You want to make sure that the "weapons" to take advantage of, and then is more dry and more practice, cylindrical, hole, length, taper, thread combination of practice, then there are complex parts of the turning exercises, Such as: inside and outside the trapezoidal thread, worm, slender shaft, thin-walled sets, etc., and learn to use the center frame and with a knife.
1. Turn the slender shaft
"Car workers afraid of the car." This sentence reflects the difficulty of turning the slender pole. Due to the characteristics and technical requirements of the elongated shaft, in the high-speed turning, easy to produce vibration, polygon, bamboo, poor cylinder and bending defects. If you want to take it smoothly, you must pay attention to the problems in the process.
1) Machine adjustment
Lathe spindle and tailstock two center line connection and lathe large rail up and down must be parallel, tolerance should be less than 0.02mm.
2) Workpiece installation
In the installation, try not to have been positioning, with a chuck clamping end, do not exceed 10mm.
3) Tool
Using Κr = 75 ° ~ 90 ° side knife, pay attention to the posterior angle α'0 ≤ 4 ° ~ 6 °, should not be large. When the tool is installed, it should be slightly higher than the center.
4) with the knife, after the installation must be trimmed
Dressing method, can be used research, hinge, boring and other methods, so that with the knife jaw and workpiece contact with the arc R ≥ workpiece radius, must not be less than the workpiece radius to prevent multi-edge generation. In the adjustment with the knife claw, the claw can contact with the workpiece, do not force to prevent the bamboo produced.
5) auxiliary support
When the aspect ratio of the workpiece is greater than 40, the auxiliary support shall be added during the turning process to prevent the workpiece from vibrating or the centrifugal force. Cutting process to pay attention to the top of the adjustment to the top of the workpiece is appropriate, should not be tight, and at any time to adjust to prevent the workpiece thermal expansion bending.
2. anti-knife turning fine rods
Turning a lot of long rods, the general use of the knife with a knife or anti-knife turning. But anti-turning and turning compared with the turning, there are many advantages, most of the use.
In the turning prone to two problems, one is multi-prism, which is mainly after the tool angle, with the knife claw of the R and the workpiece out of the diameter caused by the disc; the other is the bamboo problem, It is by the knife in the mouth with a good knife, in the knife, knife to the cutting surface, from the cutting depth from a very small to suddenly increase, so that changes in cutting force, the workpiece produced outward knife, the diameter suddenly change Large, when the knife with a large diameter, the car out of the diameter becomes smaller, so the cycle, so that the processing of the workpiece for the bamboo-shaped.
In order to prevent the generation of bamboo, when the car is good shelf mouth, carefully with a knife, knife after the anti-knife, the use of the pallet handle, eat deep (0.04 ~ 0.08) mm, but according to the cutting depth Size is flexible.
3. Rolling straightening method
In the machining, often used to improve the workpiece surface hardness, fatigue strength and wear resistance, reduce the workpiece surface roughness, extend the service life of the workpiece. At the same time, can also be used in the rolling process, the metal under the action of external plastic deformation, so that the internal stress to adjust the straight and rigid shaft and rod class workpiece.
In the process of rolling the workpiece, the workpiece was rolled under the action of external force due to uneven surface hardness and bending. Bending the height of the rotation center, bear the rolling pressure, and the resulting plastic deformation is also large, so that the degree of bending of the workpiece is more increased. Especially in the use of rigid rolling tools, this phenomenon is more prominent.
Rolling straightening method is in the workpiece after the first rolling, check the workpiece radial runout, concave at the mark, with a four-jaw chuck to the workpiece concave, adjust the height of the machine to the center of rotation , And the workpiece is proportional to the size of bending, and then the second rolling, and then use the dial indicator and adjust the four-jaw chuck claws, the workpiece correction. And then use the dial indicator to check the bending of the situation, such as bending, and then the above method, adjust the workpiece, the third rolling, until the workpiece to achieve the straightness so far. After the second time the length of the pass, should be based on specific circumstances, do not have to complete the whole process, but also to use anti-knife.
The use of rolling straightening, generally in the process of rolling the workpiece to complete, not only will not damage the surface of the workpiece, but also the workpiece surface by a more uniform rolling, will not produce dead bending, but also easy to operate.
4. screw extrusion straightening method
For the larger diameter is longer, but also the existence of a few curved screw, the use of extrusion straight, the effect is very good.
