CN114147377B - Mask for machining convex hemisphere of gyro motor and machining method thereof - Google Patents
Mask for machining convex hemisphere of gyro motor and machining method thereof Download PDFInfo
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- CN114147377B CN114147377B CN202210116077.XA CN202210116077A CN114147377B CN 114147377 B CN114147377 B CN 114147377B CN 202210116077 A CN202210116077 A CN 202210116077A CN 114147377 B CN114147377 B CN 114147377B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K28/00—Welding or cutting not covered by any of the preceding groups, e.g. electrolytic welding
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- B—PERFORMING OPERATIONS; TRANSPORTING
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- B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
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Abstract
The invention provides a mask for machining a convex hemisphere of a gyro motor and a machining method thereof, and solves the problem that the existing machining tool for the convex hemisphere cannot guarantee the machining precision of the convex hemisphere and further influences the performance of the gyro motor. The mask for processing the convex hemisphere of the gyro motor comprises a mounting sleeve, a hemisphere shell and an extension sleeve; the installation sleeve, the hemispherical shell and the extension sleeve are coaxially arranged in sequence, and a plurality of logarithmic curve spiral holes matched with the logarithmic curve spiral grooves of the convex hemispheres in shape are formed in the hemispherical shell along the circumferential direction; the invention provides a processing method of a mask for processing a convex hemisphere of a gyro motor, which comprises the following steps: step one, primary processing; step two, processing a positioning mandrel and a positioning clamp; step three, processing an outer spherical surface; step four, carrying out numerical control milling on a logarithmic curve spiral hole; removing burrs on the outer spherical surface; sixthly, separating the mask processing piece and the positioning mandrel; and seventhly, removing burrs on the inner spherical surface.
Description
Technical Field
The invention belongs to the field of gyro motors, particularly relates to a mask for processing a convex hemisphere of a gyro motor and a processing method thereof, and particularly relates to a mask for ion etching of a spiral groove of the convex hemisphere of the gyro motor of a dynamic pressure gas bearing and a processing method thereof.
Background
The three-floating gyro is a miniature gyro with highest precision and longest service life in electromechanical gyros at home and abroad at present, and is mainly applied to the fields of inertial navigation space such as satellites, manned and freight airships, space stations and the like, and a dynamic pressure gyro motor is the heart of the three-floating gyro and plays a vital role in the performance and service life of the three-floating gyro.
The dynamic pressure gas bearing in the dynamic pressure gyro motor is a key part, and the dynamic pressure effect and the air film rigidity of the dynamic pressure gas bearing have important influence on the performance of the gyro motor. The convex hemisphere is a key part of the dynamic pressure air bearing, the material of the convex hemisphere is usually high-hardness GT35 hard alloy, the requirements on the dimensional shape and position precision and the surface roughness are high, the specific requirements are that the roundness of the hemisphere surface is 0.3 mu m, the surface roughness is Ra0.012 mu m, 12 logarithmic curve spiral grooves are uniformly distributed on the hemisphere surface, the depth of the logarithmic curve spiral groove is 4 mu m +/-0.5 mu m, the groove shape consistency of the 12 logarithmic curve spiral grooves is not more than 0.01mm, the surface roughness of the groove bottom surface is Ra0.1 mu m, the processing precision of the logarithmic curve spiral groove has great influence on the dynamic pressure effect and the air film rigidity of the dynamic pressure air bearing, and further has important significance on the performance stability of a gyro motor and a three-floating gyro.
The logarithmic curve spiral groove is difficult to ensure the processing precision and quality by adopting a conventional cutting method. Currently, the most feasible method is ion beam etching. Ion beam machining is a micro-machining technology which utilizes the physical sputtering effect of high-energy inert gas ions (argon ions) on the surface of a solid to perform etching machining, namely, ions generated by an ion source are accelerated and focused under the vacuum condition to form high-energy ion beam flow to bombard the surface of a workpiece, so that the uncovered surface is etched and stripped, and a pattern is transferred to the surface of the workpiece. However, when the logarithmic curve spiral groove of the convex hemisphere is processed by adopting the ion beam, the precision of the logarithmic curve spiral groove can not meet the use requirement frequently by adopting the processing device, so that the performance of the gyro motor is influenced.
Disclosure of Invention
The invention aims to solve the problem that the existing convex hemisphere processing device cannot ensure the processing precision of a convex hemisphere so as to influence the performance of a gyro motor, and provides a mask for processing the convex hemisphere of the gyro motor and a processing method thereof.
