A fully symmetric fused silica structure blowing mold and preparation method

Abstract

The present invention discloses a fully symmetric fused silica structure blowing mold and a preparation method thereof. The fully symmetric fused silica structure blowing mold of the present invention includes a mold body made of graphite and having a fused silica structure blowing structure body in the middle, and a silicon carbide film is provided on the surface of the mold body. The preparation method of the fully symmetric fused silica structure blowing mold of the present invention includes: cutting a graphite rod into a graphite blank; performing mechanical rough machining on the graphite blank to complete the structure forming; after washing the graphite blank completed with structure forming, forming a silicon carbide film on the front surface; performing mechanical finish machining on the graphite blank with the silicon carbide film; polishing the graphite blank to obtain the prepared fully symmetric fused silica structure blowing mold. The present invention aims to significantly improve the consistency and reliability of the blown products with a fully symmetric fused silica structure, while greatly extending the service life of the blowing mold, significantly reducing the production cost, and improving the production efficiency.

Description

Technical Field

[0001] The present invention relates to auxiliary equipment for gyroscopes, and particularly to a fully symmetric fused silica structure blowing mold and a preparation method thereof. Background Art

[0002] A gyroscope is a precision sensor that uses a sensitive measurement unit to detect the angular motion of a carrier relative to inertial space, and is one of the core sensors of an inertial navigation system. Gyroscopes can be classified according to the measurement accuracy level into: rate-level gyroscopes with a zero-bias drift greater than 10° / h; tactical-level gyroscopes with a zero-bias drift of 0.1 - 10° / h; and inertial-level gyroscopes with a zero-bias drift better than 0.01° / h.

[0003] There are various structural types of gyroscopes, such as electrostatic gyroscopes, hemispherical resonant gyroscopes, ring laser gyroscopes, and micro-hemispherical resonant gyroscope sensitive structure gyroscopes, etc. Although the traditional electrostatic gyroscopes, hemispherical resonant gyroscopes, and ring laser gyroscopes can meet the requirements of weapon equipment in terms of accuracy, they have problems such as large volume and power consumption, high cost, being unsuitable for miniaturized guided weapon equipment, and being difficult to mass-produce and apply. The micro-hemispherical resonant gyroscope sensitive structure gyroscope is processed based on the advantages of low thermal expansion coefficient, low thermal conductivity, and low thermoelastic damping of fused silica materials. While maintaining the advantages of high accuracy, excellent shock resistance, and long life of traditional hemispherical vibration gyroscopes, this structure also has the characteristics of small size, low cost, and being batch-replicable, and can also achieve full-angle measurement, with great application prospects in high-speed rotating guided projectiles. During the processing of the micro-hemispherical resonant gyroscope sensitive structure gyroscope, a fused silica structure blowing mold is required. This fused silica structure blowing mold is mainly formed by high-speed rotation blowing using hydrogen-oxygen combustion or propane combustion in a vacuum negative pressure working environment, and the blowing quality of this mold determines the core accuracy index of the fused silica micro-hemispherical resonant gyroscope. However, existing blowing molds are generally made of pure graphite molds, and problems such as mold carbonization and edge chipping are likely to occur during the blowing process, resulting in problems such as asymmetric blowing structures and poor batch processing consistency. At the same time, the processing life is extremely short, leading to low overall processing efficiency and high costs. Summary of the Invention

[0004] The technical problem to be solved by the present invention: Aiming at the above problems of the prior art, a fully symmetric fused silica structure blowing mold and a preparation method thereof are provided. The present invention aims to significantly improve the consistency and reliability of the blown products with a fully symmetric fused silica structure, and at the same time greatly extend the service life of the blowing mold, significantly reduce the production cost, and improve the production efficiency.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0006] A fully symmetric fused silica structure blowing mold, comprising a mold body made of graphite and having a fused silica structure blowing structure body in the middle, and a silicon carbide film is provided on the surface of the mold body.

[0007] Optionally, the silicon carbide film is formed on the surface of the graphite substrate of the mold body by CVD deposition.

[0008] Optionally, the fused silica structure blown body includes a central support column disposed on the front surface of the mold body and two wafer support platforms of different sizes concentrically arranged around the central support column. A forming groove is provided between the central support column and the wafer support platform with a smaller radius, a vacuum adsorption groove is provided between the two wafer support platforms, a bottom vacuum adsorption through hole is provided in the forming groove, and an upper vacuum adsorption through hole is provided in the vacuum adsorption groove.

