Lesson 24 of Industrial Engineering ONLINE Course - IE Concepts Module - Contribution of Taylor, Gilbreth, Emerson, Maynard, Barnes, Shigeo Shingo.
Productivity Science of Human Effort - Variables of Importance - Frank B. Gilbreth
“Productivity science is scientific effort, that in any specific work situation, identifies the appropriate philosophy, culture, systems, processes, technology, methods and human physical action and behavior and elements of each of them of that will maximize positive (social, environmental and economic) outcomes relative to the resources consumed.” - Narayana Rao (IISE 2020 Annual Conference Proceedings)
Read the abridged version of Productivity Science of Human Effort by Frank Gilbreth in:
Frameworks for Productivity Science of Machine Effort and Human Effort
Rao, Kambhampati Venkata Satya Surya Narayana. IIE Annual Conference. Proceedings; Norcross (2020): 429-434.
https://www.proquest.com/openview/5786c4e6edff56abf808b4db26f083b3/1
Frank Gilbreth - Motion Study
Gilbreth first identified variables which have an effect on the time taken for completing motions and then developed principles of motion economy. He used the principles in redesigning the motions used in doing elements of operations. Understanding the relation of each variable to the motions made is important for industrial engineers to do effective human effort industrial engineering.
CHAPTER III - VARIABLES OF THE SURROUNDINGS
APPLIANCES - CLOTHES - COLOR - ENTERTAINMENT - HEATING, COOLING, VENTILATING - LIGHTING - QUALITY OF MATERIAL - REWARDS AND PENALTIES - SIZE OF UNIT MOVED - SPECIAL FATIGUE-ELIMINATING DEVICES - SURROUNDINGS - TOOLS - UNION RULES - WEIGHT or UNIT MOVED
We turn now to the variables of the surroundings. These differ from the variables of the worker in that we can influence them more quickly and more directly. In discussing the variables of the worker, we deal more or less with the past and the future. The variables of the surroundings are each and all distinctly of the present.
APPLIANCES
The " standard conditions" maintained by the employer are a most important factor for high outputs. It is obvious that the appliances furnished the workman and the motions used are interdependent on each other.
Examples. 1. The bricklayer could not be expected to pick up the brick so that he would not have to spin or flop it in his hand unless it were delivered to him in the right position on a packet.
2. The bricklayer could not be expected to have so high an output if he had to stoop over in order to pick up his stock as he would have to do if the scaffold did not have a bench that obviated bending.
3. The bricklayer could not be expected to lay brick without turning around or bending over unless he was provided with packs of bricks that could be lifted bodily and placed upon the wall in units as large as could be economically handled.
4. The bricklayer could not be expected to do away with those motions that are necessary to remove the lumps from under a brick if there were holes in the sand screen and no pug mill to break up the lumps.
It is most important that the workman should be given "handy conditions" under which to work, that is, the "most comfortable," or those that require the "least percentage of rest" to overcome fatigue.
Examples. 1. The bricklayer must obviously have a scaffold to stand upon that permits adjusting the height of the platform on which he stands to a standard distance below the top of the ever-growing wall on which he is laying the brick. We have found that the best height is from twenty-four to thirty-two inches below the top of the wall. If the wall is being laid overhanded, the height should not be over twenty-four inches, while if the wall is not being laid overhanded, thirty-two inches is the better
height.
It is obvious that the bench from which the stock is picked up should be maintained at a standard distance above the platform on which the man stands. Also the platform on which the laborer walks should be located at the standard distance below the stock platform that will enable him to deposit the brick and mortar in a manner that will cause the least fatigue. Therefore, the three platforms for bricklayer, stock, and tender should be fixed with relation to one another, and movable in relation to the top of the wall, capable of being hoisted as the wall grows without stopping or disturbing the men.
2. The elevator for hoisting the brick and mortar should always be arranged so that it can, when desired, land above the top of a staged wall, and thus the brick and mortar can be wheeled down to the scaffold on the floor below. Then the tenders can wheel down with full loads and wheel the empty barrows up to the floor above.
3. Make a table, barrel, or box to put near the workman, no matter what his trade is, so that he will not have to stoop over and pick up his tools. Provide something to lean his shovel against or to hang his shovel on when he is alternately shoveling and wheeling to cut down time and to reduce the fatigue of stooping over and picking up the shovel.
The motions to be used and to be avoided are largely determined and affected by the appliances used; therefore for the highest outputs the right appliances must be devised, standardized, used, and maintained, otherwise the motions cannot be standardized. Furthermore, it is much easier to standardize motions with standard appliances than without them.
