阅读说明：本技术 一种陶瓷材料风洞模型的加工方法 (Processing method of ceramic material wind tunnel model ) 是由 殷贵刚 毛代勇 周先平 于 2021-06-26 设计创作，主要内容包括：本发明涉及航空航天技术领域,提供了一种陶瓷材料风洞模型的加工方法,包括步骤有：1)准备生坯材料；2)车制内腔偏心孔和圆柱外形台阶轴；3)烧结生坯材料；4)精车削外圆基准和内腔偏心孔至最终尺寸,得到毛坯件；5)利用V型夹块将毛坯件固定于机床,进行粗加工、半精加工和精加工；6)利用去工艺头夹块将毛坯件固定于机床,先后去除头部工艺头和尾部工艺头；7)对工件进行整形、打磨、抛光,获得成品件。本发明解决了硬脆材料高效精密加工技术,制定了陶瓷零件异形曲面高效铣磨工艺工序及参数,加工陶瓷材料常见的振动及崩边现象得到了明显抑制,零件表面质量明显提升,实现了该类大尺寸异形复杂曲面氧化锆陶瓷零件的高效制造。(The invention relates to the technical field of aerospace, and provides a method for processing a ceramic material wind tunnel model, which comprises the following steps: 1) preparing a green body material; 2) turning an inner cavity eccentric hole and a cylindrical step shaft; 3) sintering the green body material; 4) finely turning the excircle reference and the inner cavity eccentric hole to a final size to obtain a blank; 5) fixing the blank piece on a machine tool by utilizing a V-shaped clamping block, and performing rough machining, semi-finish machining and finish machining; 6) fixing the blank piece on a machine tool by using a process head removing clamp block, and removing a head process head and a tail process head in sequence; 7) and shaping, grinding and polishing the workpiece to obtain a finished product. The invention solves the high-efficiency precision machining technology of hard and brittle materials, sets the high-efficiency milling and grinding process procedure and parameters of the special-shaped curved surface of the ceramic part, obviously inhibits the common vibration and edge breakage phenomena of the machined ceramic material, obviously improves the surface quality of the part, and realizes the high-efficiency manufacture of the large-size special-shaped complex curved surface zirconia ceramic part.)

1. A processing method of a ceramic material wind tunnel model is characterized by comprising the following steps:

1) preparing a green body material;

2) turning an outer cylinder and an inner cavity eccentric hole on the green material, turning a plurality of step shafts on the outer cylinder, and turning a center hole opposite to the top end of each step shaft;

3) sintering the green body;

4) a diamond insert coating turning tool is adopted, and the outer circle reference and the inner cavity eccentric hole are precisely turned to the final size by taking Aa as 0.25-0.5 mm, F as 0.03-0.1 mm/S and V as 25m/min as turning parameters to obtain a blank;

5) fixing the blank on a machine tool by using a V-shaped clamping block and a pressing plate, roughly machining by adopting an indexable 250# diamond particle coated tool bit of a hydraulic tool holder and a hard alloy tool bar, wherein the tool path adopts an oscillation cutting mode, cutting parameters are Aa equal to 0.2mm, Ar equal to 0.2mm, F equal to 0.05mm/S, V equal to 150m/min, and the machining allowance is 0.3 mm-0.6 mm;

6) performing semi-finishing by using an indexable 400# diamond particle coated tool bit with a hydraulic tool handle and a hard alloy tool bar, wherein the path of the tool adopts an equal-height cutting mode, the cutting parameters are 0.1mm for Aa, 1500mm/min for F, 9000r/min for S and 0.2mm for machining allowance;

7) performing finish machining by adopting an indexable 800# diamond particle coated tool bit with a hydraulic tool handle and a hard alloy tool bar, wherein the path of the tool adopts an equal-height cutting mode, and cutting parameters are selected from Aa being 0.02-0.05 mm, F being 1500mm/min and S being 20000 r/min;

8) unloading the V-shaped clamping block and the pressing plate, fixing the workpiece subjected to finish machining in the step 5) on a machine tool by using a process head removing clamping block, removing the process head at the head part of the workpiece in the step 7) firstly, and removing the process head at the tail part;

9) and unloading the workpiece, shaping, grinding and polishing to obtain the final part.

