CN112497452B

CN112497452B - Processing method for pyrolytic boron nitride ceramic clamping rod

Info

Publication number: CN112497452B
Application number: CN202011332999.1A
Authority: CN
Inventors: 王刚; 尚华; 段冰
Original assignee: Yibin Redstar Electronics Co ltd
Current assignee: Yibin Redstar Electronics Co ltd
Priority date: 2020-11-24
Filing date: 2020-11-24
Publication date: 2022-03-15
Anticipated expiration: 2040-11-24
Also published as: CN112497452A

Abstract

The invention discloses a processing method, particularly discloses a processing method for pyrolyzing a boron nitride ceramic clamping rod, and belongs to the technical field of processing technologies of electronic functional ceramic materials. The processing method for the pyrolytic boron nitride ceramic clamping rod can effectively process the pyrolytic boron nitride ceramic plate into the clamping rod and ensure the processing quality. The processing method comprises the steps of processing a bar-shaped blank based on a pyrolytic boron nitride ceramic plate, roughly processing the surface of a cut bar-shaped blank, precisely processing a formed blank, and carrying out shaping processing on a semi-finished clamping rod product and cleaning and calcining a shaped clamping rod product, wherein the rough processing of the surface of the cut bar-shaped blank is finished on a precise platform of corresponding processing equipment by blocking and clamping with a blocking iron, and each batch of products are processed by batch operation of simultaneously clamping and processing not less than 10 cut bar-shaped blanks.

Description

Processing method for pyrolytic boron nitride ceramic clamping rod

Technical Field

The invention relates to a processing method, in particular to a processing method for pyrolyzing a boron nitride ceramic clamping rod, and belongs to the technical field of processing technologies of electronic functional ceramic materials.

Background

The helix traveling wave tube is the most important high-power microwave amplifier at present, is a key component of electronic equipment such as radar, electronic countermeasure, relay communication, satellite communication, direct television broadcast satellite, navigation, remote sensing, remote control and remote measurement, and has important functions and wide application prospects in the fields of national defense equipment such as millimeter-wave radar, satellite, airborne communication and electronic countermeasure.

The clamping rods are used as critical parts in the helix traveling wave tube and mainly play four roles, namely clamping the helix in the tube, providing a 'carrier' of the thin film attenuator, playing a role in heat conduction, conducting heat generated in the tube to the outer surface of the tube in time, and relating the performance of the clamping rods to the high-frequency characteristics of the helix traveling wave tube, such as standing waves, phase velocity and the like. The helix traveling wave tube has high working frequency and small volume, and puts high requirements on the clamping rod, and mainly shows that the product has the straightness of 0.01mm, the surface roughness Ra of less than or equal to 0.6 mu m, the dimensional accuracy of +/-0.005 mm and the complex shape. The common aluminum oxide and beryllium oxide can not meet the technical requirements in the aspects of low dielectric loss tangent value, low dielectric constant, high-temperature thermal conductivity and the like of the clamping rod material.

The pyrolytic boron nitride PBN ceramic material is a boron nitride ceramic plate prepared by a vapor deposition method, and becomes one of the preferred materials of the clamping rod of the ultra-high-power travelling wave tube due to the characteristics of no toxicity, small attenuation of high-temperature thermal conductivity (almost no attenuation within 300 ℃), low dielectric constant and the like. The PBN clamping rod precision machining is to realize the precision size of a product by cutting, grinding and other machining processes of the pyrolytic boron nitride substrate, and the thickness of the plate is fixed and usually only has several specifications of 0.8mm, 1mm, 1.2mm and 1.5mm, and is far larger than the size of the product of the clamping rod, so that the surface machining area of the boron nitride substrate reaches 100%. Considering that the thermal conductivity of the PBN material is greatly different in the deposition direction, i.e., the thickness and length or width direction during processing, based on the heat dissipation requirement of the traveling wave tube, the boss position of the clamping rod, i.e., the contact surface with the traveling wave tube, is usually designed in the length or width direction, i.e., the heat conduction direction, of the PBN material. See the attached figures 1 and 2 in the specification.

Meanwhile, due to the low volume density of the boron nitride clamping rod and the elasticity of the material, the complexity of repeated positioning during product processing, the randomness of the size and the shape of the abrasive particles and the distribution of the abrasive particles of the processed grinding wheel and the complexity of the grinding motion rule bring great difficulty to the research of the grinding mechanism of the boron nitride clamping rod. However, the precision machining capability of the high-precision boron nitride ceramic clamping rod falls behind at present, the high-precision requirement of the product cannot be met, and the high-performance PBN clamping rod must be imported through an abnormal channel in China. However, under the influence of international environmental changes, the PBN clamping rod faces the danger of being prohibited from being transported at any time, thereby causing great influence on the development and production of related matched weaponry and civil communication electronic devices.

Therefore, the research on the processing technology of the high-precision boron nitride clamping rod is developed, and a reasonable processing technology and a reasonable control method are designed to ensure the performance of the boron nitride clamping rod substrate and improve the dimensional precision of the product, so that the technical problem which needs to be solved urgently by the technical personnel in the field is solved.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the processing method for the pyrolytic boron nitride ceramic clamping rod can effectively process the pyrolytic boron nitride ceramic plate into the clamping rod and ensure the processing quality.