In order to achieve the purpose, the invention adopts the following technical scheme:
a mask for processing a convex hemisphere of a gyro motor comprises a mounting sleeve, a hemisphere shell and an extension sleeve; the installation sleeve, the hemispherical shell and the extension sleeve are coaxially arranged in sequence, the small end of the hemispherical shell is connected with the installation sleeve, the large end of the hemispherical shell is connected with the extension sleeve, the diameter of the hemispherical shell is the same as that of the extension sleeve, and a plurality of logarithmic curve spiral holes matched with the logarithmic curve spiral grooves of the convex hemispheres in shape are circumferentially arranged on the hemispherical shell; the wall thickness of the hemispherical shell and the wall thickness of the extension sleeve are 0.1-0.2 mm; the material expansion coefficient of the installation sleeve, the hemispherical shell and the extension sleeve is smaller than or equal to that of the convex hemisphere, and the inner spherical surface of the hemispherical shell is in interference fit with the convex hemisphere by 2-5 microns.
Further, the mounting sleeve, the semispherical shell and the extension sleeve are made of TC4 titanium alloy materials.
The invention also provides a processing method of the mask for processing the convex hemisphere of the gyro motor, which comprises the following steps:
step one, primary processing;
selecting a round bar material as a mask blank, and sequentially carrying out annealing, rough turning, destressing, semi-finish turning and destressing treatment on the round bar material, so that machining allowances are left on the outer peripheral surface of the mounting sleeve, the inner spherical surface and the outer spherical surface of the hemispherical shell, and other machining surfaces are machined to the designed size to obtain a mask machining part;
then, clamping the mask machined part on a machine tool, and finely turning the inner spherical surface of the hemispherical shell to enable the matching interference magnitude of the hemispherical shell and the convex hemisphere to be 2-5 microns;
step two, processing a positioning mandrel and a positioning clamp;
the positioning core shaft comprises an installation section, a hemispherical base, a transition section, a positioning section and a clamping section which are sequentially connected, wherein the diameter of the transition section is smaller than that of the hemispherical base and that of the positioning section; the mounting section is provided with an external thread;
the positioning mandrel is provided with an axial cutting hole extending from the mounting section to the transition section; a plurality of radial grooves which extend axially and are uniformly distributed circumferentially are arranged on the hemispherical base and the transition section, and the minimum distance H between the groove bottom of each radial groove and the central axis of the positioning mandrel is greater than the radius R of the axial cutting hole;
a spherical groove matched with the hemispherical shell in shape and size is formed in the positioning clamp, a blind hole matched with the mounting sleeve in shape and size is formed in the bottom of the spherical groove, and a threaded hole is formed in the bottom end of the blind hole;
step three, processing an outer spherical surface;
3.1) sleeving a mask machining part on the positioning mandrel, wherein the fit clearance between the hemispherical base and the hemispherical shell is 0-0.003 mm; then, axially fixing the mask processing piece by adopting a nut, and screwing the nut so that the mask processing piece is tightly attached to the spherical surface of the hemispherical base;
3.2) after the mask machining part is arranged on the positioning mandrel, turning the outer spherical surface of the hemispherical shell and the outer peripheral surface of the mounting sleeve to meet the design requirement, and simultaneously ensuring that the coaxiality of the outer spherical surface and the inner spherical surface of the hemispherical shell is within phi 0.004 mm;
step four, carrying out numerical control milling on a logarithmic curve spiral hole;
mounting a mask machining piece and a positioning mandrel on a four-axis linkage milling center, and then processing a logarithmic curve spiral hole, wherein the rotating speed of a main shaft of the four-axis linkage milling center is required to be not lower than 4000 r/min;
removing burrs on the outer spherical surface;
clamping the mask workpiece and the positioning mandrel on a lathe, and removing burrs protruding from edges of logarithmic curve spiral holes on the outer spherical surface of the hemispherical shell by using metallographic abrasive paper;
sixthly, separating the mask processing piece and the positioning mandrel;
6.1) cutting and separating the positioning mandrel along the transition section, and reserving a part with a mask processing piece;
6.2) threading in the axial cutting hole of the positioning mandrel, radially cutting the positioning mandrel through a linear cutting method along a radial groove, dividing the positioning mandrel into a multi-lobe structure which is not connected with each other, and respectively taking out the cut multi-lobe structure in an inward shrinkage mode, thereby realizing the separation of the mask processing piece and the positioning mandrel;
seventhly, removing burrs on the inner spherical surface;
and (3) loading the separated mask processing piece into a positioning fixture, axially fixing the positioning fixture and the mask processing piece through a compression screw, and then removing burrs protruding from the edge of the logarithmic curve spiral hole on the inner spherical surface of the hemispherical shell on a lathe, so that the mask processing is finished.
