production management (lab) assignment

8/12/2019 Production Management (LAB) Assignment

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Ergonomics:

Ergonomics applies information about human behavior, abilities and limitations and other

characteristics to the design of tools, machines, tasks, jobs and environments for productive, safe,

comfortable and effective human use.In other way Ergonomics can be defined simply as the study of work. More specifically,

ergonomics is the science of designing the job to fit the worker, rather than physically forcing theworkers body to fit the job. Adapting tasks, work stations, tools, and equipmentto fit the workercan help reduce physical stress on a workers body and eliminate many potentially serious,

disabling work related musculoskeletal disorders (MSDs).

Factors playing role in ergonomics:

A number of factors play a role in Ergonomics; these include

Body posture and movement (sitting, standing, lifting, pulling and pushing), Environmental factors (noise, lighting, temperature, humidity).

Types of Ergonomics:

Types of ergonomics are:-


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Physical Ergonomics:

Physical ergonomics is the human body's response to physical and physiological work load.Repetitive strain injuries from repetition, vibration, force and posture .

Cognitive Ergonomics:Cognitive ergonomics deals with the mentalprocesses and capacities of human during the work.Mental strain fromworkload, decision making, human error, and training.

Organizational Ergonomics:

Organizational ergonomics deals with the organizational structures, policies and processes in the

workenvironment, such as shift work, scheduling, job satisfaction, motivation, supervision,

teamwork, telecommuting and ethics.

Reactive Ergonomics;

Reactive ergonomics is when something needs tobe fixed and corrective action is taken.

Productive ergonomics:

It is the process of seeking area that could be improved and fixing the issue before they become

the largeproblem.

Principles of Ergonomics:

1. Work in Neutral Postures

Your posture provides a good starting point for evaluating the tasks that you do. The best

positions in which to work are those that keep the body "in neutral."

Maintain the "S-

curve" of the spine

Your spinal column

is shaped more or

less like an "S."


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It is important to

maintain the natural

S-curve of the back,whether sitting or

standing. The most

important part ofthis "S" is in the

lower back, which

means that it is

good to keep aslight "sway back,"

When standing,putting one foot up

on a footrest helps

to keep the spinal

column in properalignment.

Working for long

periods with your

back in a C-curvecan place strain on

your back.

Good lumbar

support is often

helpful to maintainthe proper curve in

the small of your

back.

The Inverted V-

curve creates aneven greater strain

on your back. Even

without lifting a

load, bending overlike this creates a

great deal ofpressure on thespine.

One common


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improvement is to

use a lifter or

tilter. Or there maybe other ways of

making

improvementsdepending upon the

situation.

Keep the neck

aligned

The neck bones are

part of the spinalcolumn and thus are

subject to the samerequirements of

maintaining the S-

curve. Prolongedtwisted and bent

postures of the neck

can be as stressful

as its equivalent forthe lower back.

The best way to

make changes is

usually to adjust

equipment so thatyour neck is in its

neutral posture.

Keeps elbows at

sides

The neutral posturefor your arms is tokeep you elbows at

your sides and yourshoulders

relaxed. This ispretty obvious once

you think about it,


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but we dont always

do it.

Heres an example

of changing a

workstation to getthe arms in neutral.

In the illustration atthe left, the product

is too high, and the

employee is

hunching hershoulders and

winging out her

elbows.

In the right-handillustration, the

product has beenreoriented and the

shoulders and

elbows drop to theirrelaxed position.

Keep Wrists in

Neutral

There are several

good ways to thinkabout wrist posture.One way is to keep

the hand in the same

plane as the

forearm, as thisperson is doing here

by using a wrist rest

along with the

computer mouse.

A slightly moreaccurate approach is

to keep your hands

more or less likethey would be when

you hold the

steering wheel ofyour car at the 10


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and 2 oclock

positionslightly

in and slightlyforward.

Heres an exampleof how this

principle applies totool design.

Working

continuously with

the pliers as shownin the left-hand

picture can create a

lot of stress on the

wrist. By using

pliers with anangled grip,

however, the wriststays in its neutral

posture.