The technical scheme adopted for solving the technical problems is as follows: a processing method for pyrolytic boron nitride ceramic clamping rods comprises the steps of processing bar-shaped blanks based on pyrolytic boron nitride ceramic plates, cutting the surface of the bar-shaped blanks for rough processing, precisely processing formed blanks, processing the semi-finished products of the clamping rods for shaping, cleaning and calcining the shaped clamping rod products,

the rough machining of the surfaces of the cut strip-shaped blanks is completed on a precise platform of corresponding machining equipment by blocking and clamping the stop iron, and the machining of each batch of products is completed by batch operation of simultaneously clamping and machining the cut strip-shaped blanks by the number not less than 10 pieces in each batch.

Further, the rough surface machining of the cut strip-shaped blank comprises the steps of,

1) placing the cut rectangular ceramic strip blanks on a precise plane grinding platform tightly according to a row of 10-15 ceramic strips as a limit, blocking and clamping by using a blocking iron with the length larger than that of the rectangular ceramic strips, firstly processing one plane of the rectangular ceramic strip blanks, and then clamping and processing the other plane opposite to the processed plane by using the processed plane as a reference plane;

2) according to the method of the step 1), performing surface processing on the other two cutting planes of the rectangular ceramic strip blank; the straightness of the four sides of the blank is perpendicular to the adjacent sides.

In a preferred embodiment of the above aspect, the precision machining of the formed blank comprises the steps of,

the cutting surface of the formed blank after the surface rough machining is taken as the height direction of a clamping rod product, the thickness plane is taken as the width direction of the clamping rod product, the formed blank is ground and machined to reach the height and the width specified by a product drawing, and meanwhile, the surface roughness of the product is ensured to meet the drawing requirement,

wherein, the precision machining process has directional machining selectivity, and the cutting size of the formed blank is used as the height size of the clamping rod product.

Further, the shaping processing of the semi-finished product of the clamping rod comprises the following steps,

after a formed blank which is qualified in precision machining is clamped by a tool, a grinding wheel blade set is used on a precision cutting machine to cut and machine the convex part of the appearance of the product along the cutting surface direction of the ceramic blank,

in the machining process, the width of the boss is controlled by adopting the distance between the two grinding wheel blades of the grinding wheel blade group, and the height of the boss is controlled by adopting the cutting depth of the grinding wheel blades.

The preferable mode of the proposal is that the pyrolytic boron nitride ceramic plate is processed into a strip-shaped blank according to the following steps,

1) reserving machining allowance according to the final width dimension of the product, selecting pyrolytic boron nitride ceramic plates with corresponding thickness as cutting objects, reserving machining allowance according to the final height and length dimension of the product, calculating the dimension of a cut blank,

2) after the pyrolytic boron nitride ceramic plate is firmly adhered by a UV adhesive tape film, cutting the pyrolytic boron nitride ceramic plate on an automatic precision cutting machine according to the calculated blank size to obtain a rectangular boron nitride ceramic strip blank,

completely cutting off the pyrolytic boron nitride ceramic plate in the cutting process, but not completely cutting off the UV adhesive tape film for sticking, and then integrally taking out the cut UV adhesive tape film adhered with the boron nitride ceramic strip blank;

3) exposing the UV adhesive tape adhered with the boron nitride ceramic strip blank in ultraviolet rays for 5-10min to remove a single piece of boron nitride ceramic strip blank after the film of the UV adhesive tape loses adhesiveness, finishing the cutting work of processing the pyrolytic boron nitride ceramic plate into the strip blank,

the cutting width of the cut blank is finally processed into the height of the clamping rod product, and the thickness of the blank is finally processed into the width of the clamping rod product.

Furthermore, the cleaning of the shaped clamping rod product is carried out according to the following steps,

1) firstly, acid cleaning, alkali cleaning and tap water washing are carried out, and a shaped clamping rod product is firstly put into 15% diluted hydrochloric acid to be soaked for more than 30-40 minutes; taking out and putting into a boiled 20% sodium carbonate solution for boiling for 20-30 minutes; then washing the mixture for 3 to 5 minutes by using tap water,

2) alcohol washing, putting the fixed clamping rod product washed by tap water into an ultrasonic washing machine with alcohol, horizontally placing the fixed clamping rod product, carrying out ultrasonic washing for 10-20 minutes,

3) cleaning with acetone, placing the cleaned product into an ultrasonic cleaning machine filled with acetone, wherein the ultrasonic cleaning time is 30-40min for cleaning the product,

wherein, the final shaping clamping rod product after acetone cleaning can not be directly contacted by hands or other metal tools.

In a preferred mode of the above scheme, the calcination of the shaped clamping rod product is carried out according to the following steps,

the method comprises the steps of firstly drying the shaped clamping rod product cleaned by acetone, then preserving heat for 30min-1h at the temperature of 400-600 ℃ in a kiln in a reducing atmosphere, calcining at a low temperature, and obtaining a final boron nitride ceramic clamping rod finished product after calcining.

