CN114074247B - Machining and forming method of valve rod with quick-open type multi-head thread long and thin distance - Google Patents
Machining and forming method of valve rod with quick-open type multi-head thread long and thin distance Download PDFInfo
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- CN114074247B CN114074247B CN202010802518.2A CN202010802518A CN114074247B CN 114074247 B CN114074247 B CN 114074247B CN 202010802518 A CN202010802518 A CN 202010802518A CN 114074247 B CN114074247 B CN 114074247B
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- 238000000034 method Methods 0.000 title claims abstract description 40
- 238000003754 machining Methods 0.000 title claims description 13
- 238000007514 turning Methods 0.000 claims abstract description 91
- 238000005520 cutting process Methods 0.000 claims abstract description 73
- 210000000078 claw Anatomy 0.000 claims abstract description 25
- 230000008569 process Effects 0.000 claims abstract description 15
- 238000003672 processing method Methods 0.000 claims abstract description 14
- 238000005461 lubrication Methods 0.000 claims abstract description 10
- 238000001816 cooling Methods 0.000 claims abstract description 8
- 239000002283 diesel fuel Substances 0.000 claims abstract description 8
- 239000010705 motor oil Substances 0.000 claims abstract description 8
- 230000003746 surface roughness Effects 0.000 claims abstract description 8
- 239000007788 liquid Substances 0.000 claims abstract description 5
- 238000005498 polishing Methods 0.000 claims abstract description 4
- 235000012424 soybean oil Nutrition 0.000 claims abstract description 4
- 239000003549 soybean oil Substances 0.000 claims abstract description 4
- 235000015112 vegetable and seed oil Nutrition 0.000 claims abstract description 4
- 239000008158 vegetable oil Substances 0.000 claims abstract description 4
- 230000007704 transition Effects 0.000 claims description 8
- 239000000956 alloy Substances 0.000 claims description 6
- 229910045601 alloy Inorganic materials 0.000 claims description 6
- 230000007547 defect Effects 0.000 claims description 4
- 235000017166 Bambusa arundinacea Nutrition 0.000 claims description 3
- 235000017491 Bambusa tulda Nutrition 0.000 claims description 3
- 229910000975 Carbon steel Inorganic materials 0.000 claims description 3
- 235000015334 Phyllostachys viridis Nutrition 0.000 claims description 3
- 239000011425 bamboo Substances 0.000 claims description 3
- 239000010962 carbon steel Substances 0.000 claims description 3
- 230000008859 change Effects 0.000 claims description 3
- 239000003795 chemical substances by application Substances 0.000 claims description 3
- 238000006073 displacement reaction Methods 0.000 claims description 3
- 239000004744 fabric Substances 0.000 claims description 3
- 239000010687 lubricating oil Substances 0.000 claims description 3
- 238000009966 trimming Methods 0.000 claims description 2
- 244000082204 Phyllostachys viridis Species 0.000 claims 1
- 239000011259 mixed solution Substances 0.000 abstract description 3
- 238000005452 bending Methods 0.000 description 5
- 239000002173 cutting fluid Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 241001330002 Bambuseae Species 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
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- 238000005516 engineering process Methods 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
- B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
- B23P15/001—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass valves or valve housings
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23B—TURNING; BORING
- B23B31/00—Chucks; Expansion mandrels; Adaptations thereof for remote control
- B23B31/02—Chucks
- B23B31/10—Chucks characterised by the retaining or gripping devices or their immediate operating means
- B23B31/103—Retention by pivotal elements, e.g. catches, pawls
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
- B23Q11/00—Accessories fitted to machine tools for keeping tools or parts of the machine in good working condition or for cooling work; Safety devices specially combined with or arranged in, or specially adapted for use in connection with, machine tools
- B23Q11/10—Arrangements for cooling or lubricating tools or work
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
- B23Q3/00—Devices holding, supporting, or positioning work or tools, of a kind normally removable from the machine
- B23Q3/02—Devices holding, supporting, or positioning work or tools, of a kind normally removable from the machine for mounting on a work-table, tool-slide, or analogous part
- B23Q3/06—Work-clamping means
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Abstract
The invention relates to a processing and forming method of a quick-open type multi-head thread long-distance valve rod, which comprises the following steps: first, center positioning: the slender shaft is supported and turned by using a follower rest with three supporting claws, and the follower rest is fixed on a saddle; second, peeling rough turning and bright finish turning: turning in the opposite direction; thirdly, turning a multi-head thread: turning programming is carried out in a FANUC numerical control machine by adopting a G32 single-stroke thread cutting instruction processing method, a G92 thread cutting circulation instruction processing method or a G76 thread cutting complex circulation processing method, so that multi-head threads are turned; during coarse turning, a mixed solution of diesel oil and 10% engine oil is adopted for lubrication and cooling; when in the process of polishing and turning multiple threads, mixed liquid or vegetable oil of 40% of soybean oil, 30% of engine oil and 30% of diesel oil is used for full lubrication and cooling so as to improve the surface roughness Ra and make cutting light and fast.
