阅读说明：本技术 钛合金蒙皮型面化铣的溶液、方法及样板制作方法 (Solution and method for titanium alloy skin molding surface chemical milling and sample plate manufacturing method ) 是由 孟莉莉 朱彦海 邵杰 于 2019-10-30 设计创作，主要内容包括：本发明公开了钛合金蒙皮型面化铣的溶液、方法及样板制作方法,包括50～150g/L的硝酸,20～90g/L的氢氟酸,5～10g/L的添加剂,余量为水。硝酸和氢氟酸具有强腐蚀性能够对暴露的钛合金蒙皮进行腐蚀,添加剂加入能够确保化铣区的壁厚均匀,不会出现沟槽等缺陷,同时,也能够确保化铣胶在腐蚀过程中不会出现被腐蚀,保持不需要腐蚀区域的完整。水能够根据具体情况来稀释整体溶液,从而调整溶液的腐蚀性。从而,该溶液相对于现有技术中的溶液,能够改善蒙皮表面光洁度及壁厚均匀性以及保证了化铣过程中对化铣胶的稳定性。(The invention discloses a solution, a method and a sample plate manufacturing method for titanium alloy skin molding surface chemical milling, wherein the solution comprises 50-150g/L nitric acid, 20-90g/L hydrofluoric acid, 5-10g/L additive and the balance of water. Nitric acid and hydrofluoric acid have strong corrosivity and can corrode the exposed titanium alloy skin, and the addition of the additive can ensure that the wall thickness of a chemical milling area is uniform, so that the defects of grooves and the like can not occur, and meanwhile, the chemical milling glue can also ensure that the chemical milling glue can not be corroded in the corrosion process, and the completeness of an area which does not need to be corroded is kept. Water can dilute the bulk solution as the case may be, thereby adjusting the corrosivity of the solution. Compared with the solution in the prior art, the solution can improve the surface smoothness and the wall thickness uniformity of the skin and ensure the stability of chemical milling glue in the chemical milling process.)

1. The utility model provides a solution that titanium alloy covering profile chemical milling which characterized in that: comprises a mixed acid solution of nitric acid and hydrofluoric acid, an additive and water.

2. The titanium alloy skin profiling solution of claim 1, wherein: also included are soluble tetravalent titanium ions.

3. The titanium alloy skin profiling solution of claim 1 or 2, wherein: the concentration of the nitric acid is 50-150g/L, and the concentration of the hydrofluoric acid is 20-90 g/L.

4. The titanium alloy skin profiling solution of claim 1 or 2, characterized by: the additive is one or more of ethylene glycol monobutyl ether, sodium dodecyl sulfate, urea and an active agent HY-12.

5. The titanium alloy skin profiling solution of claim 4, characterized by: the concentration of the nitric acid is 50-150g/L, the concentration of the hydrofluoric acid is 20-90g/L, and the concentration of the additive is 5-10 g/L.

6. The manufacturing method of the titanium alloy skin molded surface chemical milling template is characterized by comprising the following steps of:

s1: designing a chemical milling template mould (1), wherein the size and the shape of the molded surface of the chemical milling template mould (1) are consistent with the size and the shape of the outer surface of the skin molded surface;

s2: a positioning hole is formed in the chemical milling template mould (1), and a pin penetrates through the positioning hole to fix the bushing;

s3: brushing resin with a desired thickness on the chemical milling sample plate mould (1) to form a resin sample plate, and curing the resin sample plate;

s4: and (3) calculating an etching ratio, determining the scaling quantity of the skin chemical milling area (5) through the etching ratio, then carrying out mechanical processing on the cured resin template chemical milling area to form a chemical milling template (2), and taking down the chemical milling template after the chemical milling template is finished.

7. The method for manufacturing the titanium alloy skin profiling template as claimed in claim 6, wherein the method comprises the following steps: in step S3, each resin layer is coated, and a glass fiber layer is further laid on the corresponding resin layer to satisfy the toughness of the chemical milling template.

