However, this kind of sawing machine has the following problems due to the limitation of structure type.
(1) The sliding rail with limited lifting stroke lifts in the sliding seat. Due to the height limitation, the lifting stroke of the sliding rail is generally within 800 mm.. However, the travel of the segmented trolley on the trolley is also small, and only waste materials with low height and narrow width can be used.
(2) Cantilever limits the saw head to be fixed on the slide rail, the saw head moves up and down in the slide seat, and the slide seat horizontally extends out of the cantilever and is fixed on the cement column. When the saw head cuts downward, the more it descends, the longer the cantilever of the slide rail will be, forming three stressed cantilever structures together with the saw blade hanging at the end of the cutter shaft. The force on the cantilever varies with the number of saw blades installed, the number of saw blades increases, the hanging weight increases, the length of the cantilever increases, and the deformation of the stressed parts of the cantilever, especially the deformation of the cutter shaft, will inevitably lead to an increase in the deflection amplitude of the saw blade at the outer end of the cutter shaft relative to the saw blade at the inner end, which is also the reason why the saw blade at the outer end is more likely to be damaged when the single-column saw is used as a multi-piece combined saw.
(3) The resistance of the blank to the saw blade can be divided into upward jacking force and horizontal thrust of the cutter head. Under the action of this force, upward jacking torque and horizontal torque are formed on the saw head and slide rail. These two moments are finally transmitted to the slide seat and borne by the slide seat. Generally, the sliding seat of a single-column saw is relatively high, and the distance between the supporting points of the push-up torque is relatively large, so the ability to bear the push-up torque is also relatively large. However, the width of the slide rail is relatively narrow, so the ability to withstand horizontal torsion is poor. With the reciprocating motion of the waste on the trolley, the direction of the torque changes constantly. There is a gap between the slide rail and the slide seat due to the lifting movement, and the cutter shaft will inevitably swing back and forth under the action of torque. Because of the gap, the cutter shaft will be lifted by the jacking torque during sawing, and when the saw blade leaves the blank, the cutter shaft will sag again under the heavy load of the saw blade. This is also one of the reasons why the cutter shaft vibrates under the action of sawing force. It can be seen that if the slide rail is longer and wider, that is, the supporting surface of the slide rail is larger, the sawing machine will be more stable. Similarly, the smaller the gap between the slide rails, the higher the accuracy of up-and-down movement, and the smaller the vibration it causes, otherwise the vibration of the sawing machine will increase. Therefore, it is an important factor to adjust the gap between the guide rail insert and the slide rail in time to ensure the stable operation of the sawing machine.
(4) The stability of the car is poor. Generally, the length of the two tracks of the trolley is about 6m, and high levelness and parallelism are required in the whole length range to ensure the uniform and stable movement of the trolley. The adjustment of flatness requires a long level and level, which is not available in general manufacturers. Even if it is adjusted correctly during new installation, its flatness will be affected by foundation deformation or uneven wear during use. At this time, it is necessary to adjust the calibration, otherwise three wheels will land and one wheel will be suspended in the air, which will affect the stability of its use.
When it is necessary to saw the second knife after sawing one knife, the slicing cars of this sawing machine are all placed on the trolley, so the overlapping of the two cars also increases the instability of the trolley.
In the sawing process, the trolley works day and night under the heavy weight of raw materials and the splash of stone powder and sewage, and the wheels and bearings of the trolley are easily damaged. If it is not adjusted and replaced in time, the normal operation of the car will also be affected.
2. Double-column gantry sawing machine The sawing head of this sawing machine is mostly fixed under the carriage box, and the carriage box does reciprocating sawing motion on the beam. In the sawing process, the trolley is fixed, which eliminates the unstable factors caused by the mechanical problems of the trolley.
