1. Accurately obtain trace food depth, clever use of trigonometric functions
In turning processing, some workpieces whose inner and outer circles are above the secondary precision are often processed. Due to various reasons such as cutting heat, friction between the workpiece and the tool, tool wear, and repeated positioning accuracy of the square tool holder, the quality is difficult to guarantee. In order to solve the precise micro-cutting depth, we use the relationship between the opposite side and the hypotenuse of the triangle according to the needs in the turning process, and move the small vertical tool holder to an angle, so as to accurately achieve the horizontal cutting depth value of the micro-moving turning tool. Purpose, saving labor and time, ensuring product quality and improving work efficiency.
The scale value of the general C620 lathe small tool post is 0.05mm per division. If you want to obtain the horizontal depth of penetration of 0.005mm, you can check the sine trigonometric function table:
sinα＝0.005/0.05＝0.1α＝5º44′
Therefore, as long as the small knife rest is moved to 5º44', every time the small knife rest is moved to engrave a grid vertically, a slight movement of the turning tool in the transverse direction with a depth of 0.005mm can be achieved.
Add pictures to WeChat: mvm9987 will send a CNC tutorial
2. Three Examples of Application of Reverse Turning Technology
The long-term production practice has proved that in the specific turning process, the use of reverse cutting technology can obtain good results. Examples are as follows:
(1) The reverse cutting thread material is martensitic stainless steel
When processing internal and external thread workpieces with a pitch of 1.25 and 1.75mm, because the pitch of the lathe screw is removed by the pitch of the workpiece, the resulting value is an indivisible value. If the thread is processed by lifting the handle of the coupling nut and withdrawing the tool, random buckling often occurs. Generally, ordinary lathes do not have a random buckling disc device, and a self-made set of random buckling discs is quite time-consuming, so it is time-consuming to process such pitches. When threaded, often. The method adopted is the low-speed parallel turning method, because it is too late to retract the tool with high-speed buckle, so the production efficiency is low, and the tool is easy to gnaw during turning, and the surface roughness is poor, especially when processing 1Crl3, 2Crl3 and other martensitic stainless steel materials When cutting at low speed, the phenomenon of biting the knife is more prominent. The "three-reverse" cutting method created in the processing practice, which is reverse loading, reverse cutting, and opposite direction of the cutting tool, can obtain a good comprehensive cutting effect, because this method can turn threads at high speed, and the moving direction of the tool is The tool exits the workpiece from left to right, so there is no disadvantage that the tool cannot retreat when cutting threads at high speed. The specific method is as follows:
When turning external threads, grind a similar internal thread turning tool (Figure 1);
When turning internal threads, grind a reverse internal thread turning tool (Figure 2).
Tighten the main shaft of the reverse friction plate slightly before processing to ensure the rotation speed at reverse start.
Align the thread cutter, close the split nut, turn forward at low speed and go to the empty tool groove, then enter the thread turning tool into the appropriate cutting depth, and then turn it reversely. At this time, the turning tool rotates from left to right at high speed. Move the tool to the right, and after cutting several times in this way, the thread with good surface roughness and high precision can be processed.
(2) Reverse car knurling
Iron filings and sundries can easily enter between the workpiece and the knurling cutter during the traditional forward knurling process, resulting in excessive stress on the workpiece, resulting in random bundles of lines, crushed patterns or double images.
If the new operation method of turning the main shaft of the lathe horizontally and reversely turning the knurling is adopted, it can effectively prevent the disadvantages caused by the parallel operation and obtain a good comprehensive effect.
(3) Reverse turning inner and outer tapered pipe threads
When turning various internal and external tapered pipe threads with low precision requirements and small batches, you can directly use the new operation method of reverse cutting and reverse tool loading without using the profiling device, and use it continuously while cutting. The hand strikes the knife horizontally (the thread of the external tapered pipe moves from left to right, and the horizontal knife is easy to control the depth of the knife from the large diameter to the small diameter) because there is pre-pressure when the knife is opened.
The range of application of this new type of reverse operation technology in turning technology is more and more extensive, and it can be flexibly applied according to various specific situations.
3. New operation method and tool innovation for drilling small holes
In turning processing, when drilling a hole smaller than 0.6mm, due to the small diameter of the drill bit, the rigidity is poor, and the cutting speed cannot be increased. The workpiece material is heat-resistant alloy and stainless steel, and the cutting resistance is large. Therefore, when drilling, if using In the way of mechanical transmission feeding, the drill bit is very easy to break. The following introduces a simple and effective tool and manual feeding method.
Firstly, the original drill chuck is changed into a straight shank floating type, and the drilling can be smoothly carried out as long as the small drill bit is clamped on the floating drill chuck during work. Because the rear part of the drill bit is a straight shank sliding fit, it can move freely in the puller sleeve. When drilling a small hole, gently hold the drill chuck with your hand to realize manual micro-feeding and quickly drill out the small hole. Maintain quality and quantity and prolong the service life of small drill bits. The modified multi-purpose drill chuck can also be used for small-diameter internal thread tapping, reaming, etc. (if drilling a larger hole, a limit pin can be inserted between the puller sleeve and the straight shank). See Figure 3.
4. Shockproof for deep hole machining
In deep hole processing, due to the small aperture and slender boring tool bar, vibration will inevitably occur when turning deep hole parts with a diameter of Φ30-50mm and a depth of about 1000mm. To prevent the tool bar from vibrating, the easiest and most effective way is Add two supports (with materials such as cloth bakelite) on the rod body, and its size is just in time consistent with the aperture size. During the cutting process, because the bakelite block acts as a positioning support, the tool rod is not easy to vibrate, and it can process deep hole parts with good quality.
5. Anti-breakage of small center drill
In turning processing, when drilling a center hole smaller than Φ1.5mm, the center drill is easily broken. The simple and effective method of preventing breakage is not to lock the tailstock when drilling the center hole, so that the weight of the tailstock and the machine bed surface The friction generated between them is used to drill the center hole. When the cutting resistance is too large, the tailstock will retreat by itself, thus protecting the center drill.
