General rules for storage and transport of abrasive tools. Inspection of grinding wheels on reception

Grinding and cutting-off processes are characterized by a high dynamics. Operating speed of 50 [m/s] corresponds to 126 [km/h] and 80 [m/s] corresponds to 290 [km/h]. Therefore, abrasive tools should be handled observing appropriate rules.

Storage and transport of abrasive tools have a close relation with work safety and require that appro­priate rules are to be observed. Users must be aware of danger if these rules are not observed.

Service reliability and work safety depend on suitable protection in the following stages: packaging, shipment, protection against damage and environmental conditions, transport, handling by forwarding agent, unloading at customer, storage, handling by customer, mounting, start-up, operation.

Abrasive tools, especially grinding wheels, though they have a high resistance to a burst, are suscep­tible to impacts, drops, bending stresses. Therefore, they are to be treated with great care during handling. Impacts, throws or drops on a hard surface may develop scratches or invisible cracks which can be a cause of burst during operation and a danger for body or life.

Grinding wheels or segments must not be wet at transport or storage, as this may be a cause of static unbalance or damage caused by frozen water.

Once a batch of goods is received its packing should be examined for possible damage in transit.

If any damage exists, make together with forwarding agent, an appropriate report including identifica­tion information, description and results of the damage. Report this information to supplier.

Then, the grinding wheels shall be subject to detailed inspection for any damages and defects, prefe­rably by using a sound test and visual inspection. In case any doubts exist, consult with the supplier.

The sound test of grinding wheels is carried out in the following manner. Vitrified grinding wheels are to be lightly tapped with a non-metallic instrument, for example a screwdriver handle in the case of small grinding wheels or a wooden mallet in the case of heavier grinding wheels, which should be stood on a hard and clean area of floor.

The best point to strike the grinding wheel is approximately 45° on either side of its vertical axis, near its periphery. Before each strike, turn it through 45° until it has been tapped around its entire circumference (see Fig.)

A good grinding wheel rings with a clear note. A cracked one rings with a dull, quickly fading note. Such grinding wheels must not be used and they shall be retested by the manufacturer’s service.

Resinoid grinding wheels are tested in the same manner but in this case they do not emit the same clear tone (muffle).

The presence of a crack may be indicated by a change of the tone as well.

Grinding wheels should be carefully unpacked and cleaned with a brush or compressed air. Striking the wheels against each other is strictly prohibited!

Fig. Sound test by tapping forgrinding wheels

 

Protective pads for safety clamping of grinding wheels shall be removed from carton boxes unless they are bonded but have been supplied loose acc. to individual agreement. They shall be transferred, to­gether with the grinding wheel, to a mounting place or directly on grinding machine.

The abrasive tool are to be stored in a dry, spacious, suitably ventilated room in possibly constant tem­perature from the range from 10 to 30°C and humidity not higher than 70%.

Due to possibility being damaged by damp and frost, the abrasive tools shall not be stored in tem­peratures below 4°C. This warning also applies to rooms where “wet” grinding operations using grinding coolant are performed or where the grinding wheels may be damped.

Organic bonded abrasive tools, marked by letters “B” or “BF”, are susceptible to moisture alkali or acid environment and temperature changes. Therefore, they are not to be stored together with chemicals and protected against excessive heat, especially from one side, by a close vicinity to heaters, for example.

Resinoid abrasive tools lose their properties as time goes on. Bonding agent is subject to deteriora­tion and improper storage conditions increases this process. It is assumed that they should be used within three years from the production date.

The way in which the grinding wheels should be laid is shown in the Figure below.

The best and at the same time comfortable solution is vertical position of grinding wheels on two parallel wooden beams. Large grinding wheels are to be laid on beams directly on an even floor and other ones on suitably profiled racks with profiles and dimensions adapted to dimensions of wheels.

These racks shall be made of wood or steel structure lined with soft material, wood or rubber for exam­ple.

Stacking height must not be a cause of damage to grinding wheels, especially those on the bottom of the stack.

The same rules are to be observed when handling grinding wheels within the area of pro­duction shops as well as on working stands. Wheels are to be handled carefully to prevent dropping them or subjecting them to impact each other or hard objects.

Position of wheels during handling should be similar to that on racks. Transport on trucks especial­ly adapted for that purpose, padded with rubber and rubber wheels, is recommended. Wheels may be rolled along the floor provided that a suitable rubber blanket or other protection is available.

 

Fig. Example of rack for storing grinding wheels

 

1 - Small dish wheels, 2 - Small plain wheels, 3 - Lightly inclined shelves for small wheels to prevent falling them out, 4 - Back wall with protective lining, 5 - Plain wheels, 6 - Small cylinder wheels, 7 - Large dish wheels, 8 - Taper cup wheels laid alternatively, one the opposite way to the other, so that large and small diameters coincide, 9 - Flat shelf for cutting-off shaped and cylinder wheels, 10 - Thin-walled and soft cylinder wheels, 11 - Separating corrugated board, 12 - Steel or ceramic even supporting plate, 13 - Two-point cradle support for wheels standing on their circumference, 14 - Front edge of wheels, 15 - Small cylinder cup wheels, 16 - Flat profile wheels, 17 - Flat cutting-off wheels, 18 - Steel or ceramic even supporting plate, 19 - Thick hard cylinder wheels, 20 - Medium size plain vitrified wheels, 21 - Large wheels