Work Factor System: Six Main Work Factor Systems
The first systems built were the comprehensive method, expanded to include:
(1) Factor of detailed work (DWF).
(2) Factor of function simplified (SWF).
(3) Job Variable Abbreviated (AWI).
(4) Factor ready for work (RWF).
(5) Factor of brief work (BWF).
(6) The Mento Factor Detailed (DMF).
1. Detailed Work Factor (DWF):
DWF is used for operations involving accurate time standards and savings that are greater than the cost of deciding such standards due to the use of accurate time standards. In many factories and bureaus DWF is able to find a wide range of applications, as both of them are popular. This is a simple method at a general level. The working element is calculated to meet the times needed with movements.
There are four major variables that influence the time to make manual motions according to the work factor system:
1. Body Member used.
2. Range is shifted in inches measured.
3. Manual control, specified or dimensional, as calculated in working factors.
4. Implied weight or strength, expressed in pounds, translated into a work factor.
1. Body Member Used:
Work factor recognizes six definite body members and provides motion times for each: Finger or hand, arm, fore arm, swivel, trunk, foot and leg. Time values for these body members are illustrated in Table 6.1.
Notations for these members are as follows:
Notation
(i) Finger or hand – (F.H)
(ii) Arm – (A)
(iii) Forearm-Swivel – (S)
(iv) Trunk – (T)
(v) Foot – (FT)
(vi) Leg – (L)
In addition to the above members of the body, detailed working factor tables also provide movement times for heading and walking.
2. Distance:
The measurements in straight lines between the starting point and stop point of the motion as defined by members of the body (except for distances with changes in direction). The tables represent the calculation of the motion of different members of the body. When the change of direction is made during travel purposefully, the distance determined in a straight line is carefully calculated by a function factor.
3. Manual Control:
Occasionally, different types of movements require different degrees of manual control. The motion time would be increased. The required manual control is defined in this system by work factor. The following classification of the types and degrees of control illustrates the difficulty involved: Definite Stop Work Factor, (D) directional control work factor (steer), (s) Care Work Factor (precaution), (p) Change of Direction Work Factor, (U).
4. Weight or Resistance (W):
The effect of weight on motion time is due to weight of the object handled as well as the need to exert force in order to overcome resistance. The effect of weight on time varies with (i) the body member used and (ii) The sex of the operator. The two variables, distance and body member are indicated in inches and the member used, respectively. They are not affected by work factors.
To order to simplify the interpretation of the Work Factor theory, the work factor can be considered a way of defining motion by weight or resistance. Weight is used in the Work Factor Method as a work factor when determining motion times.
The Tables containing motion times of this system are known as work Factor Motion Time Tables [Tables 6.1. (a), (b), (c), (d), (e), (g), (h)]
These tables can be used as follows:
(1) Analyze the motion whose time is to be determined from table and find out the following:
(i) Body member involved.
(ii) Distance moved.
(2) Identify the table and the individual row of the table based on the information given above.
(3) The first entry of the line under the bottom of the heading gives time to this step without manual testing and weight / resistance.
(4) The motion is now studied in order to determine the factors of influence. As shown in the tables, a maximum of four work factors and four times can be shown which suit 1, 2, 3, and 4 working factors.
(5) At the bottom of each table are also given the weight labor factors for both men and women. These are used for weight determination.
The explanations below would provide clear information on the use of the tables.
Example 1:
Arm moves 18 inches to toss a small coin in a tray.
The body member involved is arm (A) and the distance is 18 inch. Because there are no manual control requirements as well as weights involved this motion has no work factors due to both. Hence it is a basic motion. Thus value as per table 6.1 (a) is 55. This corresponds to 0.0055 minutes since one time unit =0.0001 minutes.
Example 2:
Arm crosses 30 inches in order to collect a table stamp. The table and distance row can be easily located. Let the requirement for manual control be tested. It is a definite stop motion (D) and hence one work factor for manual control is taken into account. There is no weight work factor involved. Thus time is 0.0096 m in.
Example 3:
A male worker pushes a 4 lb job to the end of the work table 4 inch away. This is the movement of a finger hand against a definite stop (D) and weight (W) is also involved. It is easy to locate the table and the distance row in it. Work factor due to manual control is indicated. The weight of the job shows that two work factors due to weight are involved.
Therefore a total of three work factors are involved. The time according to table 6.1 (d) is 0.0050 min. In order to analyze the various motions of complete work cycles, the Work Factor System defines certain standard elements of work which are termed as Work Factor Standard Elements of work. These may be composed of a single motion.
They are as follows:
Work Factor Standard Elements of Work
Element – Notation
1. Transport (Move and Reach) – TRP
2. Grasp – GR
3. Preposition – PP
4. Assemble – ASY
5. Use (Process or Machine Time Manual) – US
6. Disassemble – DSY
7. Mental Process – MP
8. Release – RL
2. Simplified Work Factor System:
This is a generally higher level that can be developed from a comprehensive working factor method for medium quantities. Until actual production begins, it is very successful in planning estimates. It is easier and quicker to use like many higher level systems. For ten thousandths of a minute time units for Job Factor Table are used.
3. Abbreviated Work Factor System:
This is a method of higher level built from a comprehensive system of work factors and is perfect for small quantities of workshops. Such systems have been configured to fulfill the need for a very simple system of default times. We provide a fast measurement method to the degree that time data are used.
Thus to refer to a separate table of time values becomes unnecessary. The abbreviated time unit is 0.005 (recorded as 5) minute rather than 0.0001 minute used in the Detailed and Mento system. The accuracy of the Abbreviated systems is expected to average +12 percent of the detailed system if it is correctly applied to appropriate type of work.
4. Ready Work Factor System:
A adapted method of a higher level job factor is intended for people who do not know the specifics of time test techniques. It is typically used to determine manual work in manufacturing and elsewhere. This technique was developed to meet the requirement for a simple measurement method and to compare manual movement time.
RWF is a very simple system, which is especially useful in calculating medium to long-term activities with intervals of 0.15 minutes and higher for people, such as product designers, cost estimators, methods & machine engineers, office superviseurs and others, who are familiar with production activities. A simple set of pre-estimated time criteria, which is easy to understand, remember and implement, are used in the implementation of the RWF.
5. Brief work Factor System:
The short system is quite modern and uses a time unit of 0,005 minute like Abbreviated Systems (recorded as 5). It has been planned for the Detailed and ready systems to adhere to the format.
6. Mento-Factor System:
This is a basic level method that is used to calculate mental processes like examination, proof reading, color matching and measurement and almost any repeated, or half-repeatable, and mostly mental procedure.