6. "O" type rubber mold processing technology
When turning the "O" type rubber mold, the phenomenon of misalignment between the female mold and the male mold often occurs, and the shape of the pressed "O" type rubber ring is shown in Figure 4, resulting in a large number of waste products.
After many tests, the following methods can basically be used to process "O" molds that meet the technical requirements.
(1) Male mold processing technology
①Finish the dimensions of each part and the 45° slope according to the drawing.
②Install the R forming knife, move the small knife holder to 45°, and the knife setting method is shown in Figure 5.
According to the figure, when the R knife is in the position A, the knife touches the outer circle D and the contact point is C, move the large carriage for a distance in the direction of arrow 1, and then move the horizontal tool holder by X dimension in the direction of arrow 2, press X The following formula is calculated:
X=(D-d)/2+(R-Rsin45°)
=(D-d)/2+(R-0.7071R)
=(D-d)/2+0.2929R
(ie 2X=D—d+0.2929Φ).
Then move the large carriage in the direction of arrow 3 so that the R knife touches the 45° slope, and at this time the knife is in the center position (that is, the R knife is at the B position).
③Move the cavity R of the small tool holder model in the direction of arrow 4, and the feed depth is Φ/2.
Note ① When the R knife is at the B position:
∵OC=R，OD=Rsin45°=0.7071R
∴CD=OC-OD=R-0.7071R=0.2929R,
②The X dimension can be controlled by a block gauge, and the R dimension can be controlled by a dial indicator.
(2) Die processing technology
① Process the dimensions of each part according to the requirements of Figure 6 (the cavity size is not processed).
②Grind and combine 45° inclined plane and end face.
③Install the R forming knife, move the small knife holder to 45° (move once to process the male and female molds), and when the R knife is at the position A' in Figure 6, touch the knife to the outer circle D (the contact point is C), press Move the large carriage in the direction of arrow 1 to make the tool leave the outer circle D, and then move the horizontal tool holder X distance in the direction of arrow 2, and X is calculated according to the following formula:
X=d+(D-d)/2+CD
=d+(D-d)/2+(R-0.7071R)
=d+(D-d)/2+0.2929R
(ie 2X=D+d+0.2929Φ)
Then move the large carriage in the direction of arrow 3 until the R knife touches the 45° slope, and the knife is at the center position (that is, the B' position in Figure 6).
④Move the cavity R of the small tool post model in the direction of arrow 4, and the feed depth is Φ/2.
Note: ①∵DC=R, OD=Rsin45°=0.7071R
∴CD=0.2929R,
②The X dimension can be controlled by a block gauge, and the R dimension can be controlled by a dial indicator.
7. Anti-vibration of Turning Thin-walled Workpieces
During the turning process of thin-walled workpieces, due to the poor rigidity of the workpieces, vibrations often occur; especially when turning stainless steel and heat-resistant alloys, the vibrations are more prominent, the surface roughness of the workpieces is extremely poor, and the tool life is shortened. The following are some of the simplest anti-shock methods in production.
(1) When turning the outer circle of the stainless steel hollow slender tube workpiece, the hole can be filled with sawdust and plugged tightly, and the two ends of the workpiece are plugged with cloth bakelite plugs at the same time, and then the supporting claws on the tool rest are replaced with The support melon made of bakelite material can be turned to the stainless steel hollow slender rod after correcting the required arc. This simple method can effectively prevent the vibration and deformation of the hollow slender rod during cutting.
(2) When turning the inner hole of heat-resistant (high nickel-chromium) alloy thin-walled workpiece, due to the poor rigidity of the workpiece and the slender tool rod, severe resonance occurs during the cutting process, which can easily damage the tool and produce waste products. If shock-absorbing materials such as rubber strips and sponges are wrapped on the outer circle of the workpiece, the shockproof effect can be effectively achieved.
(3) When turning the outer circle of heat-resistant alloy thin-walled sleeve workpieces, due to comprehensive factors such as the high cutting resistance of heat-resistant alloys, vibration and deformation are easily generated during cutting. If rubber and cotton silk are used to plug the workpiece holes Waiting for sundries, and then using both ends of the clamping method can effectively prevent vibration and deformation of the workpiece during cutting, and can process high-quality thin-walled sleeve workpieces.
8. Disc clamping tool
The shape of the disc-shaped part is a thin-walled part with double slopes. In the second process of turning around, it is necessary to ensure the tolerance requirements of its shape and position, and to ensure that the workpiece does not deform during clamping and cutting. For this reason, you can make a set of simple clamping tools by yourself, which is characterized by using the inclined surface processed by the previous process of the workpiece to locate, and then fastening the disc-shaped piece in this simple tool with the nut on the outer inclined surface. Carry out the arc R on the end face of the car, the hole and the outer slope, see Figure 7.
9. Fine boring large diameter soft jaw limit tool
In the turning and clamping of precision workpieces with large turning diameters, in order to prevent the movement of the three jaws due to the gap, a bar with the same diameter as the workpiece must be pre-clamped at the rear of the three jaws before boring can be repaired. Soft claw, our self-made fine boring large diameter soft claw limit tool, is characterized in that (see Figure 8), the three screws of No. Bars of various diameters and sizes.
10. Easy Precision Add-On Soft Jaws
In the turning process, we often encounter the processing of medium and small precision workpieces. Due to the complex interior and shape of the workpiece, and the stricter shape and position tolerance requirements, we add a set of self-made three-jaw chucks to C1616 and other lathes. The precision soft jaws ensure the shape and position tolerance requirements of the workpiece, and the workpiece will not be pinched and deformed during multiple clamping. This precision soft claw is easy to manufacture. Use aluminum alloy rods to turn the end as needed and then drill and bore holes. Drill a base hole on the outer circle and tap M8. After milling the two sides, it can be installed on the hard jaws of the original three-jaw chuck, locked on the three jaws with M8 inner hexagon screws, and then the workpiece can be clamped in the aluminum soft jaws after fine boring the positioning hole as required. Machining is done. The adoption of this achievement will produce significant economic benefits, as shown in Figure 9.