Description
Technical Field
The invention relates to the technical field of manufacturing and processing of valve fittings, in particular to a processing and forming method of a valve rod with a long and thin distance of a quick-opening multi-head thread.
Background
The valve rod with the long and thin distance of the quick-opening multi-head thread is a valve rod with the length of more than 2.5 meters and 4 meters, the diameter of 60mm and 100mm, more than four threads and the surface roughness Ra of the valve rod is required to be in the range of 0.1-0.8. Because the valve rod is long and has small diameter, and more than four coaxial threads are required to be turned after the surface is cut, mechanical vibration or knife binding is easy to occur due to overlong valve rod length and extremely thin diameter in the process of finish machining and threading the surface, and even the valve rod bending deformation and the like are caused due to mechanical friction thermal effect in the valve rod machining process, so that the rejection rate is extremely high.
Disclosure of Invention
The invention aims to provide a processing and forming method of a quick-open type multi-head thread long-distance valve rod, which aims to solve the technical problems of valve rod machining and thread turning deformation and the like, wherein the problems of the valve rod machining and thread turning deformation with the current length of more than 2.5 meters to 4 meters, the diameter of more than 60mm to 100mm and the surface roughness Ra of more than four threads are required to be within the range of 0.1-0.8.
The invention aims to solve the defects in the prior art and provides a processing and forming method of a valve rod with a long distance of a quick-opening multi-head thread, which comprises the following steps:
first, center positioning:
the center frame is used for directly supporting the middle of the workpiece, and when in turning, the center frame is supported in the middle of the workpiece, and lubricating oil is added at the contact part of the center frame and the workpiece;
the transition sleeve is used for supporting the turning slender shaft, four screws are respectively arranged at two ends of the transition sleeve, and the axes of the excircles of the screw sleeves are overlapped with the rotation line of the main shaft;
the slender shaft is supported and turned by using a follower rest with three supporting claws, and the follower rest is fixed on a saddle;
second, peeling rough turning and bright finish turning:
the method comprises the steps of adopting reverse turning, feeding from a lathe spindle to a tailstock, and clamping a workpiece on a three-jaw self-centering chuck during turning, so that one clamped end becomes a fixed point which can not longitudinally float; cutting by feeding the headstock to the tailstock direction, wherein the axial cutting force straightens the cut part of the workpiece and pushes the part to be processed of the workpiece to move to the tailstock direction;
thirdly, turning a multi-head thread:
and turning programming is carried out in the FANUC numerical control machine by adopting a G32 single-stroke thread cutting instruction processing method, a G92 thread cutting circulation instruction processing method or a G76 thread cutting composite circulation processing method, so that the multi-head thread is turned.
During coarse turning, a mixed solution of diesel oil and 10% engine oil is adopted for lubrication and cooling;
when in the process of polishing and threading, the mixed liquid or vegetable oil of 40% of soybean oil, 30% of engine oil and 30% of diesel oil is used for fully lubricating and cooling so as to improve the surface roughness Ra and make the cutting light and fast.
Preferably, in the step of centering, a section of groove for supporting the claw is formed in the middle of the blank before the workpiece is mounted on the center frame; and a layer of abrasive cloth or grinding agent is added between the supporting claw of the center frame and the workpiece for grinding and cohesion, so that the supporting claw and the workpiece keep good contact.
Preferably, in the steps of rough turning and bright finish turning, the follower rest is loosened before machining, then a cutter is driven to take a tool, the follower rest is quickly kept up, the cutter is not retracted and stopped when the follower rest is contacted, the adjusting force between the support claw of the follower rest and the shaft surface is controlled so as not to deform the top of the shaft part to be suitable for preventing over-loosening or over-tightening, the support claw of the follower rest is tightly contacted with the shaft surface, and the shaft and the claw are in lubrication fit to avoid the slender shaft from forming a bamboo joint shape.