8. The method for manufacturing the titanium alloy skin profiling template as claimed in claim 6, wherein the method comprises the following steps: reinforcing ribs (7) are arranged in the smooth area of the chemical milling area so as to meet the requirements of rigidity and stability of the chemical milling sample plate; the resin is epoxy resin.

9. The method for manufacturing the titanium alloy skin profiling template as claimed in claim 6, wherein the method comprises the following steps: in step S4, the etching ratio is calculated by the formula:

in the formula:

e-etching ratio;

D₁-width of the cut surface before chemical milling in millimeters (mm);

D₂the width of the section after chemical milling is in millimeters (mm);

D₃chemical milling depth in millimeters (mm).

10. A method for the surface chemical milling of a titanium alloy skin is characterized by comprising the following steps:

a. removing oil, namely cleaning the surface of the skin (6) by using a cleaning agent, cleaning the cleaning agent on the surface of the skin (6) by using flowing clear water, and finally drying the skin by using clean air;

b. coating the chemical milling glue, namely brushing the chemical milling glue on the surface of the skin (6);

c. carving, wherein manual carving is adopted, the chemical milling sample plate and the skin (6) are attached together and fixed by utilizing a positioning hole (4) on the chemical milling sample plate (2), in the process of carving, a cutter is used for vertically milling the surface, the chemical milling sample plate (2) is closely attached, and chemical milling glue in a skin chemical milling area (5) is removed after carving;

d. chemical milling, namely placing the skin subjected to the carving in a chemical milling solution;

e. and (6) inspecting, namely inspecting the chemically milled skin.

11. The method of profiling a titanium alloy skin as recited in claim 10, wherein: in the step d, continuously adjusting the angle and the direction of the skin chemical milling to avoid generating air bags; and starting compressed air to stir the solution so as to ensure the uniformity of the wall thickness of the skin chemical milling area (5).

Technical Field

The invention relates to a surface engineering technology, in particular to a solution and a method for chemical milling of a titanium alloy skin molding surface and a template manufacturing method.

Background

With the development of the aviation industry, the trend of large-scale and integration of sheet metal parts is more and more obvious, and a skin is an important component of the sheet metal parts of an airplane and is one of important key technologies for developing the airplane. The aircraft skin is complex in stress, directly contacts the outside, is seriously loaded and has extremely high requirement on the shape precision; meanwhile, in order to meet the weight reduction requirement, the aircraft skin is generally a thin plate part and is designed into unequal thickness, and some areas are even continuously variable sections. At present, numerical control machining is often adopted to ensure the final precision requirement aiming at the skin parts with complex profiles and geometric shapes.

As is well known, titanium alloy has the comprehensive properties of small density, high specific strength, good fracture resistance and good corrosion resistance, and is widely applied to the fields of aviation and aerospace. The titanium alloy skin is particularly suitable for processing the aircraft skin, and compared with the traditional aluminum alloy material, the titanium alloy skin can greatly reduce the weight of the aircraft and improve the flight performance of the aircraft, thereby reducing the operation cost of the aircraft; furthermore, when the contact surface temperature of aircraft skins is generally above 200 ℃, aluminum skins are no longer suitable and need to be replaced with titanium alloys. However, the titanium alloy has poor cutting performance, and due to the small thermal conductivity, the heat generated during cutting is not easy to dissipate, is accumulated on the cutter and the workpiece, so that the cutter is quickly worn, and is easy to ablate when a large margin is machined. Therefore, the machining difficulty is higher for the titanium alloy skin parts with thin walls and complex shapes. For this purpose, the titanium alloy aircraft skin with the complex profile is processed by adopting a chemical milling method instead of conventional mechanical processing.