Further, when the pyrolytic boron nitride ceramic plate is cut into strip-shaped blanks on an automatic precision cutting machine, a resin blade with the thickness of 0.152mm and the diameter of 50-60mm is adopted as a cutting tool, the rotating speed of the cutting machine is 2000-3000r/min, the cutting speed is 0.5-1.5mm/s, and the flow rate of cooling water is 1-2L/min;

the thickness of the UV adhesive tape film adhered with the pyrolytic boron nitride ceramic plate is 0.15-0.2mm, and when the pyrolytic boron nitride ceramic plate is cut, the resin blade is fed to cut the pyrolytic boron nitride ceramic plate and the pyrolytic boron nitride ceramic plate penetrates into the UV adhesive tape film by 0.05-0.1 mm.

The preferable mode of the scheme is that the straightness and the verticality of the stop iron for roughly processing the stop clamp on the surface of the grinding strip-shaped blank are both required to be within 0.01mm, a 180-mesh 300-mesh diamond grinding wheel is adopted for processing, and the rotating speed is 3000 r/min; the processing quantity of each batch is controlled to be 10-15 pieces, and water flow with the flow rate of 3-5L/min is adopted for flushing in the processing process; grinding according to the feed amount of 0.001-0.003 mm/time during cutting,

the shape cutting of the formed blank precision machining adopts a precision cutting machine, a tool clamp is adopted to form the blank in the width direction, a grinding wheel set is used to cut in the height direction, the length of the tool is greater than that of the formed blank, and the straightness of the tool is within 0.01 mm; the cutting sand wheel group is composed of two diamond blades of 180 meshes, 300 meshes, phi 50-60mm and 0.152-0.470mm in thickness, the coaxiality of the circle center of the grinding wheel and the circle center of the rotating shaft is within 0.01mm, the rotating speed of the precision cutting machine is 2000-3000r/min, the cutting speed is 0.5-1mm/s, and the flow rate of cooling water is 1-2L/min.

Furthermore, a kiln with reducing atmosphere for calcination adopts 99.99% pure hydrogen as protective gas.

The invention has the beneficial effects that: the application provides a processing method is through setting up the bar blank processing with pyrolytic boron nitride ceramic panel as the basis, the surperficial rough machining of cutting bar blank, the precision finishing of shaping blank, the washing of the semi-manufactured design processing of supporting rod and design supporting rod product and several processes of calcining, come pyrolytic boron nitride ceramic panel processing shape size, the holding rod that uses in the helix traveling wave tube that physical properties satisfy the requirement, prior art processing difficulty has both been solved, the finished product of processing can not effectively be guaranteed to geometry position size, physical properties receives the technical problem of restriction, again the solution of efficiency how to process into the technical problem of supporting rod with pyrolytic boron nitride ceramic panel. The processing quality is guaranteed, the processing efficiency is improved, and meanwhile the physical property of the finished product clamping rod can be effectively guaranteed.

Drawings

FIG. 1 is a schematic cross-sectional view of a clamping rod involved in the processing method for pyrolyzing boron nitride ceramic clamping rods according to the present invention;

FIG. 2 is a schematic view of the pyrolytic boron nitride ceramic plate material according to the processing method of the pyrolytic boron nitride ceramic clamping rod of the present invention, showing the heat conduction direction and the thickness direction, i.e., the deposition direction;

FIG. 3 is a schematic view of the processing shape of the processing method for pyrolyzing boron nitride ceramic clamping rods according to the invention.

Detailed Description

As shown in fig. 1, 2 and 3, in order to solve the above technical problems in the prior art, the present invention provides a processing method for a pyrolytic boron nitride ceramic clamping bar, which can effectively process a pyrolytic boron nitride ceramic plate into a clamping bar and ensure the processing quality. The processing method comprises the steps of processing a bar-shaped blank based on a pyrolytic boron nitride ceramic plate, roughly processing the surface of a cut bar-shaped blank, precisely processing a formed blank, shaping and processing a semi-finished product of a clamping rod, cleaning and calcining a shaped clamping rod product,

the rough machining of the surfaces of the cut strip-shaped blanks is completed on a precise platform of corresponding machining equipment by blocking and clamping the stop iron, and the machining of each batch of products is completed by batch operation of simultaneously clamping and machining the cut strip-shaped blanks by the number not less than 10 pieces in each batch. The application provides a processing method is through setting up the bar blank processing with pyrolytic boron nitride ceramic panel as the basis, the surperficial rough machining of cutting bar blank, the precision finishing of shaping blank, the washing of the semi-manufactured design processing of supporting rod and design supporting rod product and several processes of calcining, come pyrolytic boron nitride ceramic panel processing shape size, the holding rod that uses in the helix traveling wave tube that physical properties satisfy the requirement, prior art processing difficulty has both been solved, the finished product of processing can not effectively be guaranteed to geometry position size, physical properties receives the technical problem of restriction, again the solution of efficiency how to process into the technical problem of supporting rod with pyrolytic boron nitride ceramic panel. The processing quality is guaranteed, the processing efficiency is improved, and meanwhile the physical property of the finished product clamping rod can be effectively guaranteed.