Preferably, after rough turning, semi-finish turning and before finish turning, the shaft piece is corrected again, and the center hole error and the displacement error generated in the rough turning are corrected to eliminate internal stress.
Further preferably, the main deflection angle of the turning tool used in turning is 75-90 degrees, and the front angle is 28-30 degrees; the hard alloy blade is YT15, and the cutter bar is 45 high-quality carbon steel.
Preferably, the main deflection angle of the turning tool is 75 degrees, the main cutting edge rake angle is 25 degrees, the chamfer angle is 0.4-0.8 mm, the main relief angle of the turning tool is 8 degrees, the chamfer angle is 0.1-0.3 mm, and the edge relief angle is-12 degrees.
Further preferably, the cutter structure of the finishing tool adopts an elastic cutter bar, the hard alloy blade adopts YT15, the cutter point is lower than the center of the shaft element by 0.1mm when the cutter is assembled, the finishing cutting edge is 8-10 mm, the cutting edge is propped against the shaft element for turning, the defect of biting the cutter caused by the change of turning force is prevented, and the front angle is 30 degrees, so that the cutting is light and rapid.
Further preferably, in the reverse turning, the maximum feed is taken first to increase the axial tensile stress of the workpiece, the maximum cut is taken second, and the maximum cutting speed is taken last.
Further preferably, when the ratio of the length to the diameter of the workpiece is 40-120, if the cutting speed is 40m/min, the feeding amount is 0.35-0.5 mm/r; if v=45-100 m/min, the feeding amount is 0.6-1.2 mm/r.
Further preferably, when the rough cut is made, the cutting speed is 50-60 m/min, the feeding amount is 0.3-0.4 mm/r, and the cutting depth is 1.5-2 mm; when the precision is used, the cutting speed is 60-100 m/min, the feeding amount is 0.08-0.12 mm/r, and the cutting depth is 0.5-1 mm.
Advantageous effects
Compared with the prior art, the invention has the beneficial effects that: by adopting the processing and forming method of the quick-open type multi-head thread long-distance valve rod, the processed long-shaft-distance valve rod has the effect that the surface finish reaches 0.1-0.8, bending deformation is avoided, meanwhile, the stability of thread pitch and the surface finish are ensured in the thread turning process, and meanwhile, the problems of deformation, scrapping and the like of the valve rod caused by cutting and machine resonance in the turning process are also reduced. In conclusion, the invention has the characteristics of simple production and manufacturing process, attractive appearance of finished products, controllable product quality, high yield and the like.
Drawings
The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate and do not limit the invention.
FIG. 1 is a flow chart of a method for forming a valve rod with a quick-open type multi-start thread and a long distance.
Fig. 2 is a schematic drawing of the processing of a single start thread.
Fig. 3 is a schematic drawing of a double-start thread process.
Detailed Description
The present invention is described in more detail below to facilitate an understanding of the present invention.
As shown in FIG. 1, the processing and forming method of the quick-open type multi-head thread long-distance valve rod comprises the following steps:
first, center positioning:
1. the center frame directly supports the middle of the workpiece, when the workpiece can be turned in sections, the center frame is supported in the middle of the workpiece, so that the L/d is reduced by half, and the rigidity of the valve rod during turning can be increased by several times. Before the workpiece is mounted on the center frame, a section of groove for supporting the claw must be formed in the middle of the blank, and the surface roughness and cylindricity errors are small, otherwise, the precision of the workpiece is affected. During turning, lubricating oil should be added frequently to the contact part between the center frame and the workpiece. In order to keep the supporting claw and the workpiece in good contact, a layer of abrasive cloth or grinding agent can be added between the supporting claw of the center frame and the workpiece for grinding and cohesion.
2. The method is difficult to turn grooves of a supporting center frame by using a transition sleeve to support a valve rod with a long distance, and in order to solve the problem, the transition sleeve is sleeved on the valve rod of the pre-turning, and the outer edge of the transition sleeve is contacted with a center positioning contact of the center frame. Four screws are respectively arranged at two ends of the transition sleeve, and the turning can be realized by using the axes of the outer circles of the screw sleeves to coincide with the rotation line of the main shaft.