CLOTHES
The clothes that the workman wears may be a hindrance or a help to him in his work. Tight or ill-fitting clothing may restrict motions. Fear of ruining clothing may seriously cut down the speed of the worker.
On the other hand, clothing designed and specially adapted to the work that the worker has to do may increase output to a surprising extent.
Not till the advantages have been appreciated of having working clothes made the subject of study from the motion-economy standpoint will manufacturers provide the garments needed. But they are only too anxious to meet every demand as soon as they are conscious of it. Once let the specialized clothes for the worker be standardized and they will be placed immediately upon the market in
inexpensive, durable, and attractive shape.
As for their reception by the worker, as soon as he realizes that they increase his efficiency, and are a badge of specialization and not of servitude, he will be ready and glad to welcome them.
COLOR
The stimulating effect of color upon workers is a subject to be investigated by psychologists. The results of their study should be of great benefit, especially to indoor workers. Motions could undoubtedly be made simpler by the proper selection of the color of painting and lighting in the workroom.
In our work we have to deal chiefly with color as a saver of motions. Color can be seen quicker than shape. Therefore, distinguishing things by their color is quicker than distinguishing them by the printing on them.
Examples. 1. The various pipes in a pipe gallery can best be recognized by painting them different
calm.
2, The right-hand end of the packet is pointed black, in order that when carried in the right hand of the laborer it can be placed so that the bricklayer can pick up each brick without spinning or flopping the brick in his hand,
3, Painting took different colors, and also the place where they are to be placed in the drawer or the chest the same color, saves motions and time of motions when patting them away and finding them next time,
4. When low-priced men bring packages of any kind to higher-priced men to use or handle, the packages should always be painted stenciled, or labeled with a distinguishing color on one end and on top. This will enable the low-priced workman to place the package in the manner called for on the instruction card with the least thought, delay, and motions. It win also enable the high-priced man to handle the package with no such lost motions as turning the package around or over.
5. Oftentimes the workmen who are best fitted physically for their work cannot read, or at least cannot read English. Even if they could it would take some time to read the stenciled directions on the non-stooping-scaffold to the effect that "this side goes against the brick wall." It will greatly reduce the number of motions to paint the side that goes next to the wall a different color from the side that goes away from the wall.
ENTERTAINMENT
Music.
The inspiring and stimulating effect of music has been recognized from ancient times, as is shown by the military band, the fife and drum corps, the bagpipe of the Scotchman, down to the band that rushes the athlete around the track or across the field.
The singing of gangs at certain kinds of work, the rhythmic orders that a leader of a gang shouts to his men, and the grunting in unison of the hand drillers, show the unifying as well as the motion-stimulating effect of music and rhythm.
That some of the trades can have their motions affected in time and speed by music, to a point that will materially affect the size of their outputs, is a recognized fact.
Some of the silent trades have used phonography and musical instruments to entertain the men while they were working. It was found it paid the employer to furnish stimulating records at his own expense, so that the workmen would make more and quicker motions, rather than to permit the employees to furnish phonographic records at random at their own expense.
Reading
Reading as a stimulus to output has been used with excellent results among the cigar makers.
It is also interesting to read in an article on " Three Months in Peonage" in the March, 1910, issue of the American Magazine, that story- telling may produce the same good results.
"The four packers under me," says the writer, a German white, who was working with peons at packing tobacco in Mexico, 'knew no greater joy than to listen to a fairy tale with the regulation princess and dragon, and if I could but tell them one, or one of their number did so, the
work went twice as fast, and they were happy."
The excellent and direct effects of entertainment upon health, fatigue, etc., are subjects for the scientist to study and the planning department and the welfare worker to apply. The effects of entertainment upon output should be studied by the student of motion economy. This variable alone furnishes a vast field for investigation.
HEATING, COOLING, VENTILATING
Heating, cooling, ventilating, and humidizing are closely allied, because all can be done with one and the same apparatus, and all greatly increase the workman's comfort, health, and possible number of motions.
Maintaining desired temperature in summer as well as winter by forcing into workrooms air that has been passed over heating or refrigerating coils has a great effect on the workman. Many factories, such as chocolate factories, have found that cooling the air for better results to the manufacturing process also enables the workers to produce more output an output quite out of proportion to the cost of providing the air.
In many trades requiring great alertness and physical strength the proper heating and ventilating will allow the workman to dress in a costume specially adapted to his work, or to strip almost to the athlete's suit, with a consequent increased number and effectiveness of motions.