[0009] Optionally, the mold body is a cylinder, and the central support column is a cylinder.

[0010] Optionally, both the forming groove and the vacuum adsorption groove are annular grooves.

[0011] Optionally, both the bottom vacuum adsorption through hole and the upper vacuum adsorption through hole are circular through holes and the number is multiple. The multiple bottom vacuum adsorption through holes and the multiple upper vacuum adsorption through holes are both arranged in a circumferential array around the center of the central support column.

[0012] Optionally, the wafer support platform is annular.

[0013] Optionally, the surfaces of the central support column and the wafer support platform are located on the same plane.

[0014] Optionally, a circular sink is provided in the middle of the back surface of the mold body. After passing through the mold body, the bottom vacuum adsorption through hole and the upper vacuum adsorption through hole are both provided on the bottom surface of the circular sink. A plurality of annular sinks are arranged at intervals on the back surface of the mold body outside the circular sink, and the areas between the annular sinks are separated by a plurality of linear sinks arranged along the radial direction to form a plurality of fan-shaped support surfaces. Circular ring support planes are provided between the innermost annular sink and the circular sink, and outside the outermost annular sink.

[0015] In addition, the present invention also provides a preparation method for the aforementioned fully symmetric fused silica structure blowing mold, including:

[0016] S1, cutting a graphite rod into a graphite blank;

[0017] S2, performing mechanical rough machining on the graphite blank to complete the structure forming;

[0018] S3, after cleaning the graphite blank after completing the structure forming, forming a silicon carbide film on the front surface;

[0019] S4. Polish the graphite blank to obtain the prepared fully symmetric fused silica structure blowing mold.

[0020] In addition, the present invention also provides an application method of the fully symmetric fused silica structure blowing mold, including: placing the blown wafer in the fused silica structure blowing structure body, connecting with the vacuum pump of the blowing special equipment through the central support column, wafer support platform, bottom vacuum adsorption through hole, vacuum adsorption groove and upper vacuum adsorption through hole to form a first set of vacuum adsorption structure to vacuum adsorb and fix the blown wafer; at the same time, connecting with the vacuum pump of the blowing special equipment through the annular sink, linear sink, sector support and circular ring support surface to form a second set of vacuum adsorption structure to realize the vacuum adsorption and fixation of the mold body.

[0021] Compared with the prior art, the present invention mainly has the following advantages: The fully symmetric fused silica structure blowing mold of the present invention is coated with a silicon carbide film on the graphite substrate, making the graphite mold have the characteristics of oxidation resistance, high temperature resistance, high hardness, etc., avoiding the problems of carbonization and edge chipping in the blowing of pure graphite molds, greatly improving the blowing life of the graphite blowing mold in the air environment, and ensuring the consistency of product quality at the same time; moreover, the fully symmetric fused silica structure blowing mold of the present invention retains the thermal shock resistance characteristics of graphite, avoiding the problem of explosion of pure silicon carbide molds during high-temperature blowing, and also solving the problem of difficult processing of silicon carbide molds, thereby being able to significantly improve the consistency and reliability of the blown products with a fully symmetric fused silica structure, greatly extend the service life of the blowing mold, significantly reduce the production cost, and improve the production efficiency. Description of the Drawings

[0022] Figure 1 It is a front-side three-dimensional structure schematic diagram of the fully symmetric fused silica structure blowing mold according to the embodiment of the present invention.

[0023] Figure 2 It is a negative-side three-dimensional structure schematic diagram of the fully symmetric fused silica structure blowing mold according to the embodiment of the present invention.

[0024] Figure 3 It is a front view structure schematic diagram of the fully symmetric fused silica structure blowing mold according to the embodiment of the present invention.

[0025] Figure 4 It is Figure 3 The A-A sectional structure schematic diagram of.

[0026] Figure 5 It is a schematic diagram of the state change in the preparation process of the fully symmetric fused silica structure blowing mold according to the embodiment of the present invention.