3. The slender shaft is supported and turned by the follower rest, the follower rest is fixed on the saddle and is provided with two supporting claws, the follower rest can move along with the turning tool, the rigidity of a workpiece can be increased when radial cutting is counteracted, and deformation is reduced. Thereby improving slim profile accuracy and reducing surface roughness. From the design principle of the follower rest, only two supporting claws are needed, and the workpiece is attached to the two supporting claws of the follower rest due to the cutting resistance Fr of the lathe tool to the workpiece. However, in practice, the workpiece itself has a downward gravity and the workpiece is inevitably bent, so that when turning, the workpiece tends to instantaneously leave the support jaw due to centrifugal force and contact the support jaw to generate vibration. If the follower rest with three supporting claws is used for supporting one surface of a workpiece to be supported by the turning tool, the workpiece can not move up and down and left and right, and the workpiece is stable during turning and is not easy to vibrate. A very critical problem in turning an elongated shaft is therefore the application of a three jaw follower rest.
Second, peeling rough turning and bright finish turning:
the reasonable choice of cutting amount in the turning process, and the geometric angle and parameters of the cutter are the key for guaranteeing the one-step molding of the valve rod. Therefore, the workpiece is clamped between the main shaft and the tailstock by adopting the conventional processing method, the two ends of the workpiece are not telescopic, and the workpiece generates internal stress and bending deformation under the influence of cutting force and thermal expansion, so that the straightness and the dimensional accuracy are not easy to ensure. The reverse direction tool-feeding method is a method for overcoming the phenomenon, is suitable for medium-speed rough turning and large-feed low-speed finish turning, and has the characteristics of strong adaptability, low requirement on machine tool precision, higher machining efficiency and the like. The specific processing is as follows:
1. and in the reverse turning, the workpiece is clamped on the three-jaw self-centering chuck during turning by feeding from the lathe spindle to the tailstock direction, so that the clamped end becomes a fixed point which can not longitudinally move. At this time, the longitudinal cutting generated during cutting tends to the tailstock direction along the axis of the workpiece, and the workpiece is strained by the axial force, so that the actual rigidity of the workpiece is increased, and bending (bowing) deformation is prevented. Meanwhile, when the reverse turning is carried out, a larger feeding amount is adopted, so that the longitudinal cutting force is increased, the radial circle runout is lightened, the large-amplitude vibration is reduced and eliminated, and the quality of the processed surface is ensured. The self-centering module combining the three-jaw follower rest processed by the process has the following functions:
firstly, changing the mode of clamping a workpiece by a conventional processing method, changing the surface contact into the line contact, and reducing the stress deformation;
the tail center on the second tailstock is changed into a telescopic spring center, so that forced bending of the workpiece caused by thermal extension is eliminated;
thirdly, the three-jaw follower rest can better ensure centripetal parallel movement and prevent the vibration in the turning of the slender shaft. (note that the follower rest is firstly loosened before machining and then the tool is driven to be eaten, the follower rest is quickly kept up, the tool is not retracted and stopped when the follower rest is contacted, the adjusting force between the support claw of the follower rest and the shaft surface is proper so as not to deform the top of the shaft part to be proper, the excessive loosening or the excessive tightening is prevented, the contact between the support claw of the follower rest and the shaft surface is tight, and the shaft and the claw are in lubrication fit, so that the slender shaft can be prevented from forming a bamboo joint shape after cutting;
fourthly, cutting by feeding from the headstock to the tailstock, wherein the axial cutting force straightens the cut part of the workpiece and pushes the part to be processed of the workpiece to move to the tailstock;
fifthly, correcting the shaft piece again after rough turning and before semi-finish turning, correcting tip hole errors and displacement errors generated in rough turning, and eliminating internal stress.