1) working principle
Using the straightening tool, under the action of external force, squeeze the surface of the screw tooth bottom, so that the surface of plastic deformation, axial extension, change the internal stress of the screw, and make it straight.
2) straighten the method
First on the lathe or platform, measured the location and direction of the screw bending, and then bend the concave up, convex face down with the metal pad, with a flat shovel and hand hammer hit the bottom of the screw, so that silk Bar diameter metal deformation, and to achieve the purpose of straightening. In the whole straightening process, the detection of bending, blow the flat shovel extrusion staggered until the screw straightened. This method is simple and easy, not only for the size of the screw, but also for the straightening of the shaft rough, straighten it is not easy to recover.
3) should pay attention to the problem
The width of the special flat shovel should be greater than half the diameter of the root of the screw, b is less than the width of the tooth, α is less than the tooth angle; contact with the workpiece R cross section, should be grinding out the arc; Apply the file to trim the pressed teeth.
5. Rubber thread processing
As the hardness of rubber is very low, elastic modulus is only 2.35N, equivalent to carbon steel 1/85000, under the action of external force, easy to deformation, cutting is very difficult. Especially cutting some special-shaped thread, more difficult.
In order to solve the rubber thread processing, in the lathe to install a can adjust the helix angle of the grinding head, or in the case of high precision thread can also be used instead of pneumatic grinding head. Grinding wheel with diameter Φ60mm ~ Φ80mm, particle size 60 # ~ 100 # white corundum wheel. After the grinding wheel is installed, the diamond pen is used to trim the wheel shape. The shape of the grinding wheel is the normal section of the thread.
Thread guide small, lathe nameplate, you can directly pull the lathe handle to obtain. When there is no sign on the lathe, the required wheel must be calculated. General can be found manual, can also be used to calculate the method, find and manufacture the required wheel.
When the general thread lead is greater than 300mm, the spindle speed must be reduced so as to avoid the quality of the thread grinding due to the high spindle speed, but also to make the operation tight or damage the parts of the feed box. Deceleration methods are: change the main and passive pulley diameter; in the lathe outside the increase gear box.
The method of dividing the head is the same as the method of car threading.
Grinding rubber thread on the lathe is a kind of high efficiency and high quality processing technology. It has adopted the grinding method, the processing lead is (1.5 ~ 1280) mm single head and long rubber thread, its quality is consistent Claim.
6. Step deep hole turning method
Turning holes with an aspect ratio greater than 4 on the lathe is difficult due to the poor rigidity of the arbor, the vibration at the time of cutting, the efficiency of the cutting and the quality of the machined surface. In particular, the hole is large and the hole is very deep, and with the steps of the case, due to the arbor, machine tool rigidity, processing more difficult.
First in the lathe with the chuck and the central frame to install the workpiece, with the hole knife at both ends of the workpiece processing short hole, and each with a set and dedicated Arbor. In the middle of the long hole in the turning, the left end of the support package into the workpiece hole, and then install the workpiece on the lathe, the head out of the length of the adjustment in the pole, together with the left side of the support sleeve into the workpiece hole , With a knife pad to adjust the height of the knife, the knife cannula fixed on the lathe square knife table, so that the knife can slide freely in the sleeve, you can make the workpiece rotation, began to knife cutting, until the workpiece longitudinal depth.
When the workpiece is finished, move the large carriage in the opposite direction and exit the workpiece together with the support sleeve and the arbor at the right end to remove the workpiece. When machining the second piece, install the support sleeve on the left side, insert the workpiece, and then insert the tool bar into the support sleeve on the left end of the workpiece, and install the right end support sleeve to start the turning of the second workpiece.
Tooling features: both ends with a support sleeve support the arbor, greatly increased the rigidity of the arbor, so that no vibration cutting to ensure that the surface has been machined roughness; both ends with a support sleeve support rods to ensure that the hole between Position accuracy; easy to operate, the efficiency of the hole than the traditional method to improve more than 5 times.
7. Adjust the method of the center frame
In the length of the car, the diameter of the hollow parts of the hollow hole, the end of the need to use the center frame. If the center frame is not properly adjusted, the axis of the workpiece and the spindle axis of the machine does not coincide, the processing will produce the face of the heart and the drum and the hole taper error. When serious, the workpiece from the chuck out, causing the accident.