In the implementation method, in order to effectively ensure the processing quality and the physical performance of a finished product clamping rod on the premise of improving the processing efficiency to the maximum extent, each process is further limited and improved, namely, the rough processing of the surface of a cut strip-shaped blank comprises the following steps of 1) tightly placing the cut rectangular blank of the ceramic strip on a precise plane grinding platform according to a row of 10-15 as limits, blocking and clamping by using a blocking iron with the length being larger than that of the rectangular ceramic strip, processing one plane of the rectangular blank of the ceramic strip firstly, and then clamping and processing the other plane opposite to the processing surface by using the processed plane as a reference plane; 2) according to the method of the step 1), performing surface processing on the other two cutting planes of the rectangular ceramic strip blank; and processing to ensure that four side surfaces of the rectangular blank have certain straightness and verticality. The precision machining of the formed blank comprises the following steps of machining the cutting width of the formed blank after the surface rough machining is finished into the height of a clamping rod product, machining the formed blank into the height and the width specified by a product drawing by grinding, and meanwhile ensuring that the surface roughness of the product meets the drawing requirement. Correspondingly, the shaping processing of the semi-finished clamping rod comprises the following steps of clamping a formed blank qualified in precision processing by a tool, cutting and processing the appearance convex part of a product on a precision cutting machine by a grinding wheel blade group along the height of the ceramic formed blank, wherein in the processing process, the width of a boss is controlled by adopting the distance between two grinding wheel blades of the grinding wheel blade group, and the height of the boss is controlled by adopting the depth of the cutting of the grinding wheel blades. And the pyrolytic boron nitride ceramic plate is processed into a strip-shaped blank according to the following steps,

1) reserving machining allowance according to the final width dimension of the product, selecting a pyrolytic boron nitride ceramic plate with corresponding thickness as a cutting object, reserving machining allowance according to the final height and length dimension of the product, and calculating the dimension of a cut blank;

Meanwhile, the washing procedure and the forging and pouring procedure which are used as the final shape and ensure the physical properties of the finished clamping rod are carried out according to the following steps when the shaped clamping rod product is cleaned,

The calcination of the shaped clamping rod product is carried out according to the following steps,

the method comprises the steps of firstly drying the shaped clamping rod product cleaned by acetone, then preserving heat for 30min-1h at the temperature of 400-600 ℃ in a kiln in a reducing atmosphere, calcining at a low temperature, and obtaining a final boron nitride ceramic clamping rod finished product after calcining. At this time, the kiln with reducing atmosphere used for calcination adopts 99.99% pure hydrogen as the protective gas.

Furthermore, in order to ensure that the quality of each procedure can meet corresponding requirements in the processing process, when the pyrolytic boron nitride ceramic plate is cut into strip-shaped blanks on an automatic precision cutting machine, a resin blade with the thickness of 0.152mm and the diameter of 50-60mm is adopted as a cutting tool, the rotating speed of the cutting machine is 2000-3000r/min, the cutting speed is 0.5-1.5mm/s, and the flow rate of cooling water is 1-2L/min;

The straightness and the verticality of a stop iron for roughly processing the stop clamp on the surface of the grinding strip-shaped blank are both required to be within 0.01mm, a 180-mesh 300-mesh diamond grinding wheel is adopted for processing, and the rotating speed is 3000 r/min; the processing quantity of each batch is controlled to be 10-15 pieces, and water flow with the flow rate of 3-5L/min is adopted for flushing in the processing process; grinding according to the feed amount of 0.001-0.003 mm/time during cutting,

In conclusion, the processing method provided by the application also has the following advantages,

1. the boron nitride clamping rod prepared by the method for precisely processing and manufacturing the pyrolytic boron nitride ceramic clamping rod has the advantages that the precision (height and width) of the key dimension can reach +/-0.005 mm, the straightness, the symmetry and the verticality can reach within 0.01mm, the surface roughness of the side surface can reach Ra of less than or equal to 0.4 mu m, and the design precision requirement of the conventional high-performance high-power wide-frequency-band traveling wave tube is met.

2. By adopting the processing method provided by the application, the wafer cutting and semiconductor cutting process is used for reference, the UV cutting is carried out by adopting high rotating speed and film-sticking code, the stable surface quality of the cut product is ensured, the fixed-number processing and the step-by-step processing are adopted in the surface processing process, the mode of micro feed and large water flow washing, grinding and cutting scraps is adopted to ensure that the qualification rate of the whole preparation process in the whole process reaches more than 95%, and the yield of the product is ensured.

3. By adopting the method for cleaning and calcining the clamping rods, various volatile impurities introduced in the machining process can be eliminated to the greatest extent, the clamping rod products are guaranteed not to generate an air release phenomenon in the high-temperature working process, and the failure of the vacuum traveling wave piece caused by the phenomenon is avoided.

The PBN boron nitride clamping rod prepared by the processing method provided by the application has the advantages of high dimensional accuracy, good straightness, high surface roughness and less product surface defects, the integral qualification rate can reach more than 95%, and the PBN boron nitride clamping rod can be mainly used in an aerospace-grade traveling wave tube helix slow-wave circuit, can improve the coupling impedance of a high-frequency system, reduce the high-frequency loss of the traveling wave tube and improve the output power capability and reliability of the traveling wave tube due to the low dielectric loss, high heat conduction and high-temperature high heat conduction performance attenuation, high mechanical strength and good chemical stability.