[0027] Legend: 1. Mold body; 11. Circular sunk groove; 12. Ring-shaped sunk groove; 13. Linear sunk groove; 14. Sector-shaped support surface; 15. Circular ring support plane; 2. Fused silica structure blown structure body; 21. Central support column; 22. Wafer support platform; 23. Forming groove; 231. Bottom vacuum adsorption through hole; 24. Vacuum adsorption groove; 241. Upper vacuum adsorption through hole; 3. Silicon carbide film. Detailed implementation manners

[0028] As Figure 1 shown, this embodiment provides a fully symmetric fused silica structure blowing mold, including a mold body 1 made of graphite and having a fused silica structure blown structure body 2 in the middle. A silicon carbide film 3 is provided on the surface of the mold body 1. By providing the silicon carbide film 3 on the surface of the mold body 1, the graphite mold has characteristics such as oxidation resistance, high temperature resistance, and high hardness, avoiding problems such as carbonization and edge chipping in the blowing of pure graphite molds, greatly improving the blowing life of the graphite blowing mold in an air environment, and at the same time ensuring the consistency of product quality; moreover, the fully symmetric fused silica structure blowing mold of this embodiment retains the thermal shock resistance characteristics of graphite, avoiding the problem of explosion of pure silicon carbide molds during high-temperature blowing, and also solving the problem of difficult processing of silicon carbide molds, thereby being able to significantly improve the consistency and reliability of the blown products with a fully symmetric fused silica structure, greatly extending the service life of the blowing mold, significantly reducing production costs, and improving production efficiency.

[0029] As an alternative implementation manner, in this embodiment, the silicon carbide film 3 is formed on the surface of the graphite substrate of the mold body 1 by means of CVD deposition. In addition, other methods can also be used to form the silicon carbide film 3 (or silicon carbide layer) on the surface of the graphite substrate of the mold body 1 according to needs.

[0030] As Figure 1 , Figure 2 , Figure 3 and Figure 4 shown, the fused silica structure blown structure body 2 of this embodiment includes a central support column 21 provided on the front surface of the mold body 1 and two wafer support platforms 22 of different sizes arranged concentrically around the central support column 21. A forming groove 23 is provided between the central support column 21 and the wafer support platform 22 with a smaller radius, a vacuum adsorption groove 24 is provided between the two wafer support platforms 22, a bottom vacuum adsorption through hole 231 is provided in the forming groove 23, and an upper vacuum adsorption through hole 241 is provided in the vacuum adsorption groove 24. By adjusting the height, depth, and shape of the central support column 1 and the forming groove 23, a specific blowing structure required for blowing can be achieved.

[0031] As Figure 1 shown, the mold body 1 of this embodiment is a cylinder, and the central support column 21 is a cylinder.

[0032] As Figure 1 shown, the formed groove 23 and the vacuum adsorption groove 24 in this embodiment are both annular grooves.

[0033] As Figure 1 shown, the bottom vacuum adsorption through holes 231 and the upper vacuum adsorption through holes 241 in this embodiment are both circular through holes and the number is multiple. The multiple bottom vacuum adsorption through holes 231 and the multiple upper vacuum adsorption through holes 241 are both circumferentially arrayed around the center of the center support column 21. As an alternative implementation, the number of the upper vacuum adsorption through holes 241 in this embodiment is 15, the diameter of the circular holes is 1 mm; the number of the bottom vacuum adsorption through holes 231 is 10, and the diameter of the circular holes is 1 mm.

[0034] As Figure 1 shown, the wafer support platform 22 in this embodiment is annular.

[0035] As Figure 1 shown, the surfaces of the center support column 21 and the wafer support platform 22 in this embodiment are on the same plane.

[0036] As Figure 1 、 Figure 2 、 Figure 3 and Figure 4 shown, on the middle upper part of the back surface of the mold body 1 in this embodiment, there is a circular sunk groove 11. After the bottom vacuum adsorption through holes 231 and the upper vacuum adsorption through holes 241 penetrate through the mold body 1, they are both arranged on the bottom surface of the circular sunk groove 11. On the back surface of the mold body 1 and outside the circular sunk groove 11, there are multiple ring-shaped sunk grooves 12 arranged at intervals, and between each ring-shaped sunk groove 12, they are interconnected by multiple linear sunk grooves 13 arranged along the radial direction and the area between each ring-shaped sunk groove 12 is separated to form multiple fan-shaped support surfaces 14. Between the innermost ring-shaped sunk groove 12 and the circular sunk groove 11, and outside the outermost ring-shaped sunk groove 12, there are circular ring support planes 15. Through the above structure, the fully symmetric fused silica structure blowing mold in this embodiment has a fully symmetric structure. The front and back surfaces of the fully symmetric fused silica structure blowing mold in this embodiment are parallel. When the fully symmetric fused silica structure blowing mold in this embodiment works, two sets of vacuum systems are used. Among them, the bottom vacuum adsorption through holes 231, the upper vacuum adsorption through holes 241 on the front surface of the blowing mold, and the circular sunk groove 11 on the back surface share one of the vacuum systems; the multiple groups of ring-shaped sunk grooves 12 and the multiple groups of linear sunk grooves 13 on the back surface use another set of vacuum systems.