When installing such workpieces, one end of the workpiece with three-jaw chuck or four-jaw chuck, the other end on the center frame. And then in the workpiece hole in a piece of wood or in the end of the workpiece with butter paste a piece of paper, the tailstock tip tip on the board or paper, the choice of lower spindle speed, the workpiece turn a week or two , Then the board or paper on the top to draw a circle, and then adjust the center frame of three care, so that the center of the circle is the top of the tip, so that basically the center line and the machine tool spindle axis Basic coincidence. After semi-finishing, such as measuring the flatness of the end face and the hole degree of the tolerance, and then the center of the three care of the cable to adjust, to be eliminated.
8. Take the center of the hole in the hole
In the drilling of the center hole, due to the center of the lathe and the workpiece rotation center is inconsistent, or excessive force, the workpiece material plastic and chip plugging and other reasons, often caused by the center drill broken in the center hole, easy to remove.
Such as the use of the method to expand the center hole to take, then the center hole will change the original size, fail to meet the quality requirements. At this time, as long as the use of a sharpened wire, the tip into the hole in the hole hole drill bit trough, a few times, drill a move, with a magnet or magnetic table seat suction, broken in the center hole Inside the center of the drill tip to take out.
9. Defects when the slender shaft is cut
1) drum belly shape
That is, after turning, the workpiece two small diameter, the middle diameter. The reason for this defect is due to the poor rigidity of the elongated shaft, which is in contact with the surface of the tool holder and the surface of the workpiece. The wear causes a gap. When the vehicle is turned to the middle part, The rotation center of the workpiece is pressed to the right side of the center of rotation of the spindle so that the cutting depth is reduced and the rigidity of both ends of the workpiece is better and the cutting depth is substantially unchanged. As the central produce "let the knife" leaving the slender shaft into a bulging shape.
Eliminate the method. In the knife with the knife when the claws, be sure to carefully, so that the surface of the claw surface contact with the workpiece, not a gap. The main declination of the turning tool should be selected from 75 ° to 90 ° to reduce the radial force. With the knife claw, should choose a better wear resistance of cast iron.
2) Bamboo
Shaped like a bamboo, the pitch is approximately equal to the distance between the tool holder support claw and the tool nose, and is a cycle. The cause of this defect, due to the gap between the lathe and the middle of the lathe is too large, the blank material bending rotation caused by centrifugal force and with the tool holder support reference knife, resulting in knife when the "knife" A section of the diameter of the car is slightly larger than the reference section, continue to take the knife turning, with the knife support jaw contact with the workpiece diameter of a large section, so that the workpiece rotation center to the side of the turning tool, cut the workpiece diameter decreases. In this way, with the knife frame has a circular support in the workpiece diameter, so that the workpiece to leave and near the turning tool, and the formation of a regular bamboo-shaped. As well as in the knife with the knife jaw claws, forced too large, so that the workpiece rotation center pressed to the knife side, resulting in the car out of the smaller diameter, continue to take the knife, so the cycle, but also the formation of bamboo.
Elimination of the method: to adjust the gap between the machine parts, and enhance machine rigidity. In the knife with the knife claws, so that the claw is not only with the workpiece contact real, and do not force large. (0.05 ~ 0.1) mm, in order to eliminate the knife when the "knife" phenomenon, cut the size of the depth, to master the law of the machine, flexible control.
10. Reverse knurling
The traditional forward roll, in the process of rolling the chip easily into the workpiece and knurled between the workpiece caused by excessive force generated tattoo buckle and ghosting and so on. If the spindle is reversed, it can effectively prevent the above ills, rolling out the lines of clear lines.
11. Prevent the center from breaking the method
When drilling a center hole with a diameter less than 1.5mm on the lathe, the center drill is easily broken. In addition to drilling and careful handling of chip removal, that is, drilling, do not lock the tailstock, so that the tailstock's weight and machine tool rail friction to drill. When the resistance of the drilling is too large, the tailstock will self-back, and protect the center drill.
12. Small sets of small eccentric workpieces
With the sleeve to clamp the workpiece car eccentric, the clamping efficiency than the four-jaw chuck 6 to 8 times higher. Given the eccentricity e and the workpiece outer diameter Φ2, you can find the inner diameter of the clamp sleeve Φ1, Φ1 = 2e + Φ2. When machining the inner diameter Φ1 of the clamp, be sure to pay attention to the accuracy of the hole so as to avoid the eccentricity of the workpiece.