As mentioned above, the torque generated by the resistance of raw materials to the cutter shaft in the sawing process can be divided into vertical jacking force and horizontal torque, both of which act on the beam through the cutter shaft and the slide plate, and then are transmitted to the two columns for bearing. Because most of the slide rails of the carriage are designed to be long, the bearing fulcrum distance of horizontal torsion is large, and the bearing capacity of horizontal torque is also large, while the cross beam is generally narrow, and the bearing fulcrum distance of the two rails on the cross beam as vertical jacking torque is narrow, so the bearing capacity of jacking torque is poor. However, the weight of the saw blade head and the carriage box of this sawing machine is relatively large, which is generally enough to bear horizontal force and lifting torque. In order to prevent lifting, there is an anti-jacking wheel under the carriage box of the sawing machine. Once the jacking force is too large, which is greater than the sum of the weights, if it is not limited by the idler, the slide rail of the pallet box will be lifted out of contact with the rail surface of the beam, so that the idler can prevent the jacking and ensure the normal contact of the slide rail, thus realizing stable sawing. When this sawing machine is equipped with more combined saw blades, if the lifting force exceeds the weight of downward pressure during sawing, causing the carriage to vibrate, it is necessary to adjust the support conveyor in time to contact with the lower guide rail of the beam, so that the support wheel rotates with the movement of the carriage box. However, the pressure on the idler should not be adjusted too tightly, otherwise it will increase the resistance of the slide rail. Therefore, it is necessary to properly adjust the jacking force of the idler so that it can rotate freely with the movement of the slide rail, but it is not tight but not dead.
The cutter shaft of this sawing machine is also cantilever. With the increase of the number of saw blades, hanging weight and cantilever length, the deformation of cutter shaft will also increase, which will lead to the swing and vibration of saw blades and affect the sawing effect. Therefore, the number of combined saw blades on this sawing machine is also limited.
Of course, this model is used as a single saw or a combination of large and small saw blades, and the sawing effect is still very good, so it is widely used in plate factories and stone tablet factories, which is also the most basic model for sawing stone.
Compared with gantry saw, single-column saw has its own advantages in bearing capacity, but the cantilever structure of cutter shaft also has the same characteristics. Therefore, its use as a combined saw and its development in the direction of multi-blade combination are also limited by the structural form.
3. Four-column frame saw Most saws of this structure are combination saws, especially large-scale combination saws, because the four columns connected up and down and their frames form a very solid foundation. Moreover, the column is high, the beam is long, and the Liang Kuan is vertical, so it can be sawed with large pieces of waste. The cutter shaft adopts non-cantilever multi-support structure, and the distance between the vertical and horizontal stress points of the cutter seat is large, which is not affected by the deflection moment, and the force is uniform, so more saw blades can be installed. For example, foreign large-scale group saws can hold 70 knives, and domestic machines can also hold 30 knives. In this way, after the large-size blank is loaded, multi-stage sawing can be carried out with high efficiency and high quality, and the best sawing parameters can be selected according to the different specifications and materials of the blank. If frequency conversion speed regulation is adopted, the rotating speed and cutting speed of the saw blade can be easily changed, and the feed speed and chip displacement can be accurately controlled. The main sawing parameters are controlled by computer or displayed on screen, and the whole sawing process can be completed automatically.
As a combination saw, it can be said that this model is the most ideal, but the expensive price is unacceptable to the majority of users. Take 30 saw as an example, the import price is between 6.5438+0.5 million yuan and 2 million yuan, and the price of domestic machine is between 200,000 yuan and 300,000 yuan, so foreign-funded, joint venture or large-scale export plate manufacturers are selected for this type of machine.
Second, the equipment requirements, adjustment and use
1. Mechanical equipment should run in balance with less vibration. Repeated impact of diamond saw blade caused by vibration will lead to fracture, falling off or abnormal wear of diamond bit. Therefore, it is very important to fasten the connecting parts of mechanical equipment and fix the clamping of raw materials. Therefore, we should minimize the vibration during sawing to ensure the normal and stable operation of the equipment.
2. The accuracy and wear resistance of the cutter shaft are the benchmarks for installing the saw blade, and its accuracy largely determines the installation accuracy of the saw blade. When installing and disassembling the saw blade, the repeated push-pull friction of the saw blade on the shaft can easily cause the wear or scratch of the cutter shaft, especially after the equipment is used for a long time.
Therefore, in order to ensure that the accuracy of the cutter shaft will not change greatly, it is also important to check and adjust the installation accuracy of the cutter shaft, select the material, heat treatment and surface treatment of the cutter shaft. The cutter shaft of our group saw is made of alloy steel. In addition to quenching and tempering to ensure that the cutter shaft is rigid and not easy to deform, the deep surface is also quenched by ultrasonic frequency (higher frequency quenching hard layer depth). Then the outer surface is plated with hard chromium, and finally polished with a grinder. The tool shaft machined by this method has smooth surface, no corrosion, high hardness (above HRC60) and thick hard layer, which is not easy to wear and scratch, and can still ensure the high precision of the tool shaft after long-term use.