11. Additional anti-vibration tools
Due to the poor rigidity of the slender shaft workpiece, it is easy to generate vibration during the multi-groove cutting process, resulting in poor surface roughness of the workpiece and damage to the tool. A self-made set of additional anti-vibration tools can effectively solve the vibration problem of slender parts during grooving (see Figure 10).
Install the self-made additional anti-vibration tool on a suitable position on the square tool holder before work. Then install the required groove-shaped turning tool on the square tool holder, adjust the distance and the compression of the spring, and then start the operation. When the turning tool cuts into the workpiece, the additional anti-vibration tool will be pushed against the surface of the workpiece at the same time to play a good anti-vibration effect.
12. Additional live tip cap
When turning small shafts of various shapes for finishing, it is necessary to use the live center to support the workpiece before cutting. Due to the different shapes and small diameters of the ends of the workpiece, and the common live center can not be used, I have made various shapes of additional live center caps in production practice, and installed them on the ordinary live center. Tip on and ready to use. The structure is shown in Figure 11.
13. Difficult-to-machine materials apply honing finishing
When we finish turning high-temperature alloys, hardened steel and other difficult-to-machine materials, the surface roughness of the workpiece is required to be Ra0.20-0.05μm, and the dimensional accuracy is also high. Final finishing is usually performed on a grinding machine.
Make a set of simple honing tools and honing wheels by yourself, and use honing instead of fine grinding on the lathe to get better economic results.
honing wheel
Manufacture of honing wheels
① Ingredients
Adhesive: 100 grams of epoxy resin
Abrasive: Carborundum (single crystal corundum for difficult-to-process high-temperature nickel-chromium materials) 250-300 grams. For Ra0.80μm, use No. 80, for Ra0.20μm, use No. 120-150, and for Ra0.05μm, use No. 200-300.
Hardener: 7-8 grams of ethylenediamine.
Plasticizer: 10-15 grams of dibutyl phosphophthalate.
Mold material: HT15~33 shape.
② Pouring method
Release agent: heat the epoxy resin to 70-80°C, add 5% polystyrene, 95% toluene solution, dibutyl phosphophthalate and stir evenly, then put corundum (or single crystal corundum) into it and stir evenly , and then heated to 70-80°C, when cooled to 30°-38°C, add ethylenediamine, and stir quickly evenly (2-5 minutes), then pour it into the mold, and keep it warm at 40°C for 24 hours Re-mold.
③Linear speed V=V1COSα (V is the relative speed to the workpiece, that is, the grinding speed under the condition that the honing wheel does not perform longitudinal feed), thus producing a grinding effect on the workpiece. In addition to rotation, the axis of the workpiece is also given a speed during honing. Feed amount S for reciprocating motion.
V1=80～120m/min
t=0.05～0.10mm
Margin<0.1mm
④Cooling: 70% kerosene mixed with 30% No. 20 engine oil, correct the honing wheel before honing (pre-honing).
The honing tool structure is shown in Figure 13.
14. Quick release mandrel
In the turning process, various types of bearing kits are often encountered in the finishing turning of the outer circle and the reverse guide cone angle. Due to the large batch size, the auxiliary tool change time is longer than the cutting time during the process of loading and unloading, and the production efficiency Low. The quick loading and unloading mandrel and single-knife multi-edged (tungsten carbide) turning tool introduced below can save auxiliary time and ensure product quality in the processing of various bearing sleeve parts. The production method is as follows.
Make a simple mandrel with small taper. The principle is to use the 0.02mm taper at the back of the mandrel. After the bearing set is installed, the parts will be tightened on the mandrel by friction. After rounding and inverting the cone angle of 15°, the parking wrench is used to eject the parts quickly and well, as shown in Figure 14.
15. Turning of hardened steel parts
(1) One of the key examples of turning hardened steel parts
① Remanufacturing and regeneration of high-speed steel W18Cr4V hardened broach (repair after fracture)
② Self-made non-standard threaded plug gauge (hardened hardware)
③Turning of quenched hardware and sprayed parts
④ Turning of quenched hardware smooth plug gauge
⑤Reformed with high-speed steel cutting tools
1. Accurately obtain trace food depth, clever use of trigonometric functions
In turning processing, some workpieces whose inner and outer circles are above the secondary precision are often processed. Due to various reasons such as cutting heat, friction between the workpiece and the tool, tool wear, and repeated positioning accuracy of the square tool holder, the quality is difficult to guarantee. In order to solve the precise micro-cutting depth, we use the relationship between the opposite side and the hypotenuse of the triangle according to the needs in the turning process, and move the small vertical tool holder to an angle, so as to accurately achieve the horizontal cutting depth value of the micro-moving turning tool. Purpose, saving labor and time, ensuring product quality and improving work efficiency.
The scale value of the general C620 lathe small tool post is 0.05mm per division. If you want to obtain the horizontal depth of penetration of 0.005mm, you can check the sine trigonometric function table:
sinα＝0.005/0.05＝0.1α＝5º44′
Therefore, as long as the small knife rest is moved to 5º44', every time the small knife rest is moved to engrave a grid vertically, a slight movement of the turning tool in the transverse direction with a depth of 0.005mm can be achieved.
Add pictures to WeChat: mvm9987 will send a CNC tutorial
2. Three Examples of Application of Reverse Turning Technology
The long-term production practice has proved that in the specific turning process, the use of reverse cutting technology can obtain good results. Examples are as follows:
(1) The reverse cutting thread material is martensitic stainless steel
When processing internal and external thread workpieces with a pitch of 1.25 and 1.75mm, because the pitch of the lathe screw is removed by the pitch of the workpiece, the resulting value is an indivisible value. If the thread is processed by lifting the handle of the coupling nut and withdrawing the tool, random buckling often occurs. Generally, ordinary lathes do not have a random buckling disc device, and a self-made set of random buckling discs is quite time-consuming, so it is time-consuming to process such pitches. When threaded, often. The method adopted is the low-speed parallel turning method, because it is too late to retract the tool with high-speed buckle, so the production efficiency is low, and the tool is easy to gnaw during turning, and the surface roughness is poor, especially when processing 1Crl3, 2Crl3 and other martensitic stainless steel materials When cutting at low speed, the phenomenon of biting the knife is more prominent. The "three-reverse" cutting method created in the processing practice, which is reverse loading, reverse cutting, and opposite direction of the cutting tool, can obtain a good comprehensive cutting effect, because this method can turn threads at high speed, and the moving direction of the tool is The tool exits the workpiece from left to right, so there is no disadvantage that the tool cannot retreat when cutting threads at high speed. The specific method is as follows:
When turning external threads, grind a similar internal thread turning tool (Figure 1);
When turning internal threads, grind a reverse internal thread turning tool (Figure 2).