13. The method of rotating the shaft
Screw conveyor, in the transport of granular materials, the application of more factories. The screw shaft in the body is made of steel plate when it is manufactured. This spiral plate of the tooth height, bottom diameter is small, diameter and journal must be coaxial. To achieve this requirement, you must use the lathe to turn the outer diameter of the screw shaft.
This type of shaft is generally long, in the processing of outer diameter, due to the pitch, tooth depth, thin teeth, poor rigidity, but also intermittent cutting, tooth by the impact of cutting vibration, so that it can not be normal cutting, but also damage Tool. In order to solve this problem, the cutting speed has to be reduced, the cutting depth and the feed rate are reduced, so that the work efficiency is greatly reduced.
In order to improve work efficiency and quality, to take a simple method of turning the thread, according to the screw shaft hanging hanging wheel, the use of large screw drive to drive the big carriage to turn. When the car finished the first knife, remember the trailer scale, the big carriage back, with a small knife to move forward (0.5 ~ 0.7) mm, and then start the second knife, so until the caster is good.
With this method to cut out the spiral shaft tooth top flat, basically eliminating the intermittent cutting, processing efficiency than the original increase of nearly 10 times.
14. Machining of threads outside the lathe nameplate
In a large number of mechanical transmission, multi-head worm, multi-head screw, long spiral spline, variable lead worm, double lead teeth thick worm, helical gear meshing worm, etc., lead in the lathe on the nameplate Processing difficult. It is a kind of solution that can not find the required pitch (or lead) on the lathe nameplate, which can save the trouble of hanging wheel.
For example, the imported milling machine with the helical gear meshing worm, the normal modulus of 3.175, the circumference of the modulus of 3.184, in the lathe can not find 3.184 modulus, to be calculated and production processing wheel. After calculation and analysis, the modulus pitch into metric pitch, that is, 3.184 × 3.1416 = 10.003mm, so you can press the pitch 10mm processing.
In the equipment overhaul and maintenance, mostly in meters to measure the thread pitch, so there will be non-standard pitch. In practice, the threads are divided into plain, inch, modular, diametric and nonstandard threads, and their pitch can be switched to each other. Such as 9.4248mm, 12.5664mm, 12.7mm, 25.4mm and 7.9756mm, etc., can press
1. Turn the slender shaft
"Car workers afraid of the car." This sentence reflects the difficulty of turning the slender pole. Due to the characteristics and technical requirements of the elongated shaft, in the high-speed turning, easy to produce vibration, polygon, bamboo, poor cylinder and bending defects. If you want to take it smoothly, you must pay attention to the problems in the process.
1) Machine adjustment
Lathe spindle and tailstock two center line connection and lathe large rail up and down must be parallel, tolerance should be less than 0.02mm.
2) Workpiece installation
In the installation, try not to have been positioning, with a chuck clamping end, do not exceed 10mm.
3) Tool
Using Κr = 75 ° ~ 90 ° side knife, pay attention to the posterior angle α'0 ≤ 4 ° ~ 6 °, should not be large. When the tool is installed, it should be slightly higher than the center.
4) with the knife, after the installation must be trimmed
Dressing method, can be used research, hinge, boring and other methods, so that with the knife jaw and workpiece contact with the arc R ≥ workpiece radius, must not be less than the workpiece radius to prevent multi-edge generation. In the adjustment with the knife claw, the claw can contact with the workpiece, do not force to prevent the bamboo produced.
5) auxiliary support
When the aspect ratio of the workpiece is greater than 40, the auxiliary support shall be added during the turning process to prevent the workpiece from vibrating or the centrifugal force. Cutting process to pay attention to the top of the adjustment to the top of the workpiece is appropriate, should not be tight, and at any time to adjust to prevent the workpiece thermal expansion bending.
2. anti-knife turning fine rods
Turning a lot of long rods, the general use of the knife with a knife or anti-knife turning. But anti-turning and turning compared with the turning, there are many advantages, most of the use.
In the turning prone to two problems, one is multi-prism, which is mainly after the tool angle, with the knife claw of the R and the workpiece out of the diameter caused by the disc; the other is the bamboo problem, It is by the knife in the mouth with a good knife, in the knife, knife to the cutting surface, from the cutting depth from a very small to suddenly increase, so that changes in cutting force, the workpiece produced outward knife, the diameter suddenly change Large, when the knife with a large diameter, the car out of the diameter becomes smaller, so the cycle, so that the processing of the workpiece for the bamboo-shaped.
