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TI 2111 Work System Design and Ergonomics 5. Predetermined Time System.

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Presentation on theme: "TI 2111 Work System Design and Ergonomics 5. Predetermined Time System."— Presentation transcript:

1 TI 2111 Work System Design and Ergonomics 5. Predetermined Time System

2 TI 2111 Work System Design and Ergonomics 2 Classifications

3 TI 2111 Work System Design and Ergonomics 3 Advantages of predetermined times Setting standards for a very short motions (very hard to evaluate using other measures) Standard “language” of documenting sequences of elements which define operations Enable to determine standard times for new operations for whom we don’t have past data Enable to compare different methods of performing a new task (before applying the preferred method) Usable for workers training

4 TI 2111 Work System Design and Ergonomics 4 Methods Time Measurements (MTM) The data for the development of MTM was obtained from motion pictures (using mechanical cameras) of skilled workers performing a wide range of motions Influence factors were identified and isolated in the motion analysis The influence factors became the motion characteristics which are used for determining the standard times Each motion was separately defined and tabulated for setting the standard times MTM was accepted as a standard method in many countries all over the world

5 TI 2111 Work System Design and Ergonomics 5 MTM-1 – the basic MTM module Basic time unit: TMU = time Measurement Unit 1 TMU= hour = min = sec This time unit was a result of the picture technology This time unit enable investigating much shorter motions (around 3-4 hundredth of a second) than using a stopwatch

6 TI 2111 Work System Design and Ergonomics 6 MTM-1 (1948) – definition & characteristics A procedure which analyses manual work into a basic motions required to perform it The procedure assigns to each motion a pre- determined time standard which is influenced by the environmental conditions Based on 23 basic motions and consists of approximately 5,000 time values (4,988)

7 TI 2111 Work System Design and Ergonomics 7 Basic Elements Reach (R): move the hand or finger to a destination – affected by the length of the motion and the type of reach Move (M): transport an object to a destination – affected by length of a motion, the weight of the object and the type of move Grasp (G): secure sufficient control on one or more objects with the fingers or hand in order to permit the performance of the next required motion – affected by the size shape and location of the object Position (P): align, orient, and engage object with another object (when only minor motions required) – affected by the ease of handling, symmetry and the amount of pressure required for insertion Release (RL): relinquish control of an object by the fingers or hand

8 TI 2111 Work System Design and Ergonomics 8 Basic Elements (cont.) Disengage (D): break contact between one object to another – affected by the amount of effort required Turn (T): the motion employed to turn the hand, either empty or loaded, by a movement that rotates the hand, wrist, and forearm about the long axis of the forearm – affected by the degree of rotation and by the weight of the object Apply pressure (AP) Eye Travel (ET): considered only when the eyes must direct the hand or the body movements (includes eye focus and eye travel time) – affected by the distance between the travel points and the distance between the eye to the line of travel Body leg and foot motion (BMF): other motions which are associated with the body and legs (walking, standing, bending etc.)

9 TI 2111 Work System Design and Ergonomics 9 Other MTM Based Methods MTM-2 (1965):  Used for setting standard time for longer tasks  Based on 9 basic motions and consists of 39 time values MTM-3 (1970):  Consists of 4 categories of manual motions (10 time values):  Handle, Transport, Step & foot motion, and Bend & arise MTM-V : Metal cutting operations MTM-C : Clerical work

10 TI 2111 Work System Design and Ergonomics 10 MOST – Maynard Operation Sequence Technique In MTM:  the elements are stand alone and do not relate to the sequence of the operation In MOST:  The compete sequence of the operation, which consists of smaller elements, is addressed

11 TI 2111 Work System Design and Ergonomics 11 What is MOST ? Maynard Operation Sequence Technique Developed by Zandin (1980) Utilizes larger blocks of fundamental motions than MTM-1 General Move  A B G A B P A Controlled Move  A B G M X I A Tool Use  A B G A B P _ A B P A

12 TI 2111 Work System Design and Ergonomics 12 Three activity sequences in MOST The General Move Sequence (for a free movement through air) The Controlled Move Sequence (for a movement in which the object remains in contact with a surface or is attached to another object during the movement) The Tool Use Sequence (for the use of common hand tools)

13 TI 2111 Work System Design and Ergonomics 13 Why MOST? It is much faster than traditional time study technique (e.g. Basic MOST is 40 times faster than MTM-1) Accuracy of up to 95% can be obtained It requires less documentation

14 TI 2111 Work System Design and Ergonomics 14 Remember TMU ? Time for therbligs is measured in Time Measurement Unit (TMU) 1 TMU = hour = minute = second 1 hour = 100,000 TMU 1 minute = 1,667 TMU 1 second = 27.8 TMU

15 TI 2111 Work System Design and Ergonomics 15 Sequence Models Basic MOST  WORK MEASUREMENT TECHNIQUE ACTIVITYSEQUENCE MODELSUB – ACTIVITIES General MoveA B G A B P AA – Action Distance B – Body Motion G – Gain Control P – Placement Controlled MoveA B G M X I AM – Move Controlled X – Process Time I – Alignment Tool UseA B G A B P _ A B P AF – Fasten L – Loosen C – Cut S – Surface Treat M – Measure R – Record T - Think

16 TI 2111 Work System Design and Ergonomics 16 MOST Study Form MOST - Calculation Code: Date: Area: Sign: Page: / Activity: Conditions: No.Method Sequence Model Fr.TMU 1Describe activity 1 Ax Bx Gx Ax Bx Px Ax 2 Describe activity 2 Ax Bx Gx Ax Bx Px Ax 3 Describe activity 3 Ax Bx Gx Mx Xx Ix Ax Ax Bx Gx Ax Bx Px _ Ax Bx Px Ax TIME =minutes (min.)

17 TI 2111 Work System Design and Ergonomics 17 MOST Study Form

18 TI 2111 Work System Design and Ergonomics 18 Example  Get cover, and place in front. Reach 24”, grasp, move 24” in front.  Open cover. Reach the cover with other hand by 30”, grasp the flap of cover, disengage the flap with normal effort, turn flap by 120 degree.  Remove spec from the cover, and place aside on table. Grasp the spec inside the cover, move it out of the frame by 4”, move it on the table by 30”  Close the cover. Reach for the cover flap in other hand, turn the cover to close, apply slight pressure  Put the cover aside. Move it back to previous position in 30”

19 TI 2111 Work System Design and Ergonomics 19 Example  Get cover, and place in front. Reach 24”, grasp, move 24” in front. A1 B0 G1 A1 B0 P1 A0  Open cover. Reach the cover with other hand by 30”, grasp the flap of cover, disengage the flap with normal effort, turn flap by 120 degree. A1 B0 G3 M1 X0 I0 A0  Remove spec from the cover, and place aside on table. Grasp the spec inside the cover, move it out of the frame by 4”, move it on the table by 30” A1 B0 G3 A1 B0 P1 A0

20 TI 2111 Work System Design and Ergonomics 20 Example  Close the cover. Reach for the cover flap in other hand, turn the cover to close, apply slight pressure A1 B0 G1 M3 X0 I0 A0  Put the cover aside. Move it back to previous position in 30” A0 B0 G0 A1 B0 P1 A1


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