The degree of temperature and the percentage of humidity desired for each day of the year should be determined. The man in charge of the heating should receive no bonus for small consumption of fuel unless he also maintained the temperature and humidity called for on his instruction card.
The subjects of heating, ventilating, etc., are well covered by Mr. Hugo Diemer in his book on " Factory Organization and Administration." The proper time to consider these subjects is when the building is designed, but too often at that time the all-important question is, How cheaply can the building be built? Ultimate saving will justify almost any conceivable first costs.
LIGHTING
The subject of lighting has, indirectly as well as directly, a great influence upon output and motions, as upon the comfort of the eye depends, to a large extent, the comfort of the whole body.
The arrangement of lighting in the average office, factory, or house is generally determined by putting in the least light necessary in order that the one who determined the location of the light may be able to see perfectly. This is wrong. The best light is the cheapest. By that is not meant that which gives the brightest light. In fact, the light itself is but a small part of the question. Go into any factory and examine every light, and you will notice that as a rule they are obviously wrong. A light
to be right must pass five tests:
a. It must furnish the user sufficient light so that he can see.
b. It must be so placed that it does not cause the user's eyes to change the size of the diaphragm when ordinarily using the light.
c. It must be steady.
d. There shall not be any polished surfaces in its vicinity that will reflect an unnecessary bright spot anywhere that can be seen by the eyes of the worker.
e. It must be protected so that it does not shine in the eyes of some other worker.
The use of polished brass and nickel should be abandoned wherever it will shine in the worker's eye.
For work done on a flat surface, like the work of a bookkeeper or a reader, the light should be placed where the glare will reflect least in the worker's eyes; where the work is like the examining of single threads, the relative color and figured pattern of the background, as well as good light, is important. This is obvious. So is nearly everything else in good management. Go into the buildings among the workers, the students, and the scientists and see how rarely it is considered. All of this is not a question of getting the most out of the light. Light in a factory is the cheapest thing there is. It is wholly a question of fatigue of the worker. The best lighting conditions will reduce the percentage of time required for rest for overcoming fatigue. The difference between the cost of the best lighting and the poorest is nothing compared with the saving in money due to decreased time for rest period due to less fatigued eyes.
It is a similar case to the taxicab concerns they charge their drivers with gasoline and tires and mileage, accidents, etc., but they furnish the lubricating oil free. The fallacy of the common practice of putting the lighting in the hands of the man whose merit is measured inversely as the coal bill is obvious.
The sub-variables involved make the problem as to exactly what lighting is most desirable difficult of solution. The proper solution will have such a beneficial effect, not only upon the man's work, but also upon his welfare, that no time or effort expended upon it can be too great.
QUALITY OF MATERIAL
It is essential to the use of standard motions and the resulting large output that all material used shall be in exactly that state in which it can be most easily handled by the worker.
Examples. 1. If there are lumps in the mortar, due to pieces of brick or shavings or lumps of lime, or cement or coarse pebbles in the sand, it is impossible for the bricklayer to do his best work.
2. If the sand is not selected with reference to the thickness of joints, if the sequence of tiers and courses (see Figs. 15 and 16) and the thickness of joints is determined by the whim of the bricklayer on the lead, instead of by the planning department, it is out of the question to expect high outputs. On the other hand, if the material is of exactly that consistency with which it can be best handled, and the other conditions are determined on the instruction card, much better speed can be obtained.
3. When using cement mortar made of cement and sand and no lime, the bricklayer will do more and better work if a tender is kept on the stock platform tempering the mortar to just the right consistency for the bricklayers.
4. If the brick are all handled in packs on packets from the time that they arrive upon the job until they reach the bricklayer's hand, they will each be of better quality, due to there being little or no chipping from handling and throwing about. The bricklayer will then be saved the useless motions of picking up brick that are chipped and discarding them again, to be used only when laying in the filling tiers.
REWARDS AND PENALTIES
The stimulus that rewards and penalties give motions is obvious. The discussion of reward and punishment would come under the head of compensation. It must be left to the cost reducing system to determine just what system of compensation will induce the men to do their swiftest, best work.
SIZE OF UNIT MOVED
The most advantageous size of unit to use is a difficult problem to solve, and is often controlled by some outside factor. For example, the most economical size of brick has been determined by the cost and other conditions relating to the making and baking, and not by the conditions of handling and laying. When the conditions of laying are studied scientifically, as they are to-day, one is forced to the conclusion that, for the greatest economy, the size of common brick should be changed materially from that of the present practice in America. The usual size of the brick used in England is much larger than the customary size used here.