In order to prevent the generation of bamboo, when the car is good shelf mouth, carefully with a knife, knife after the anti-knife, the use of the pallet handle, eat deep (0.04 ~ 0.08) mm, but according to the cutting depth Size is flexible.
3. Rolling straightening method
In the machining, often used to improve the workpiece surface hardness, fatigue strength and wear resistance, reduce the workpiece surface roughness, extend the service life of the workpiece. At the same time, can also be used in the rolling process, the metal under the action of external plastic deformation, so that the internal stress to adjust the straight and rigid shaft and rod class workpiece.
In the process of rolling the workpiece, the workpiece was rolled under the action of external force due to uneven surface hardness and bending. Bending the height of the rotation center, bear the rolling pressure, and the resulting plastic deformation is also large, so that the degree of bending of the workpiece is more increased. Especially in the use of rigid rolling tools, this phenomenon is more prominent.
Rolling straightening method is in the workpiece after the first rolling, check the workpiece radial runout, concave at the mark, with a four-jaw chuck to the workpiece concave, adjust the height of the machine to the center of rotation , And the workpiece is proportional to the size of bending, and then the second rolling, and then use the dial indicator and adjust the four-jaw chuck claws, the workpiece correction. And then use the dial indicator to check the bending of the situation, such as bending, and then the above method, adjust the workpiece, the third rolling, until the workpiece to achieve the straightness so far. After the second time the length of the pass, should be based on specific circumstances, do not have to complete the whole process, but also to use anti-knife.
The use of rolling straightening, generally in the process of rolling the workpiece to complete, not only will not damage the surface of the workpiece, but also the workpiece surface by a more uniform rolling, will not produce dead bending, but also easy to operate.
4. screw extrusion straightening method
For the larger diameter is longer, but also the existence of a few curved screw, the use of extrusion straight, the effect is very good.
1) working principle
Using the straightening tool, under the action of external force, squeeze the surface of the screw tooth bottom, so that the surface of plastic deformation, axial extension, change the internal stress of the screw, and make it straight.
2) straighten the method
First on the lathe or platform, measured the location and direction of the screw bending, and then bend the concave up, convex face down with the metal pad, with a flat shovel and hand hammer hit the bottom of the screw, so that silk Bar diameter metal deformation, and to achieve the purpose of straightening. In the whole straightening process, the detection of bending, blow the flat shovel extrusion staggered until the screw straightened. This method is simple and easy, not only for the size of the screw, but also for the straightening of the shaft rough, straighten it is not easy to recover.
3) should pay attention to the problem
The width of the special flat shovel should be greater than half the diameter of the root of the screw, b is less than the width of the tooth, α is less than the tooth angle; contact with the workpiece R cross section, should be grinding out the arc; Apply the file to trim the pressed teeth.
5. Rubber thread processing
As the hardness of rubber is very low, elastic modulus is only 2.35N, equivalent to carbon steel 1/85000, under the action of external force, easy to deformation, cutting is very difficult. Especially cutting some special-shaped thread, more difficult.
In order to solve the rubber thread processing, in the lathe to install a can adjust the helix angle of the grinding head, or in the case of high precision thread can also be used instead of pneumatic grinding head. Grinding wheel with diameter Φ60mm ~ Φ80mm, particle size 60 # ~ 100 # white corundum wheel. After the grinding wheel is installed, the diamond pen is used to trim the wheel shape. The shape of the grinding wheel is the normal section of the thread.
Thread guide small, lathe nameplate, you can directly pull the lathe handle to obtain. When there is no sign on the lathe, the required wheel must be calculated. General can be found manual, can also be used to calculate the method, find and manufacture the required wheel.
When the general thread lead is greater than 300mm, the spindle speed must be reduced so as to avoid the quality of the thread grinding due to the high spindle speed, but also to make the operation tight or damage the parts of the feed box. Deceleration methods are: change the main and passive pulley diameter; in the lathe outside the increase gear box.
The method of dividing the head is the same as the method of car threading.
Grinding rubber thread on the lathe is a kind of high efficiency and high quality processing technology. It has adopted the grinding method, the processing lead is (1.5 ~ 1280) mm single head and long rubber thread, its quality is consistent Claim.