This application the supporting rod be the supporting rod that pyrolytic boron nitride ceramic material made, bar blank wherein, cutting bar blank, shaping blank and supporting rod semi-manufactured goods are the cross section and are made for the pyrolytic boron nitride ceramic material of rectangle structure with design supporting rod product, the supporting rod name term of different stages in the course of working. Accordingly, the code number of pyrolytic boron nitride is PBN, i.e., PBN represents pyrolytic boron nitride.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

The invention provides a precision machining and manufacturing method of a pyrolytic boron nitride ceramic clamping rod. The boron nitride clamping rod prepared by the method has the advantages of high dimensional precision, good straightness, high surface roughness, few product surface defects and high overall qualification rate of more than 95 percent.

The method comprises the following steps:

A. cutting the PBN ceramic plate:

a) according to the drawing size of the product, considering the machining grinding allowance in each direction, selecting a PBN plate with a proper size as a cutting object, and calculating the size of the cut blank.

b) And after the PBN plate is pasted by the UV adhesive tape, cutting the PBN plate on an automatic precision cutting machine according to the calculated blank size, and cutting the PBN plate into rectangular ceramic strips. And in the cutting process, the PBN plate is completely cut off, but the back UV adhesive tape which damages the cutting table top cannot be completely cut off, and the cut UV film adhered with the boron nitride ceramic strip is integrally taken out.

c) Exposing the UV adhesive tape adhered with the boron nitride ceramic strips in ultraviolet rays for 5-10min to remove the ceramic strips after the UV adhesive tape film loses adhesiveness.

B. Surface processing of the cutting blank:

closely placing the cut rectangular blank on a precise plane grinding platform, and blocking and clamping by using a blocking iron with the length being larger than that of the porcelain strip, and firstly processing one plane of the PBN rectangular blank; after processing, processing the opposite plane by taking the processed plane as a reference plane;

the basic parallelism and the verticality of the product are guaranteed through the processing.

C. Size finishing

And taking the cutting width of the processed blank as the height of the clamping rod product, and taking the thickness as the height and width of the product width which are finally required by the product grinding processing. Meanwhile, the surface roughness of the product in the height direction is ensured to reach Ra less than or equal to 0.6 mu m.

D. Contour machining

And D, tightly clamping the finish-machined blank obtained in the step C by using a tool, and cutting and machining the convex part of the appearance of the product in the direction of the cutting surface of the porcelain rod by using a grinding wheel blade in a precision cutting machine. The cutting width is the width of the boss, and the cutting depth controls the height of the boss.

E. Cleaning of

a) Acid washing: soaking the product in 15% dilute hydrochloric acid for over 30-40 min; alkali washing: putting the product into a boiled 20% sodium carbonate solution to be boiled for 20-30 minutes; washing the product after alkali washing with tap water for 3-5 minutes;

b) alcohol washing: putting the product cleaned by tap water into an ultrasonic cleaning machine filled with alcohol, and horizontally placing the product for 10-20 minutes;

c) cleaning with acetone: and putting the product after the alcohol is cleaned into an ultrasonic cleaning machine filled with acetone, and horizontally placing the product for 30-40 minutes. The product cleaned by acetone can not be directly contacted by hands or other metal tools.

F. Calcination of

And (3) keeping the dried PBN clamping rod product in a kiln in a reducing atmosphere at the temperature of 400-600 ℃ for 30min-1h, calcining at a low temperature, and obtaining the final PBN ceramic clamping rod product after a later stage.

In the method for precisely machining and manufacturing the pyrolytic boron nitride ceramic clamping rod, in the step A, the thickness and the length of the PBN plate are greater than the width and the length of a product of the clamping rod, so that the cutting and the cutting are convenient; when cutting, the cutting width is the height of the clamping rod product and the grinding allowance of 0.3-0.4 mm. The length of the clamping bar is directly cut to the product size.

In the method for precisely machining and manufacturing the pyrolytic boron nitride ceramic clamping rod, in the step A, the optimal cutting is carried out on an automatic precise cutting machine, a resin blade with the thickness of 0.152mm and the diameter of 50-60mm is used as a cutting tool, the rotating speed of the cutting machine is 2000-3000r/min, and the cutting speed is 0.5-1.5 mm/s.

In the method for precisely machining and manufacturing the pyrolytic boron nitride ceramic clamping rod, in the step A, the thickness of the preferably adopted UV adhesive tape is 0.15-0.2mm, and during cutting, the PBN plate is cut by a blade and penetrates into the UV adhesive tape by 0.05-0.1 mm.

In the step B, preferably, a precision surface grinding machine is adopted to process the surface of the blank, a stop iron with the length greater than that of the ceramic rod blank is adopted to stop and clamp, the straightness and the verticality of the stop iron are required to be within 0.01mm, a 400-plus 600-mesh diamond grinding wheel is adopted, and the rotating speed is 2000 r/min; in order to avoid the phenomenon that the ground chips are accumulated on the grinding wheel and the surface of a product to cause scratches in the grinding process, water flow is controlled to be 3-5L/min; the feed amount should be controlled at 0.005-0.01 mm/time during the processing, and the grinding allowance of 0.05mm is ensured on each side surface of the product after surface processing.