2. The method for processing the wind tunnel model of the ceramic material according to claim 1, wherein the method comprises the following steps: in the step 1), the preparation method of the green material comprises the following steps: according to the designed shape of the enveloped green body, a dry mixing compression molding process is adopted to compress the cylindrical green body, and the middle hole is formed by pressing a steel core.

3. The method for processing the wind tunnel model of the ceramic material according to claim 1, wherein the method comprises the following steps: in the step 3), the sintering temperature is 1400-1600 ℃.

4. The method for processing the wind tunnel model of the ceramic material according to claim 1, wherein the method comprises the following steps: in the step 5), the V-shaped clamping block comprises a head V-shaped clamping block and a tail V-shaped clamping block, the head V-shaped clamping block and the tail V-shaped clamping block both comprise supporting blocks, a V-shaped groove attached to the outer contour surface of the workpiece is formed in each supporting block, and a cushion block is further arranged at the bottom of each supporting block of the head V-shaped clamping block to keep the same height as the tail V-shaped clamping block.

5. The method for processing the wind tunnel model of the ceramic material according to claim 1, wherein the method comprises the following steps: in the step 8), the process head removing clamping block comprises an upper clamping block and a lower clamping block, arc-shaped grooves attached to the outer contour of the workpiece are formed in the opposite surfaces of the upper clamping block and the lower clamping block, and the upper clamping block and the lower clamping block are fixed into a whole through screws.

6. The method for processing the wind tunnel model of the ceramic material according to claim 5, wherein the method comprises the following steps: and 8), temporarily fixing the upper clamping block and the lower clamping block with the workpiece at the arc-shaped groove through an adhesive.

7. The method for processing the wind tunnel model of the ceramic material according to claim 1, wherein the method comprises the following steps: in the step 8), before the process head is removed, the workpiece with the process head clamp block needs to be subjected to three-coordinate measurement on a machine tool, the process head clamp block is adjusted, and the assembly error between the process head clamp block and the ceramic part is reduced.

8. The method for processing the wind tunnel model of the ceramic material according to claim 1, wherein the method comprises the following steps: in step 8), after the head process head is removed, rough machining, semi-finish machining and finish machining are required to be carried out on the head of the workpiece.

9. The method for processing the wind tunnel model of the ceramic material according to claim 1, wherein the method comprises the following steps: in the step 8), the method for removing the tail process head comprises the following steps: the large allowance is integrally cut and removed by a diamond cutting blade, then finish machining is carried out, a hydraulic tool shank, a hard alloy tool shank and an indexable 800# diamond particle coating tool bit are adopted during finish machining, the path of a tool adopts a mode of equal-height cutting, cutting parameters are selected from Aa being 0.02-0.05 mm, F being 1500mm/min and S being 20000 r/min.

Technical Field

The invention relates to the technical field of aerospace, in particular to a method for processing a ceramic material wind tunnel model.

Background

With the development of high-altitude high-speed aircrafts, corresponding wind tunnel test researches are developed more and more, requirements are higher and more, and a series of wind tunnel test models which can meet the scientific researches such as wind tunnel test precision researches, wind tunnel standard database establishment, wind tunnel performance examination, wind tunnel performance calibration and measurement are urgently manufactured.

The Y-TZP material is a tetragonal zirconia polycrystalline ceramic material taking Y203 as a stabilizer, the composition of the Y203 is 1.5-3.0 percent (mole fraction), a small amount of nano Al2O3 micro powder is doped in zirconia powder stabilized by the Y203 to promote the compact sintering of a ZrO2 blank and increase the mechanical property, the sintering is generally carried out in a tetragonal or tetragonal and cubic 2-phase region within the temperature range of 1400-1600 ℃, and a small amount of glass phase exists in a crystal boundary. The Y-TZP ceramic can lead the material to have excellent mechanical property and linear expansion coefficient which are close to those of steel through a stress induced phase change toughening mechanism.