2. Reduce Excessive Force

For example, pulling a heavycart might create excessive

force for your back. To makeimprovements it might help to

make sure the floor is in good

repair, that the wheels on thecart are sufficiently large, and

that there are good grips on the

cart. Or a power tugger might

be needed.


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Excessive force on your joints can create a potential for fatigue and injury. In practical terms,the action item is for you to identify specific instances of excessive force and think of ways to

make improvements.

3. Keep Everything in Easy Reach

The next principle deals with keeping things within easy reach. In many ways, this principle is

redundant with posture, but it helps to evaluate a task from this specific perspective.

Reach Envelope

One concept is to think about

the "reach envelope." This isthe semi-circle that your arms

make as you reach out. Things

that you use frequently shouldideally be within the reach

envelope of your full arm.

Or another example of

reducing force is to use a hoistfor lifting heavy objects, likethis vacuum hoist in the

drawing.

Another kind of example is

having handholds on boxes or

carrying totes. Having the

handhold reduces the exertionyour hands need to carry the

same amount of weight.

Point:

There are thousands of other examples and the field of ergonomics

includes much information on conditions that affect force. The basic pointis to recognize activities that require excessive force, then think of any way

you can to reduce that force.


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Things that you use extremely

frequently should be within the

reach envelope of yourforearms.

Much of the time, problemswith reach are simply matters

of rearranging your work areaand moving things closer to

you. This is not exactly a hard

concept to grasp; what is

difficult is having the presenceof mind to notice and change

the location of things that you

reach for a lot.

Often it is a matter of habityou are unaware that you

continually reach forsomething that could be easily

moved closer.

Or sometimes, the work

surface is just too big, causingyou to reach across to get

something. One option is just

to get a smaller surface.

Another option is to make a

cutoutthis way yourreaches are cut, but you still

have plenty of space forthings.

Or another common problem

is reaching into boxes. A good

way to fix this is to tilt thebox.

Once again, there are

thousands of other examples ofways to reduce long reaches.

The point is for you to think

about when you make longreaches, then figure out how to

reduce that reach.


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4. Work at Proper Heights

Working at the right height is also a way to make things easier.

Do most work at elbow

height

A good rule of thumb is that

most work should be done at

about elbow height, whethersitting or standing.

A real common example isworking with a computer

keyboard. But, there are many

other types of tasks where the

rule applies.

Exceptions to the Rule

There are exceptions to thisrule, however. Heavier work is

often best done lower than

elbow height. Precision work

or visually intense work isoften best done at heights

above the elbow.

Sometimes you can adjust

heights by extending the legsto a work tables or cutting

them down. Or you can either

put a work platform on top ofthe table (to raise the work up)

or stand on a platform (to raise

YOU up).

Or to be a little more

complicated, there are ways tomake stands and work tablesinstantaneously adjustable

with hand cranks or

pushbutton controls.


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5. Reduce Excessive Motions

The next principle to think about is the number of motions you make throughout a day, whether

with your fingers, your wrists, your arms, or your back.

One of the simplest ways to

reduce manual repetitions is touse power tools whenever

possible.

Another approach is to change

layouts of equipment to

eliminate motions. In theexample here, the box is

moved closer and tilted, so that

you can slide the products in,rather than having to pick

them up each time.

Or sometimes there are uneven

surfaces or lips that are in theway. By changing these, you

can eliminate motions.

As always, there are moreexamples, but you should be

getting the idea.

6. Minimize Fatigue and Static Load

Holding the same position for a period of time is known as static load. It creates fatigue anddiscomfort and can interfere with work.

A good example of static load

that everyone has experienced

is writers cramp. You do not

need to hold onto a pencil veryhard, just for long periods.

Your muscles tire after a timeand begin to hurt.


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In the workplace, having tohold parts and tools

continually is an example of

static load.

In this case, using a fixture

eliminates the need to hold

onto the part.

Having to hold your arms

overhead for a few minutes is

another classic example ofstatic load, this time affecting

the shoulder muscles.

Sometimes you can change theorientation of the work area to

prevent this, or sometimes you

can add extenders to the tools.