Further, step eight, storing the mask; and (4) clamping the processed mask on the positioning mandrel in the second step for storage, wherein the mask is in a vertical state during storage, so that the mask is prevented from being damaged and deformed.
And further, in the seventh step, the burrs are removed by adopting a metallographic abrasive paper or grinding method or a resin material brush.
Further, in the step 3.1), after the mask workpiece is sleeved on the positioning mandrel, the matching part of the inner surface of the extension sleeve and the hemispherical base is glued and fixed by glue.
Further, in the step 3.1), a pressing sleeve and an elastic washer are arranged between the nut and the mask workpiece.
Compared with the prior art, the invention has the following beneficial technical effects:
1. the positioning core shaft in the method better solves the problems of clamping and processing deformation of finish turning and logarithmic curve spiral hole milling procedures of a mask processing piece, so that the processing standards of the two procedures are consistent, the processing efficiency and the processing precision are improved, the positioning core shaft can also be used as a transferring and protecting tool, the mask is prevented from being deformed and damaged, and one tool has multiple purposes.
2. The positioning mandrel in the method is provided with a radial groove and an axial cutting hole, the positioning mandrel is decomposed into a multi-lobe structure by adopting a linear cutting mode and is taken out in a retraction mode, so that the mask workpiece and the positioning mandrel are quickly separated, the problem that the mask workpiece and the positioning mandrel are difficult to separate due to the fact that tiny burrs are arranged between the inner spherical surface of the mask workpiece and the positioning mandrel after the logarithmic curve spiral hole is milled is solved, the mask workpiece is guaranteed not to deform during machining, and machining damage of the mask workpiece is avoided.
3. The method provided by the invention is used for designing a special positioning clamp, and the inner spherical surface of the hemispherical shell is polished by a clamping mode of positioning the outer spherical surface of the hemispherical shell and axially pressing the screw, so that the clamping problem of deburring of the inner spherical surface of the thin-wall hollowed mask is solved, the rigidity and deburring effect of the mask are improved, and the deformation damage generated during deburring of the mask is effectively avoided.
4. According to the method, the inner spherical surface of the mask is precisely machined, and the mask machined part is tightly and firmly matched with the positioning core shaft by adopting a small interference fit of 0.002-0.005 mm and an assembly mode of gluing one end and pressing a nut at one end, so that the machining precision is prevented from being influenced by deformation and looseness of the mask machined part in the processes of finish turning and spiral groove milling.
5. The method adopts the processing technical processes of rough turning, semi-finish turning, finish turning and twice stress relief treatment, and better ensures the precision of the processed mask and the stability of the precision.
6. The mask processing piece adopts a structure and a mounting mode of combination of tension and compression, namely, one end of the mask processing piece is pressed on the end surface of the mounting sleeve through the nut, and the other end of the mask processing piece pulls the convex edge part of the extension sleeve through the threaded sleeve, so that the mask processing piece can be ensured to be more tightly attached to the convex hemisphere, the thin-wall mask is prevented from warping and deforming, and the precision of the spiral groove shape on the mask is maintained.
7. The thickness dimension of the wall of the mask hemispherical shell is less than 0.2mm, so that the adverse effect of secondary sputtering on the shape of the side wall of the groove shape when the spiral groove is etched by the ion beam can be reduced.
8. The mask is made of metal materials such as titanium alloy and the like with the thermal expansion coefficient close to that of the etched convex hemisphere material, can bear higher environmental temperature of ion etching, and reduces adverse effects on the etching precision of the spiral groove caused by the clearance of a spherical matching part due to the fact that the expansion size of the mask is inconsistent with that of the convex hemisphere in the high-temperature environment of ion etching.
Drawings
FIG. 1 is a front view of a mask for machining a convex hemisphere of a gyro motor according to the present invention;
FIG. 2 is a right side view of a mask for machining a convex hemisphere of a gyro motor in accordance with the present invention;
FIG. 3 is a cross-sectional view of a mask for processing a convex hemisphere of a gyro motor according to the present invention;
FIG. 4 is a flow chart of a method for processing a mask for processing a convex hemisphere of a gyro motor according to the present invention;
FIG. 5 is a schematic view of a positioning mandrel used in the method of the present invention;
FIG. 6 is a view from the c direction of FIG. 5;
FIG. 7 is a schematic view of the alignment mandrel and mask in the process of the present invention;
FIG. 8 is a schematic structural view of a positioning jig in the machining method of the present invention;
FIG. 9 is a schematic view of the positioning fixture and the mask in the processing method of the present invention.