The Mohs hardness of the zirconia ceramic is 8.5, and the zirconia ceramic is similar to sapphire, wear-resistant and scratch-resistant; the zirconia ceramic has low thermal conductivity, is moist like jade in touch, is a non-conductive material, cannot shield signals, cannot influence the layout of the antenna, and can be conveniently integrally formed; the dielectric constant of the zirconia ceramics is 3 times of that of sapphire, and the zirconia ceramics has better high-temperature mechanical property, chemical erosion resistance, electrical insulation property, higher hardness, wear resistance and the like.

As shown in figure 1, the large Y-TZP zirconia finished part 1 has long and deep three-stage inner cavity eccentric holes and duckbill special-shaped outer surfaces, the whole length is 400mm, the maximum oval outer diameter is 130mm, the maximum inner square hole edge is 75mm, the maximum inner circular hole diameter is 40mm, and the part has the characteristics of high toughness, high strength and high density, and the manufacturing accuracy is difficult to ensure in the machining process. Therefore, how to solve the above problems becomes a focus of research by those skilled in the art.

Disclosure of Invention

The invention aims to provide a method for processing a ceramic material wind tunnel model, which aims to solve the problem of the prior art.

The embodiment of the invention is realized by the following technical scheme:

a processing method of a ceramic material wind tunnel model comprises the following steps:

1) preparing a green body material;

2) turning an outer cylinder and an inner cavity eccentric hole on the green material, turning a plurality of step shafts on the outer cylinder, and turning a center hole opposite to the top end of each step shaft;

3) sintering the green body;

4) a diamond insert coating turning tool is adopted, and the outer circle reference and the inner cavity eccentric hole are precisely turned to the final size by taking Aa as 0.25-0.5 mm, F as 0.03-0.1 mm/S and V as 25m/min as turning parameters to obtain a blank;

5) fixing the blank on a machine tool by using a V-shaped clamping block and a pressing plate, roughly machining by adopting an indexable 250# diamond particle coated tool bit of a hydraulic tool holder and a hard alloy tool bar, wherein the tool path adopts an oscillation cutting mode, cutting parameters are Aa equal to 0.2mm, Ar equal to 0.2mm, F equal to 0.05mm/S, V equal to 150m/min, and the machining allowance is 0.3 mm-0.6 mm;

6) performing semi-finishing by using an indexable 400# diamond particle coated tool bit with a hydraulic tool handle and a hard alloy tool bar, wherein the path of the tool adopts an equal-height cutting mode, the cutting parameters are 0.1mm for Aa, 1500mm/min for F, 9000r/min for S and 0.2mm for machining allowance;

7) performing finish machining by adopting an indexable 800# diamond particle coated tool bit with a hydraulic tool handle and a hard alloy tool bar, wherein the path of the tool adopts an equal-height cutting mode, and cutting parameters are selected from Aa being 0.02-0.05 mm, F being 1500mm/min and S being 20000 r/min;

8) unloading the V-shaped clamping block and the pressing plate, fixing the workpiece subjected to finish machining in the step 5) on a machine tool by using a process head removing clamping block, removing the process head at the head part of the workpiece in the step 7) firstly, and removing the process head at the tail part;

9) and unloading the workpiece, shaping, grinding and polishing to obtain the final part.

Further, in step 1), the preparation method of the green material comprises the following steps: according to the designed shape of the enveloped green body, a dry mixing compression molding process is adopted to compress the cylindrical green body, and the middle hole is formed by pressing a steel core.

Further, in the step 3), the sintering temperature is 1400-1600 ℃.

Further, in the step 5), the V-shaped clamping block comprises a head V-shaped clamping block and a tail V-shaped clamping block, the head V-shaped clamping block and the tail V-shaped clamping block both comprise supporting blocks, each supporting block is provided with a V-shaped groove attached to the outer contour surface of the workpiece, and the bottom of each supporting block of the head V-shaped clamping block is further provided with a cushion block to keep the same height as the tail V-shaped clamping block.