Tighten the main shaft of the reverse friction plate slightly before processing to ensure the rotation speed at reverse start.
Align the thread cutter, close the split nut, turn forward at low speed and go to the empty tool groove, then enter the thread turning tool into the appropriate cutting depth, and then turn it reversely. At this time, the turning tool rotates from left to right at high speed. Move the tool to the right, and after cutting several times in this way, the thread with good surface roughness and high precision can be processed.
(2) Reverse car knurling
Iron filings and sundries can easily enter between the workpiece and the knurling cutter during the traditional forward knurling process, resulting in excessive stress on the workpiece, resulting in random bundles of lines, crushed patterns or double images.
If the new operation method of turning the main shaft of the lathe horizontally and reversely turning the knurling is adopted, it can effectively prevent the disadvantages caused by the parallel operation and obtain a good comprehensive effect.
(3) Reverse turning inner and outer tapered pipe threads
When turning various internal and external tapered pipe threads with low precision requirements and small batches, you can directly use the new operation method of reverse cutting and reverse tool loading without using the profiling device, and use it continuously while cutting. The hand strikes the knife horizontally (the thread of the external tapered pipe moves from left to right, and the horizontal knife is easy to control the depth of the knife from the large diameter to the small diameter) because there is pre-pressure when the knife is opened.
The range of application of this new type of reverse operation technology in turning technology is more and more extensive, and it can be flexibly applied according to various specific situations.
3. New operation method and tool innovation for drilling small holes
In turning processing, when drilling a hole smaller than 0.6mm, due to the small diameter of the drill bit, the rigidity is poor, and the cutting speed cannot be increased. The workpiece material is heat-resistant alloy and stainless steel, and the cutting resistance is large. Therefore, when drilling, if using In the way of mechanical transmission feeding, the drill bit is very easy to break. The following introduces a simple and effective tool and manual feeding method.
Firstly, the original drill chuck is changed into a straight shank floating type, and the drilling can be smoothly carried out as long as the small drill bit is clamped on the floating drill chuck during work. Because the rear part of the drill bit is a straight shank sliding fit, it can move freely in the puller sleeve. When drilling a small hole, gently hold the drill chuck with your hand to realize manual micro-feeding and quickly drill out the small hole. Maintain quality and quantity and prolong the service life of small drill bits. The modified multi-purpose drill chuck can also be used for small-diameter internal thread tapping, reaming, etc. (if drilling a larger hole, a limit pin can be inserted between the puller sleeve and the straight shank). See Figure 3.
4. Shockproof for deep hole machining
In deep hole processing, due to the small aperture and slender boring tool bar, vibration will inevitably occur when turning deep hole parts with a diameter of Φ30-50mm and a depth of about 1000mm. To prevent the tool bar from vibrating, the easiest and most effective way is Add two supports (with materials such as cloth bakelite) on the rod body, and its size is just in time consistent with the aperture size. During the cutting process, because the bakelite block acts as a positioning support, the tool rod is not easy to vibrate, and it can process deep hole parts with good quality.
5. Anti-breakage of small center drill
In turning processing, when drilling a center hole smaller than Φ1.5mm, the center drill is easily broken. The simple and effective method of preventing breakage is not to lock the tailstock when drilling the center hole, so that the weight of the tailstock and the machine bed surface The friction generated between them is used to drill the center hole. When the cutting resistance is too large, the tailstock will retreat by itself, thus protecting the center drill.
6. "O" type rubber mold processing technology
When turning the "O" type rubber mold, the phenomenon of misalignment between the female mold and the male mold often occurs, and the shape of the pressed "O" type rubber ring is shown in Figure 4, resulting in a large number of waste products.
After many tests, the following methods can basically be used to process "O" molds that meet the technical requirements.
(1) Male mold processing technology
①Finish the dimensions of each part and the 45° slope according to the drawing.
②Install the R forming knife, move the small knife holder to 45°, and the knife setting method is shown in Figure 5.
According to the figure, when the R knife is in the position A, the knife touches the outer circle D and the contact point is C, move the large carriage for a distance in the direction of arrow 1, and then move the horizontal tool holder by X dimension in the direction of arrow 2, press X The following formula is calculated:
X=(D-d)/2+(R-Rsin45°)
=(D-d)/2+(R-0.7071R)
=(D-d)/2+0.2929R
(ie 2X=D—d+0.2929Φ).
Then move the large carriage in the direction of arrow 3 so that the R knife touches the 45° slope, and at this time the knife is in the center position (that is, the R knife is at the B position).
③Move the cavity R of the small tool holder model in the direction of arrow 4, and the feed depth is Φ/2.
Note ① When the R knife is at the B position:
∵OC=R，OD=Rsin45°=0.7071R
∴CD=OC-OD=R-0.7071R=0.2929R,
②The X dimension can be controlled by a block gauge, and the R dimension can be controlled by a dial indicator.
(2) Die processing technology
① Process the dimensions of each part according to the requirements of Figure 6 (the cavity size is not processed).
②Grind and combine 45° inclined plane and end face.
③Install the R forming knife, move the small knife holder to 45° (move once to process the male and female molds), and when the R knife is at the position A' in Figure 6, touch the knife to the outer circle D (the contact point is C), press Move the large carriage in the direction of arrow 1 to make the tool leave the outer circle D, and then move the horizontal tool holder X distance in the direction of arrow 2, and X is calculated according to the following formula:
X=d+(D-d)/2+CD
=d+(D-d)/2+(R-0.7071R)
=d+(D-d)/2+0.2929R
(ie 2X=D+d+0.2929Φ)
Then move the large carriage in the direction of arrow 3 until the R knife touches the 45° slope, and the knife is at the center position (that is, the B' position in Figure 6).
