flashlight assembly - methods engineering
TRANSCRIPT
Flashlight Assembly
By: Group 5
Agacita, AngelicaPanes, Isabel FruileneMabasa, LanmarkAndales, Ian
Theoretical Background• There are three special interpretations that must be
considered in the left-hand/right-hand chart as stated by Aft
(2000). First is that the hands do not perform inspection.
Second is that transportations are defined as movements
of the hands from one location to another location.
Lastly, holds are considered to be delays.
• There are factors or classification as well, to be considered in
the process of improving the productivity of the worker.
These are the use of the human body, workplace
arrangement and the design of tools and equipment.
• An ideal worker in the workstation must be productive as to
keeping a sufficient amount of work. There must not be an
idle time at all and everything has to be balance, the starting
and stopping times of the hands (based from Principle 2 of
motion economy principles).
• Rhythm must be followed where there is a moderate flow of
the worker’s performance because a slowing pace and
speeding up makes the operator less productive (Principle 4).
• According to O’Neill (2007), a machine is purely viewed as
an overhead cost to the organization, not as a potential tool
for strategic advantage.
•As the company reorganize, whether enlarging or
reducing their work forces, the cost associated with
housing employees and providing their work tools
continues to increase.
•A research study made by Karasek and Theorell (1990)
proved that an enhanced control over the workspace
and job control decreases or reduced the risk of stress
on the workers. They also argue that that there are two
significant sources of stress in the work environment;
the way jobs are designed and the design of work
environments.
• In order to keep things systematized, these principles of
ergonomics must be taken into consideration:
• Principle 1- Work in neutral postures,
• Principle 2 – Keep everything in easy reach, Principle 4 –
Work at proper heights,
• Principle 5 – Reduce excessive motions,
• Principle 9 – Move, exercise and stretch
• Principle 10–Maintain a comfortable environment
• In designing a work station, it is important to know the
relevance and taking into considerations the variations of body
measurements, whether you are designing for the average or the extreme.
•ISO defines usability as “The extent to which a
product can be used by specified users to
achieve specified goals with effectiveness,
efficiency and satisfaction in a specified context
of use.”
•dexterity or fine motor skills are the
coordination of the small muscle movements
which occurs in the fingers, usually in
coordination of the eyes.
Methodology
The proponents made some observations in the process
of the flashlight assembly. The data gathered were being
analyzed and the weaknesses were being determined.
Books were used as the secondary source for
constructing a left-hand/right-hand chart. Only one person
is being considered as the performer of the activity. The
chart was constructed as to the details of every operation.
In which, the weaknesses gathered were the bases for
generating proposals for improvement.
Statement of the problem• The purpose of this activity is to assess the present method in
the flashlight assembly considering the 3 factors in improving
the worker’s productivity where it also answers the following
questions:
▫What are the unnecessary operations to be eliminated?
▫What are the sequences of activities that need to be changed
or simplified?
• Based on the findings of the study, what proposals could be
recommended improving the existing method of flashlight
assembly.
Objectives:• Investigate specific operations in order to
improve them by using operations chart
•Eliminate all unnecessary motions and to arrange the remaining motions in the best sequence
Apparatus: Flashlight
PRESENT METHOD
WORK STATION DESIGN
FINISHED ASSEMBLIES
CASES
BULBS
REFLECTORS
LENSES BOTTOMS
CASES TOPS
WORKER
WEAKNESSES:
•Principle 1 – “The two hands should begin as
well as complete their motions at the same time”
The present method failed to adapt the first
principle because the right hand did most of the
operations. It is seen that the there was a
transportation made from the right hand to the left
hand, in which it is unnecessary. In result, the left
hand made most of the idleness instead of having a
fair routine in the operations.
•Principle 2 – “Motions of the arms should
be made in opposite and symmetrical
directions, and should be made
simultaneously”
The present method failed to perform in
this manner since the left hand is in idle and
does not permit the operator to work faster.
There must be the same command for both of
the hands in order to make the operations
effective.
•Principle 8 – “Work should be arranged to
permit easy and natural rhythm wherever
possible”
Although, the operation permits the right-
handed person to do the task, the location of the
materials are not appropriate for the right hand to
develop the certain habit. The rhythm of the
process forces the operator to take the habits
instead of allowing both hands to perform normally.
•Principle 9 – “Eye fixations should be as
few and as close together as possible”
The distances or the arrangements of
the materials make the method ineffective
in such a way that the operator tends to
search for the next material. The operator
has the tendency to get disorganize and
interrupts the normal motion cycle.
