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The MTM-2 System

  • The MTM-2 System

  • The MTM-2 System

The MTM-2 System

The MTM-2 System

MTM-2 was developed by the International Standing Committee for Applied Research on instruction from the Managing Board of the International MTM Directorate. The project was submitted on the 2nd of October, 1964, and was completed by the end of May, 1965. The rapid rate of progress was made possible by the generous contribution by Svenska MTM Foreningen of a philosophy relating to combined MTM data, together with extensive material from carefully conducted industrial studies.

 

MTM–2 was approved by the Managing Board of the IMD, in Munich, on the 11th of June,1965.

 

All data used in the development of MTM-2 are stored at the French MTM Association in Paris (France) and the MTM-2 project research can be seen there. Due to a large number of applications in France, the French MTM Association assures the maintenance of the system.

 

Development of the MTM-2 System

 

Definition

MTM–2  MTM-2 is a procedure which analyzes any manual operation or method into the Motion Sequences required to perform it, and assigns to each Motion Sequence a predetermined time standard which is determined by the Influencing Factors under which it is made.

 

Thus MTM-2 is a system on the hierarchical level of Motion Sequences, designed for modeling processes that are represented by Process Type 2.

 

MTM-2 Motion Sequences are based exclusively on MTM-1 and consist of:

 

  • MTM-1 Basic Motions
  • Combinations of MTM-1 Basic Motions

 

MTM-2 satisfies the demands on the quality of MTM building block systems, required to have:

 

Stability of the building blocks

 

  • Reproducibility – Each building block is characterized by a Description (universally named), a Code, a Scope (Starts, Includes, Ends and Limitations), Influencing Factors and a time standard.
  • Objectivity (comparability, interpersonal stability) – Analysts, creating analyses under identical conditions and in accordance with the Application Rules, arrive at the same result.
  • Reliability (repeatability, intrapersonal stability) – Analysts, creating analyses repeatedly over a longer period, arrive at almost the same result, because they use the Motion Sequences according to the Application Rules.

 

Validity of the Motion Sequences

 

  • Reference performance consistency – This reference performance is the MTM Standard Performance defined in MTM-1, because all building blocks in MTM-2 conform to either Combinations of MTM-1 Basic Motions or MTM-1 Basic Motions

 

  • Statistical accuracy (System Deviation compared with MTM-1) – The combined system and application derivation is such that MTM-2 analyses are within + or – 5 % with 95 % confidence from MTM -1 analyses at non-repetitive cycles of 3,2 minutes or more.

 

Economic efficiency – Fast to apply – Easy to understand – The analyzing speed in MTM-2 is almost 3 or 4 times faster than applying MTM-1.

 

The Motion Sequence is adapted to the operator and is independent of the workplace or equipment used.

 

MTM-2 satisfies the principal demands on MTM building block systems required to be:

 

  • Consistent between analysts and between areas of application
  • Fast to apply
  • Universally named
  • Easy to understand
  • Method descriptive
  • Combinable with other MTM basic data or MTM building block systems
  • Based on MTM-1
  • Specified in relation to speed of application and accuracy of results

Data Construction

The demands on data, particularly speed of application, indicate that simplicity of the system is a fundamental quality. Simplicity was achieved in the MTM-2 system by MTM technical simplification and statistical simplification.

 

MTM technical simplification produced easy to learn decision models and a limited number of alternatives from which to choose. The decision making processes are designed to identify the difficult alternatives by exception.

 

The Influencing Factors of MTM-2 have been made easy to observe and judge.

 

Statistical simplification was achieved by employing theories of probability to reduce the vast amount of data available in the MTM-1 Data Card in a way that minimizes loss of accuracy.

 

Different principles of simplification used are:

 

  • Combining motions

 

e.g.: Reach, Grasp and Release are combined to give the Motion Sequence Get

 

  • Averaging motions

 

e.g.: APA and APB are averaged to give the Motion Sequence Apply Pressure

 

  • Substituting

 

e.g.: Turn is substituted by Reach in the Motion Sequence Get and for Move in the Motion Sequence Put

 

  • Elimination

 

e.g.: Sit and Stand are eliminated and analyzed as Bend and Arise plus other relevant motions

 

  • Reduction of Influencing Factors

 

e.g.: Formation of distance classes from motion lengths in MTM-1

Data derivation

The material used in the construction of MTM-2 was derived principally by the KMD (combined MTM data) project group of Svenska MTM Föreningen and Swedish Industry. MTM analyses from different industries and work areas with different degrees of mechanization and rationalization were collected and rigorously checked.

 

The analyses were audited to ensure their complete conformity with the theoretical demands of detailed MTM-1. Distances and weights were checked to establish that they had been correctly measured.

 

The MTM analyses were analyzed by a computer which was programmed to yield information about Motion Sequences and Motion Frequencies.

 

A pictorial representation of the data on Motion Sequences is given in the next figure.

 

Flow of MTM 1 Motions

 

int-9

 

Legend:

R: Reach                                                                                                           AP: Apply Pressure

G: Grasp                                                                                                           SC: Static Constant

M: Move                                                                                                            C: Crank

P: Position                                                                                                         B: Bend

RL: Release

The flow is proportional to the quantity of motions in each category. There is a broad main flow of motions Reach, Grasp, Move and Release. There is also a broad circular flow of Move, which indicates repeating Move motions. All other motions appear in a way that disturbs the main flow. The flow chart shows that the only sequences that could be of real value in a combined MTM system are those formed from RGM and RL. With the exception of the relationship of M-C (a high control Move) to P, other motions do not easily fit into any common sequences.

 

The predominance of the Basic sequence, RGMRL, suggests an apparent solution of a four Motion Sequence in MTM-2. However, with this sequence, it is not easy to analyze two-handed overlapping motions.

 

The final solution, after also considering the other less important sequences, is to have two basic sequences:

 

  • one of Reach, Grasp and Release
  • the other of Move or Move and Position

 

MTM-1 is divided into a large number of basic motions. MTM-2 is divided into 39 essential Motion Sequences.

MTM Motion Distribution

The following bar chart gives the relative frequencies of the main motion groups. Move is the most numerous category. The relatively unimportant nature of Turn and Disengage is also apparent. A more detailed analysis is given in the MTM-2 Project Archive.

 

int-10

 

 

The bar chart also illustrates the general similarity in the distribution of motion classes in the USA, Sweden and UK. There are small differences and this is to be expected. There are differences between industries and between work areas.

 

However, the averages in MTM-2 have been carefully constructed to achieve minimum deviations over a huge sample of data and the evidence indicates that valid results are achieved in all but the most highly repetitive areas. In these areas, MTM-1 should be used.

 

Accuracy

 

The very close similarity between Swedish and UK data for one of the principal Influencing Factors, distance, is evident from the graph of the distribution of Reach and Move distances.

 

The graph is in the form of the usual frequency distribution used in the research project.

 

int-11

 

 

 

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