Reference numerals: 1-mounting sleeve, 2-hemispherical shell, 3-extending sleeve, 4-mounting section, 5-hemispherical base, 6-transition section, 7-positioning section, 8-clamping section, 9-positioning clamp, 10-radial groove, 11-axial cutting hole, 12-pressing sleeve, 13-elastic washer, 14-nut, 15-pressing screw, 16-spherical groove, 17-blind hole, 18-threaded hole and 21-logarithmic curve spiral hole.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention and are not intended to limit the scope of the present invention.
The processing degree of difficulty of the logarithmic curve spiral groove of the convex hemisphere lies in the control of the groove depth size, during ion etching, an ion beam is projected to the surface of the convex hemisphere from one direction along a straight line, the convex hemisphere is driven to rotate at a certain speed around the axis of the convex hemisphere through a tool, and therefore the plurality of spiral grooves uniformly distributed on the whole spherical surface of the convex hemisphere can be etched. Based on the mask, the mask for processing the convex hemisphere of the gyro motor is used for processing the logarithmic curve spiral groove on the convex hemisphere of the gyro motor, so that the processing quality of the convex hemisphere is greatly improved.
As shown in fig. 1 to 3, the mask of the present invention includes a mounting sleeve 1, a hemispherical case 2, and an extension sleeve 3; the installation sleeve 1, the hemispherical shell 2 and the extension sleeve 3 are coaxially arranged in sequence, and the diameter of the hemispherical shell 2 is the same as that of the extension sleeve 3; the small end of the hemispherical shell 2 is connected with the installation sleeve 1, the large end of the hemispherical shell is connected with the extension sleeve 3, and a plurality of logarithmic curve spiral holes 21 matched with the logarithmic curve spiral grooves of the convex hemispheres in shape are formed in the hemispherical shell 2 along the circumferential direction. The mask has great influence on the ion etching quality of the logarithmic curve spiral groove of the convex hemisphere, and the shape and the precision of the logarithmic curve spiral hole 21 of the mask directly determine the shape precision of the etched logarithmic curve spiral groove. During processing, the inner spherical surface of the hemispherical shell 2 and the convex hemisphere are in tight fit without a gap as much as possible, and the fit interference is 2-5 mu m, because the shape accuracy of the logarithmic curve spiral groove profile is affected by the gap between the inner spherical surface of the hemispherical shell 2 and the convex hemisphere. The thickness of the hemispherical shell 2 has a great influence on etching quality, the requirement on the wall thickness is as thin as possible, however, considering that the processing difficulty is higher when the wall thickness is thinner, the requirement on the wall thickness of the mask is combined with the repeated usability of the mask, the wall thickness of the hemispherical shell 2 and the wall thickness of the extension sleeve 3 are selected to be 0.1-0.2 mm after balancing, and the mask is sleeved on the convex hemisphere by adopting a method of heating the mask or/and freezing the convex hemisphere, so that no gap exists between the mask and the convex hemisphere, and the groove shape precision of the ion beam etching logarithmic curve spiral groove and the steep shape of the groove side wall are ensured.
The mask material of the invention is selected mainly by considering two factors: firstly, the ion etching resistance and the machinability are required, and secondly, the material matching property with the etched part is realized; because the temperature during ion etching is 200-300 ℃, the influence of thermal expansion and cold contraction on the fit clearance is considered, the mask and the convex hemisphere are made of materials with the same or similar expansion coefficients as far as possible, and the expansion coefficient of the mask material is preferably smaller than that of the convex hemisphere material, so that the etching precision of the logarithmic curve spiral groove cannot be influenced due to the fact that the fit clearance between the mask and the etched convex hemisphere is enlarged at the etching temperature of 200-300 ℃. The mask made of the material with the low titanium alloy plasma beam etching removal rate can be repeatedly used for many times, and has long service life. When the thermal expansion coefficient of the mask material is larger than that of the convex hemisphere material, the inner spherical surface of the mask and the convex hemisphere are in interference fit, so that the phenomenon that the etching precision of the spiral groove is affected due to the fact that a gap appears at the joint of the mask and the convex hemisphere caused by temperature rise in the etching process is avoided.
The mask and the convex hemisphere are in interference fit, namely the spherical diameter of the inner spherical surface of the mask is 4-6 mu m smaller than that of the convex hemisphere, and the mask and the convex hemisphere are assembled by heating the mask and/or freezing the convex hemisphere, so that zero clearance between the inner spherical surface of the mask and the spherical surface of the convex hemisphere can be ensured, and the problem that the groove shape precision of a spiral groove of the etched convex hemisphere is poor due to the fact that an ion beam irradiates the surface of the convex hemisphere through the clearance when clearance fit is adopted originally is solved, and the part, which is not etched, of the convex hemisphere is etched and removed.