④Move the cavity R of the small tool post model in the direction of arrow 4, and the feed depth is Φ/2.
Note: ①∵DC=R, OD=Rsin45°=0.7071R
∴CD=0.2929R,
②The X dimension can be controlled by a block gauge, and the R dimension can be controlled by a dial indicator.
7. Anti-vibration of Turning Thin-walled Workpieces
During the turning process of thin-walled workpieces, due to the poor rigidity of the workpieces, vibrations often occur; especially when turning stainless steel and heat-resistant alloys, the vibrations are more prominent, the surface roughness of the workpieces is extremely poor, and the tool life is shortened. The following are some of the simplest anti-shock methods in production.
(1) When turning the outer circle of the stainless steel hollow slender tube workpiece, the hole can be filled with sawdust and plugged tightly, and the two ends of the workpiece are plugged with cloth bakelite plugs at the same time, and then the supporting claws on the tool rest are replaced with The support melon made of bakelite material can be turned to the stainless steel hollow slender rod after correcting the required arc. This simple method can effectively prevent the vibration and deformation of the hollow slender rod during cutting.
(2) When turning the inner hole of heat-resistant (high nickel-chromium) alloy thin-walled workpiece, due to the poor rigidity of the workpiece and the slender tool rod, severe resonance occurs during the cutting process, which can easily damage the tool and produce waste products. If shock-absorbing materials such as rubber strips and sponges are wrapped on the outer circle of the workpiece, the shockproof effect can be effectively achieved.
(3) When turning the outer circle of heat-resistant alloy thin-walled sleeve workpieces, due to comprehensive factors such as the high cutting resistance of heat-resistant alloys, vibration and deformation are easily generated during cutting. If rubber and cotton silk are used to plug the workpiece holes Waiting for sundries, and then using both ends of the clamping method can effectively prevent vibration and deformation of the workpiece during cutting, and can process high-quality thin-walled sleeve workpieces.
8. Disc clamping tool
The shape of the disc-shaped part is a thin-walled part with double slopes. In the second process of turning around, it is necessary to ensure the tolerance requirements of its shape and position, and to ensure that the workpiece does not deform during clamping and cutting. For this reason, you can make a set of simple clamping tools by yourself, which is characterized by using the inclined surface processed by the previous process of the workpiece to locate, and then fastening the disc-shaped piece in this simple tool with the nut on the outer inclined surface. Carry out the arc R on the end face of the car, the hole and the outer slope, see Figure 7.
9. Fine boring large diameter soft jaw limit tool
In the turning and clamping of precision workpieces with large turning diameters, in order to prevent the movement of the three jaws due to the gap, a bar with the same diameter as the workpiece must be pre-clamped at the rear of the three jaws before boring can be repaired. Soft claw, our self-made fine boring large diameter soft claw limit tool, is characterized in that (see Figure 8), the three screws of No. Bars of various diameters and sizes.
10. Easy Precision Add-On Soft Jaws
In the turning process, we often encounter the processing of medium and small precision workpieces. Due to the complex interior and shape of the workpiece, and the stricter shape and position tolerance requirements, we add a set of self-made three-jaw chucks to C1616 and other lathes. The precision soft jaws ensure the shape and position tolerance requirements of the workpiece, and the workpiece will not be pinched and deformed during multiple clamping. This precision soft claw is easy to manufacture. Use aluminum alloy rods to turn the end as needed and then drill and bore holes. Drill a base hole on the outer circle and tap M8. After milling the two sides, it can be installed on the hard jaws of the original three-jaw chuck, locked on the three jaws with M8 inner hexagon screws, and then the workpiece can be clamped in the aluminum soft jaws after fine boring the positioning hole as required. Machining is done. The adoption of this achievement will produce significant economic benefits, as shown in Figure 9.
11. Additional anti-vibration tools
Due to the poor rigidity of the slender shaft workpiece, it is easy to generate vibration during the multi-groove cutting process, resulting in poor surface roughness of the workpiece and damage to the tool. A self-made set of additional anti-vibration tools can effectively solve the vibration problem of slender parts during grooving (see Figure 10).
Install the self-made additional anti-vibration tool on a suitable position on the square tool holder before work. Then install the required groove-shaped turning tool on the square tool holder, adjust the distance and the compression of the spring, and then start the operation. When the turning tool cuts into the workpiece, the additional anti-vibration tool will be pushed against the surface of the workpiece at the same time to play a good anti-vibration effect.
12. Additional live tip cap
When turning small shafts of various shapes for finishing, it is necessary to use the live center to support the workpiece before cutting. Due to the different shapes and small diameters of the ends of the workpiece, and the common live center can not be used, I have made various shapes of additional live center caps in production practice, and installed them on the ordinary live center. Tip on and ready to use. The structure is shown in Figure 11.
13. Difficult-to-machine materials apply honing finishing
When we finish turning high-temperature alloys, hardened steel and other difficult-to-machine materials, the surface roughness of the workpiece is required to be Ra0.20-0.05μm, and the dimensional accuracy is also high. Final finishing is usually performed on a grinding machine.
Make a set of simple honing tools and honing wheels by yourself, and use honing instead of fine grinding on the lathe to get better economic results.
honing wheel
Manufacture of honing wheels
① Ingredients
Adhesive: 100 grams of epoxy resin
Abrasive: Carborundum (single crystal corundum for difficult-to-process high-temperature nickel-chromium materials) 250-300 grams. For Ra0.80μm, use No. 80, for Ra0.20μm, use No. 120-150, and for Ra0.05μm, use No. 200-300.
Hardener: 7-8 grams of ethylenediamine.
Plasticizer: 10-15 grams of dibutyl phosphophthalate.
Mold material: HT15~33 shape.