2. Turning process description:
because of the longer length of the valve stem, the rigidity is insufficient, and the smaller the radial cutting force is required, the better. Therefore, the cutter is required to have sharp cutting edge, light and rapid cutting, smooth chip removal and high durability. The principle is to enlarge the rake angle and the principal deflection angle as much as possible under the premise of not influencing the strength of the cutter. The principal deviation angle phi=75 to 90 deg., and the front angle gamma=28 to 30 deg. The hard alloy blade is yT15, and the cutter bar is 45 high-quality carbon steel. Preferably, the principal deviation angle Φ=75°. The main cutting edge rake angle gamma=25°, the edge rake angle is 25 °, the chamfer is 0.4-0.8 mm, and the chip breaking performance is good due to the chamfer and the R4mm chip breaking groove. Meanwhile, the strength of the cutter point and the heat dissipation condition are increased due to the increase of the angle of the cutter point. The main back angle alpha=8° of the turning tool, the chamfer angle is 0.1-0.3 mm, the chamfer angle is-12 °, thus the contact area of the back clearance surface of the turning tool supported on the workpiece is increased, the biting phenomenon caused by uneven internal tissue of the workpiece material is prevented, and the low-frequency vibration can be eliminated.
The finishing tool adopts an elastic cutter bar to play a role in damping and improve cutting conditions, and the hard alloy blade adopts YT15, so that the cutter point is lower than the center of the shaft element by 0.1mm when the cutter is assembled. The cutting edge is wider, and the trimming cutting edge is 8-10 mm. The lathe tool and the shaft piece can be kept to have a certain contact area, the cutting edge is propped against the shaft piece for turning, and the defect of biting the tool caused by the change of turning force can be prevented. The principal deflection angle is small so as to form a thin cutting with small deformation, which is beneficial to improving the finish of the processed surface, and the front angle gamma=30°, so that the cutting is light and quick.
Reasonable cutting amount is selected, and special requirements are made on the cutting amount in reverse turning. The maximum feed f is required to increase the axial tensile stress of the workpiece and prevent the workpiece from vibrating greatly. The choice of cutting volume is limited by the geometric errors of the machined surface, and is typically selected in the order: firstly, taking the maximum feeding amount, secondly, taking the maximum cut amount ap, and finally, taking the maximum cutting speed v. Practice proves that when the ratio of the length to the diameter of the workpiece is 40-120, if v=40m/min (V represents cutting speed), f is preferably 0.35-0.5 mm/r; if v=45 to 100m/min, f is preferably 0.6 to 1.2mm/r. Cutting amount selection in actual operation: when in rough cutting, the cutting speed is 50-60 m/min, the feeding amount is 0.3-0.4 mm/r, and the cutting depth is 1.5-2 mm; when the precision is used, the cutting speed is 60-100 m/min, the feeding amount is 0.08-0.12 mm/r, and the cutting depth is 0.5-1 mm.
Thirdly, turning a multi-head thread:
the multi-start thread means that there are more than two spiral grooves. The thread having one helical groove is called a single start thread. In the current FANUC numerical control machine, three types of thread cutting instructions are commonly used: g32 single-stroke thread cutting instruction processing method, G92 thread cutting cycle instruction processing method, and G76 thread cutting compound cycle processing method.
Thread machining is commonly used in numerical control turning, the turning programming of single-head threads is simple, operators use the single-head threads widely, and for double-head (or multi-head) thread turning, the use is not so much, and the operators often do not know how to start. The method for processing the multi-start thread is described below by taking one of the instructions G92 as an example.
The instruction format of the G92 thread cutting cycle instruction is G92X (U) _Z (W) _F_;
where X, Z denotes the thread end point coordinate value.
U, W the coordinate component of the thread end point relative to the start of the cycle.
F represents the thread lead (the lead of a single start thread is the same as the pitch value).
The lead is different from the pitch in a multi-start thread because the lead is the distance that progresses one revolution along a helical groove, and the pitch is the distance between two adjacent helical grooves on the thread. The relationship between lead and pitch can be expressed by the following formula:
L＝t×n
wherein L is thread lead (mm);
n is the number of thread starts;
t is the thread pitch (mm).
In the processing of the single start thread shown in fig. 2, the following is programmed using the cylindrical thread cutting cycle instructions:
O 001；
T 0101；
M 03；
G 00X 35Z3；
G 92X 29.2Z-21F 1.5；
X 28.6；
X 28.2；
X 28.05；
G 00X 100Z50；
M 05；
M 02。
when machining the single start thread shown in fig. 3, the thread turning start point coordinates are first shifted. The setting of the starting point of the first spiral groove of the double-head thread is consistent with the setting of the starting point of the single-head thread, the Z coordinate value of the starting point of the first spiral groove is only required to be shifted when the second spiral groove is machined, the offset is the pitch value of the thread, the X value is not required to be changed, and the like can be adopted when the multi-head thread is machined. The processing program is programmed as follows:
O 002；
T 0101；
M 03；
g00x35z 3; (first spiral groove)
G 92X 29.2Z-21F3；
X 28.6；
X 28.2；
X 28.05；
G00x 35Z 1.5 (or Z4.5); (second spiral groove)
G 92X 29.2Z-21F3；
X 28.6；
X 28.2；
X 28.05；
G 00X 100Z50；
M 05；
M 02；
Note that in the above procedure F is lead 3 instead of pitch P1.5; the coordinate Z can be shifted positively or negatively by a pitch value, and attention is paid to the fact that the coordinate Z is shifted continuously in one direction when the multi-start thread is machined.