Further, in the step 8), the process head removing clamping block comprises an upper clamping block and a lower clamping block, arc-shaped grooves attached to the outer contour of the workpiece are formed in opposite surfaces of the upper clamping block and the lower clamping block, and the upper clamping block and the lower clamping block are fixed into a whole through screws.

Further, in the step 8), the upper clamping block and the lower clamping block are temporarily fixed with the workpiece at the arc-shaped grooves through adhesives.

Further, in step 8), before the process head is removed, the workpiece with the process head clamp block needs to be measured in three-coordinates on a machine tool, the process head clamp block is adjusted, and the assembly error between the process head clamp block and the ceramic part is reduced.

Further, in step 8), after the head process head is removed, rough machining, semi-finish machining, and finish machining are required to be performed on the workpiece head.

Further, in step 8), the method for removing the tail process head includes: the large allowance is integrally cut and removed by a diamond cutting blade, then finish machining is carried out, a hydraulic tool shank, a hard alloy tool shank and an indexable 800# diamond particle coating tool bit are adopted during finish machining, the path of a tool adopts a mode of equal-height cutting, cutting parameters are selected from Aa being 0.02-0.05 mm, F being 1500mm/min and S being 20000 revolutions/min.

The technical scheme of the embodiment of the invention at least has the following advantages and beneficial effects:

1. according to the structural characteristics and the processing difficulty of the product, aiming at the special-shaped curved surfaces with complex inner cavities and outer cavities, the invention develops the researches of ceramic blank preparation, cutting processing process planning, cutting tool design, cutting efficiency and quality, successfully manufactures large Y-TZP zirconia finished parts, and the processing surface quality and the dimensional precision of the parts meet the design and assembly requirements.

2. The invention solves the high-efficiency precision machining technology of hard and brittle materials, sets the high-efficiency milling and grinding process procedure and parameters of the special-shaped curved surface of the ceramic part, obviously inhibits the common vibration and edge breakage phenomena of the machined ceramic material, obviously improves the surface quality of the part, and realizes the high-efficiency manufacture of the large-size special-shaped complex curved surface zirconia ceramic part.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic perspective view of a large Y-TZP zirconia finished part according to the present invention;

FIG. 2 is a cross-sectional view of a large Y-TZP zirconia finished part provided by the present invention;

FIG. 3 is a first diagram of the shape change of a large Y-TZP zirconia finished part in the machining process;

FIG. 4 is a second diagram of the shape change of a large Y-TZP zirconia finished part in the machining process;

FIG. 5 is a third diagram of the shape change of a large Y-TZP zirconia finished part in the machining process;

FIG. 6 is a diagram of the shape change of a large Y-TZP zirconia finished part in the machining process;

FIG. 7 is a five-diagram showing the shape change of a large Y-TZP zirconia finished part in the machining process

FIG. 8 is a schematic structural view of a V-shaped head clamp block;

FIG. 9 is a schematic structural view of a tail V-clamp block;

fig. 10 is a schematic view of the structure of the de-process head clamp block.

Icon: 1-finished part, 2-blank piece, 3-tail V-shaped clamping block, 4-head V-shaped clamping block, 5-cushion block, 6-pressing plate, 7-process head removing clamping block, 701-upper clamping block and 702-lower clamping block.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

Referring to fig. 1 to 3, the present embodiment provides a method for processing a wind tunnel model of a ceramic material, including the following steps:

the method comprises the following steps: preparing a green body material; specifically, the shape of an envelope green body is designed according to the theoretical shape of a ceramic material wind tunnel model, a cylindrical green body is pressed by adopting a dry mixing compression molding process according to the shape of the envelope green body, and a middle hole is formed by pressing a steel core;

step two: turning an inner cavity eccentric hole on a green blank material by using a lathe, turning the outer contour into an outer shape cylinder, turning the outer shape cylinder into step shafts with different diameters, and turning a center hole for opposite vertex at the center of the top end of a workpiece;

step three: sintering and molding the green body at 1400-1600 ℃;