PROPOSED METHOD
WORK STATION DESIGN
WORKER
CASES
BULBS TOP
RINGS
REAR
CAPS
LENSES REFLECTORS
FINISHED ASSEMBLIES
DISTANCES FROM THE WORKER:
FINISHED ASSEMBLIES -13 inches
CASES -6 inches
TEST JIG -4 inches
MAGNETIC HOLDER -4 inches
REFLECTORS -6 inches
LENSES -8 inches
BULBS -10 inches
TOP RINGS -8 inches
REAR CAPS -10 inches
LEGEND:
-TEST JIG
-MAGNETIC HOLDER
HEIGHT OF THE TABLE: 3.01 ft
VERTICAL CLEARANCE: 2.10 ft
HEIGHT OF THE CHAIR: 2.04 FT
4 ft
3 ft
Magnetic holder - flashlight
STEPS IN MAKING A TEST JIG
SCHEMATIC OF THE TEST JIG
1. Remove the HS-flat of the flashlight 2. Connect the wire, black for negative and red for the positive to the HS-flat, then
solder. 3. Connect the other ends of the wire, black for positive and red for the negative of
the dry cell. 4. Enclose the test jig with any recyclable case.
HS -FLAT
DRY CELL
+ -
- +
WORKSTATION DESIGN
2.10 FT
3.01 FT
2.04 FT
Summary of the Left-Right Hand Chart
PRESENT LEFT-RIGHT HAND CHART
Left Hand Right Hand
Transportation Operation Transportation Operation
1 3 17 21
PROPOSED LEFT-RIGHT HAND CHART
Left HandRight Hand
Transportation Operation Transportation Operation
7 8 8 9
COST-BENEFIT ANALYSISTOOLS QTY COST (Php) BENEFIT
*MAGNETIC HOLDER 1 849.25 The operator will no longer hold the
case of the flashlight
TESTJIG HS-flat of the flashlight Electrical wire (3’ – black
and red) Dry cell (1.5V) Soldering wire Soldering iron
11
111
20 5
34 3 49
The dry cells will no longer be part of the operations, instead it make use of the testing of the bulb before the latter will be attached to the reflector.
1/2 x 4 x 8Plywood – ordinary (P170/pc)
2 340Will be used to construct a table and chair in which it adds comfort and the operator will have a chance to take a rest after long hours of standing.
2 x 2 x 10 – mahogany (P93/pc)
4 372
COST-BENEFIT ANALYSISTOOLS QTY COST (Php) BENEFIT
Common nails – 2” ( 35 / kg)
1 kg. 35Will be used for constructing a table and chair
Labor for 1 day (305/day)
3 915
TOTAL 2622.25
* Total cost is subject to change due to shipping cost of magnetic holder, since it is made available in www.aircraftspruce.com
STRENGTH:
•Principles 1 – 3: “Two hands begin and complete
their motions at the same time..Two hands should
not be idle at the same time..and Motions are
made in opposite and symmetrical directions”
The proposed method used of the two hands in
which the motions made fair distribution of the
operation. Although, there was an idle on the part of
the left hand (in holding the lens) but the thought of
having both hands work simultaneously has been one
of the advantages.
• Principle 8 – 9: “Work should be arranged to permit
easy and natural rhythm..Eye fixations should be as
few and as close together as possible”
The arrangement of the spare parts or materials for
flashlight assembly is made closer in order to work easily
and to avoid stress on the part of the operator. The
distances are as well made easy to reach and arranged
according to the sequence of the operation. On the part of
the operator, he or she is not force to follow habits for the
sake of symmetry since most of the operations are done
on the right hand, to compensate the right handed person.
•Principle 16–17:“The height of the work place
and the chair should be arranged..A chair of the
type and height to permit good posture should
be provided”
Bad posture can tire the operator much more
quickly than good posture. In which, tired operator is
not as productive as rested workers. Good posture
is encouraged through the use of comfortable chairs
allowing the operator to sit or stand.
• Principle 18-19:“The hands should be relieved of all work
that can be done by a jig or fixture..Two or more tools
should be combined wherever possible”
The added tools or fixtures eliminate the need for the
hands to function as holding the materials and promote the
performance of simultaneous motions. It is very important to
respect the capabilities of the human since he or she is not
automated. Providing the workstation with devices that will help
the operator, although it is costly, much make sense to what
productivity is concern. As stated by Aft (2000), use people
where they are most effective and use machines where they are
most effective.
CONCLUSIONUnnecessary movements cause delay and delay means additional cost.
So, in this, unnecessary movements should be removed and that includes
the transferring of the material form one hand to the other and doing the
job one at a time where in fact the operator can do multiple jobs on the
same time. Distance traveled by the worker or the material really matters,
the closer the distance of the materials from the worker is, the better it
would be and the process should be systematic in such a way that the
materials should be orderly sequenced by their use. The goal of this work
is to obtain the best method to perform the operation and these include the
performing of two jobs at a time and letting both hands work beneficially
with each other to minimize the time consumed in performing a job.
RECOMMENDATIONTo obtain the improvement goals, the researchers
recommend the company to apply the proposed method
which is the best possible method in improving the
productivity of the worker. The proposed method includes the
arrangement of the work station putting the first material to be
used on the nearest place from the worker followed by the
next material and so on. Also on the proposed method
suggests eliminating the unnecessary movements which
cause delay. Management in imposing the proposed method
is advised and training the worker to be skilled on the
proposed method is urged.