The instruction format of the specified thread start angle is G92X (U) _Z (W) _F_Q_;
where Q represents the thread start angle in 0.001 degree increments, a decimal point cannot be specified (e.g., 180 phase shift angle, Q180000 is specified). The rest parameters are consistent with the single-start thread.
Taking the processing of the single start thread shown in fig. 3 as an example, the processing program is programmed as follows:
O 002；
T 0101；
M 03；
G 00X 35Z3；
G92X 29.2Z-21F3; (first spiral groove)
Q180000; (second spiral groove)
X 28.6；
Q 180000；
X 28.2；
Q 180000；
X 28.05；
Q 180000；
G 00X 100Z50；
M 05；
M 02；
From the above procedure, it can be seen that the principle of using the thread start angle is to specify the offset angle of the spindle one rotation signal from the thread start point with address Q. When the double-head thread is processed, the initial angle of the first spiral groove is Q0, and the first spiral groove can be omitted from writing; the start angle of the second spiral groove is Q180000, if the multi-start thread is processed, 360 DEG/head number is calculated to calculate the angle between two spiral grooves, and the angles are expressed by the start angle one by one (for example, the angle between two spiral grooves separated by three-head thread is 120 DEG, the first spiral groove start angle is Q0, which can be omitted, the second spiral groove start angle is Q120000, and the third spiral groove is Q24000).
It is also noted that when programming with thread start angles, the thread start angle is not a modal value, and each use must be specified, if not specified, as 0. F in the program is still the lead value.
Fourth, the ratio of cutting fluid and use:
1. during rough turning, in order to reduce friction between the follower rest and the outer circle of the workpiece and reduce temperature rise, a mixed liquid of diesel oil and 10% engine oil is adopted for lubrication and cooling in the turning process.
2. In the process of polishing and threading, in order to improve the surface roughness Ra, the cutting is light and quick, and a mixed solution of 40% of soybean oil, 30% of engine oil and 30% of diesel oil or vegetable oil is used for sufficient lubrication and cooling. Thereby ensuring the control of the dimensional accuracy and turning qualified workpieces.
In summary, the valve rod process for machining the quick-open type multi-head thread long distance is quite difficult to achieve, but by adopting the series of methods, key technologies such as the centering clamping support of a workpiece, the multi-head thread turning method and skill, the proportioning and the use of cutting fluid are reasonably selected, the surface quality and the thermal deformation elongation of the workpiece are solved, the rigidity of a process system of a machine tool, a cutter, a clamp and the workpiece is ensured, and the deformation of a product is effectively prevented.
The foregoing describes preferred embodiments of the present invention, but is not intended to limit the invention thereto. Modifications and variations to the embodiments disclosed herein may be made by those skilled in the art without departing from the scope and spirit of the invention.