Chemical milling (chemical milling for short) is a special processing method for exposing a part to be processed on a part to a chemical medium (solution) for corrosion to obtain a required shape and size, the method can improve the physical property of the surface of a material and reduce the abrasion of a cutter in processing, so that the method is widely applied to the aerospace industry, and the titanium alloy chemical milling process level is greatly improved along with the rapid development of the aerospace industry in China in recent years, and the titanium alloy chemical milling method is gradually applied to processing parts in various shapes, such as flat plates, thin plates, cylindrical parts, single-curvature parts and the like.

The titanium alloy skin part for the airplane in the prior part has the problems of complex structure, obvious torsion and bending, small curvature radius, narrow width of a chemical milling area rib and difficulty in accurate control of precision in processing by adopting the existing chemical milling process.

Firstly, the chemical milling liquid proportion influences the precision of parts. When the existing chemical milling solution is used for proportioning chemical milling, the surface roughness of the part basically meets Ra of less than or equal to 3.2 microns, but the uniformity of the wall thickness of a chemical milling area is poor, and the defects of grooves and the like are often caused; in addition, in the chemical milling process by adopting the existing chemical milling solution, the stability of the chemical milling protective glue is poor, so that the existing titanium alloy chemical milling solution is difficult to realize accurate processing on parts with high requirements on wall thickness precision.

Secondly, the chemical milling area engraving method affects the precision of the part. At present, two methods are universal for engraving types in chemical milling areas, wherein one method is manual engraving; another is laser scribing, which uses a combination of laser and digital manufacturing processes. For a part with a complex structure, if the thin-wall type sample plate is adopted, the rigidity is low, the sample plate is not tightly attached to the part in the using process, and the situation that the sample plate deforms to cause inaccurate positioning can occur; the precision of the laser-etching type is higher, but for parts with complex structures and smaller curvature radius, a positioner on the existing laser-etching type machine is blocked in the parts and cannot be positioned, and the laser-etching type machine cannot be adopted.

Therefore, the invention provides a solution, a method and a template manufacturing method for the titanium alloy skin profile chemical milling to solve the problems.

Disclosure of Invention

Technical problem to be solved

The invention provides a solution, a method and a template manufacturing method for chemical milling of a titanium alloy skin molding surface, which are used for solving the problems that in the prior art, a chemical milling solution is not uniform in corrosion of a titanium alloy skin, a groove is formed, chemical milling protective glue in the chemical milling solution is poor in stability, a chemical milling template in manual engraving is low in rigidity, and the template is not tightly attached to the skin, so that the positioning is not accurate.

(II) technical scheme

In order to solve the technical problem, the invention provides a solution for titanium alloy skin molding surface chemical milling, which comprises a mixed acid solution of nitric acid and hydrofluoric acid, an additive and water.

Preferably, soluble tetravalent titanium ions are also included.

Preferably, the concentration of the nitric acid is 50-150g/L, and the concentration of the hydrofluoric acid is 20-90 g/L.

Preferably, the additive is one or more of ethylene glycol monobutyl ether, sodium dodecyl sulfate, urea and an active agent HY-12.

Preferably, the concentration of the nitric acid is 50-150g/L, the concentration of the hydrofluoric acid is 20-90g/L, and the concentration of the additive is 5-10 g/L.

The invention also provides a manufacturing method of the titanium alloy skin molded surface chemical milling sample plate, which comprises the following steps:

s1: designing a chemical milling template mould, wherein the size and the shape of the molded surface of the chemical milling template mould are consistent with the size and the shape of the outer surface of the skin molded surface;

s2: a positioning hole is formed in the chemical milling template mould, and a pin penetrates through the positioning hole to fix the bushing;

s3: brushing resin with a desired thickness on the chemical milling template mould to form a resin template, and curing the resin template;

s4: and calculating an etching ratio, determining the scaling quantity of the skin chemical milling area through the etching ratio, then carrying out mechanical processing on the cured resin template chemical milling area to form a chemical milling template, and taking down the chemical milling template after the chemical milling template is finished.