In the step C, the size fine machining adopts a stop iron with the length larger than that of the porcelain rod blank to stop and clamp, the straightness and the verticality of the stop iron are required to be within 0.01mm, a 180-mesh and 300-mesh diamond grinding wheel is adopted, and the rotating speed is 3000 r/min; in order to avoid the generation of scratches on the product caused by the accumulation of ground chips on the grinding wheel and the surface of the product in the grinding process, the water flow is 3-5L/min; the required width and height of the product should be ground and processed according to the feed amount of 0.001-0.003 mm/time in the cutting process.

In the step D, the optimal shape cutting adopts a precision cutting machine, the width direction of the clamping rod is clamped by adopting a tool, the cutting height direction of the blade is required to be larger than the length of the clamping rod, the straightness is within 0.01mm, the cutting blade adopts a 180-plus-300-mesh diamond blade with the diameter of 50-60mm and the thickness of 0.152-0.470mm, the coaxiality of the circle center of the grinding wheel and the circle center of the rotating shaft is within 0.01mm, the rotating speed of the precision cutting machine is 3000r/min, the cutting speed is 0.5-1mm/s, and the cooling water flow is 1-2L/min.

In the step e (a), the preferable acid washing is to soak the pyrolytic boron nitride ceramic clamping rod in 15% diluted hydrochloric acid for 30-40min, and the alkali washing is to boil the pyrolytic boron nitride ceramic clamping rod in a boiled 20% sodium carbonate solution for 20-30 min. Then, the mixture is rinsed with tap water for 3-5 minutes.

In the step e (b), the preferable alcohol cleaning is performed in an ultrasonic cleaning machine for 10-20min by using analytically pure alcohol;

in the step e (c), the preferable acetone cleaning is performed in an ultrasonic cleaning machine for 30-40min by using analytically pure acetone, and the cleaned product cannot be contacted with a hand or a tool made of other metal materials.

In the step F, 99.99% pure hydrogen is adopted as a protective gas in a preferable reduction atmosphere kiln for calcination, the sintering temperature is 400-600 ℃, and the heat preservation time is 30min-1 h.

Example one

According to the drawing size of a product, the width of a clamping rod is 0.4mm, the height of the clamping rod is 0.7mm, the width of a boss is 0.2mm, the height of the boss is 0.28mm, the length of the boss is 100mm, and a general PBN plate with the thickness of 168mm multiplied by 80mm multiplied by 0.8mm is selected. Calculating the size of the cut porcelain strips: the length is 100mm, the thickness is 0.8mm, and the cutting width is 1.2 mm. A UV tape with a thickness of 0.15mm was adhered to the surface of the PBN plate, and placed on an automatic cutter.

When cutting, a resin blade with the thickness of 0.152mm and the diameter of 50mm is used as a cutting tool, the rotating speed of the cutting machine is 30000r/min, the cutting speed is 0.5mm/s, the cutting depth is 0.85mm, and the cooling water flow is 2L/min. And (4) placing the cut ceramic strip into an exposure machine for exposure, tearing off the ceramic strip, and performing surface processing on the blank.

Clamping the blank at four sides by using a stop iron with the length of 110mm and the straightness and perpendicularity within 0.01mm, and adopting a 400-mesh diamond grinding wheel at the rotating speed of 2000 r/min; in order to avoid the phenomenon that the ground chips are accumulated on the grinding wheel and the surface of a product to cause scratches in the grinding process, the water flow is controlled to be 3L/min; in the processing process, the feed amount is controlled to be 0.01 mm/time, and the grinding allowance of 0.05mm is still left on the single surface of the product in the height direction after the surface processing. Processing the surface of the opposite surface by taking the surface as a reference after the processing is finished; the same method is adopted to process the cutting surface of the porcelain strip, and the perpendicularity and the parallelism of 4 side surfaces of the product are ensured.

Placing the blank with the finished surface on a processing platform, blocking and clamping a stop iron, and adopting a 180-mesh diamond grinding wheel at the rotating speed of 3000 r/min; controlling the water flow for 3L/min; the required width and height dimensions of the product are ground according to the feed amount of 0.003mm per time in the cutting process, and the surface roughness of two side surfaces in the height direction is enabled to be less than 0.6 mu m.

Clamping the width direction of a clamping rod by a tool with the straightness within 0.01mm and the length of 110mm, cutting the shape in an automatic cutting machine, wherein a cutting grinding wheel adopts a diamond blade with 180 meshes, the diameter is 50mm and the thickness is 0.152mm, the coaxiality of the circle center of the grinding wheel and the circle center of a rotating shaft is within 0.01mm, the rotating speed of a precision cutting machine is 30000r/min, the cutting speed is 0.5mm/s, the shape is cut, the cutting depth is 0.28mm, and the cutting width is 0.2 mm.