3. Inspection and adjustment of cutter shaft accuracy
(1) Turn the cutter shaft slowly and check with a dial indicator. Requirements to meet the following indicators:
Radial runout of cutter shaft A≤0.04 mm; The run-out of the outer end face of the backing plate is B≤0.05mm(2) Check the levelness of the cutter shaft with a frame level. C≤0.04mm (only upper deviation is allowed). If it exceeds this ratio, adjust the tool holder bracket (or saw head) until the levelness of the tool shaft is within the tolerance range.
(3) The perpendicularity between the cutter shaft and the beam guide shaft or the trolley track is out of tolerance, that is, the deviation angle of the saw blade relative to the blank sawing plane is out of tolerance, which will cause the sawing seam on the upper part of the blank to be too wide. When there are many out-of-tolerance, it can be concluded that the sawn wool board is thin on the top and thick on the bottom (commonly known as axe board), which is caused by the cross * vertical out-of-tolerance of cutter shaft guide rail and needs to be adjusted and corrected.
When the above situation occurs, please saw this layer of wool board to the required depth and raise the saw blade. Then remove the outer layer of the cut piece. Draw the AB line with the same height as the saw seam on the left vertical wool board, stick the dial indicator on the lower edge of the saw blade, rotate the saw blade to turn the dial indicator contact to points A and B on the contour line, lift the saw blade and adjust the distance between the detection points of points A and B to be greater than 1m, and the difference between the two points shall not be greater than 0.05 mm/1m. If the ratio exceeds, it shall be adjusted. When adjusting, just loosen the fixing bolt of the saw head gently, tap the saw head slightly to make it swing, and lock the bolt after adjusting to the required position. In order to prevent the position from changing again after loosening, it is best to add a positioning pin after adjustment. If there is an original locating pin, the pin must be removed before adjustment, and then another hole is drilled to pin it.
4. Precision of the backing plate When the combined sawing machine is equipped with large and small saw blades for combined use, the overlapping degree of the saw seam required for moving the blade is directly related to the deflection of the saw blade, the width error of the cutter head, the welding symmetry deviation and the precision of the backing plate in addition to the moving distance.
The gasket is mainly made of cast iron and aluminum alloy. Aluminum alloy is light in weight, wear-resistant, easy to process and non-corrosive. It is an ideal gasket material, but its price is much higher than that of cast iron. In order to improve the accuracy, the concave surface and concave hole of the backing plate should be processed first. Then it is fixed on a special fixture by locating the concave hole and concave surface, and the other concave surface is ground flat by one-time clamping to complete the inner hole and excircle on both sides. The deviation error on both sides of the pad processed in this way can be controlled within 0.0 1 ~ 0.0 15 mm, and the thickness difference is within 0.02mm, so the precision is high, and the influence of the pad error on the saw blade deviation and saw seam lap joint is reduced.
Pay attention to the storage of the mat, and don't throw it around, causing collision and scratch. When installing, the dirt on the joint surface should be carefully removed to ensure the installation accuracy of the saw blade.
Three. Installation and adjustment of saw blade
1. Adjustment of several saw blades Sometimes, one, two or several saw blades are out of tolerance. At this time, the out-of-tolerance saw blades can be removed, the rust spots and dirt on the saw blades and the backing plate can be removed, and then these saw blades can be reinstalled at the outer end (tailstock end) of the cutter shaft according to the marks when they are removed. If the rotation check is still out of tolerance, the pad between the saw blade and the saw blade can be rotated by a certain angle before the locking check. For example, after repeated rotation,
2. Adjustment of the whole set of saw blades The installation of the combined saw blades sometimes causes the whole set of saw blades to swing in one direction at the same time. Due to the centrifugal force in the process of rotation, this deflection produces a horizontal component of cyclic action.