6. Step deep hole turning method
Turning holes with an aspect ratio greater than 4 on the lathe is difficult due to the poor rigidity of the arbor, the vibration at the time of cutting, the efficiency of the cutting and the quality of the machined surface. In particular, the hole is large and the hole is very deep, and with the steps of the case, due to the arbor, machine tool rigidity, processing more difficult.
First in the lathe with the chuck and the central frame to install the workpiece, with the hole knife at both ends of the workpiece processing short hole, and each with a set and dedicated Arbor. In the middle of the long hole in the turning, the left end of the support package into the workpiece hole, and then install the workpiece on the lathe, the head out of the length of the adjustment in the pole, together with the left side of the support sleeve into the workpiece hole , With a knife pad to adjust the height of the knife, the knife cannula fixed on the lathe square knife table, so that the knife can slide freely in the sleeve, you can make the workpiece rotation, began to knife cutting, until the workpiece longitudinal depth.
When the workpiece is finished, move the large carriage in the opposite direction and exit the workpiece together with the support sleeve and the arbor at the right end to remove the workpiece. When machining the second piece, install the support sleeve on the left side, insert the workpiece, and then insert the tool bar into the support sleeve on the left end of the workpiece, and install the right end support sleeve to start the turning of the second workpiece.
Tooling features: both ends with a support sleeve support the arbor, greatly increased the rigidity of the arbor, so that no vibration cutting to ensure that the surface has been machined roughness; both ends with a support sleeve support rods to ensure that the hole between Position accuracy; easy to operate, the efficiency of the hole than the traditional method to improve more than 5 times.
7. Adjust the method of the center frame
In the length of the car, the diameter of the hollow parts of the hollow hole, the end of the need to use the center frame. If the center frame is not properly adjusted, the axis of the workpiece and the spindle axis of the machine does not coincide, the processing will produce the face of the heart and the drum and the hole taper error. When serious, the workpiece from the chuck out, causing the accident.
When installing such workpieces, one end of the workpiece with three-jaw chuck or four-jaw chuck, the other end on the center frame. And then in the workpiece hole in a piece of wood or in the end of the workpiece with butter paste a piece of paper, the tailstock tip tip on the board or paper, the choice of lower spindle speed, the workpiece turn a week or two , Then the board or paper on the top to draw a circle, and then adjust the center frame of three care, so that the center of the circle is the top of the tip, so that basically the center line and the machine tool spindle axis Basic coincidence. After semi-finishing, such as measuring the flatness of the end face and the hole degree of the tolerance, and then the center of the three care of the cable to adjust, to be eliminated.
8. Take the center of the hole in the hole
In the drilling of the center hole, due to the center of the lathe and the workpiece rotation center is inconsistent, or excessive force, the workpiece material plastic and chip plugging and other reasons, often caused by the center drill broken in the center hole, easy to remove.
Such as the use of the method to expand the center hole to take, then the center hole will change the original size, fail to meet the quality requirements. At this time, as long as the use of a sharpened wire, the tip into the hole in the hole hole drill bit trough, a few times, drill a move, with a magnet or magnetic table seat suction, broken in the center hole Inside the center of the drill tip to take out.
9. Defects when the slender shaft is cut
1) drum belly shape
That is, after turning, the workpiece two small diameter, the middle diameter. The reason for this defect is due to the poor rigidity of the elongated shaft, which is in contact with the surface of the tool holder and the surface of the workpiece. The wear causes a gap. When the vehicle is turned to the middle part, The rotation center of the workpiece is pressed to the right side of the center of rotation of the spindle so that the cutting depth is reduced and the rigidity of both ends of the workpiece is better and the cutting depth is substantially unchanged. As the central produce "let the knife" leaving the slender shaft into a bulging shape.
Eliminate the method. In the knife with the knife when the claws, be sure to carefully, so that the surface of the claw surface contact with the workpiece, not a gap. The main declination of the turning tool should be selected from 75 ° to 90 ° to reduce the radial force. With the knife claw, should choose a better wear resistance of cast iron.
