Safety Recommendation for the Use of Superabrasives

(Diamond and CBN): General Applications

The recommendations of this document are only a summary of the most important precautions. All users must strictly follow the safety instructions existing in the laws, decrees and technical standards of their country and in machine instructions.

The term superabrasive product used in this leaflet means any shape of Diamond or CBN abrasive product used on a machine. Superabrasive products are breakable, it is important that users take sensible precautions. Superabrasive products which are damaged, improperly mounted or misused are dangerous and can cause serious injuries.

Contents

  1. Handling, transport and storage
  2. Selection of the abrasive product
  3. Inspection and testing before mounting
  4. Mounting
  5. Before starting
  6. Starting the machine
  7. Operatring the machine
  8. Safety at the workplace
  9. Pictograms

Specific safety instructions exist for Diamond discs (Saws) used on hand held machines

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1. Handling, transport and storage

Upon delivery, the packaging must be carefully inspected and any deterioration shall lead to a special examination of the products.

Superabrasive products should be handled carefully, never dropped, knocked or rolled along the floor.

Superabrasive products should be stored at moderate temperature and humidity in such a manner that mechanical damage is avoided and that the items concerned are not subjected to the damaging influences of moisture, frost, uneven heating or cooling or chemically aggressive media.

For superabrasive products with resin bonds and /or resin wheel cores, use the oldest first. Superabrasives should be kept in their original packaging until immediately before use.

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2. Selection of the superabrasive product

Carefully read the label or the markings on the superabrasive product and make sure that:

• the superabrasive product is suitable for the application and has the correct dimensions.
• check that the maximum revolutions per minute (rpm) of the machine spindle on which you will mount the superabrasive never exceeds the maximum rpm printed on the label or on the product.

Follow any restriction of use and any specific instruction which may be indicated on the superabrasive or on the attached documents.

Colour stripes When a colour stripe is used, to make the identification of the maximum operating speed easier,the different colours indicate the following maximum operating speeds:

The maximum peripheral speed corresponding to the colour stripe shall never be exceeded.

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3. Inspection and testing before mounting

Always carefully inspect the superabrasive product before mounting, for possible damage.

Certain types of superabrasive products with a vitrified core exceeding 80 mm in diameter, can be subjected to a sound test. Light products are held on a mandrel or finger and heavier wheels are stood on a firm base and are tapped at several points with a non-metallic object. (see examples: )

Superabrasives that are in good condition ring clearly but products that are damaged give a dull or chattering sound.

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4. Mounting

This operation shall be performed by a qualified trained person only.

No modification should be made to the bore and/or recesses of a product after delivery.

Follow the instructions in the machine manual and, in addition, take the following steps:

4.1 Machine Inspection

Make sure that there is no risk of accidental starting of the spindle.

Carefully inspect the mounting of spindle and flanges: they must be in good mechanical condition and free of foreign bodies such as pieces of old blotters or grinding debris.

4.2 Wheel Mounting

Depending on the type of superabrasive product, it must be mounted by one of the following systems:

4.2.1 Clamping flanges

Ensure that the clamping flanges are chosen to suit the specific wheel size and design. The gripping faces of the flanges must be flat, clean and without grease.

Straight adaptor flanges hub flanges

The superabrasive product should be placed and adjusted on the machine shaft or securing system without the application of force.

Where the wheel has to be clamped between flanges by means of several bolts, they should be tightened diagonally, using a torque wrench whenever possible. Overclamping should be avoided.

Make sure that the nuts and bolts are clean and in good condition.

4.2.1.1 Blotters

When mounting superabrasives with a plain vitrified core between flanges, blotters of soft or flexible material such as for example plastic, have to be fitted between the gripping faces of the flanges and the wheel.

Blotters are not required for the mounting of vitrified superabrasives cemented to a plate, for small vitrified wheels with a diameter D < 20 mm or vitrified honing stones.

4.2.1.2 Reducing bushes

When using a removable bush as a means of reducing the bore of a superabrasive, care must be taken to ensure that the annular gripping faces of the clamping flanges do not contact the reducing bush.

The tolerance on the inner and outer diameter of the reducing bush should be such as to minimise the wheel out of roundness when mounted on the machine spindle.

4.2.2 Mounting of disc wheels and cylinder wheels on support plates

Disc wheels and cylinder wheels usually have threaded holes by means of which they can be bolted to a support plate.

Blotters must not be used.

When bolting the wheel to the plate use all provided fixing elements.
The bolts must be of such a length that they do not reach the end of the threaded holes.

Grinding wheel bolted to a backplate

Correct insertion of the bolt

4.2.3 Fitting of wheels with integral spindles on hand-held grinding machines

It must be ensured that the spindle of the mounted wheel is firmly held in the chuck or collet.

The length of spindle in the chuck or collet L3 for 3 and 6 mm spindles shall be a least 10 mm and 15 mm for 8 and 10 mm spindles. The overhang Lo applicable to the maximum permissible speed of the mounted wheel shall not be exceeded.

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5. Before starting

• Make sure that all adjustable machine parts are set in the right position according to the machine instruction manual.
• Adjust the balancing device, if any, for minimum out of balance.
• Make sure that the part to be ground is firmly secured.
• Check that the wheel guard compulsory for this machine is properly mounted and adjusted to the wheel, closed and locked.

Personal protection
Depending upon application, certain personal protection equipment such as eye and face protection, ear protection, gloves and dust masks, a leather apron and safety shoes may be required.

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6. Starting the machine

After mounting a wheel of D>8O mm, it must be test run on the grinding machine at the speed at which it is operated. The maximum permissible speed for the wheel concerned must not be exceeded. During such a test run, nobody should stand within the danger area.

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7. Operating the machine

Truing, dressing and cleaning
When applicable, true, sharpen and clean the wheel with specially designed wheel dressers and tools.

It is necessary to partially open the guards in order to be able to dress the wheel on the grinding machine, suitable measures must be taken to avoid the risk of injury from flying particles or the possible breakage of the grinding wheel.

Grinding with superabrasives with a vitrified core
Ensure that the dressing tools do not contact the vitrified core. It is not permitted to modify the shape of the core.

Use of grinding fluids (coolants and lubricants)
For wet grinding, apply the fluid only to the already rotating wheel, in order to avoid unbalance, as this could lead to the rupture of the wheel.

Where fluid is used, once the grinding operation is completed, the fluid supply should be turned off and the grinding machine kept running at no-load until centrifugal force has drained all the fluid from the wheel.

If the grinding wheel is not to be used again for any length of time, it should be ensured that the fluid is prevented from being absorbed by the grinding wheel.

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8. Safety at the workplace

All safety devices provided with the grinding machines such as guards and covers, should be utilised and should not be modified in any way.

Where flying sparks could prove a hazard, screens should be set up to provide protection. Hand held grinders should be used in such a manner that sparks fly away from the operator's body.

Equipment should be provided to keep the air around the workplace clean where it would otherwise be possible to breathe in hazardous concentrations of dust, vapour or aerosols.

The necessary equipment should be used to ensure reliable extraction of grinding dust without the risk of causing fire or explosion if the dusts, vapours or aerosols concerned could be of a flammable or explosive nature.

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9. Pictograms

Pictograms may appear on posters, on packaging, on machines and on products. They describe the main safety instructions.

9.1 Safety instructions

Wear safety glasses	Use ear muffs
Wear safety gloves	Wear a dust mask

Read the instructions

9.2 Restrictions of use

Do not use for side grinding

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