And soaking the finished pyrolytic boron nitride clamping rod product in 15% dilute hydrochloric acid for 30min, and then performing alkali washing, wherein the alkali washing is to boil the pyrolytic boron nitride clamping rod product in a boiled 20% sodium carbonate solution for 20 min. And then rinsed with tap water for 3 minutes. Cleaning with alcohol after alkaline cleaning, wherein the cleaning is carried out in an ultrasonic cleaning machine for 10min by adopting analytically pure alcohol; cleaning with acetone in an ultrasonic cleaning machine for 30min, wherein the acetone is used for cleaning, and the cleaned product can not be contacted with a hand or other tools made of metal materials. And finally, the product is subjected to a reducing atmosphere kiln, 99.99% pure hydrogen is used as protective gas, the sintering temperature is 400 ℃, and the heat preservation time is 1h, so that the final clamping rod product is obtained.

The product made by this embodiment was C1, with the C1 related properties shown in table 1.

Example two

According to the drawing size of a product, the width of a clamping rod is 0.5mm, the height of the clamping rod is 0.9mm, the width of a boss is 0.15mm, the height of the boss is 0.4mm, the length of the boss is 100mm, and a general PBN plate with the thickness of 168mm multiplied by 80mm multiplied by 0.8mm is selected. Calculating the size of the cut porcelain strips: the length is 100mm, the thickness is 0.8mm, and the cutting width is 1.3 mm. A UV tape with a thickness of 0.2mm was adhered to the surface of the PBN plate, and the PBN plate was placed on an automatic cutter.

When cutting, a resin blade with the thickness of 0.152mm and the diameter of 60mm is used as a cutting tool, the rotating speed of the cutting machine is 20000r/min, the cutting speed is 1.5mm/s, and the cutting depth is 0.9 mm. And (4) placing the cut ceramic strip into an exposure machine for exposure, tearing off the ceramic strip, and performing surface processing on the blank.

Clamping the blank at four sides by using a stop iron with the length of 110mm and the straightness and perpendicularity within 0.01mm, and adopting a 600-mesh diamond grinding wheel at the rotating speed of 2000 r/min; in order to avoid the phenomenon that the ground chips are accumulated on the grinding wheel and the surface of a product to cause scratches in the grinding process, the water flow is controlled to be 5L/min; in the processing process, the feed amount is controlled to be 0.01 mm/time, and the grinding allowance of 0.05mm is still left on the single surface of the product in the height direction after the surface processing. Processing the surface of the opposite surface by taking the surface as a reference after the processing is finished; the same method is adopted to process the cutting surface of the porcelain strip, and the perpendicularity and the parallelism of 4 side surfaces of the product are ensured.

Placing the blank with the finished surface on a processing platform, blocking and clamping a stop iron, and adopting a 300-mesh diamond grinding wheel at the rotating speed of 3000 r/min; controlling the water flow to be 5L/min; the required width and height dimensions of the product are ground according to the feed amount of 0.003mm per time in the cutting process, and the surface roughness of two side surfaces in the height direction is enabled to be less than 0.6 mu m.

Clamping the width direction of a clamping rod by a tool with the straightness within 0.01mm and the length of 110mm, cutting the shape in an automatic cutting machine, wherein a cutting grinding wheel adopts a diamond blade with the mesh size of 300, the diameter of 60mm and the thickness of 0.203, the coaxiality of the circle center of the grinding wheel and the circle center of a rotating shaft is within 0.01mm, the rotating speed of the precision cutting machine is 20000r/min, and the cutting speed is 1.5 mm/s. When the profile was cut, the cutting width was 0.15mm and the cutting depth was 0.5 mm.

And soaking the finished pyrolytic boron nitride clamping rod product in 15% dilute hydrochloric acid for 40min, and then performing alkali washing, wherein the alkali washing is to boil the pyrolytic boron nitride clamping rod product in a 20% sodium carbonate solution for 30 min. And rinsed with tap water for 5 minutes. Cleaning with alcohol after alkaline cleaning, and cleaning with analytically pure alcohol in an ultrasonic cleaning machine for 20 min; cleaning with acetone in an ultrasonic cleaning machine for 40min, wherein the acetone is used for cleaning, and the cleaned product can not be contacted with a hand or other tools made of metal materials. And finally, the product is treated by a reducing atmosphere kiln with 99.99 percent pure hydrogen as protective gas, the sintering temperature is 600 ℃, and the heat preservation time is 30min to obtain the final clamping rod product.

The sample made in this embodiment was C2 with the relevant properties of C2 shown in Table 1.

EXAMPLE III

According to the drawing size of a product, the width of a clamping rod is 0.6mm, the height of the clamping rod is 1.25mm, the width of a boss is 0.35mm, the height of the boss is 0.5mm, the length of the boss is 100mm, and a general PBN plate with the thickness of 168mm multiplied by 80mm multiplied by 0.8mm is selected. Calculating the size of the cut porcelain strips: the length is 100mm, the thickness is 0.8mm, and the cutting width is 1.6 mm. A UV tape with a thickness of 0.15mm was adhered to the surface of the PBN plate, and placed on an automatic cutter.

When cutting, a resin blade with the thickness of 0.152mm and the diameter of 50mm is used as a cutting tool, the rotating speed of the cutting machine is 30000r/min, the cutting speed is 0.5mm/s, and the cutting depth is 0.85 mm. And (4) placing the cut ceramic strip into an exposure machine for exposure, tearing off the ceramic strip, and performing surface processing on the blank.

