Sintering method of special-shaped optical-mechanical integrated light reflecting mirror

Abstract

The invention relates to a sintering method of a special-shaped optical-mechanical integrated light reflector, belongs to the technical field of optical processing, and solves the problems that a titanium alloy glass sintering method in the prior art is poor in sintering quality, and the edge of optical glass is prone to glue failure and cracks. According to the sintering method of the special-shaped optical-mechanical integrated light reflecting mirror, before a metal matrix and optical glass are sintered, the placement layout of parts is designed, and an optical glass underneath type part set is formed and sequentially comprises the metal matrix, the optical glass, a fire blanket piece and a refractory brick from top to bottom. And high-quality sintering and preparation of the optical-mechanical integrated light reflecting mirror are realized.

Description

Technical Field

[0001] The invention relates to the technical field of optical processing, and in particular to a sintering method for a special-shaped optical-mechanical integrated lightweight reflector. Background Art

[0002] Opto-mechanical integrated lightweight reflectors are widely used in multiple scenarios due to their lightweight, high power density, and good thermal stability.

[0003] The optical-mechanical integrated lightweight reflector is a 0.7mm thick glass layer sintered on the titanium alloy surface. The glass is polished and vacuum-plated with a reflective film to form a lightweight reflector with a high surface shape and reflectivity. The titanium alloy substrate is machined into a machined component with a positioning threaded hole to support the lightweight reflector. The optical-mechanical integrated lightweight reflector requires titanium alloy lightweight processing technology, precision mechanical grinding technology, titanium alloy glass sintering technology, heat treatment stabilization technology, lightweight reflector stress-free polishing technology, large-area silver reflective film plating technology, etc. Through a series of processing, the overall weight of the entire reflector is greatly reduced, achieving the purpose of integrated lightweight.

[0004] When processing special-shaped integrated lightweight reflectors using existing methods, during the cooling process at the end of sintering, debonding or cracks may occur on the edges of the optical glass, and the sintering quality cannot be guaranteed. Summary of the invention

[0005] In view of the above analysis, an embodiment of the present invention aims to provide a sintering method for a special-shaped optical-mechanical integrated lightweight reflector, so as to solve the problems of poor sintering quality and easy debonding and cracking of the edges of the optical glass in the existing titanium alloy glass sintering method.

[0006] The embodiment of the present invention provides a sintering method for a special-shaped optical-mechanical integrated lightweight reflector. Before the metal substrate and the optical glass are sintered, a parts layout is designed to form an optical glass bottom-placed parts group: from top to bottom, the metal substrate, the optical glass, the fire blanket and the refractory bricks.

[0007] Furthermore, the sintering process is carried out in a sealing furnace, and the sintering process flow is as follows:

[0008] Step 1, place the optical glass bottom-mounted parts assembly into a sealing furnace, raise the temperature in the sealing furnace from room temperature 25°C to 620±5°C, and control the heating time to be 10 to 12 hours;

[0009] Step 2: Maintain a constant temperature of 620±5℃ for 5-6h;

[0010] Step 3: After the parts assembly is cooled to below 40°C in the furnace, take out the parts assembly and inspect whether it is qualified.

[0011] It should be noted that before the metal substrate and the optical glass are combined into a parts assembly, the metal substrate needs to be machined and the optical glass needs to be processed.

[0012] Specifically, the machining technical requirements for the metal substrate are: flatness 0.01 mm, surface roughness Ra 1.6 μm.

[0013] Exemplarily, the technical requirements for the optical glass processing are: flatness 0.01mm, parallelism 0.05mm, thickness 2.5±0.1mm, surface roughness Ra1.6um, no sand holes with a diameter greater than 0.5mm and scratches with a length greater than 15mm and a width greater than 0.07mm.

[0014] Furthermore, before the metal substrate and the optical glass are combined into a parts assembly, the sintering surface of the metal substrate and the surface of the optical glass need to be treated.

[0015] Specifically, the surface treatment process is as follows: sandblasting the machined sintered surface of the metal substrate with a dry sandblasting machine to remove stains on the sintered surface; and cleaning the sintered surface of the metal substrate and the processed optical glass with ether to remove surface dust.

[0016] Preferably, the width dimension of the optical glass is 2 mm±0.2 mm greater than the width dimension of the sintered surface of the metal substrate, and the length dimension is 0.5 mm±0.1 mm greater than the width dimension of the sintered surface of the metal substrate.

