department of industrial engieering chapter...
TRANSCRIPT
1
Islamic University of Gaza - Palestine
Department of Industrial Engieering
Chapter : Predetermined Time Systems (PTS)
Assistant Prof. Abed Schokry
Islamic University of Gaza - Palestine
Predetermined Time Systems
• To increase productivity for a particular task:
– Frank and Lillian Gilbreth broke work into therbligs (elements).
– Then assign time values to the elements.
– Times for elements are added to obtain a total time.
• Independence and additivity are assumed.
• PTS are based on the concept that there are basic, universal units of work with standard amounts of time.
Generated by Foxit PDF Creator © Foxit Softwarehttp://www.foxitsoftware.com For evaluation only.
2
Islamic University of Gaza - Palestine
Purposes of PTS Studies
• Make a methods analysis to determine an efficient work method.
• Determine the amount of time necessary to do the job.
Islamic University of Gaza - Palestine
Methods-Time Measurements
• Developed in 1946
• Simplified versions are available.
• A training course is required for using the system correctly.
• TIME UNITS:
1 TMU = 0.00001 HOUR 1 HOUR = 100000 TMU1 TMU = 0.0006 MINUTES 1 MINUTE = 1667 TMU1 TMU = 0.036 SECONDS 1 SECOND = 27.8 TMU
•
Generated by Foxit PDF Creator © Foxit Softwarehttp://www.foxitsoftware.com For evaluation only.
3
Islamic University of Gaza - Palestine
Why MTM?
• In order to effectively utilize the man power,
• To balance the line and to establish the no. of workstations,
• Then to determine the moving speed, which depends upon the time taken at each station.
Islamic University of Gaza - Palestine
MTM-1
• 10 categories of movements
• Times in TMUs (1 TMU = .000 010 h)
• Times are for an experienced worker working at a normal pave.
• No allowances are included in the times.
Generated by Foxit PDF Creator © Foxit Softwarehttp://www.foxitsoftware.com For evaluation only.
4
Islamic University of Gaza - Palestine
Types of Reach
• To an object in a fixed location or in the other hand.
• To a single object whose general location is known.
• To an object jumbled with others in a group.
• To a very small object or where accurate grasp is required.
• To an indefinite location.
Islamic University of Gaza - Palestine
Types of Move
• Move object to the other hand or against stop.
• Move object to an approximate or indefinite location.
• Move object to an exact location.
Generated by Foxit PDF Creator © Foxit Softwarehttp://www.foxitsoftware.com For evaluation only.
5
Islamic University of Gaza - Palestine
Turn
• A movement that rotates the hand, wrist, and forearm about the long axis of the forearm.
• Time depends on degrees of turn, weight of the object, and resistance against turn.
Islamic University of Gaza - Palestine
Apply Pressure
• Application of force without resultant movement.
Generated by Foxit PDF Creator © Foxit Softwarehttp://www.foxitsoftware.com For evaluation only.
6
Islamic University of Gaza - Palestine
Grasp
• Pickup grasp
• Regrasp
• Transfer grasp
• Jumbled grasp
• Contact, sliding, or hook grasp
Islamic University of Gaza - Palestine
Position
• Aligning, orienting, or engaging one object with another
• Position times vary with:
– Amount of pressure needed to fit
– Symmetry of the object
– Ease of handling
Generated by Foxit PDF Creator © Foxit Softwarehttp://www.foxitsoftware.com For evaluation only.
7
Islamic University of Gaza - Palestine
Disengage (free)
• Breaking contact between one object and another
• Times vary with:
– Class of fit
– Ease of handling
– Care in handling
Islamic University of Gaza - Palestine
Release
• Relinquishing (letting go) control of an object by the hand or fingers
• Two types:
– Simple opening of the fingers
– Contact release
Generated by Foxit PDF Creator © Foxit Softwarehttp://www.foxitsoftware.com For evaluation only.
8
Islamic University of Gaza - Palestine
Other Motions
• Body, leg, and foot motions
• Eye motions
• Combined motions
• Limited motions
Islamic University of Gaza - Palestine
MTM Form
Generated by Foxit PDF Creator © Foxit Softwarehttp://www.foxitsoftware.com For evaluation only.
9
Islamic University of Gaza - Palestine
MTM-2
• Takes about 40% of the time of MTM-1 to analyze a task.
• Has only 37 times in all.
• Key categories are GET and PUT.
• Provides decision trees to determine case.
• User estimates distance and uses time from table.
• Includes seven other motions.
Islamic University of Gaza - Palestine
MTM-2 Analysis
Generated by Foxit PDF Creator © Foxit Softwarehttp://www.foxitsoftware.com For evaluation only.
10
Islamic University of Gaza - Palestine
MTM-3
• Takes about 15% of the time of MTM-1 to analyze a task.
• Has only 10 times.
• Key categories are HANDLE and TRANSPORT.
• Provides decision trees to determine case.
• User estimates distance (< 6 in. or > 6 in.) and uses time from table.
• Includes two other motions.
Islamic University of Gaza - Palestine
MTM-3 Analysis
Generated by Foxit PDF Creator © Foxit Softwarehttp://www.foxitsoftware.com For evaluation only.
11
Islamic University of Gaza - Palestine
MOST Work Measurement System
• Based on observation that the majority of activities are associated with a limited number of motion sequences.
• Significantly reduces time required to perform an analysis.
• Four sequence models
The four sequences are:
• Basic MOST, Mini MOST, Maxi MOST, Admin MOST
(Maynard Operation Sequence Technique)
Islamic University of Gaza - Palestine
General Move Sequence Model
Generated by Foxit PDF Creator © Foxit Softwarehttp://www.foxitsoftware.com For evaluation only.
12
Islamic University of Gaza - Palestine
MODlar Arrangement Of Predetermined Time Standards
MODAPTS
• Based on the concept that the body member used is the key variable.
• All body movements are multiples of a MOD (1 MOD = .129 s).
Islamic University of Gaza - Palestine
Comments about PTS
• In theory, PTS can accurately predict task times.
• Evidence shows reality and theory don’t agree.
• Analyst judgment is required (could be a problem).
• Most managements are not concerned with a great deal of accuracy.
• Managements are concerned with cost of analysis.
Generated by Foxit PDF Creator © Foxit Softwarehttp://www.foxitsoftware.com For evaluation only.