It is obvious that there is some size of unit that is the most economical to make the standard package for handling brick in bulk. We have found it to be ninety-two pounds for a first-class laborer, either for piling or loading and unloading brick from carts. (See Figs. 17 and 18.)
Careful examination of brickwork with the object in view of selecting the most profitable motions has entirely revolutionized the methods of bricklaying. For example, the size of unit that is picked up when loose brick are handled must be one brick for each hand. The packet enables us to pick up about eighteen brick at once.
The fountain trowel permits us to pick up and carry to the wall and spread mortar for twenty-one brick at one time without dropping the regular trowel which forms a temporary handle to it. (See Fig. 19.)
The two-wheeled trucket permits carrying twelve packets, or 216 brick (see Fig. 20), while the hod carries 18 brick, and the one-wheeled barrow carries 60 loose brick.
SPECIAL FATIGUE-ELIMINATING DEVICES
Only the careful student of management realizes how much the speed of the worker can be increased by providing him with all possible aids toward doing his work.
Mr. Fred. W. Taylor, in his paper on " Shop Management," tells of a study he made of overhauling a set of boilers.
"He [the writer] did all of the work of chipping, cleaning, and overhauling a set of boilers, and at the same time made a careful time study of each of the elements of the work. This time study showed that a great part of the time was lost owing to the constrained position of the workman. Thick pads were made to fasten to the elbows, knees, and hips; special tools and appliances were made for the various details of the work. . . . The whole scheme was much laughed at when it first went into use, but the trouble taken was fully justified, for the work was better done than ever before, and it cost only eleven dollars to completely overhaul a set of 300 horse-power boilers by this method, while the average cost of doing the same work on day work without an instruction card was sixty- two dollars."
In reading this, it must be remembered that the fatigue-eliminating devices were only one element in increasing speed and reducing costs. But, on the other hand, it must be remembered also what a large element they were in adding to the comfort and ultimate well-being of the worker.
SURROUNDINGS
"Surroundings" have been previously discussed under "Fatigue," . "Appliances," etc. It is only necessary to say here that the surroundings of the worker should be standardized, the standard being derived from a study of all the variables.
It is obvious that the highest possible records of output cannot be obtained unless the workers are furnished with a standard instruction card made out by the best man obtainable, one who knows more about their work than they do, and who can, and does, provide them with standard conditions that fulfill the most economical conditions of motions. Even then daily outputs and unit costs must be watched, so as to take advantage of the slightest change of conditions that affect costs. In practice, the unit costs must always also include the wages of the recorder, otherwise one cannot tell when the wages of the recorders are not deceiving as to actual unit costs under this intensive management.
TOOLS
The influence of the tools used upon the output is large. No workman can possibly comply with standard motions unless he has the standard tools. No worker should ever be obliged to furnish his own tools, if large output is expected. When workmen are obliged to furnish their own tools (due to their having too much thrift, lack of money, or fear of having them stolen), they usually use one size only of the same kind of tool. On many kinds of work greater output can be obtained by using two or more sizes of a tool.
Example. The bricklayer should use a smaller trowel on pressed brick and a larger trowel on common brick.
Again, where workmen furnish their own tools, they use them after they are too much worn. A shovel with a worn blade will require several motions to push it into the material to fill it. It is cheaper in this case to cut off the handle of the shovel, so that the men cannot use it. Where no records are kept of their individual outputs the men always choose the shovel with the small blade.
It is especially important that apprentices should be supplied with proper tools. According to the usual practice the apprentice is taught with any tool procurable. He becomes adept and skilled, but often becomes so accustomed to the poor tool he has used that he finds it difficult to adapt himself to the use of a better new tool. This seriously hinders his complying with demands for standard quantities of output.
Tools should be of standard size and pattern. Workmen should invariably be made to use a tool that will enable them to make standard-sized outputs instead of using a tool that may seem " handier" to them. You cannot expect a man to comply with standard motions unless he has the standard tool for which his standard instruction card was made out.
The customary method in the past for determining the best weight of tool to use was to guess at it, and to use that size of tool which was thought to be the "handiest," or which it seemed could be used with the least fatigue.