Having to stand for a long timecreates a static load on your

legs. Simply having a footrest

can permit you to reposition

your legs and make it easier tostand.

Were going come back to this

point later.

7. Minimize Pressure Points

Another thing to watch out for is excessive pressure points, sometimes called "contact stress."

A good example of this is

squeezing hard onto a tool,like a pair of pliers. Adding a

cushioned grip and contouringthe handles to fit your hand

makes this problem better.


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Leaning your forearms againstthe hard edge of a work table

creates a pressure point.

Rounding out the edge andpadding it usually helps.

Weve all had to sit on chairsthat had cushioning and so

understand almost everything

we need to know aboutpressure points. A particularly

vulnerable spot is behind your

knees, which happens if your

chair is too high or when youdangle your legs. Another

pressure point that can happen

when you sit is between yourthigh and the bottom of a

table.

A slightly more subtle kind of

pressure point occurs when

you stand on a hard surface,like concrete. Your heels and

feet can begin to hurt and your

whole legs can begin to tire.The answer is anti-fatigue

matting or sometimes usingspecial insoles in your shoes.

Like the other basic principlesthat weve covered so far,

pressure points are things thatyou can look for in your work

areas to see if there are ways

to make improvements.

8. Provide Clearance

Having enough clearance is a concept that is easy to relate to.


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Work areas need to be set up

so that you have sufficient

room for your head, yourknees, and your feet. You

obviously dont want to have

to bump into things all thetime, or have to work in

contorted postures, or reach

because there is no space for

your knees or feet.

Being able to see is another

version of this principle.Equipment should be built and

tasks should be set up so that

nothing blocks your view.

9. Move, Exercise, and Stretch

To be healthy the human body needs to be exercised and stretched.

You should not conclude afterreading all the preceding

information about reducing

repetition, force, and awkward

postures, that youre best offjust lying around pushing

buttons. Muscles need to be

loaded and your heart rateneeds periodic elevation.

Depending upon the type of

work you do, different

exercises on the job can behelpful.

If you have aphysically demandingjob, you may find it

helpful to stretch and

warm up before anystrenuous activity.

If you have a sedentaryjob, you may want to


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take a quick "energy

break" every so often

to do a few stretches.

If you sit for long periods, youneed to shift postures:

Adjust the seat up anddown throughout theday.

Move, stretch, andchange positions often.

It actually would be ideal if

you could alternate between

sitting and standing throughoutthe day. For some tasks, such

as customer service, desks are

available that move up anddown for this purpose (this is

not new; Thomas Jefferson

built a desk like this for

himself).

10. Maintain a Comfortable Environment

This principle is more or less a catch-all that can mean different things depending upon thenature of the types of operations that you do.

Lighting and Glare

One common problem islighting.

In the computerized office,lighting has become a bigissue, because the highly

polished computer screen

reflects every stray bit of lightaround.


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But many other types of tasks

can be affected by poor

lighting, too. Concerns includeglare, working in your own

shadow, and just plain

insufficient light.

One good way to solvelighting problems is by usingtask lighting; that is, having a

small light right at your work

that you can orient and adjust

to fit your needs.

Vibration

Vibration is another commonproblem that can benefit fromevaluation. As an example,

vibrating tools can be

dampened.

Applications of Ergonomics:

Ergonomic principles have been widely used in the design of both consumer andindustrial products. Examples include screwdriver handles made with serrations to

improve finger grip, and use of soft thermoplastic elastomers to increase friction between

the skin of the hand and the handle surface.

HF&E continues to be successfully applied in the fields of aerospace, aging, healthcare, IT, product design, transportation, training, nuclear and virtual environments.

Physical ergonomics is important in the medical field, particularly to those diagnosedwith physiological ailments or disorders such as arthritis or carpal tunnel syndrome.

Many ergonomically designed products are also used or recommended to treat or preventsuch disorders, and to treat pressure-related chronic pain.