Preferably, in step S3, for each resin coating, another glass fiber layer is laid on the corresponding resin layer to satisfy the toughness of the chemical milling template.

Preferably, reinforcing ribs are arranged in a smooth area of the chemical milling area so as to meet the requirements of rigidity and stability of the chemical milling sample plate; the resin is epoxy resin.

Preferably, in step S4, the etching ratio is calculated by the formula:

in the formula:

e-etching ratio;

D₁-width of the cut surface before chemical milling in millimeters (mm);

D₂the width of the section after chemical milling is in millimeters (mm);

D₃chemical milling depth in millimeters (mm).

The invention also provides a method for the molding surface chemical milling of the titanium alloy skin, which comprises the following steps:

a. removing oil, namely cleaning the surface of the skin by using a cleaning agent, cleaning the surface of the skin by using flowing clear water, and finally drying the skin by using clean air;

b. coating the chemical milling glue, namely brushing the chemical milling glue on the surface of the skin;

c. carving, namely manually carving, sticking the chemical milling sample plate and the skin together by using a positioning hole on the chemical milling sample plate and fixing, in the scribing process, vertically milling the surface by using a cutter, tightly sticking the chemical milling sample plate, and removing chemical milling glue in the chemical milling area of the skin after carving;

d. chemical milling, namely placing the skin subjected to the carving in a chemical milling solution;

e. and (6) inspecting, namely inspecting the chemically milled skin.

Preferably, in the step d, the angle and the direction of the chemical milling of the skin are continuously adjusted to avoid generating air bags; and starting compressed air to stir the solution so as to ensure the uniformity of the wall thickness of the skin chemical milling area.

(III) advantageous effects

The technical scheme of the invention has the following advantages:

(1) the chemical milling solution comprises nitric acid, hydrofluoric acid, an additive and water, wherein the nitric acid and the hydrofluoric acid have strong corrosivity and can corrode an exposed titanium alloy skin, the addition of the additive can ensure that the wall thickness of a chemical milling area is uniform, the defects of grooves and the like cannot occur, meanwhile, the chemical milling glue can also ensure that the chemical milling glue cannot be corroded in the corrosion process, and the integrity of an area which does not need to be corroded is kept. Water can dilute the bulk solution as the case may be, thereby adjusting the corrosivity of the solution. In the post chemical milling process, the angle and the direction of the chemical milling of the skin are continuously adjusted, and meanwhile, compressed air is started to stir the solution, so that the surface smoothness and the wall thickness uniformity of the chemical milling area of the skin can be improved and the stability of chemical milling glue in the chemical milling process is ensured compared with the solution in the prior art.

(2) The material adopted by the method for manufacturing the titanium alloy skin molding surface chemical milling sample plate is epoxy resin, the epoxy resin has plasticity and good machinability and can be better attached to the surface of the skin, and the reinforcing ribs are arranged in the smooth area of the chemical milling area, so that the rigidity and the stability of the chemical milling sample plate can be increased.

Drawings

FIG. 1 is a schematic structural diagram of a chemical milling template manufactured in the titanium alloy skin molding surface chemical milling method and the template manufacturing method of the present invention;

FIG. 2 is a schematic structural diagram of the titanium alloy skin in the method for forming the titanium alloy skin surface and the template manufacturing method according to the present invention;

fig. 3 is a schematic structural diagram of a chemical milling template in the titanium alloy skin molding surface chemical milling method and the template manufacturing method of the present invention.

FIG. 4 is a schematic structural diagram of another chemical milling template in the titanium alloy skin molding surface chemical milling method and the template manufacturing method of the present invention.

In the figure: 1. chemically milling a template mould; 2. chemically milling a sample plate; 3. a chemical milling template chemical milling area; 4. positioning holes; 5. a skin chemical milling area; 6. covering a skin; 7. and (5) reinforcing ribs.

Detailed Description

The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.