The invention also provides a processing method of the mask, the mask is a thin-wall hollow spherical shell structure with thin wall, low rigidity and a plurality of logarithmic curve spiral holes 21, the size and the form and position precision of the mask are in micron order, and difficult processing materials such as TC4 titanium alloy and the like are adopted, so that the processing of the mask is very difficult. The processing of the mask mainly solves the problems of precision turning of a thin-wall spherical surface, precision milling of the logarithmic curve spiral hole 21, deburring of the logarithmic curve spiral hole 21 after milling, part processing deformation prevention and the like. The method solves the problem that the thin wall has poor rigidity and is easy to deform in the precise turning of the mask and the numerical control milling of the logarithmic curve spiral hole 21 by manufacturing the positioning mandrel. As shown in fig. 4, the mask is specifically processed as follows:
step one, primary processing;
1.1) selecting a round bar as a mask blank, annealing the round bar, heating to 800 ℃ during annealing, keeping the temperature, and cooling along with a furnace, so as to improve the plasticity and the stable structure of the material and facilitate subsequent processing;
1.2) rough turning: turning the annealed round bar stock to enable the size of each processing surface to leave 1mm of processing allowance;
1.3) destressing: carrying out stress relief heat treatment, wherein the treatment parameters are heating to 450 +/-20 ℃, preserving heat for 3 hours, and then cooling along with a furnace;
1.4) semi-finish turning; performing semi-finish turning to ensure that the size of each machined surface is reserved with a machining allowance of 0.2 mm;
1.5) destressing: then, performing high-low temperature circulation stabilization treatment to remove stress, wherein the parameters are that the temperature is maintained at 120 ℃ for 2 hours at high temperature, the temperature is maintained at 60 ℃ below zero for 2 hours, and then performing three temperature circulations in total during heating and low-temperature treatment to obtain a mask workpiece;
1.6) finish turning; clamping a mask machining piece on a machine tool, and finely turning the inner spherical surface of the hemispherical shell 2 according to design requirements; during fine machining, the inner spherical surface and the convex hemisphere of the hemispherical shell 2 are matched and machined, so that the matching magnitude of interference of the hemispherical shell 2 and the convex hemisphere surface is 2-5 microns, and the spherical precision is guaranteed to be 0.001 mm;
step two, processing a positioning mandrel and a positioning clamp 9;
in order to solve the difficulty of turning and milling processing caused by thin wall and low rigidity of the mask, a positioning mandrel is manufactured; as shown in fig. 5 and 6, the positioning mandrel comprises a mounting section 4, a hemispherical base 5, a transition section 6, a positioning section 7 and a clamping section 8 which are connected in sequence, wherein the diameter of the transition section 6 is smaller than that of the hemispherical base 5 and that of the positioning section 7; the mounting section 4 is provided with an external thread; the positioning mandrel is provided with an axial cutting hole 11 extending from the mounting section 4 to the transition section 6; a plurality of radial grooves 10 which extend axially and are uniformly distributed circumferentially are arranged on the hemispherical base 5 and the transition section 6, and the minimum distance H between the groove bottom of each radial groove 10 and the central axis of the positioning mandrel is greater than the radius R of the axial cutting hole 11;
in the embodiment of the invention, 3 long grooves (namely radial grooves 10) with the width of 0.8mm are uniformly distributed on a hemispherical base 5 and a transition section 6 of a positioning mandrel, and an axial cutting hole 11 with the diameter of phi 2 is machined at the center of the positioning mandrel, so that a mask can be smoothly separated from the positioning mandrel after milling a logarithmic curve spiral hole 21, the mask is difficult to separate from the positioning mandrel due to burrs generated by milling the logarithmic curve spiral hole 21, if the mask is forcibly separated, the mask can be deformed to be scrapped, and the radial grooves 10 and the axial cutting hole 11 can be cut through by linear cutting after the groove is formed, so that the positioning mandrel is cut into a plurality of pieces, the cut multi-piece structure can be retracted inwards to be taken out, so that the separation from the mask is realized, the mask is very easy to take down at the moment, and the mask can be ensured not to be deformed or damaged;
as shown in fig. 8, a spherical groove 16 matched with the shape and size of the hemispherical shell 2 is arranged in the positioning clamp 9, a blind hole 17 matched with the shape and size of the mounting sleeve 1 is arranged at the bottom of the spherical groove 16, and a threaded hole 18 is arranged at the bottom end of the blind hole 17;
step three, processing an outer spherical surface;