[0017] It should be noted that after sintering is completed and passed inspection, the surface of the optical glass is ground to eliminate the imprint on the glass surface, and then it is transferred to the subsequent polishing process for further processing.

[0018] Specifically, the optical glass model is H-K9L, and the metal substrate is a titanium alloy substrate with a brand name of TC4.

[0019] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0020] 1. The present invention optimizes the layout of parts before sintering the metal substrate and the optical glass, and adopts an optical glass bottom-placed parts assembly method, thereby effectively avoiding the phenomenon of debonding and cracking of the glass edge due to stress release during the sintering process.

[0021] 2. The present invention optimizes the sintering method and sintering procedure to ensure firm sintering while ensuring that the surface quality of the optical glass meets the use requirements, thereby improving the sintering quality of the optical glass and the metal substrate.

[0022] 3. The present invention adds a fire extinguishing blanket between the optical glass and the supporting structure (refractory bricks) to ensure that the imprint depth on the optical glass surface during the sintering process and after sintering is controllable (the imprint depth is less than 0.5 mm), thereby ensuring that after sintering is completed and the imprint on the glass surface is eliminated, the requirements of optical glass thickness of 2 mm, surface roughness Ra of 3.2 μm, and flatness of 0.01 mm are met.

[0023] 4. The present invention adopts a parts assembly method in which the optical glass is placed below, which avoids the need to design fixing devices such as buckles when the metal substrate is irregularly shaped, thereby greatly reducing the difficulty of sintering parts and improving production efficiency.

[0024] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings are only for the purpose of illustrating specific embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0026] Figure 1 The front view, left view and partial cross-sectional view of the special-shaped optical-mechanical integrated lightweight reflector of the present invention;

[0027] Figure 2 This is a schematic diagram of the parts placement method in the sintering process of the lightweight reflector of the present invention;

[0028] Figure 3 This is a diagram showing the arrangement of the lightweight reflector of the present invention before sintering;

[0029] Figure 4 The fire blanket of the present invention leaves an imprint on the glass surface;

[0030] Figure 5 This is a part processing diagram of Example 1 of the present invention;

[0031] Figure 6 This is a picture of the parts of Example 1 of the present invention after sintering and removing the imprint.

[0032] Reference numerals:

[0033] 1-Metal substrate; 2-Optical glass; 3-Fire blanket; 4-Refractory brick. DETAILED DESCRIPTION

[0034] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0035] A specific embodiment of the present invention discloses a sintering method for a special-shaped optical-mechanical integrated lightweight reflector, such as Figure 2 , 3 As shown, before the metal substrate and the optical glass are sintered, the parts layout is designed to form an optical glass bottom-placed parts group: from top to bottom, there are metal substrate 1, optical glass 2, fire blanket 3 and refractory bricks 4.

[0036] Among them, the metal matrix of the special-shaped optical-mechanical integrated lightweight reflector is in the shape of a hollow triangular prism, including two triangular bases parallel to each other and of the same shape and three rectangular sides. Each rectangular side of the hollow triangular prism has two side edges, adjacent sides share one side edge, and the two bases are connected by the side edges. The metal matrix of the existing integrated lightweight reflector is mostly in the shape of a flat plate structure, or a hollow structure, honeycomb structure, mesh structure, etc. are designed on the basis of the flat plate structure to reduce weight. During the sintering process, the optical glass is placed on the metal matrix, which is prone to poor sintering quality and problems such as debonding and cracks on the edges of the optical glass. With respect to the special-shaped optical-mechanical integrated lightweight reflector described in the present invention, the metal substrate has a special shape and the above-mentioned technical problems exist during sintering. In addition, due to the characteristics of the metal substrate triangular prism structure with one side facing horizontally downward and the other two sides forming a certain angle with the horizontal direction when it is laid flat, there is also the problem of difficulty in placing the optical glass. The present invention adopts a bottom-mounted parts layout for the optical glass, which can fix the position of the optical glass and the metal substrate during the sintering process without the need for special structural design, and effectively avoids the phenomenon of debonding and cracking of the glass edge due to stress release during the sintering process.

[0037] The refractory bricks play a supporting role during the sintering process. The high-temperature resistant fire blanket is placed between the optical glass and the refractory bricks to ensure that the surface marks of the optical glass can be eliminated and meet the use requirements when it is subjected to the gravity of the metal matrix during the high-temperature sintering process.