The magnitude of horizontal component increases with the increase of deflection. In severe cases, it will cause the sawing machine to oscillate laterally, making it unable to work normally at all. For this reason, we set an adjusting disc at the outer end of the cutter shaft to adjust the deflection of the whole set of saw blades (Figure 3). When adjusting, the saw blade should be pre-locked, and the degree of pre-tightening is determined by the adjusting screw on the adjusting plate, and the saw blade should not rebound due to loose locking. The adjustment should be carried out under the monitoring of a dial indicator. According to the detection of the dial indicator, the point with the largest deviation will be pushed back by adjusting the screw, and it will be detected while adjusting until it meets the requirements. Then lock all the adjusting screws, and finally lock the saw blade, and then put it into use after re-inspection. This adjustment method is easy to learn and can be mastered by general operators. After correct adjustment, the deflection of the whole set of saw blades can be controlled in the range of 0.3 ~ 0.5 mm, and the use accuracy is high.
3. Installation position of the saw blade The saw blade is installed on the cutter shaft and rotates around the center line of the cutter shaft. The dimensional tolerance of the cutter shaft is 100-0.036, for example, the dimensional tolerance of the saw blade hole is 100+0.066. The clearance between the shaft and the hole varies in the range of 0.048 ~ 0. 137 (see Figure 5). When the saw blade is installed, the cutter shaft stops. After the saw blade is installed, the gap between the whole group of saw blades and the cutter shaft appears under the cutter shaft due to the weight, resulting in the deviation between the rotation center of the saw blade around the cutter shaft and the center of the saw blade of 0.048 ~ 0.137 mm. After grinding the saw blade 1 ~ 2 hours, the emery at the head of the saw blade is exposed, forming a cutting edge (commonly known as trimming) with the cutter shaft as the rotation center. After the relative position between saw blades changes, the direction of cutting edge changes with the change of rotation center. Therefore, if it is necessary to disassemble the saw blade after its installation and edging, please write down the dead point when disassembling, and install it as marked when reassembling, and do not change the rotation direction and position of the saw blade. Otherwise, the change of cutting edge direction will affect sawing efficiency and service life of saw blade.
Four. Requirements for saw blade 1. Requirements for the saw blade matrix The inner hole of the saw blade matrix should be strictly controlled within the tolerance range. If the inner hole is too small and the cutter shaft is too tight, it will be difficult to install and affect the adjustment of saw blade deflection. Because of the high hardness of the plate, uneven reaming with grinding wheel is easy to cause eccentricity. So it is impossible to smooth the hole with a semicircular file. Adding difficulty to users is time-consuming and laborious.
The transverse deflection of the plate should be controlled within 0.3mm.
The stress (tension) in the chip should be uniform and not easy to deform, thus prolonging the life of the chip.
2. Requirements for the cutter head The width of the cutter head should be grouped according to its size error, and the error of the width of the cutter head on the same saw blade should be controlled within 0.05 mm ..
The cutter heads are symmetrically welded on the wafer, and the error of the side face of each cutter head relative to the side face of the wafer after welding is not more than 0.08 mm. ..
The sharpness of the cutter head directly affects the sawing efficiency and service life. When in use, the appropriate cutting amount and cutting speed should be selected according to different materials of the blank, the cutting current should be controlled within 80% ~ 90% of the rated value, and the cutting sound should be soft and supple. Sometimes, after a period of use, the sharp cutter head will be difficult to cut, the current will increase and the sound will become coarse. This is because the emery is worn off or mixed unevenly in the manufacturing process of the cutter head, which makes the emery content in this layer insufficient and can not be sawed effectively. At this time, the sawing performance can be restored after the emery is exposed.
V. Requirements for the use of 1. In order to improve the output rate and reduce the unnecessary wear of saw blades, please pay attention to the placement and fixation of waste materials.
2. When sawing, the spark generated by the strong impact friction between the cutter head and the stone generates heat and needs enough cooling water for cooling. Insufficient water will burn the cutter head, so it is necessary to ensure sufficient water supply continuously.
3. Add lubricant on time and in quantity. Adequate lubrication can reduce friction, reduce noise, improve productivity and prolong the service life of saw blades.
4. When sawing stones with different materials, please adjust the sawing depth and sawing speed in time according to the change of main motor current.
5. Pay attention to the change of sawing sound and current at any time during sawing. If there is any abnormality, it should be eliminated in time.
6. Monitor the quality of sawed cotton board, and investigate and deal with its influencing factors in time according to the degree and quantity of cotton board out of tolerance.
7. When the saw blade is removed and stored, it should be hung vertically to reduce deformation.