1. Installation rules of the grinding wheel
The installation of the grinding wheel must be carried out according to the following rules:
(1) Clean the grinding wheel flange, the screw holes on the flange, the balance slide, and the grinding wheel mud of the slider.
(2) Before the installation of the new grinding wheel, it must be tested by tapping, and the grinding wheel with noise is prohibited.
(3) The clearance between the grinding wheel and the flange is controlled within 0.5mm, but the over-tight grinding wheel is also prohibited.
(4) Where the end face of the grinding wheel is in contact with the flange, the paper pad must be evenly padded.
(5) The screws fixing the grinding wheel on the wheel flange must be complete, oiled before installation, and evenly tightened by symmetrical circulation method.
(6) The fastened grinding wheel for static balance, to erect the installation of the balance shaft, the edge of the grinding wheel in contact with the ground must be cushioned with soft products.
(7) The vertical and horizontal of the grinding wheel static balance frame must be level, and the balance shaft and the grinding wheel flange must be completely ground.
(8) The balanced grinding wheel, fix the balance block, lift off the balance frame, remove the balance shaft, and lift it into the specified shelf.
(9) The guide shaft on the balance shaft and the balance screws and nuts are wiped clean, coated with oil, and placed in the specified position.
When the grinding wheel is working, it rotates at a high speed and bears a large centrifugal force. If it is improperly installed or the grinding wheel itself has cracks, it will cause the grinding wheel to burst and have serious consequences. Therefore, the grinding wheel must be tested for resonance before use.
2. Resonance test method
Before testing, check whether the grinding wheel has been damaged during transportation or due to other reasons.
The test can be done by gently tapping a small metal tool on the grinding wheel, such as a screwdriver handle on a small grinding wheel, or using a wooden hammer on a harder grinding wheel.
If the grinding wheel produces a distorted sound, then the grinding wheel may have cracks, and the grinding wheel cannot be used. This check is called a "resonance test."
At the time of this test, the grinding wheel should be dry, and there must be no sawdust and other debris, otherwise it will weaken the sound.
It should be noted that the organic sintered block grinding wheel does not produce a clear metallic sound, which is a characteristic of the glass mixture or silicone grinding wheel.
Gently tap on both sides of the vertical center line of the grinding wheel about 45° and the circumference about 25 mm. Repeat the test after rotating the wheel about 45°.
An intact grinding wheel will produce a clear metallic sound, and if the grinding wheel is cracked, there will be a weak or dull sound.
3. Precautions for installing and disassembling the grinding wheel
The following work should be done when installing and disassembling the grinding wheel:
(1) Before installing the grinding wheel, visual observation and resonance test should be used to carefully check whether the grinding wheel has cracks and damage;
(2) The coordination between the inner hole of the grinding wheel and the flange should have appropriate clearance to avoid the expansion of the grinding wheel during thermal expansion;
(3) The diameter of the two flanges must be equal, and the size should not be less than 1/3 of the outer diameter of the grinding wheel; It is not allowed to knock the flange with a hand hammer or heavy object to prevent damage and deformation of the flange;
(4) Between the flange, washer and the end face of the grinding wheel, a liner should be placed to make it compact;
(5) When tightening, the bolt cannot be tightened too tightly. When using several bolts to tighten the flange, it must be divided into several diagonal times and gradually tightened, and only a standard wrench can be used;
(6) The cone hole of the flange must be wiped very clean with the cone on the grinding machine spindle;
(7) After the new grinding wheel is static balanced, when the grinder is installed for the first time, it must be idled for 3 to 5 minutes with a protective cover. At this time, no one in front of the grinding wheel;
(8) When removing the grinding wheel, do not make the wrong rotation direction of the compression nut.
(9) Each time when replacing the grinding wheel, it is necessary to check whether the mushroom head used to lock the grinding wheel in the flange is loose and damaged. If there is an abnormality, the flange will stop using;
4. Grinding wheel balance
Because the speed of the grinding wheel is very high, if the grinding wheel is not balanced, it will produce a large centrifugal force, so that the machine tool vibration, thereby producing vibration ripples on the surface of the workpiece, affecting the quality of the machining surface. In addition, it will accelerate the wear of the main shaft bearing, and even crack the grinding wheel. In order to make the grinding wheel work smoothly, the new grinding wheel with a diameter of more than 250mm must be balanced before being installed on the grinding machine. Larger grinding wheels wear more after a period of time and need to be re-balanced.
Grinding wheel balance often has two methods: static balance and dynamic balance.
Static balance is to install the grinding wheel flange, lift the special static balance frame, use the balance block to adjust the unbalanced position of the grinding wheel to achieve balance. The specific operation method is described in detail on the operating rules of the grinder.
Dynamic balancing is to install the grinding wheel on the grinding machine, and use the dynamic balancing device of the grinding machine to balance. The specific operation method is described in detail on the operating rules of the grinder.