Makers of hand tools cater to the whims of the local workmen, and, as a result, hand tools are made of many different designs in different parts of the country. Makers spend and waste great sums of money making experiments and conducting selling campaigns of odd or new designs of tools that have no merit from a motion-economy standpoint. There should be a bureau of testing, where the actual value of new shapes, designs, and sizes of tools could be tested and rated in percentages of efficiency from the standpoint of motion study.
Critics will say that such a scheme will crowd out new designs, and the benefit of the individual's inventions will be lost. But it would not; on the contrary, the testing would give great stimulus to inventors, designers, and tool makers, for they could then obtain the immediate attention of the buyers, because they would have the standard stamp of merit that comes from the record of a test that
excelled previous standards.
We have testing stations for everything else. Think what the societies for testing materials have done for the progress of the world! Their records are usable forever, in any part of the world, once they are made.
When machines have to be tended, two separate sets of motions must be provided for:
1. The set that the worker uses when he is tending the machine.
2. The set that the worker uses to prepare tools and material for the machine while it does not require his attention.
All machines have to be tended more or less. Even automatic machinery has to have attention, and it is most important here to have motion study, because of the earning value of the machine being lost while it is shut down.
One sees occasionally a machine that can have any and every lever operated without the operator taking a single step, but comparatively few machines are constructed with this in mind.
Machines requiring constant starting and stopping and hand feeding or adjusting should have their various levers so positioned that the "laws of least effort of simultaneous motions" are complied with.
These laws will be discussed under " Variables of the Motion." It is only necessary to say here that motions should be similar on each side of a fore and aft vertical plane passing through the body. It is so necessary to have the motions similar that often counterbalances and springs can be installed to reverse the motion, thus also causing the hardest work to be done in the most convenient direction.
Anything that is used very often can be returned to place better, as well as with less motions, by gravity, or by the application of the gravity by some such means as a string and a weight. It requires some skill to use a wrench, but it requires no skilled motion or thought to return the wrench to its exact resting place with handle pointing in the most economical direction for picking up the next time it is used.
The average machine to-day is designed for a short demonstration of quick output, with less regard for the least percentage of rest required for overcoming fatigue due to continuous operation. With demand will come supply of machines that fulfill all economical motion requirements.
UNION RULES
The local rules of some unions are sometimes a hindrance to standardizing motions and thereby increasing output. The higher wages from higher outputs under intensive management soon convert the desirable members, however.
Many unions believe that extremely high outputs per man are against the interests of the union as a whole, on the theory that they may "work all of their members out of a job." Furthermore, they often think that the sacrifice that their one union may make in the world's endeavor to reduce the cost of living generally, is not properly offset by having any one trade or any one locality practicing intensive outputs. A few practical object lessons of the general increase in business resulting from higher wages and simultaneously created lower-production costs will, however, always convince the most prejudiced believer in artificially restricted maximum outputs.
The compensation of workers will not be discussed here, although the basis of compensation does affect motions.
WEIGHT or UNIT MOVED
Generally speaking, the weight of the unit moved is of three kinds:
1. The weight of that part of the body that is moved.
2. The weight of a tool used, such as a hammer or a trowel.
3. The weight of material used, such as a brick, or the mortar on the trowel.
Other things being equal, the less of the body moved the less fatigue.
The weight that the tool should be is determined by the use of the tool. In the case of a sledge hammer, increased weight means increased efficiency. A twenty-five pound sledge might break a block of granite in halves in five blows, while a ten pound hammer might require one hundred blows. In the case of a trowel, increased weight means decreased efficiency. The heavier the trowel, the greater the fatigue with no accompanying gain in output. .
We have determined that a cutting-out hammer for brickwork should weigh, exclusive of the handle, 3.75 pounds, but that a hammer for drilling plug holes in granite, for making dog holes in heavy stone blocks, should weigh 4 pounds.
The weight of units moved should be standardized.
Example. There is undoubtedly a certain sized load in a shovel that will enable a first-class man to accomplish the largest output with his maximum effort. Taylor has found his weight to be 21.5 pounds. The size of shovels that should be used should therefore be designated on the instruction card accordingly, and exactly 21.5 pounds should be the standard unit of weight of material shoveled.
SUMMARY
This discussion of the variables of the surroundings, etc., is not detailed because general discussion is self-evident, and detailed discussion must be too specialized to interest the general reader.
It is only necessary to call attention to the general laws, logical and psychological, which underlie these variables, and their effect on standardizing motions. Each student naturally applies these laws to his own field, and sees for himself the opportunities for further study and application.
Next Part 5
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Updated 22 June 2021
10 June 2020, 11 September 2019, 30 September 2017, 19 August 2015
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