Wait, Help and Hold
Build-up of the Work-Factor system
Together with the physiological and psychological views on labour, the WORK-FACTOR system has achieved a special meaning as a tool for the build-up of working methods, because the application of WORK-FACTOR systems require imperatively an analytical splitting up of the work in motion elements and their influencial factors.
Through the analytical approach of manual work and the search for alternatives, one is directed to formulate the optimal working method and come up with improvements on auxilaries, aiding tools and equipment.
By comparison of the alternative analyses on basis of WORK-FACTOR times, the efficiëncy is increased as well.
As stated before, the principle of the system is based on the fact that all human activitites can be split up in ever the same elementary elements, the so-called standard elements. WF-systemes use the following standard elements:
Transportation of a body part to an object or to a particular place.
(Finger) movements necessary to gain control over an object.
Motions to bring an object in the right position to be used in the next standard element, if that object can not be grasp in the correct position immediately.
The transportation of an object to another object or to a particular place.
Joining two objects together:
- pin into a hole ................................................................................................................... a mechanical assembly
- placing objects with its surfaces in a prescribed position w.r.t. each other .............................. a surface assembly
The separation of objects that were asembled before.
The separation of body part and object.
Times which can not or hardly be influenced by the operator, like machine times and process times (paint spraying).
The activities of the senses, the nerves, the central nervous system and the brains for seeing and recognition,
- like focus, inspect, and react, f.i. the execution of visual inspection; and the activities
- for memorizing and recallection, f.i. reading, counting, writing and calculating;
- and decide, for instance in what catagory a faulty product must be placed.
The body part does nothing at all, or waits (for the other hand or for a process), or is merely used as a sort of container or vice.
The times for waiting and holding can be determined with a stop watch or be determined by analysis of f.i. the other hand.
Through analysis of actual methods, the (frequent) occurrence of these two standard elements, Wait and Hold, are an indication that the method can be improved. In setting up a new or modified working method one should strive for the elimination of these two elements or at least to minimize the occurrence.
Process times are mostly determined in the conventional way, with the aid of f.i. a stop watch.
For the other standard elements a standard time is determined per element depending on primary factors like body part and distance, and on a (variable) number of secondary factors. A secondary factor is called an “influencial factor”. Quick c.s. succeeded to determine the time delay per influencial factor and to establish the unit of delay. This unit of delay is called a “Work-Factor” and is denoted with WF.
Tables are used to display all these time values.
For a fast and efficient analysis symbols are used, named therbligs. These therbligs are derived from the original symbols used by Gilbreth. For international use, also the English abbreviations may be used, as indicated in the tabel below. In German-speaking areas also the German abbreviations may be used, while in the French-speaking areas the French abbreviations may be used.
To avoid misunderstandings it is recommended to use the therbligs.
Montage de surface
You will not succeed in showing the therbligs, if you did not install a letter type of WF (arial or courier)! So, with the installed software for f.i. RWF, VWF or BWF, you should succeed.
Of course, the ALT-key only functions if a WF-font is selected.
See, Hear, Feel,
Taste and Smell
Build-up of the Mento-Factor system
As with manual Work-Factor the principle of the Mento-Factor system is also based on the fact that all human mental functions can be divided in always the same parts or elements, the so-called basic elements. MF-systems use the following basic elements:
The Eye Motions (EM) are subdivide into two sorts of motions, viz.
- Eye Focus (Fo): the focussing of the eye is necessary if the object to be seen is at a different distance than the object
that is focussed on yet. The eye must focuss again in order to see sharp.
- Eye Shift (Es): change in direction. The direction of view is established through the little eye muscles that could roll the
eyes in all directions over any angle.
Seeing (See) concerns the collection of information in the form of light energy and the conversion into nerve energy or impulses. This is also true for Hearing (Hea) regarding the collection of energy of sound waves and for Feeling (Tou) concerning the collection of energy of pressure.
Taste (Tas) and Smell (Sme) are not mentioned in the Mento-Factor system and therefore are not discussed..
Conduct (Con In/Out) is the conduction of the impuls along/through the nerves from the “sensor” to the brain and from the brain to the other parts of the brain or (back) to the “sensor” or to the various muscles of the various body parts.
The function of Identify (Id) is the comparison of the information conducted to the brain with information already stored in the brain in order to recognize that a noticed identifying mark has indeed the characteristics looked for.
Decide (De) comprises the determination of the proper action following on what is recognized just before. So, reacting on a action signal or signals that are related to the work and the task of the worker.
The basic element Discriminate (Disc) comprises the ability to distinguish between measures, forms, colours, texture a.s.o. of objects. It plays an important role at inspection work.
The element Span (Sp) relates to the simultaneously seeing and processing of a group of marks as one whole. It enables us to read words in stead of seeing letters and numbers, or after a grasp to determine that exactly 4 washers are grasped without even counting them, or at inspection work to inspect and chech a group of f.i. soldering points in one glance in stead of looking at each point individually.
By Scan (Sc) is understood the disturbing or distracting effect that is caused when a group of markings is surrounded at more than one side by similar markings. Scan is an allowance on Span.
By the element Convert (Cvt) is understood the convertion or transformation or translation of a mark into another corresponding mark. As with the convertion of the colour code on a resistor into a number.
The function of Temporary Memorize and Recall (Mem and Rec) is the temporary storage of information into memory that will be needed moments later and to be able to recall this information before it is used (again). “Moments later” means in this case “within a minute”.
Compute comprises of Compute and Sustain (Com and Su). The function of Compute is: adding digits, subtracting, multplying and dividing numbers. Sustain is the Work-Factor term for the extra strain necessary when the number of calculations increase.
The function of Transfer Attention (TA) in the Work-factor system is to set free the attention and focuss on task A and to concentrate on task B.
These 11 (13) mento basic elements form the foundation of the Mento-Factor system.
It is shown that Mento Processes may be comprised of a considerable number of basic elements. In manual work we distinguish 6 standard elements. The first is Transport (Reach and Move). The basic elements of Transport are the motions of the fingers, arms an other body members. The 5 other standard elements (Grasp, Preposition, Assemble (mechanical and surface), Disassemble and Release) are all build-up from the same basic elements, micro-motions. In order to be able to analyze always in the same way and order certain frequently occuring work elements like grasping from a pile and assemblies a.s.o., these basic transport motions have been combined to the other standard elements: Grasp, Preposition, Assemble, Disassemble and Release.
In the same way the basic elements of Mental Processes that occur frequently in certain combinations, are combined into so-called “Mento Intervals”. A Mento Interval is understood to be one cycle of a mental process. This cycle often occurs between two eye motions. A Mento Interval comprises 3 functions::
1. recording of information,
2. recognition of information,
3. the corresponding reaction (decision) upon the recognized information..
We will distinguish 4 kinds of Mento Intervals:
- React Interval : reaction on a signal: light, sound, touch/pressure, (smell and taste),
- Inspect Interval : recognition of marking(s),
- Compute lnterval : calculating, mainly adding and subtracting,
- Read Interval : reading to take action based on what is read.
These 4 mento intervals form the basis of the Mento-Factor Compact system.