This article throws light upon the ten basic motion elements of MTM. The elements are: 1. Reach (R) 2. Move (M) 3. Turn 4. Apply Pressure 5. Grasp 6. (Position-P) 7. Release 8. Disengage-D 9. Eye Times (ET & EF) 10. Body Leg and Foot Motions.
Element # 1. Reach (R):
Reach is the basic element used when moving the hand or finger to a certain destination or a general location is a predominant goal.
The time for making a reach varies with the following factors:
(i) Status (destination nature)
(ii) Motion and Duration
(iii) Ability sort (i.e. if hands move / accelerate / decelerate at start / end).
Classes of Reach:
Five classes of reach are available. The time to reach the object to which the reach is drawn is affected by its nature. The Reach motion contains five cases.
Case A Reach:
Reach an object in another location or to an object at a fixed location.
Case B Reach:
Get to the item defined for its general location. The location can differ somewhat between periods.
Case C Reach:
Reach the jumbled object in a group with other objects. This case will require scanning and choosing.
Case D Reach:
Access to an extremely small object or to an exact group.
Case E Reach:
Reach to an unspecified location for the equilibrium of the body, or next step or discharge.
The duration of a step, not just the line between the two end points is the true path.
There are three types of reach to be taken into consideration:
(1) Hand does not move at start and finish.
(2) Hand moves at the beginning or the end.
(3) Hand is moving at the start and at the end of reach.
In tables published by MTM Association for Standards and Research, the time values are available for the reach type. The sample tables for the purpose of illustration and use are shown and Table 18.2 (a), (h), (c), (d), (e), (g), (h) and (i) for various motion elements of MTM.
Element # 2. Move (M):
Move is the main element used when moving an object to a destination is the main purpose.
There are three classes of moves:
Case A Move:
Object to or against other side
Case B Move:
Approximate or indefinite placement object.
Case C Move:
Exactly position entity.
The time for move will depend upon the following variables:
(1) Motion length that is regulated in a similar way to reach.
(2) State (destination nature) as decided by the three cases referred to above.
(3) Movement types that are the same as ' reach. '
(4) Weight factor, (static and dynamic):
The weight of the body influences the travel time in two ways. Initial resistance before movement is generated by weights and not only the step is reversed (i.e. time increased).
This also increases time. Table 18.2(b) for move contains weight factor: To find out the time allowed for move with weight, it is essential to multiply the basic move time with appropriate weight factor. A suitable weight constant is applied in addition to this product if possible.
Element # 3. Turn:
When the hand is either empty or loaded, it is the basic element employed. Such movement revolves around the long axis of the forearm, hand, and forearm.
The quantity / length of the turn is determined by the degree of turning of wrist, handle and forearm from natural position.
The table for turn contains time values (i.e., TMU) for 30° turn to 180° turn with increments of 15°. The time for turn depends on two variables:
(i) Degrees turned and
(i) Weight factor.
The turning time depends on the weight when the hand is not empty. There are three classification of weight i.e. small, medium and large as illustrated in Table 18.2(c).
Element # 4. Apply Pressure:
When the precise control is applied, this aspect is carried out. It is considered a separate break before the following basic elements are performed. Table 18.2 (d) presents the time values for apply pressure. It gives complete cycle time or the components development in connection with other motions. There were two cases in the tables i.e. Apply Case A and Case B Pressure.
These are as follows:
Stress Apply Case A. Pressure control only. Of reality, this would take less time than B.
Press Case B. Remove or sequence and apply pressure. Pressure. It requires more than standard precision.
Element # 5. Grasp:
The fundamental element is performed in the case of an appropriate regulation of one or more objects with fingers or hands, so that the next essential element is performed.
It starts when the preceding basic element has ended and stops when the succeeding element has started. Hence mental Therbligs such as search and select are included in the grasp time values. The format of table for grasp is shown in Table 18.2 (e) which illustrates various cases TMU and description of activities.
Element # 6. (Position-P):
Place is the basic element used to connect a component with a particular object in which the movements used are so small that they do not explain themselves as other basic elements. The place time will be affected.
(a) Class of fit. Loose close and Exact.
(b) Symmetry:
Symmetrical (S) non symmetrical NS and semi symmetrical (SS).
(c) Facility to handle. Easy to handle or hard to handle.
This is illustrated in Table 18.2(i).
Element # 7. Release (RL):
The release is the fundamental element for giving up the hand finger control of an object.
There are two types of release:
(i) Normal Release:
You just open the fingers to let go of the piece.
(ii) Contact Release:
When the following reach motion starts, it occurs and is completed. Time for release of this case TMU is not allowed, and Table 18.2 shows activities.
Release-RL
Element # 8. Disengage-D:
Disengagement is the fundamental element used to break contact between objects. The artifacts are isolated from each other.
Disengage times depend upon:
(a) Class of fit.
(b) Ease of handling
(c) Care in handling
Disengage times given in Table 18.2(h).
Element # 9. Eye Times (ET & EF):
The eye is not a limiting factor for most work times to shift and concentrate, and therefore does not impact operating time. In all such cases, however, some cases require consideration of practice. In the MTM, eye time (ET) and eye focus time (EF) exist two forms of eye times.
The time of the eye concentrating is the time to focus and look at an object for enough time to recognize those features easily distinguishable in and without eye shifting.
The distance from and to which the eye moves and the distance from the eye to the line shown in Table 18.2 affects the duration of eye travel.
Element # 10. Body Leg and Foot Motions:
Mainly used movement of body, leg and foot has been categorized under MTM and tabulated. They have their time values in Table 18.2(f).