[0037] In addition, this embodiment also provides a preparation method for the foregoing fully symmetric fused silica structure blowing mold, including:

[0038] S1, cutting a graphite rod into a graphite blank;

[0039] S2. Machine-process the graphite blank to form a forming groove 23 and a vacuum adsorption groove 24 on the front surface, a circular sink 11, an annular sink 12, and a linear sink 13 on the back surface, and form a through-bottom vacuum adsorption via 231 and an upper vacuum adsorption via 241.

[0040] S3. After cleaning the graphite blank, form a silicon carbide film 3 on the front surface.

[0041] S4. Polish the graphite blank to obtain a prepared fully symmetric fused silica structure blowing mold.

[0042] In this embodiment, the prepared graphite rod is as shown in a of Figure 5 , and then in step S1, use a wire cutting machine tool to cut the graphite rod into a standard cylinder, as shown in b of Figure 5 . In this embodiment, a cylinder with a diameter of 60 mm and a height of 12 mm is used; use a double-sided grinding wheel grinder to grind the upper and lower circular surfaces of the graphite cylinder flat, so that the parallelism between the two is better than 3 μm, and at the same time the surface roughness is better than 1.6.

[0043] Step S2 of this embodiment includes: as shown in c of Figure 5 , use a CNC machine tool to rough-machine the central support column 21 and the forming groove 23 on the front surface, and use a five-axis machining center precision grinder to finely machine the central support column 21 and the forming groove 23. Through multiple repeated fine machining, the roundness of the central support column 21 and the forming groove 23 is better than 5 μm, and at the same time the coaxiality between the two is better than 5 μm. As shown in d of Figure 5 , use a CNC machine tool to machine the vacuum adsorption groove 24 on the front surface. As shown in e of Figure 5 , use a CNC machine tool to machine the circular sink 11 on the back surface. In this embodiment, the circular sink 11 has a diameter of 50 mm and a depth of 2 mm, and is coaxial with the central support column 21 on the front surface of the blowing mold. As shown in f of Figure 5 , use a CNC machine tool to machine the annular sink 12 on the back surface. In this embodiment, the number of annular sinks 12 is 3. As shown in g of Figure 5 , use a CNC machine tool to machine the linear sink 13 on the back surface. In this embodiment, there are a total of 10 linear sinks 13, and they are axially symmetrically distributed about the center point of the mold. As shown in h of Figure 5 , use a CNC machine tool and a five-axis machining center machine tool to rough and finish machine the upper vacuum adsorption via 241. In this embodiment, there are 15 upper vacuum adsorption vias 241, the diameter of the round holes is 1 mm, and they are also circumferentially arrayed about the center point of the mold; as shown in i of Figure 5 , use a CNC machine tool and a five-axis machining center machine tool to rough and finish machine the bottom vacuum adsorption via 231. In this embodiment, there are a total of 10 bottom vacuum adsorption vias 231 with a diameter of 1 mm, which are circumferentially arrayed about the center point of the mold.

[0044] In step S3 of this embodiment, specifically, a silicon carbide film 3 is formed on the front surface of the graphite blank by CVD deposition, as shown in j of Figure 5 ; in this embodiment, a sic film layer of 20 μm is deposited by the CVD process.

[0045] In this embodiment, in step S4, a polishing device is used to polish the surface of the mold as a whole flat by 3 μm, and the surface roughness is better than 1.6, and then the prepared fully symmetric fused silica structure blowing mold can be obtained.

[0046] In this embodiment, the fully symmetric fused silica structure blowing mold mainly uses oxy-hydrogen combustion or propane combustion to generate a temperature exceeding the softening temperature point of the fused silica vitreous body, and uses the pressure difference formed by vacuum negative pressure, combined with the high-speed rotation of the fully symmetric fused silica structure blowing mold body to complete the structure forming. The overall process mainly includes the processes of adsorption fixation, high-temperature combustion and rotational forming.