Claims (6)
1. A processing and forming method of a quick-open type multi-head thread long-distance valve rod is characterized by comprising the following steps:
first, center positioning:
the center frame is used for directly supporting the middle of the workpiece, and when in turning, the center frame is supported in the middle of the workpiece, and lubricating oil is added at the contact part of the center frame and the workpiece;
the transition sleeve is used for supporting the turning slender shaft, four screws are respectively arranged at two ends of the transition sleeve, and the axis of the excircle of the sleeve is overlapped with the rotation line of the main shaft by using the screws;
the slender shaft is supported and turned by using a follower rest with three supporting claws, and the follower rest is fixed on a saddle;
second, peeling rough turning and bright finish turning:
the method comprises the steps of adopting reverse turning, feeding from a lathe spindle to a tailstock, and clamping a workpiece on a three-jaw self-centering chuck during turning, so that one clamped end becomes a fixed point which can not longitudinally float; cutting by feeding the headstock to the tailstock direction, wherein the axial cutting force straightens the cut part of the workpiece and pushes the part to be processed of the workpiece to move to the tailstock direction;
thirdly, turning a multi-head thread:
turning programming is carried out in a FANUC numerical control machine by adopting a G32 single-stroke thread cutting instruction processing method, a G92 thread cutting circulation instruction processing method or a G76 thread cutting complex circulation processing method, so that multi-head threads are turned;
in the reverse turning, firstly taking the maximum feeding amount to increase the axial tensile stress of the workpiece, secondly taking the maximum cut amount and finally taking the maximum cutting speed;
when the ratio of the length to the diameter of the workpiece is 40-120, if the cutting speed is 40m/min, the feeding amount is 0.35-0.5 mm/r; if v=45-100 m/min, the feeding amount is 0.6-1.2 mm/r;
when in rough cutting, the cutting speed is 50-60 m/min, the feeding amount is 0.3-0.4 mm/r, and the cutting depth is 1.5-2 mm; when the precision is used, the cutting speed is 60-100 m/min, the feeding amount is 0.08-0.12 mm/r, and the cutting depth is 0.5-1 mm.
2. The method for forming the quick-open type multi-head thread long-pitch valve rod according to claim 1, wherein during the rough turning process, a mixed liquid of diesel oil and 10% engine oil is adopted for lubrication and cooling; when in the process of polishing and turning multiple threads, mixed liquid or vegetable oil of 40% of soybean oil, 30% of engine oil and 30% of diesel oil is used for full lubrication and cooling so as to improve the surface roughness Ra and make cutting light and fast.
3. The method of forming a quick open multi-start thread long pitch valve stem according to claim 1, wherein in the step of centering, a groove for supporting a claw is formed in the middle of the blank before the workpiece is mounted on the center frame; adding a layer of abrasive cloth or grinding agent between the supporting claw of the center frame and the workpiece for grinding and cohesion, so that the supporting claw and the workpiece keep good contact; in the step of rough turning and bright finish turning, the follower rest is loosened before machining, then the turning and the cutting are started, the follower rest is quickly kept up, the follower rest is not retracted and stopped when contacted, the adjusting force of the support claw of the follower rest and the shaft surface is controlled so as not to deform the top of the shaft part to be suitable, the excessive loosening or the excessive tightening is prevented, the contact between the support claw of the follower rest and the shaft surface is tight, and the shaft and the claw are in lubrication fit, so that the slender shaft is prevented from forming a bamboo joint shape.
4. The method for forming a stem for a quick-open type multi-start thread with a long pitch according to claim 1, wherein the correction is performed again on the shaft member after rough turning, before semi-finish turning and finish turning, and the tip hole errors and displacement errors generated in the rough turning are corrected to eliminate internal stress.
5. The method for forming the valve rod with the quick-opening multi-head thread long distance according to claim 1, wherein the main deflection angle of a turning tool used in turning is 75-90 degrees, and the front angle is 28-30 degrees; the hard alloy blade is YT15, and the cutter bar is 45 high-quality carbon steel.
6. The method for processing and forming the valve rod with the quick-opening multi-head thread long distance according to claim 1, wherein the cutter structure of the finishing tool adopts an elastic cutter rod, the hard alloy cutter blade adopts YT15, the cutter tip is lower than the center of the shaft member by 0.1mm when the cutter is assembled, the trimming cutter blade is 8-10 mm, the cutter blade is propped against the shaft member for turning, the defect of biting the cutter caused by the change of turning force is prevented, and the rake angle is 30 degrees, so that the cutting is light and quick.
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| CN102744423A (en) * | 2012-07-03 | 2012-10-24 | 池州市邦鼐机电科技有限公司 | Quenched steel long axis excircle and thread hard turning machining process |
| CN103611948A (en) * | 2013-11-29 | 2014-03-05 | 内蒙古北方重工业集团有限公司 | Method for machining long and thin rod part on ordinary lathe |
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Denomination of invention: A machining and forming method for a quick opening multi head thread slender distance valve stem Granted publication date: 20230505 Pledgee: Zhejiang Juzhou Commercial Bank Co.,Ltd. Wenzhou Ouhai Branch Pledgor: ZHEJIANG TINGYU FLUID EQUIPMENT Co.,Ltd. Registration number: Y2024980034854 |