The Occupational Safety and Health Administration (OSHA) have found substantialevidence that ergonomics programs can cut workers' compensation costs, increase

productivity and decrease employee turnover. Therefore, it is important to gather data to


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identify jobs or work conditions that are most problematic, using sources such as injury

and illness logs, medical records, and job analyses.

The emerging field of human factors in highway safety uses human factor principles tounderstand the actions and capabilities of road users - car and truck drivers, pedestrians,

bicyclists, etc. - and use this knowledge to design roads and streets to reduce trafficcollisions.

Anthropometry:

Anthropometry measures all physical aspects of your body. Simple measurements include height

and width. But a more thorough body of measurements is usually needed for Human Factors

work. Measurements such as the length from your elbow to the tip of your finger or the

circumference of your skull are some examples. In a complete anthropometric survey

measurements are taken between every joint and across hinge joints (such as the knee andelbow). Range of motion is also recorded. Thickness or girth is measured as well.

OR

Anthropometry is the branch of the human sciences that deals with body measurements:

particularly with measurements of body size, shape, strength and working capacity.

Anthropometries are a very important branch of ergonomics. It stands alongside (for example)

cognitive ergonomics (which deals with information processing), environmental ergonomics, and

a variety of other identifiable sub disciplines which progress (in parallel, as it were) towards the

same overall end.


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Types of Anthropometry Measurements:

Static dimensions

These are the measurements which are taken when the body is in a fixed (static) position. They

consist of skeletal dimensions (between the centers of joints, such as between the elbow and the

wrist) or of contour dimensions (skin-surface dimensions such as height or seat breadth).

Dynamic dimensions

These are taken under conditions in which the body is engaged in some physical activity. In most

physical activities (whether one is operating a steering wheel, assembling a mousetrap, or

reaching across the table for the salt) the individual body members function in concert. The

practical limit, of arm reach, for example, is not the sole consequence of arm length; the limit is

also affected by shoulder movement, partial trunk rotation, possible bending of the back, and the

function to be performed by the hand.

Uses of Anthropometrical Data:

To fit the task to the person To avoid physical mismatches between dimensions of equipment and products and the

corresponding user.

To design for variability in people and not for the average.Criteria for Design:

Determine the user population Determine the relevant body dimensions Determine the percentage of the population to be accommodated Determine the percentile value of the selected anthropometric dimension Make necessary design modifications to the data from the anthropometric tables Use mock-ups or simulators to test the design

9

Principles of Anthropometry:

Following are the principles of anthropometry:

Design for extremes of individuals:

In some circumstances a specific design dimension or feature is a limiting factor that might

restrict the use of the facility for some people; that limiting factor can dictate either a maximum

or minimum value of the population variable or characteristic in question.


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Designing for Adjustable Range:

Certain features of 'equipment or facilities can be designed so they can be adjusted to the

individuals who use them. Some examples are automobile seats, office chairs, etc.

Designing forthe Average:

There is average individual and a person may be average on one or two dimensions. Designers

often design for average as a compromise as they do not have to deal with anthropometric data.

Variability of population:

Anthropomorphic measurements are a function of age, gender, nationality, user type and several

other factors

Applications of Anthropometry:

It is used in ergonomics to specify physical dimensions of:

Work space Equipment and tools Clothing Car interior dimension Airplane cockpits Helmets Submarine dimensions Furniture Shoes


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Chart for recommended sound intensity levels:

No of hours exposed Sound Level (Decibel - dB)

8 Hours 90

6 Hours 92

4 Hours 95

3 Hours 97

2 Hours 100

1.5 Hours 102

1 Hours 105

0.5 Hours 110

0.25 or less 115


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Chart for recommended light intensity levels:

Type of activity Ranges of illumination (LUX)

Public spaces with dark surroundings20-50

Simple orientation for short temporary visits

50-100

Working spaces where visual tasks are only

occasionally performed 100-200

Performance of visual tasks of high contrast orlarge scale 100-200

Performance of visual tasks of medium

contrast or small size 500-1000

Performance of visual tasks of low contrast or

very small size 1000-2000

Performance of visual tasks of low contrast

and very small size over a prolonged period 2000-5000

Performance of very prolonged and exacting

visual tasks 5000-10000

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