AUTOMATIC GRINDING POLISHING MACHINE FOR GRANITE SLABS - LM 2000 G/13P-3PL

AUTOMATIC GRINDING POLISHING MACHINE FOR GRANITE SLABS TYPE “LM 2000 G/13P-3PL”
A basement for the sliding of the conveyor belt. Its technical characteristics allow the maximum stability, high quality and long life. The basement is made up of:
- A stiff electrowelded steel section basement with stainless steel rollers for the belt driving housed on its ends.
- Driving roller and belt tensioning roller, with special devices to control and regulate the sliding and the tensioning of the belt.
- Splash guards and lateral shields to avoid water slashes.
- A complete speed variator of 4 HP which allow to adjust the conveyor belt speed from 0 to 1,5 mt./min.
- A thicker conveyor belt with a tooth surface to avoid slabs slipping.
- A push button panel located over the spindles in order to make the control operation easier. It is made of steel unit containing control board for: the spindles, the belt, the hydraulic cabinet, the slabs reader, the brush and the blowing group for slabs drying
The bridge, realised in a very thick box structure guarantees a high mechanical stiffness in order to avoid vibrations during working motion. On the bridge are located the spindles with 4 abrasive oscillating bricks heads. The bridge runs over steel tracks equipped with rollers bearing in oil bath. The trucks are rectified and protected by a stainless steel seal. The bridge movement is controlled by a hydraulic motor of 7,5 HP whose speed is adjustable from 0 - 12 cycles/min. continuously Spindles with oscillating bricks plates. The spindle body is seasoned cast-iron made. Technical solutions guarantee an absolute absence of vibrations and very long life. It is made up of :
- A flange motor of 15 HP.
- A belt transmission pulley with belt tensioning device.
- A tube of chromium plate steel holding the axle spindle, protected by rubber bellow.
- A splined shaft rectified in the ball bearing housing in order to provide a perfect coupling with the pulley. The shaft is equipped with oscillating brick plate or, on request, with planetary plate with 4 satellites. The up and down movements and the working pressure of the plates are controlled by a hydraulic cylinder which is driven by a support unit composed, for each head, of a solenoid valve and servo valve for working pressure adjustment. The hydraulic plant includes an adjustable counter pressure device which allow to balance the plate weight in order to realise very low working pressures too (to polish fragile and thin slabs). The spindles are driven by a second hydraulic unit of 5,5 HP. Each spindle is controlled by the following instrumentation:
- Manometers for abrasive pressure reading.
- Command device for the up and down movements of the spindle.
- Hydraulic counter pressure setting valve. - Knob for working pressure adjusting.
- Cylinders and pistons for rapid hoisting of the holding spindle tube, the descend and regulation of the pressure on the uniform abrasive, independently from the consumption of
the same.
- Water connection tubes and pipe-fittings.
Between the dressing and the polishing plates it is installed a cleaning slabs device to avoid that eventual rough materials from the grinding phase come under the polishing plates. This device is composed of a rubber scraper supplied with motorized lifting to adjust working height according to the slabs thickness. On the external part of the bridge at the end of the polishing zone, there is applied a rolling brush ? 400 mm. actioned by 4 HP motor. It provides to eliminate the wastes of the polishing process from the polished surface. The brush, same as the spindles, has an automatic up and down hydraulic movement, synchronised with the slab passage.
The slabs presence reader device type: “STEPMATIC” is made up of INFRA RED sensor located on the front part of the machine, provide to check the slab presence thanks to electronic device which controls the plate and brush up and down movements according with the belt speed and the presence of the slab. This system allows to anticipate or to postpone, directly from the control board the lifting/lowering of the plates in order to follow the speed of the belt and to modify the lateral position of the sensors according to an eventual defect of the block.
The electric plant is made up of a board with “Telemecanique” components for the command and the protection of the motor, made up of:
- Iron made waterproof box containing valves, remote control switches thermal cut outs and all
equipment for the starting, the switching off and the control of each motor.
- Low tension push button command