since been developed. MTM-2, a second generation system was developed under IMD auspices in 1965; MTM–3, a further simplification, was developed in 1970. The original MTM system is now commonly referred to as MTM-1. Other systems based on MTM have been developed for particular work areas by National Associations. The most recent development is MTM-UAS, created by a consortium from the German, Swiss and Austrian National Associations during the mid 1970s.
Films were taken using constant speed cameras, running at 16 frames per second, of the work performed by qualified workers on the shop floor at the Westinghouse Brake and Signal Corporation. Each sequence was rated during filming by three qualified Industrial Engineers. These ratings had to agree within a close band, otherwise the sequence was not used.
The rating, or Levelling, system used was the Westinghouse or LMS system – so called after its originators Lowry, Maynard and Stegemerten. This system considers four factors independently:
- Skill – Proficiency in following the given method
- Effort – The will to work
- Conditions – The general work surroundings
- Consistency – of performance
Each factor is assigned an alpha rating, e.g. “B-“, “C+”, “A”, etc. which has a numeric value which is applied later. This reduces the possibility of “clock rating” and ensures that all factors are considered in the composite rating. Appendix 1 shows the model for Causes of Difference in Output on which the LMS system is based.
Layout, distances, sizes of parts and tools and tolerances were accurately measured and recorded on the shop floor to complement the later analyses.