Wednesday, August 19, 2015

MOTION STUDY VARIABLES - Frank B. Gilbreth - Part 2

VARIABLES

Every element that makes up or affects the amount of
work that the worker is able to turn out must be con-
sidered separately; but the variables which must be
studied in analyzing any motion, group themselves natu-
rally into some such divisions as the following:

I. Variables of the Worker.

1 . Anatomy.

2. Brawn.

3. Contentment.

4. Creed.

5. Earning Power.

6. Experience.

7. Fatigue.

8. Habits.

9. Health.

10. Mode of living.

1 1 . Nutrition.

12. Size.

13. Skill.

14. Temperament.

15. Training.

II. Variables of the Surroundings, Equipment, and Tools.

1. Appliances.

2. Clothes.

3. Colors.

4. Entertainment, music, reading, etc.

5. Heating, Cooling, Ventilating.

6. Lighting.

7. Quality of material.

8. Reward and punishment.

9. Size of unit moved.

10. Special fatigue-eliminating devices.

11. Surroundings.

12. Tools.

13. Union rules.

14. Weight of unit moved.

III. Variables of the Motion.

1. Acceleration.

2. Automaticity.

3. Combination with other motions and sequence.

4. Cost.

5. Direction.

6. Effectiveness.

7. Foot-pounds of work accomplished.

8. Inertia and momentum overcome.

9. Length.

10. Necessity,

n. Path.

12. "Play for position."

13. Speed.

In taking up the analysis of any problem of motion
reduction we first consider each variable on the list separately, to see if it is an element of our problem.

Our discussion of these variables must of necessity be
incomplete, as the subject is too large to be investigated
thoroughly by any one student. Moreover, the nature of
our work is such that only investigations can be made as
show immediate results for increasing outputs or reducing
unit costs.

The nature of any variable can be most clearly shown
by citing a case where it appears and is of importance.
But it is obviously impossible in a discussion such as this
to attempt fully to illustrate each separate variable even
of our incomplete list.

Most of our illustrations are drawn from bricklaying.
We have applied motion study to our office and field forces,
and to many of the trades, but our results on bricklaying
are the most interesting, because it is the oldest mechan-
ical trade there is. It has passed through all the eras of
history, it has been practiced by nations barbarous and
civilized, and was therefore in a condition supposed to
be perfection before we applied motion study to it, and
revolutionized it.

Since first writing these articles for Industrial Engineer-
ing it has been of great interest to the writer to learn
of the conscious and successful application of the prin-
ciples involved to the particular fields of work that
have interested various readers. It was thought that
unity might be lent to the argument by choosing the
illustrations given from one field. The reader will prob-
ably find himself more successful in estimating the value
of the underlying laws by translating the illustrations
into his own vocabulary, by thinking in his own chosen
material.


The practical value of a study such as this aims to be
will be increased many fold by cooperation in application
and illustration. The variables, at best an incomplete
framework, take on form and personality when so con-
sidered.



CHAPTER II  VARIABLES OF THE WORKER

ANATOMY

A CAREFUL study of the anatomy of the worker will enable
one to adapt his work, surroundings, equipment, and tools
to him. This will decrease the number of motions he must
make, and make the necessary motions shorter and less
fatiguing.

Examples. i. If the bricklayer is left-handed the
relative position of the pile of packs to the mortar box is
reversed.

2. The staging is erected so that the uprights will be
out of the bricklayer's way whenever reaching for brick
and mortar at the same time. (See Fig. i.)

3. Packs can be piled at a height with reference to the
height of the mortar box that will enable stock to be picked
up more easily by bending over sideways than by bending
forwards. This latter case is, of course, on work where
the non-stooping scaffold is not used.

4. The planks on the bricklayer's platform of the non-
stooping scaffold, if made of two unconnected planks, will
enable the bricklayer to lean either toward the stock plat-
form or toward the wall without any other effort than that
of throwing his weight on one foot or the other, taking
advantage of the spring of the planks. (See Fig. 2.)

5. The inside plank of the bricklayer's platform must
extend in under the stock platform, or the bricklayer's leg
will strike the edge of the plank of the stock platform
when he reaches for stock.

6. The stock platform must not be wider than the
minimum width that will permit holding the packets, or
the lower-priced packet man will not place the packs
exactly in that position that will require the least amount
of straining of the high-priced workman, the bricklayer.



The numbers show the correct sequence of courses and tiers as laid from
the non-stooping scaffold for the fewest, shortest, and most economical
motions under the " Pack-on-the-wali " method.


BRAWN

Workmen vary widely as to their brawn and strength.