② Pouring method
Release agent: heat the epoxy resin to 70-80°C, add 5% polystyrene, 95% toluene solution, dibutyl phosphophthalate and stir evenly, then put corundum (or single crystal corundum) into it and stir evenly , and then heated to 70-80°C, when cooled to 30°-38°C, add ethylenediamine, and stir quickly evenly (2-5 minutes), then pour it into the mold, and keep it warm at 40°C for 24 hours Re-mold.
③Linear speed V=V1COSα (V is the relative speed to the workpiece, that is, the grinding speed under the condition that the honing wheel does not perform longitudinal feed), thus producing a grinding effect on the workpiece. In addition to rotation, the axis of the workpiece is also given a speed during honing. Feed amount S for reciprocating motion.
V1=80～120m/min
t=0.05～0.10mm
Margin<0.1mm
④Cooling: 70% kerosene mixed with 30% No. 20 engine oil, correct the honing wheel before honing (pre-honing).
The honing tool structure is shown in Figure 13.
14. Quick release mandrel
In the turning process, various types of bearing kits are often encountered in the finishing turning of the outer circle and the reverse guide cone angle. Due to the large batch size, the auxiliary tool change time is longer than the cutting time during the process of loading and unloading, and the production efficiency Low. The quick loading and unloading mandrel and single-knife multi-edged (tungsten carbide) turning tool introduced below can save auxiliary time and ensure product quality in the processing of various bearing sleeve parts. The production method is as follows.
Make a simple mandrel with small taper. The principle is to use the 0.02mm taper at the back of the mandrel. After the bearing set is installed, the parts will be tightened on the mandrel by friction. After rounding and inverting the cone angle of 15°, the parking wrench is used to eject the parts quickly and well, as shown in Figure 14.
15. Turning of hardened steel parts
(1) One of the key examples of turning hardened steel parts
① Remanufacturing and regeneration of high-speed steel W18Cr4V hardened broach (repair after fracture)
② Self-made non-standard threaded plug gauge (hardened hardware)
③Turning of quenched hardware and sprayed parts
④ Turning of quenched hardware smooth plug gauge
⑤Reformed with high-speed steel cutting tools
1. Accurately obtain trace food depth, clever use of trigonometric functions
In turning processing, some workpieces whose inner and outer circles are above the secondary precision are often processed. Due to various reasons such as cutting heat, friction between the workpiece and the tool, tool wear, and repeated positioning accuracy of the square tool holder, the quality is difficult to guarantee. In order to solve the precise micro-cutting depth, we use the relationship between the opposite side and the hypotenuse of the triangle according to the needs in the turning process, and move the small vertical tool holder to an angle, so as to accurately achieve the horizontal cutting depth value of the micro-moving turning tool. Purpose, saving labor and time, ensuring product quality and improving work efficiency.
The scale value of the general C620 lathe small tool post is 0.05mm per division. If you want to obtain the horizontal depth of penetration of 0.005mm, you can check the sine trigonometric function table:
sinα＝0.005/0.05＝0.1α＝5º44′
Therefore, as long as the small knife rest is moved to 5º44', every time the small knife rest is moved to engrave a grid vertically, a slight movement of the turning tool in the transverse direction with a depth of 0.005mm can be achieved.
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2. Three Examples of Application of Reverse Turning Technology
The long-term production practice has proved that in the specific turning process, the use of reverse cutting technology can obtain good results. Examples are as follows:
(1) The reverse cutting thread material is martensitic stainless steel
When processing internal and external thread workpieces with a pitch of 1.25 and 1.75mm, because the pitch of the lathe screw is removed by the pitch of the workpiece, the resulting value is an indivisible value. If the thread is processed by lifting the handle of the coupling nut and withdrawing the tool, random buckling often occurs. Generally, ordinary lathes do not have a random buckling disc device, and a self-made set of random buckling discs is quite time-consuming, so it is time-consuming to process such pitches. When threaded, often. The method adopted is the low-speed parallel turning method, because it is too late to retract the tool with high-speed buckle, so the production efficiency is low, and the tool is easy to gnaw during turning, and the surface roughness is poor, especially when processing 1Crl3, 2Crl3 and other martensitic stainless steel materials When cutting at low speed, the phenomenon of biting the knife is more prominent. The "three-reverse" cutting method created in the processing practice, which is reverse loading, reverse cutting, and opposite direction of the cutting tool, can obtain a good comprehensive cutting effect, because this method can turn threads at high speed, and the moving direction of the tool is The tool exits the workpiece from left to right, so there is no disadvantage that the tool cannot retreat when cutting threads at high speed. The specific method is as follows:
When turning external threads, grind a similar internal thread turning tool (Figure 1);
When turning internal threads, grind a reverse internal thread turning tool (Figure 2).
Tighten the main shaft of the reverse friction plate slightly before processing to ensure the rotation speed at reverse start.
Align the thread cutter, close the split nut, turn forward at low speed and go to the empty tool groove, then enter the thread turning tool into the appropriate cutting depth, and then turn it reversely. At this time, the turning tool rotates from left to right at high speed. Move the tool to the right, and after cutting several times in this way, the thread with good surface roughness and high precision can be processed.
(2) Reverse car knurling
Iron filings and sundries can easily enter between the workpiece and the knurling cutter during the traditional forward knurling process, resulting in excessive stress on the workpiece, resulting in random bundles of lines, crushed patterns or double images.
If the new operation method of turning the main shaft of the lathe horizontally and reversely turning the knurling is adopted, it can effectively prevent the disadvantages caused by the parallel operation and obtain a good comprehensive effect.
(3) Reverse turning inner and outer tapered pipe threads
When turning various internal and external tapered pipe threads with low precision requirements and small batches, you can directly use the new operation method of reverse cutting and reverse tool loading without using the profiling device, and use it continuously while cutting. The hand strikes the knife horizontally (the thread of the external tapered pipe moves from left to right, and the horizontal knife is easy to control the depth of the knife from the large diameter to the small diameter) because there is pre-pressure when the knife is opened.
The range of application of this new type of reverse operation technology in turning technology is more and more extensive, and it can be flexibly applied according to various specific situations.