[0047] In addition, the present invention also provides an application method of the foregoing fully symmetric fused silica structure blowing mold, including: placing the blown wafer in the fused silica structure blowing structure 2, and connecting it to the vacuum pump of the blowing special equipment through the central support column 21, the wafer support table 22, the bottom vacuum adsorption through hole 231, the vacuum adsorption groove 24 and the upper vacuum adsorption through hole 241 to form a first set of vacuum adsorption structures to vacuum-adsorb and fix the blown wafer; at the same time, connecting it to the vacuum pump of the blowing special equipment through the annular sink 12, the linear sink 13, the sector support 14 and the circular ring support surface 15 to form a second set of vacuum adsorption structures to realize the vacuum adsorption and fixation of the mold body 1. By the above method, the fully symmetric fused silica structure blowing mold adopts two sets of independent vacuum adsorption structures, which can effectively solve the stability and independent operability of the overall vacuum system. Among them, placing the blown wafer in the fused silica structure blowing structure 2 is generally realized by using tweezers. In addition, required tools can also be used according to needs, which will not be elaborated here. On this basis, combined with high-temperature combustion and rotational forming, the required symmetric fused silica structure blown parts can be obtained.

[0048] The above is only the preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the idea of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, several improvements and retouches made without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A fully symmetric fused silica structure blowing mold, comprising a mold body (1) made of graphite and having a fused silica structure blowing structure body (2) provided in the middle thereof, characterized in that, A silicon carbide film (3) is provided on the surface of the mold body (1); The fused quartz structure blowing structure (2) includes a central support column (21) provided on the front surface of the mold body (1) and two wafer support platforms (22) with different sizes arranged concentrically around the central support column (21). A forming groove (23) is provided between the central support column (21) and the wafer support platform (22) with a smaller radius. A vacuum adsorption groove (24) is provided between the two wafer support platforms (22). A bottom vacuum adsorption through hole (231) is provided in the forming groove (23), and an upper vacuum adsorption through hole (241) is provided in the vacuum adsorption groove (24); In the middle of the back surface of the mold body (1), a circular sink (11) is provided. After the bottom vacuum adsorption through hole (231) and the upper vacuum adsorption through hole (241) penetrate the mold body (1), they are both provided on the bottom surface of the circular sink (11). On the back surface of the mold body (1) and outside the circular sink (11), a plurality of annular sinks (12) are arranged at intervals, and the areas between the annular sinks (12) are interconnected by a plurality of linear sinks (13) arranged along the radial direction and separated to form a plurality of fan-shaped support surfaces (14). Between the innermost annular sink (12) and the circular sink (11), and outside the outermost annular sink (12), circular ring support planes (15) are provided.

2. The blown mold of the fully symmetric fused silica structure according to claim 1, characterized in that The silicon carbide film (3) is formed on the surface of the graphite substrate of the mold body (1) by CVD deposition.

3. The blow mold of the fully symmetric fused silica structure according to claim 1, characterized in that, The mold body (1) is a cylinder, and the central support column (21) is a cylinder.

4. The blown mold of the fully symmetric fused silica structure according to claim 3, characterized in that, The forming groove (23) and the vacuum adsorption groove (24) are both annular grooves, and the wafer support platform (22) is annular.

5. The all-symmetric fused silica structure blowing mold according to claim 4, characterized in that, The bottom vacuum adsorption through hole (231) and the upper vacuum adsorption through hole (241) are both circular through holes and the number is multiple. A plurality of bottom vacuum adsorption through holes (231) and a plurality of upper vacuum adsorption through holes (241) are both arranged in a circumferential array around the center of the central support column (21).

6. The blown mold of the fully symmetric fused silica structure according to claim 5, characterized in that, The surfaces of the central support column (21) and the wafer support platform (22) are on the same plane.

7. A method for preparing a fully symmetric fused silica structure blowing mold according to any one of claims 1 to 6, characterized in that, Including: S1, cutting a graphite rod into a graphite blank; S2, performing mechanical rough machining on the graphite blank to complete the structure forming; S3, after cleaning the graphite blank after completing the structure forming, forming a silicon carbide film on the front surface; S4, polishing the graphite blank to obtain a prepared fully symmetric fused quartz structure blowing mold.

8. A method for applying a fully symmetric fused silica structure blowing mold according to any one of claims 1 to 6, characterized in that Including: Place the blown wafer inside the fused silica structure blown structure (2), and connect it to the vacuum pump of the special blowing equipment through the central support column (21), wafer support platform (22), bottom vacuum adsorption through-hole (231), vacuum adsorption groove (24) and upper vacuum adsorption through-hole (241) to form a first set of vacuum adsorption structures to vacuum-adsorb and fix the blown wafer; at the same time, connect it to the vacuum pump of the special blowing equipment through the circular ring sink (12), linear sink (13), fan-shaped support surface (14) and circular ring support plane (15) to form a second set of vacuum adsorption structures to realize the vacuum adsorption and fixation of the mold body (1).

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