step four: a diamond insert coating turning tool is adopted, and the excircle reference and the inner cavity eccentric hole are finely turned to the final size by taking Aa as 0.25-0.5 mm, F as 0.03-0.1 mm/S and V as 25m/min as cutting parameters, so that a blank 2 is obtained;

designing two V-shaped clamping blocks, fixing the blank 2 on a machine tool, and enabling the axis of the sintered green compact to be parallel to the processing working platform after the sintered green compact is clamped; the V-shaped clamping block comprises a head V-shaped clamping block 4 and a tail V-shaped clamping block 3, the head V-shaped clamping block 4 and the tail V-shaped clamping block 3 both comprise supporting blocks, a V-shaped groove attached to the outer contour surface of a workpiece is formed in each supporting block, and a cushion block 5 is further arranged at the bottom of each supporting block of the head V-shaped clamping block 4 so as to keep the same height as the tail V-shaped clamping block 3;

step six: the cylindrical blank is placed in the two V-shaped blocks, the axis and the technological platform reference are aligned, the left and right pressing plates 6 are used for applying pressure to compress the workpiece, and a high-precision, high-rotating-speed and high-rigidity numerical control machine tool is selected to perform rough machining on the first surface of the model part. When milling, a hydraulic tool handle, a hard alloy tool bar and an indexable 250# diamond particle coated tool bit are adopted, the tool path adopts an oscillation cutting mode, cutting parameters are selected from Aa being 0.2mm, Ar being 0.2mm, F being 0.05mm/S and V being 150 m/min. During rough machining, semi-finish machining and finish machining allowance of 0.3-0.6 mm are uniformly reserved on the molded surface of the part;

step seven: disassembling the machined workpiece, turning over, re-clamping and aligning the workpiece, roughly machining the second surface of the part by adopting the same technological method and technological parameters as those in the sixth step, and uniformly reserving semi-finish machining and finish machining allowance of 0.3-0.6 mm on the molded surface of the part during rough machining;

step eight: and seventhly, performing semi-finishing on the second surface of the part, wherein in the semi-finishing process, a hydraulic tool holder, a hard alloy tool bar and an indexable 400# diamond particle coated tool bit are adopted, the tool path adopts an equal-height cutting mode, and cutting parameters are Aa equal to 0.1mm, F equal to 1500mm/min and S equal to 9000 r/min. In semi-precision machining, a precision machining allowance of 0.2mm is uniformly reserved on the molded surface of the part;

step nine: and (3) disassembling the machined workpiece, turning over, re-clamping and aligning the workpiece, wherein the clamping state is the same as that in the step eight, performing semi-finish machining on the first surface of the part, and during the semi-finish machining, adopting a hydraulic tool shank, a hard alloy tool bar and an indexable 400# diamond particle coated tool bit, wherein the tool path adopts a mode of equal-height cutting, and cutting parameters are Aa equal to 0.1mm, F equal to 1500mm/min and S equal to 9000 r/min. In semi-precision machining, a precision machining allowance of 0.2mm is uniformly reserved on the molded surface of the part;

step ten: and (4) performing finish machining on the first surface of the part in the same clamping state as the ninth step, wherein during finish machining, a hydraulic tool shank, a hard alloy tool bar and an indexable 800# diamond particle coated tool bit are adopted, the path of the tool adopts an equal-height cutting mode, cutting parameters are 0.02-0.05 mm (Aa), 1500mm/min (F) and 20000 revolutions/min (S). During fine machining, no allowance is left on the molded surface, and the molded surface is machined in place.

Step eleven: the machining workpiece is detached, the workpiece is clamped and aligned again in a turned-over mode, the clamping state is identical to the step ten, the first surface of the part is subjected to finish machining, during finish machining, a hydraulic tool shank, a hard alloy tool bar and an indexable 800# diamond particle coating tool bit are adopted, the tool path adopts a mode of equal-height cutting, cutting parameters are selected from Aa being 0.02-0.05 mm, F being 1500mm/min, and S being 20000 r/min. During fine machining, no allowance is left on the molded surface, and the molded surface is machined in place.