3. New operation method and tool innovation for drilling small holes
In turning processing, when drilling a hole smaller than 0.6mm, due to the small diameter of the drill bit, the rigidity is poor, and the cutting speed cannot be increased. The workpiece material is heat-resistant alloy and stainless steel, and the cutting resistance is large. Therefore, when drilling, if using In the way of mechanical transmission feeding, the drill bit is very easy to break. The following introduces a simple and effective tool and manual feeding method.
Firstly, the original drill chuck is changed into a straight shank floating type, and the drilling can be smoothly carried out as long as the small drill bit is clamped on the floating drill chuck during work. Because the rear part of the drill bit is a straight shank sliding fit, it can move freely in the puller sleeve. When drilling a small hole, gently hold the drill chuck with your hand to realize manual micro-feeding and quickly drill out the small hole. Maintain quality and quantity and prolong the service life of small drill bits. The modified multi-purpose drill chuck can also be used for small-diameter internal thread tapping, reaming, etc. (if drilling a larger hole, a limit pin can be inserted between the puller sleeve and the straight shank). See Figure 3.
4. Shockproof for deep hole machining
In deep hole processing, due to the small aperture and slender boring tool bar, vibration will inevitably occur when turning deep hole parts with a diameter of Φ30-50mm and a depth of about 1000mm. To prevent the tool bar from vibrating, the easiest and most effective way is Add two supports (with materials such as cloth bakelite) on the rod body, and its size is just in time consistent with the aperture size. During the cutting process, because the bakelite block acts as a positioning support, the tool rod is not easy to vibrate, and it can process deep hole parts with good quality.
5. Anti-breakage of small center drill
In turning processing, when drilling a center hole smaller than Φ1.5mm, the center drill is easily broken. The simple and effective method of preventing breakage is not to lock the tailstock when drilling the center hole, so that the weight of the tailstock and the machine bed surface The friction generated between them is used to drill the center hole. When the cutting resistance is too large, the tailstock will retreat by itself, thus protecting the center drill.
6. "O" type rubber mold processing technology
When turning the "O" type rubber mold, the phenomenon of misalignment between the female mold and the male mold often occurs, and the shape of the pressed "O" type rubber ring is shown in Figure 4, resulting in a large number of waste products.
After many tests, the following methods can basically be used to process "O" molds that meet the technical requirements.
(1) Male mold processing technology
①Finish the dimensions of each part and the 45° slope according to the drawing.
②Install the R forming knife, move the small knife holder to 45°, and the knife setting method is shown in Figure 5.
According to the figure, when the R knife is in the position A, the knife touches the outer circle D and the contact point is C, move the large carriage for a distance in the direction of arrow 1, and then move the horizontal tool holder by X dimension in the direction of arrow 2, press X The following formula is calculated:
X=(D-d)/2+(R-Rsin45°)
=(D-d)/2+(R-0.7071R)
=(D-d)/2+0.2929R
(ie 2X=D—d+0.2929Φ).
Then move the large carriage in the direction of arrow 3 so that the R knife touches the 45° slope, and at this time the knife is in the center position (that is, the R knife is at the B position).
③Move the cavity R of the small tool holder model in the direction of arrow 4, and the feed depth is Φ/2.
Note ① When the R knife is at the B position:
∵OC=R，OD=Rsin45°=0.7071R
∴CD=OC-OD=R-0.7071R=0.2929R,
②The X dimension can be controlled by a block gauge, and the R dimension can be controlled by a dial indicator.
(2) Die processing technology
① Process the dimensions of each part according to the requirements of Figure 6 (the cavity size is not processed).
②Grind and combine 45° inclined plane and end face.
③Install the R forming knife, move the small knife holder to 45° (move once to process the male and female molds), and when the R knife is at the position A' in Figure 6, touch the knife to the outer circle D (the contact point is C), press Move the large carriage in the direction of arrow 1 to make the tool leave the outer circle D, and then move the horizontal tool holder X distance in the direction of arrow 2, and X is calculated according to the following formula:
X=d+(D-d)/2+CD
=d+(D-d)/2+(R-0.7071R)
=d+(D-d)/2+0.2929R
(ie 2X=D+d+0.2929Φ)
Then move the large carriage in the direction of arrow 3 until the R knife touches the 45° slope, and the knife is at the center position (that is, the B' position in Figure 6).
④Move the cavity R of the small tool post model in the direction of arrow 4, and the feed depth is Φ/2.
Note: ①∵DC=R, OD=Rsin45°=0.7071R
∴CD=0.2929R,
②The X dimension can be controlled by a block gauge, and the R dimension can be controlled by a dial indicator.
7. Anti-vibration of Turning Thin-walled Workpieces
During the turning process of thin-walled workpieces, due to the poor rigidity of the workpieces, vibrations often occur; especially when turning stainless steel and heat-resistant alloys, the vibrations are more prominent, the surface roughness of the workpieces is extremely poor, and the tool life is shortened. The following are some of the simplest anti-shock methods in production.
(1) When turning the outer circle of the stainless steel hollow slender tube workpiece, the hole can be filled with sawdust and plugged tightly, and the two ends of the workpiece are plugged with cloth bakelite plugs at the same time, and then the supporting claws on the tool rest are replaced with The support melon made of bakelite material can be turned to the stainless steel hollow slender rod after correcting the required arc. This simple method can effectively prevent the vibration and deformation of the hollow slender rod during cutting.
(2) When turning the inner hole of heat-resistant (high nickel-chromium) alloy thin-walled workpiece, due to the poor rigidity of the workpiece and the slender tool rod, severe resonance occurs during the cutting process, which can easily damage the tool and produce waste products. If shock-absorbing materials such as rubber strips and sponges are wrapped on the outer circle of the workpiece, the shockproof effect can be effectively achieved.
(3) When turning the outer circle of heat-resistant alloy thin-walled sleeve workpieces, due to comprehensive factors such as the high cutting resistance of heat-resistant alloys, vibration and deformation are easily generated during cutting. If rubber and cotton silk are used to plug the workpiece holes Waiting for sundries, and then using both ends of the clamping method can effectively prevent vibration and deformation of the workpiece during cutting, and can process high-quality thin-walled sleeve workpieces.