When the actual work is being done, due consideration
should be given to the percentage of efficiency that the
men available possess. But all calculations should be
made on the basis of using first-class men only. All data
should be gathered from observations on first-class men
only. In fact, so-called first-class men are not good enough.
The best man obtainable anywhere is the best for obser-
vation purposes. The data gathered on that best man
will then be considered as loo-per-cent quality. The men
finally used can then be considered as of a certain percent-
age of perfect quality, and it should then be the aim of the
management to attain loo-per-cent quality. This is one
of the most important factors in the success of intensive
management. The manager who wins is the one who has
the men best suited for the purpose. Intensive manage-
ment must not only recognize quickly the first-class man,
but must also attract first-class men.

Everybody concedes that the size of the output depends,
first of all, on the quality of the men.

Example. We have found that a first-class laborer, if
his work is so arranged that he does not have to stoop
over, but can do his work with a straight back, can handle
ninety pounds of brick on a packet (see Fig. 3) day after
day and keep in first-class physical condition, while laborers
of a class that does not have the right food cannot handle
continuously over sixty to seventy pounds of bricks on a
packet.

It is obviously better to have all one class of men, so
that all instruction cards will be as nearly alike as possible.
The size of the shovel, the weight of the hammer, the num-
ber of brick on the packet these are variables that must
also be considered when making out the instruction card
and these are all influenced by the brawn of the worker.

CONTENTMENT

Contentment affects the output of the worker. If he is
contented, he will have his mind on his work, and he will
be more willing to carry out the motions exactly as directed
on the instruction card.


The contented worker does not require so large a per-
centage of rest for overcoming fatigue from his intensive
efforts.

Contentment makes for loyalty to the management, for
cooperating for maintainment of the best conditions, and
for the protection and preservation of the property of the
employer.

CREED

The term "'creed" is used to cover religion, nationality,
etc., everything that might act as a bond of sympathy
between workers and the people with whom they come in
contact. On work where the output of each man is re-
corded separately, the question as to whether the creed of
the workman is the same as that of his foreman, or super-
intendent, or employer, is of little consequence.

In places where the output of each man is not recorded
separately, it is a recognized fact that instructions of the fore-
man or employer will be more apt to be carried out where
there is a bond of sympathy between the employees, the fore-
man, and the employers. A bond of sympathy between
the workman and the people who are to occupy the edifice
upon which they are working will also increase the output.

The motions of a bricklayer working upon the wall of
a church differing from his own religion are often vastly
different from those that he is careful to make when the
congregation to occupy it coincides with his belief.

In planning athletic contests also, it is well to group
men according to their affiliations.


Example. On engine beds and similar work, where
the pieces are isolated, assigning gangs of men of different
nationalities to the different beds will create extra interest
in the contests. If this is not feasible, put the tall men
on one bed and the short men on the other, or the single
men against the married men, or eastern " pick-and-dip "
men against western " string-mortar " men.

EARNING POWER

The matter of classifying men by their relative earning
power is as important as classifying them by their relative
brawn. It is better, of course, to have men as nearly as
possible of one class only, and that the best class. Class-
ing men by their earning power simplifies the work of the
planning department in many ways. It enables it to pre-
scribe the same motions to the entire class of men, to
place them all under nearly the same conditions, to pre-
scribe the same tools and surroundings, to place them
together, and, finally, to have an athletic contest between
the men of the same class.

Furthermore, the motions to be made are often entirely
different for workmen of different earning power.

Examples. i. With masons and laborers of low earn-
ing power it is sometimes advisable to place the brick on
the packets any way that will give the fewest motions for
loading the packets, and to let the bricklayers lay them
with their customary numerous motions, until men of
higher earning power may be obtained to take their places.


2. With bricklayers and laborers of high earning power
it is better to have the laborers pile the brick upon the
packets so that the brick will be in that position that
requires the least amount of motions of the bricklayer to
pick them up and to lay them.

It is obvious that all motions performed in handling or
transporting material before the material is used, cut up,
or fabricated, should, theoretically, be performed by low-
priced men, and that the work done by the high-priced
men should be limited as far as possible to the work of per-
manent character. As an example of this, the carrying of
the brick and mortar to the scaffold is done by the mason's
helper, while the carrying of the brick from the packet to
its final resting place in the wall is done by the mason.
This same principle can be carried much further in all
trades than is usually customary to-day. For example,
we have found that piling the brick face up and with
the top side nearest the palm of the bricklayer's hand
when his arm hangs in a natural position will save an
average of one motion of the high-priced bricklayer per
brick. (See Figs. 4, 5, 6, and 7.)

We have found a great increase in the number of brick
it is possible to lay, and a decrease in the cost of laying
them if the brick are placed by the low-priced man in the
nearest practicable place in feet and inches from the place
where they will finally rest in the wall. Not only this,
but the receptacle must be left with the material on it, so
that the higher-priced man can lift the receptacle and its
contents simultaneously at the exact time the materials
are wanted to a place still nearer to the place where the
material will be finally used, to be transported from there
to their final resting place by a still higher-priced man.
(See Figs. 2 and 8.)

This use of "low-priced men" does not mean the use of
mediocre men. The men used, of whatever price, should
be the best men of that class obtainable.

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