Motion time systems


1. Methods Time Measurement (MTM)

In this method, predetermined time values for basic motions or therbligs such as reach, move, turn, apply pressure, grasp, position release and disengage etc. are established in terms of TMU’s(i.e. Time measurement Units). One TMU= 10-5 hour or .00001 hour or 0.0006 minutes or 0.036 seconds. The time values are listed in tables in terms of TMU’s for basic motions and may be applied to any type of operations that may be resolved to the basic motions, thus eliminating the use of stop-watch.

Application of MTMs Techniques
MTM has been used for :

1. Developing effective methods in advance of beginning the production.
2. Improving existing methods.
3. Establishing standard time data.
4. Estimating labor time and cost.
5. Training supervisors to be method-conscious.
6. Choosing between alternative methods.

2. Work Factor

This technique is based on basic on basic motions which are modified elements of difficulty, all of which tend to make movement slower. These features or work factors are weight or resistance, change of direction, need of care, stopping a motion and manual control. Each of these features is known as ‘work factor’ and it modifies the basic time value.

3. Basic Motion Times (BMT)

In this system, the times were derived from laboratory experiments and were carefully checked against a variety of factory operations before being accepted for general use. BMT data are based on basic motions. A basic motion occurs every time a body member which is at rest moves and again comes to rest. For example, the action of knocking on a door, requires two basic motions for every knock-one to draw the hand back and another to move the hand forward and knock.

Basic motions are classified as : finger, hand, and arm motions, foot and leg motions and miscellaneous body motions. The motions of finger, hand and arm are further classified as ‘class A’ motions, ‘class B’ motions and ‘class C’ motions, depending on the use of muscular control in stopping the motion ‘class A’ motions are stopped without muscular control by impact with an object , ‘class B ‘ motions are stopped entirely by the use of muscular control and ‘class C’ motions are stopped by the use of muscular control both to slow down the motion and to end it in grasping or placing action.