3.1) as shown in fig. 7, a mask workpiece is arranged on a positioning mandrel, the fit clearance between a hemispherical base 5 and a hemispherical shell 2 is 0-0.003 mm, the positioning mandrel is positioned by using an inner hole of the mask workpiece, the mask workpiece is fixed on the positioning mandrel by using a nut 14, the tightening force of the nut 14 is enough to ensure that the mask workpiece is tightly attached to the spherical surface of the positioning mandrel, and the matched large end surface part of the inner spherical surface of the hemispherical shell 2 and the positioning mandrel is glued by using 502 glue, so that the rigidity of the mask workpiece is improved, the processing performance is enhanced, and the mask workpiece can not fall off automatically in the processing process of cutting the positioning mandrel into a multi-lobe structure in the rear linear cutting process;
in addition, a pressing sleeve 12 and an elastic washer 13 can be arranged between the nut 14 and the mask workpiece, the pressing sleeve 12 plays a role in transmitting pressure, protecting the mask workpiece and preventing the mask workpiece from rotating when the nut 14 is screwed, and the elastic washer 13 plays a role in preventing the pressing from loosening;
3.2) after the mask machining part is arranged on the positioning mandrel, turning the outer spherical surface of the hemispherical shell 2 and the outer peripheral surface of the mounting sleeve 1 to meet the design requirement, and simultaneously ensuring that the coaxiality phi of the outer spherical surface and the inner spherical surface of the hemispherical shell 2 is within 0.004 mm;
step four, carrying out numerical control milling on a logarithmic curve spiral hole;
after the outer spherical surface of the hemispherical shell 2 and the outer peripheral surface of the mounting sleeve 1 are subjected to finish turning, a mask machining piece is directly subjected to milling of the logarithmic curve spiral hole 21 without being dismounted on a positioning mandrel; milling a logarithmic curve spiral hole 21 is carried out on a four-axis linkage milling center, and the rigidity is improved by a positioning mandrel so as to prevent a mask machining piece from deforming during milling;
in actual processing, the width of the logarithmic curve spiral hole 21 is only about 1mm, so that a diamond-coated end mill with the cutting edge diameter phi of 0.5-0.7 mm is selected. Because the milling cutter has small diameter and poor rigidity and strength, multiple times of feed milling are required, cutting parameters such as cutting depth, feed amount and the like are strictly controlled, the rotating speed of a main shaft is not lower than 4000r/min, and a machining allowance of 0.05mm is reserved after rough milling for carrying out full-depth profile finish milling on the side wall of the spiral hole. Therefore, the machining process better ensures that the spiral side wall has higher surface roughness and generates as few burrs as possible by adopting higher rotating speed, lower feeding speed and proper cutting depth, and effectively controls the distortion of the logarithmic curve spiral hole 21 of the mask workpiece during the machining process; meanwhile, UG software can be adopted to carry out numerical control machining program compilation of the logarithmic curve spiral hole 21 and carry out simulation of actual numerical control milling, so as to optimize the machining program and verify the machining effect; monitoring the abrasion of the cutter in the machining process so as to avoid adverse effects on machining precision and surface roughness;
removing burrs on the outer spherical surface;
after the mask machining piece is subjected to numerical control milling, burrs generated at the edges of the logarithmic curve spiral holes 21 on the inner spherical surface and the outer spherical surface of the hemispherical shell 2 need to be removed, and any tiny burr can influence the installation and etching precision of the mask machining piece; the method comprises the following steps that (1) burrs on the outer spherical surface of the hemispherical shell 2 are removed after a numerical milling process, at the moment, a mask machining piece is still installed on a positioning mandrel, the mask machining piece is clamped on a lathe, and metallographic abrasive paper is used for removing the burrs protruding from the edge of the logarithmic curve spiral hole 21 on the outer spherical surface of the hemispherical shell 2, so that the mask machining piece can be prevented from being deformed;
sixthly, separating and positioning the mandrel;
6.1) after the mask workpiece is subjected to numerical control milling, if the mask workpiece is directly taken down from the positioning mandrel due to burrs and other reasons, the mask workpiece is deformed and damaged, at the moment, a thin neck part (namely a transition section 6) of the positioning mandrel can be cut off by a lathe worker, the part with the mask workpiece is reserved after cutting off, and the nut 14, the elastic washer 13 and the pressing sleeve 12 are taken down from the positioning mandrel;
6.2) threading in the axial cutting hole 11 of the positioning mandrel, cutting the original radial grooves 10 in the radial direction by adopting a wire cutting method, dividing the positioning mandrel into a multi-lobe structure which is not connected with each other equally,