And a twelfth step of designing two process head removing clamping blocks 7, wherein the process head removing clamping blocks 7 comprise an upper clamping block 701 and a lower clamping block 702, arc-shaped grooves attached to the outer contour of the workpiece are formed in the opposite surfaces of the upper clamping block 701 and the lower clamping block 702, the special-shaped profile of the process head removing clamping block 7 is finely machined in place according to the outer shape surface of the ceramic wind tunnel model main body, the upper clamping block 701 and the lower clamping block 702 are tightly attached to each other in a sticking mode, the upper clamping block 701 and the lower clamping block 702 are fixed to the ceramic parts temporarily and firmly through adhesives, and the upper clamping block 701 and the lower clamping block 702 are positioned through pins and are connected in a tightening mode through screws.

And thirteen, performing three-coordinate measurement on the workpiece with the process head clamping block 7 removed to ensure that the relative position of the workpiece and the process head clamping block 7 is accurate, and repairing the process head clamping block 7 again if an assembly error occurs so as to ensure that the relative position between the process head clamping block 7 and the ceramic part is accurate and reliable.

And step fourteen, firstly removing the head process head, converting the process reference to the process head removing clamping block 7, clamping, aligning and aligning the workpiece by using the process head removing clamping block 7, and performing rough machining, semi-finish machining and finish machining on the head of the workpiece, wherein the process method adopted by the rough machining, the semi-finish machining and the finish machining is the same as the method for machining the first profile and the second profile.

And fifthly, removing the tail process head, and synchronously clamping, aligning and aligning the tail process head in a tool setting mode. Because the tail process head is made of a large material, a diamond cutting blade is selected to integrally cut and remove large allowance, then finish machining is carried out, a hydraulic tool handle, a hard alloy tool bar and an indexable 800# diamond particle coating tool bit are adopted during finish machining, the tool path adopts a mode of equal-height cutting, cutting parameters are selected from Aa being 0.02-0.05 mm, F being 1500mm/min and S being 20000 r/min. During fine machining, no allowance is left on the molded surface, and the molded surface is machined in place.

Seventhly, removing the process head removing clamp blocks 7 bonded at two positions in the middle of the workpiece, and shaping, grinding and polishing the ceramic part to obtain the final quality requirement.

From the above, the method for processing the wind tunnel model of the ceramic material provided by the invention has the beneficial effects that:

1. according to the structural characteristics and the processing difficulty of the product, aiming at the special-shaped curved surfaces with complex inner cavities and outer cavities, the invention develops the researches of ceramic blank preparation, cutting processing process planning, cutting tool design, cutting efficiency and quality, successfully manufactures large Y-TZP zirconia finished parts, and the processing surface quality and the dimensional precision of the parts meet the design and assembly requirements.

2. The invention solves the near-net forming process technology of the ceramic parts, prepares the zirconia ceramic blank with high toughness, high strength and high density, solves the problem of manufacturing the integral blank of the parts, overcomes the problem that the precision is difficult to ensure because the blank is decomposed, prepared and then assembled, and lays a foundation for the high-precision assembly of subsequent finished parts.

3. The invention solves the high-efficiency precision machining technology of hard and brittle materials, sets the high-efficiency milling and grinding process procedure and parameters of the special-shaped curved surface of the ceramic part, obviously inhibits the common vibration and edge breakage phenomena of the machined ceramic material, obviously improves the surface quality of the part, and realizes the high-efficiency manufacture of the large-size special-shaped complex curved surface zirconia ceramic part.

4. The application of the invention covers the knowledge of the interdiscipline of materials and machinery, such as ceramic material preparation, hard and brittle material cutting processing, cutter design, process planning and the like. By the method, a high-temperature insulation wind tunnel test model which is high in wear resistance, scratch resistance, good in chemical stability, small in specific heat and heat conductivity coefficient and high in temperature can be processed; the wind tunnel test model can meet a series of scientific researches such as wind tunnel test precision research, wind tunnel standard database establishment, wind tunnel performance examination, wind tunnel performance calibration and measurement and the like.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.