2) Bamboo
Shaped like a bamboo, the pitch is approximately equal to the distance between the tool holder support claw and the tool nose, and is a cycle. The cause of this defect, due to the gap between the lathe and the middle of the lathe is too large, the blank material bending rotation caused by centrifugal force and with the tool holder support reference knife, resulting in knife when the "knife" A section of the diameter of the car is slightly larger than the reference section, continue to take the knife turning, with the knife support jaw contact with the workpiece diameter of a large section, so that the workpiece rotation center to the side of the turning tool, cut the workpiece diameter decreases. In this way, with the knife frame has a circular support in the workpiece diameter, so that the workpiece to leave and near the turning tool, and the formation of a regular bamboo-shaped. As well as in the knife with the knife jaw claws, forced too large, so that the workpiece rotation center pressed to the knife side, resulting in the car out of the smaller diameter, continue to take the knife, so the cycle, but also the formation of bamboo.
Elimination of the method: to adjust the gap between the machine parts, and enhance machine rigidity. In the knife with the knife claws, so that the claw is not only with the workpiece contact real, and do not force large. (0.05 ~ 0.1) mm, in order to eliminate the knife when the "knife" phenomenon, cut the size of the depth, to master the law of the machine, flexible control.
10. Reverse knurling
The traditional forward roll, in the process of rolling the chip easily into the workpiece and knurled between the workpiece caused by excessive force generated tattoo buckle and ghosting and so on. If the spindle is reversed, it can effectively prevent the above ills, rolling out the lines of clear lines.
11. Prevent the center from breaking the method
When drilling a center hole with a diameter less than 1.5mm on the lathe, the center drill is easily broken. In addition to drilling and careful handling of chip removal, that is, drilling, do not lock the tailstock, so that the tailstock's weight and machine tool rail friction to drill. When the resistance of the drilling is too large, the tailstock will self-back, and protect the center drill.
12. Small sets of small eccentric workpieces
With the sleeve to clamp the workpiece car eccentric, the clamping efficiency than the four-jaw chuck 6 to 8 times higher. Given the eccentricity e and the workpiece outer diameter Φ2, you can find the inner diameter of the clamp sleeve Φ1, Φ1 = 2e + Φ2. When machining the inner diameter Φ1 of the clamp, be sure to pay attention to the accuracy of the hole so as to avoid the eccentricity of the workpiece.
13. The method of rotating the shaft
Screw conveyor, in the transport of granular materials, the application of more factories. The screw shaft in the body is made of steel plate when it is manufactured. This spiral plate of the tooth height, bottom diameter is small, diameter and journal must be coaxial. To achieve this requirement, you must use the lathe to turn the outer diameter of the screw shaft.
This type of shaft is generally long, in the processing of outer diameter, due to the pitch, tooth depth, thin teeth, poor rigidity, but also intermittent cutting, tooth by the impact of cutting vibration, so that it can not be normal cutting, but also damage Tool. In order to solve this problem, the cutting speed has to be reduced, the cutting depth and the feed rate are reduced, so that the work efficiency is greatly reduced.
In order to improve work efficiency and quality, to take a simple method of turning the thread, according to the screw shaft hanging hanging wheel, the use of large screw drive to drive the big carriage to turn. When the car finished the first knife, remember the trailer scale, the big carriage back, with a small knife to move forward (0.5 ~ 0.7) mm, and then start the second knife, so until the caster is good.
With this method to cut out the spiral shaft tooth top flat, basically eliminating the intermittent cutting, processing efficiency than the original increase of nearly 10 times.
14. Machining of threads outside the lathe nameplate
In a large number of mechanical transmission, multi-head worm, multi-head screw, long spiral spline, variable lead worm, double lead teeth thick worm, helical gear meshing worm, etc., lead in the lathe on the nameplate Processing difficult. It is a kind of solution that can not find the required pitch (or lead) on the lathe nameplate, which can save the trouble of hanging wheel.
For example, the imported milling machine with the helical gear meshing worm, the normal modulus of 3.175, the circumference of the modulus of 3.184, in the lathe can not find 3.184 modulus, to be calculated and production processing wheel. After calculation and analysis, the modulus pitch into metric pitch, that is, 3.184 × 3.1416 = 10.003mm, so you can press the pitch 10mm processing.
In the equipment overhaul and maintenance, mostly in meters to measure the thread pitch, so there will be non-standard pitch. In practice, the threads are divided into plain, inch, modular, diametric and nonstandard threads, and their pitch can be switched to each other. Such as 9.4248mm, 12.5664mm, 12.7mm, 25.4mm and 7.9756mm, etc., can press
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