6.3) the combination with the mask processing piece and part of the positioning mandrel is placed in an acetone solution for soaking so that 502 glue is dissolved, thereby the multi-petal structures of the positioning mandrel can be respectively taken out inwards to complete the separation of the mask processing piece and the positioning mandrel, and the separation method can not cause deformation and other damages to the mask processing piece outside;
seventhly, removing burrs on the inner spherical surface;
the inner spherical surface of the hemispherical shell 2 has a small amount of fine burrs, if the burrs are not removed or cannot be completely removed, the matching precision of the mask workpiece and the convex hemisphere can be influenced, and the surface of the convex hemisphere is scratched, the burrs of the inner spherical surface are carried out after the mask workpiece is separated from the positioning mandrel, and because the mask workpiece is a thin-wall hollow structure and has very poor rigidity, the part deformation is easily caused during deburring, so that the precision of the processed logarithmic curve spiral hole 21 is damaged;
for this reason, a positioning fixture 9 for positioning the outer spherical surface of the hemispherical shell 2 is designed and manufactured, as shown in fig. 9, the separated mask workpiece is loaded into the positioning fixture 9, the positioning fixture 9 and the mask workpiece are axially fixed by a compression screw 15, and the outer spherical surface of the hemispherical shell 2 and the inner spherical surface of the positioning fixture 9 are precisely matched with each other with micron-sized gaps; then, a small amount of fine burrs protruding from the edge of the inner spherical logarithmic curve spiral hole 21 are removed by polishing on a lathe by adopting metallographic abrasive paper or a grinding method, or the burrs are removed by adopting a resin material brush with proper hardness, so that the mask workpiece can be prevented from being damaged, and the mask workpiece can be prevented from deforming and the like;
step eight, storing the mask;
the finished mask is required to be clamped on the positioning mandrel in the second step for turnover, and the mask is required to be in a vertical state when being stored so as to prevent the mask from being damaged and deformed.
Claims (5)
1. A processing method for processing a mask of a gyro motor convex hemisphere comprises a mounting sleeve (1), a hemisphere shell (2) and an extension sleeve (3); the installation sleeve (1), the hemispherical shell (2) and the extension sleeve (3) are coaxially arranged in sequence, the small end of the hemispherical shell (2) is connected with the installation sleeve (1), the large end of the hemispherical shell is connected with the extension sleeve (3), the diameter of the hemispherical shell (2) is the same as that of the extension sleeve (3), and a plurality of logarithmic curve spiral holes (21) matched with the shape of the logarithmic curve spiral grooves of the convex hemispheres are formed in the hemispherical shell (2) along the circumferential direction;
the processing method is characterized by comprising the following steps:
step one, primary processing;
the method comprises the following steps that a mask blank selects a round bar, annealing, rough turning, stress relieving, semi-finish turning and stress relieving are sequentially carried out on the round bar, machining allowances are reserved on the outer peripheral surface of an installation sleeve (1), the inner spherical surface and the outer spherical surface of a hemispherical shell (2), and other machining surfaces are machined to the designed size to obtain a mask machining part;
then, clamping a mask workpiece on a machine tool, and finely turning the inner spherical surface of the hemispherical shell (2) to enable the fit interference magnitude of the hemispherical shell (2) and the convex hemisphere to be 2-5 microns;
step two, processing a positioning mandrel and a positioning clamp (9);
the positioning mandrel comprises an installation section (4), a hemispherical base (5), a transition section (6), a positioning section (7) and a clamping section (8) which are sequentially connected, wherein the diameter of the transition section (6) is smaller than that of the hemispherical base (5) and that of the positioning section (7); the mounting section (4) is provided with an external thread; the positioning mandrel is provided with an axial cutting hole (11) extending from the mounting section (4) to the transition section (6); a plurality of radial grooves (10) which extend axially and are uniformly distributed circumferentially are arranged on the hemispherical base (5) and the transition section (6), and the radial grooves (10) and the axial cutting holes (11) are cut through by linear cutting to realize the separation from the mask; the minimum distance H between the groove bottom of the radial groove (10) and the central axis of the positioning mandrel is larger than the radius R of the axial cutting hole (11); a spherical groove (16) matched with the hemispherical shell (2) in shape and size is formed in the positioning clamp (9), a blind hole (17) matched with the mounting sleeve (1) in shape and size is formed in the bottom of the spherical groove (16), and a threaded hole (18) is formed in the bottom end of the blind hole (17);