Clamping the width direction of a clamping rod by a tool with the straightness within 0.01mm and the length of 110mm, cutting the shape in an automatic cutting machine, wherein a cutting grinding wheel adopts a diamond blade with 180 meshes, the diameter is 50mm and the thickness is 0.152mm, the coaxiality of the circle center of the grinding wheel and the circle center of a rotating shaft is within 0.01mm, the rotating speed of a precision cutting machine is 30000r/min, the cutting speed is 0.5mm/s, the shape is cut, the cutting depth is 0.5mm, and the cutting width is 0.35 mm.

The product made by this embodiment was C3, with the C3 related properties shown in table 1.

Table 1 the properties of the PBN clamping rods prepared in the respective examples are as follows,

performance of clamping rod	International level	C1	C2	C3
					Tolerance of width	±0.005mm	-0.004-+003	±0.004	±0.003
Height tolerance	±0.005mm	-0.04-+003	±0.04	±0.003
					Degree of symmetry	0.01mm	0.006	0.007	0.005
Surface roughness	Ra＜0.6μm	Ra0.4	Ra0.5	Ra0.4
					Verticality	0.01mm	0.008	0.008	0.008
Straightness accuracy	0.01mm	0.005	0.005	0.005

。

Claims

1. A processing method for pyrolyzing a boron nitride ceramic clamping rod is characterized by comprising the following steps: the processing method comprises the steps of processing a bar-shaped blank based on a pyrolytic boron nitride ceramic plate, roughly processing the surface of a cut bar-shaped blank, precisely processing a formed blank, shaping and processing a semi-finished product of a clamping rod, cleaning and calcining a shaped clamping rod product,

during rough machining of the surfaces of the cut strip-shaped blanks, blocking and clamping are carried out on a precise platform of corresponding machining equipment by using a stop iron to finish machining, and batch operation of clamping and machining the cut strip-shaped blanks in quantity not less than 10 pieces is adopted for each batch to finish machining of products of each batch;

the pyrolytic boron nitride ceramic plate is processed into a strip-shaped blank according to the following steps,

the cutting width of the cut blank is finally processed into the height of the clamping rod product, and the thickness of the blank is finally processed into the width of the clamping rod product;

when the pyrolytic boron nitride ceramic plate is cut into strip-shaped blanks on an automatic precision cutting machine, a resin blade with the thickness of 0.152mm and the diameter of 50-60mm is adopted as a cutting tool, the rotating speed of the cutting machine is 2000-3000r/min, the cutting speed is 0.5-1.5mm/s, the flow rate of cooling water is 1-2L/min,

2. The processing method for pyrolytic boron nitride ceramic clamping rods according to claim 1, wherein: the rough surface machining for cutting the bar-shaped blank includes the steps of,

1) placing the cut rectangular ceramic strip blanks on a precise plane grinding platform tightly according to a row of 10-15 ceramic strips as a limit, blocking and clamping by using a blocking iron with the length larger than that of the rectangular ceramic strip, firstly processing one plane of the rectangular ceramic strip blanks in the thickness direction, and then clamping and processing the other plane opposite to the processed plane by using the processed plane as a reference plane;

2) according to the method of the step 1), performing surface processing on the other two cutting planes of the rectangular ceramic strip blank;

3) after the four side surfaces of the rectangular ceramic strip blank are machined, the rectangular ceramic strip blank is vertically placed, the matrix is arranged neatly and precisely, the number of single surface machining is not more than 50, the two end surfaces of the rectangular ceramic strip blank are machined by adopting the stop iron retaining clamps, and the basic parallelism and the verticality of a product are guaranteed in the machining through tools.

3. The processing method for pyrolytic boron nitride ceramic clamping rods according to claim 1, wherein: the precision machining of the formed blank comprises the following steps,

4. The processing method for pyrolytic boron nitride ceramic clamping rods according to claim 3, wherein: the shaping processing of the semi-finished product of the clamping rod comprises the following steps,

after the formed blank qualified by precision machining is clamped by a tool, a grinding wheel blade set is used on a precision cutting machine to cut and machine the convex part of the appearance of the product along the cutting surface direction of the ceramic formed blank,

5. The processing method for pyrolyzing boron nitride ceramic clamping rods according to claim 1, 2, 3 or 4, wherein: the cleaning of the shaped clamping rod product is carried out according to the following steps,

6. The processing method for pyrolytic boron nitride ceramic clamping rods according to claim 5, wherein: the calcination of the shaped clamping rod product is carried out according to the following steps,

7. The processing method for pyrolytic boron nitride ceramic clamping rods according to claim 1, wherein: the straightness and the verticality of a stop iron for roughly processing the stop clamp on the surface of the grinding strip-shaped blank are both required to be within 0.01mm, a 180-mesh 300-mesh diamond grinding wheel is adopted for processing, and the rotating speed is 3000 r/min; the processing quantity of each batch is controlled to be 10-15 pieces, and water flow with the flow rate of 3-5L/min is adopted for flushing in the processing process; grinding according to the feed amount of 0.001-0.003 mm/time during cutting,

8. The processing method for pyrolytic boron nitride ceramic clamping rods according to claim 6, wherein: the kiln with reducing atmosphere for calcination adopts 99.99% pure hydrogen as protective gas.