8. Disc clamping tool
The shape of the disc-shaped part is a thin-walled part with double slopes. In the second process of turning around, it is necessary to ensure the tolerance requirements of its shape and position, and to ensure that the workpiece does not deform during clamping and cutting. For this reason, you can make a set of simple clamping tools by yourself, which is characterized by using the inclined surface processed by the previous process of the workpiece to locate, and then fastening the disc-shaped piece in this simple tool with the nut on the outer inclined surface. Carry out the arc R on the end face of the car, the hole and the outer slope, see Figure 7.
9. Fine boring large diameter soft jaw limit tool
In the turning and clamping of precision workpieces with large turning diameters, in order to prevent the movement of the three jaws due to the gap, a bar with the same diameter as the workpiece must be pre-clamped at the rear of the three jaws before boring can be repaired. Soft claw, our self-made fine boring large diameter soft claw limit tool, is characterized in that (see Figure 8), the three screws of No. Bars of various diameters and sizes.
10. Easy Precision Add-On Soft Jaws
In the turning process, we often encounter the processing of medium and small precision workpieces. Due to the complex interior and shape of the workpiece, and the stricter shape and position tolerance requirements, we add a set of self-made three-jaw chucks to C1616 and other lathes. The precision soft jaws ensure the shape and position tolerance requirements of the workpiece, and the workpiece will not be pinched and deformed during multiple clamping. This precision soft claw is easy to manufacture. Use aluminum alloy rods to turn the end as needed and then drill and bore holes. Drill a base hole on the outer circle and tap M8. After milling the two sides, it can be installed on the hard jaws of the original three-jaw chuck, locked on the three jaws with M8 inner hexagon screws, and then the workpiece can be clamped in the aluminum soft jaws after fine boring the positioning hole as required. Machining is done. The adoption of this achievement will produce significant economic benefits, as shown in Figure 9.
11. Additional anti-vibration tools
Due to the poor rigidity of the slender shaft workpiece, it is easy to generate vibration during the multi-groove cutting process, resulting in poor surface roughness of the workpiece and damage to the tool. A self-made set of additional anti-vibration tools can effectively solve the vibration problem of slender parts during grooving (see Figure 10).
Install the self-made additional anti-vibration tool on a suitable position on the square tool holder before work. Then install the required groove-shaped turning tool on the square tool holder, adjust the distance and the compression of the spring, and then start the operation. When the turning tool cuts into the workpiece, the additional anti-vibration tool will be pushed against the surface of the workpiece at the same time to play a good anti-vibration effect.
12. Additional live tip cap
When turning small shafts of various shapes for finishing, it is necessary to use the live center to support the workpiece before cutting. Due to the different shapes and small diameters of the ends of the workpiece, and the common live center can not be used, I have made various shapes of additional live center caps in production practice, and installed them on the ordinary live center. Tip on and ready to use. The structure is shown in Figure 11.
13. Difficult-to-machine materials apply honing finishing
When we finish turning high-temperature alloys, hardened steel and other difficult-to-machine materials, the surface roughness of the workpiece is required to be Ra0.20-0.05μm, and the dimensional accuracy is also high. Final finishing is usually performed on a grinding machine.
Make a set of simple honing tools and honing wheels by yourself, and use honing instead of fine grinding on the lathe to get better economic results.
honing wheel
Manufacture of honing wheels
① Ingredients
Adhesive: 100 grams of epoxy resin
Abrasive: Carborundum (single crystal corundum for difficult-to-process high-temperature nickel-chromium materials) 250-300 grams. For Ra0.80μm, use No. 80, for Ra0.20μm, use No. 120-150, and for Ra0.05μm, use No. 200-300.
Hardener: 7-8 grams of ethylenediamine.
Plasticizer: 10-15 grams of dibutyl phosphophthalate.
Mold material: HT15~33 shape.
② Pouring method
Release agent: heat the epoxy resin to 70-80°C, add 5% polystyrene, 95% toluene solution, dibutyl phosphophthalate and stir evenly, then put corundum (or single crystal corundum) into it and stir evenly , and then heated to 70-80°C, when cooled to 30°-38°C, add ethylenediamine, and stir quickly evenly (2-5 minutes), then pour it into the mold, and keep it warm at 40°C for 24 hours Re-mold.
③Linear speed V=V1COSα (V is the relative speed to the workpiece, that is, the grinding speed under the condition that the honing wheel does not perform longitudinal feed), thus producing a grinding effect on the workpiece. In addition to rotation, the axis of the workpiece is also given a speed during honing. Feed amount S for reciprocating motion.
V1=80～120m/min
t=0.05～0.10mm
Margin<0.1mm
④Cooling: 70% kerosene mixed with 30% No. 20 engine oil, correct the honing wheel before honing (pre-honing).
The honing tool structure is shown in Figure 13.
14. Quick release mandrel
In the turning process, various types of bearing kits are often encountered in the finishing turning of the outer circle and the reverse guide cone angle. Due to the large batch size, the auxiliary tool change time is longer than the cutting time during the process of loading and unloading, and the production efficiency Low. The quick loading and unloading mandrel and single-knife multi-edged (tungsten carbide) turning tool introduced below can save auxiliary time and ensure product quality in the processing of various bearing sleeve parts. The production method is as follows.
Make a simple mandrel with small taper. The principle is to use the 0.02mm taper at the back of the mandrel. After the bearing set is installed, the parts will be tightened on the mandrel by friction. After rounding and inverting the cone angle of 15°, the parking wrench is used to eject the parts quickly and well, as shown in Figure 14.
15. Turning of hardened steel parts
(1) One of the key examples of turning hardened steel parts
① Remanufacturing and regeneration of high-speed steel W18Cr4V hardened broach (repair after fracture)
② Self-made non-standard threaded plug gauge (hardened hardware)
③Turning of quenched hardware and sprayed parts
④ Turning of quenched hardware smooth plug gauge
⑤Reformed with high-speed steel cutting tools