step three, processing an outer spherical surface;
firstly, sleeving a mask machining part on a positioning mandrel, wherein the fit clearance between a hemispherical base (5) and a hemispherical shell (2) is 0-0.003 mm; then, axially fixing the mask processing piece by adopting a nut (14), and screwing the nut (14) to enable the mask processing piece to be tightly attached to the spherical surface of the hemispherical base (5);
then, after the mask machining piece is installed on the positioning mandrel, the outer spherical surface of the hemispherical shell (2) and the outer peripheral surface of the installation sleeve (1) are turned, so that the design requirements are met, and meanwhile, the coaxiality of the outer spherical surface and the inner spherical surface of the hemispherical shell (2) is ensured to be within phi 0.004 mm;
step four, machining a logarithmic curve spiral hole (21) by numerical control milling;
mounting a mask machining piece and a positioning mandrel on a four-axis linkage milling center, and then processing a logarithmic curve spiral hole (21) with the requirement that the rotating speed of a main shaft of the four-axis linkage milling center is not lower than 4000 r/min;
removing burrs on the outer spherical surface;
clamping a mask machining piece and a positioning mandrel on a lathe, and removing burrs protruding from the edge of a logarithmic curve spiral hole (21) on the outer spherical surface of the hemispherical shell (2) by adopting metallographic abrasive paper;
sixthly, separating the mask processing piece and the positioning mandrel;
firstly, cutting and separating the positioning mandrel along a transition section (6), and reserving a part with a mask processing piece;
then, wire threading is carried out in an axial cutting hole (11) of the positioning mandrel, the positioning mandrel is radially cut through along a radial groove (10) by adopting a linear cutting method, the positioning mandrel is divided into a multi-petal structure which is not connected with each other, and the cut multi-petal structure is respectively taken out in a retraction mode, so that the separation of the mask processing piece and the positioning mandrel is realized;
seventhly, removing burrs on the inner spherical surface;
and (3) loading the separated mask workpiece into a positioning clamp (9), axially fixing the positioning clamp (9) and the mask workpiece through a compression screw (15), and then removing burrs protruding from the edge of the logarithmic curve spiral hole (21) on the inner spherical surface of the hemispherical shell (2) on a lathe, so that the mask processing is completed.
2. The processing method according to claim 1, characterized in that:
step eight, storing the mask;
and (4) clamping the processed mask on the positioning mandrel in the second step for storage, wherein the mask is in a vertical state during storage, so that the mask is prevented from being damaged and deformed.
3. The processing method according to claim 2, characterized in that: and seventhly, polishing and removing burrs by adopting a metallographic abrasive paper or grinding method, or removing the burrs by adopting a resin material brush.
4. The processing method according to claim 3, characterized in that: and in the third step, after the mask machining piece is sleeved on the positioning mandrel, gluing and fixing the matched part of the inner surface of the extension sleeve (3) and the hemispherical base (5) by using glue.
5. The processing method according to claim 4, characterized in that: in the third step, a pressing sleeve (12) and an elastic washer (13) are also arranged between the nut (14) and the mask workpiece.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202210116077.XA CN114147377B (en) | 2022-02-07 | 2022-02-07 | Mask for machining convex hemisphere of gyro motor and machining method thereof |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210116077.XA CN114147377B (en) | 2022-02-07 | 2022-02-07 | Mask for machining convex hemisphere of gyro motor and machining method thereof |
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| CN114147377A CN114147377A (en) | 2022-03-08 |
| CN114147377B true CN114147377B (en) | 2022-06-07 |
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| CN114589520B (en) * | 2022-05-10 | 2022-07-15 | 西安航天精密机电研究所 | Positioning fixture and machining method for gyro motor dynamic pressure air bearing rotor cover |
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| AU2003211404A1 (en) * | 2002-02-28 | 2003-09-09 | Fujitsu Limited | Dynamic pressure bearing manufacturing method, dynamic pressure bearing, and dynamic pressure bearing manufacturing device |
| KR100962778B1 (en) * | 2007-12-13 | 2010-06-09 | 현대자동차주식회사 | Mask making method for forming wood grain |
| RU2668664C2 (en) * | 2014-04-25 | 2018-10-02 | Джонсон Энд Джонсон Вижн Кэа, Инк. | Methods of patterning and making masks for three-dimensional substrates |
| CN108277510A (en) * | 2018-01-22 | 2018-07-13 | 京东方科技集团股份有限公司 | A kind of mask plate and preparation method thereof, display base plate |
| CN113639691A (en) * | 2021-08-03 | 2021-11-12 | 西安航天精密机电研究所 | Evaluation device and evaluation method for sputtering coating uniformity of hemispherical harmonic oscillator |
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