Abrasive Wheel Awareness 27-01-09

7/29/2019 Abrasive Wheel Awareness 27-01-09

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Course Content Course Duration - 1hr

Hazards and risks arising from use of AbrasiveWheels and the Control Measures.

Inspection and Test.Functions of Components - flanges, guards etc.Proper PPE/RPE.Health Risks - Noise Dust Vibration.


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This course will give advice on the

prevention of accidents when using

Abrasive Wheels, in particular:-

Injury from breakage Injury from contact Injury from noise Injury from dust & FumeThe impact of Noise, Vibration and

Dust will also be discussed.


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An abrasive wheel is usually defined as a

wheel consisting of abrasive particles bondedtogether using organic or inorganicsubstances such as resin.


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The Risk of Breakage is inherent in every Abrasive Wheel

It is prevented by:-

Care exercised in design, in manufacture and testingSafe measures by users. Injury statistics show that nearly half ofaccidents are due to an unsafe system of

work or operator error.


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SAFETY - Wheel Breakage

Abrasive Wheel Manufacturerscarry out tests and inspection to

ensure the integrity of their wheels.

They willalso reinforce wheels.

Resin coated glass fibre mats are

used in organic wheels to help

withstand high stresses and to

contain fragments


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SAFETY - Wheel Breakage

Breakage may occur in service due to:-

Bad storage and handling Incorrect selection of wheel Improper mountingExcessive imbalanceExcessive speedGrinding machine defectsMalpracticeTwo or more factors may act together.


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Examination of Wheels

Visual checkCheck classification for

suitability

Ensure suitability forgrinder - depressed centre or flat?

Ensure suitability for taskgrinding or cutting?

If in doubt consult Supervisor


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HAZARDS NOISEDUST AND FUMEVIBRATIONCONTACT WITHWHEELWHEEL BREAKINGRISK TO OTHERS


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NOISE

DEPENDS ON WORKPLACEDEPENDS ON MATERIALGRINDERS ALWAYS

ABOVE 70DB

USE PROTECTIONTHINK OF OTHERS INAREA

MANAGE PPE


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DUST AND FUME

DEPENDS ONENVIRONMENTDEPENDS ON MATERIALPAINT REMOVAL

CHEMICALS,

TEMPERATURE

WEAR PPE/RPE


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VIBRATION

USE LOW VIBRATIONTOOLS

KEEP HANDS WARMDONT GRIP TOO HARDMAINTAIN CIRCULATIONREPORT PROBLEMSDO NOT APPLYEXCESSIVE

PRESSURE


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CONTACT WITH WHEEL & JOB

PLAN THE JOBGET IN A GOOD BALANCEDPOSITION

DONT OVER REACH ORSTRETCH

DONT USE UNSUITABLE ACCESS


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WHEEL BREAKINGCHOSE, RIGHT WHEEL FOR THE TASK.DONT BEND OR STRESS WHEEL.ENSURE DISC IS COMPATIBLE WITHGRINDER.ENSURE DISC IS CORRECTLY FITTED.WEAR CORRECT PPE FOR THE TASK


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RISK TO OTHERS

PLAN THE JOBCONSIDER BARRIERS USE SHEETING OR TENTS IFPOSSIBLE


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SPINDLE SPEED

Peripheral speed on a fixed speed spindlewill decrease as diameter of wheel shrinks.

Tendency to use more force - may causebreakage, Change disc before it gets to low.

SPEED REDUCES

TEND TO USE MORE PRESSURE


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FLANGESStresses on an Abrasive Wheelare greater nearer the hole.

Hence flanges are fitted.

Flanges should be at least onethird diameter of wheel.

Therefore if unreasonable sideforce is applied disc may breakOr disintegrate near centre.

STRESS

INCREASES


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G

Type 41

G

Type 42

Reinforced resin bonded wheels

Cutting or Grinding

Flat or depressed centre

Up to 230mm diameter

Portable Machines

May have smaller flanges


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Securing the Wheel

Fit freely but not loosely - if tight, spindlecould expand and crack wheel.

Central nut fixing - only tight enough toprevent wheel slipping

WHEELKEYS

After mountingcheck speedmarked on wheelor blotter is notexceeded bythat marked on

spindle.


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Summary of Wheel Mounting Procedures

Trained PersonCompatible Machine Inspect for damageFlanges correct for wheelWheels and flanges free from

foreign matter


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GUARDS - three main functions

1. To contain wheel if it bursts2. To prevent operator comingin

contact with wheel.

3. Also protects wheel from damageand prevents fitting of oversize

wheel.


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Guards - for portable machines

Enclosure 1750

Front Lip 5mm


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PORTABLE ANDHAND HELD GRINDING

MACHINES


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PORTABLE AND HAND HELD GRINDERS

Only organic bonded wheels to be used.Cutting wheels should have fibreglassreinforcement.

Machine guards must be securely in placeGuard between user and rotating wheel.Serious often fatal incidents, when guardremoved to allow larger wheel to befitted.


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ELECTRIC GRINDERS

Damaged cables are not to repairedunder any circumstances

Plug and sockets compatibleRegular Inspections by competent

electricianDo not try to repair, return to storesAlways inspect daily before use


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CHOP SAW - maximum peripheral speed

ACME

REINFORCED ORGANICBOND - 100 m/s

Type 41


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SUMMARY OF PRECAUTIONS

TrainingHousekeepingMounting of WheelsSpeedGuardsRestsLubricationNew WheelsStopping WheelsOverhang on Mounted Wheels


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Thank you

Abrasive Wheel Awareness 27-01-09

Documents

Transcript of Abrasive Wheel Awareness 27-01-09