[0038] It should be noted that the width of the optical glass is 2mm±0.2mm larger than the width of the metal substrate sintered surface, and the length is 0.5mm±0.1mm larger than the width of the metal substrate sintered surface, so as to ensure the effective size of the parts; to ensure that the parts assembly is easy to take and place before sintering, the size of the refractory brick is larger than the size of the fire blanket, and the edge exceeds it by at least 2cm; the size of the fire blanket is larger than the size of the optical glass and the metal substrate sintered surface, and the edge exceeds it by at least 2cm;

[0039] In one possible design, Figure 3As shown, the optical glass bottom-mounted parts group includes 3 metal substrates, 3 optical glasses, 1 fire-extinguishing blanket and 1 refractory brick. The edge of the refractory brick in the width direction exceeds the fire-extinguishing blanket by 4 cm, and the edge in the length direction exceeds the fire-extinguishing blanket by 2 cm. The edge of the fire-extinguishing blanket exceeds the 3 groups of optical glass and metal substrate combinations placed below by 2 cm, and the intervals between the 3 groups of optical glass and metal substrate combinations are greater than 2 cm.

[0040] Furthermore, the sintering process is carried out in a sealing furnace, and the sintering process flow is as follows:

[0041] Step 1, place the optical glass bottom-mounted parts assembly into a sealing furnace, raise the temperature in the sealing furnace from room temperature 25°C to 620±5°C, and control the heating time to be 10 to 12 hours;

[0042] Step 2: Maintain a constant temperature of 620±5℃ for 5-6h;

[0043] Step 3: After the parts assembly is cooled to below 40°C in the furnace, take out the parts assembly and inspect whether it is qualified.

[0044] The criteria for judging sintering qualification are: no bubbles between the glass and the metal, no cracks in the glass, and uniform color of the sintered layer.

[0045] The present invention adopts a bottom-mounted optical glass parts assembly and combines an appropriate sintering process. Compared with the sintering method of the optical glass on top, the present invention effectively avoids the phenomenon of debonding and cracking of the glass edge due to stress release during the sintering process.

[0046] Furthermore, before the metal substrate and the optical glass are combined into a parts assembly, the metal substrate needs to be machined and the optical glass needs to be machined.

[0047] Specifically, the machining technical requirements for the metal substrate are: flatness 0.01 mm, surface roughness Ra 1.6 μm.

[0048] Preferably, the technical requirements for the optical glass processing are: flatness 0.01mm, parallelism 0.05mm, thickness 2.5±0.1mm, surface roughness Ra1.6um, no large sand holes (sand holes with a diameter less than 0.5mm are allowed) and large scratches (scratches with a length less than 15mm and a width less than 0.07mm are allowed), so as to avoid internal cracks in the optical glass during the sintering process and ensure its sintering quality.

[0049] Furthermore, before the metal substrate and the optical glass are combined into a parts assembly, the sintering surface of the metal substrate and the surface of the optical glass are treated.

[0050] The specific process of the surface treatment is: sandblasting the machined sintered surface of the metal substrate (i.e., the bonding surface with the optical glass) with a dry sandblasting machine to remove stains on the sintered surface to enhance the sintering bonding force; wiping the machined optical glass on the sintered surface of the metal substrate with ether to remove surface dust and ensure that the metal body and the optical glass fit tightly.

[0051] It should be noted that during the sintering process, the optical glass softens due to heat. Under the condition of bearing the gravity of the metal matrix, the fire blanket leaves marks on the lower surface of the optical glass, such as Figure 4 As shown, under the sintering process and sintering temperature of the present invention, the depth of the imprint is less than 0.5 mm and can be eliminated by grinding; the control of the sintering temperature and the constant temperature time is very important. If the temperature is too low, the optical glass will not soften enough and the sintering will not be firm. If the temperature is too high, the imprint left on the lower surface of the glass will be too deep and cannot be eliminated.

[0052] Furthermore, after sintering is completed and inspected, the surface of the optical glass is ground to eliminate the imprint on the glass surface and ensure the thickness of the glass layer of the part, and then it is further processed in the subsequent fine grinding, pre-polishing and fine polishing steps in sequence to achieve the surface roughness and surface shape requirements of the parts.

[0053] After eliminating the imprint on the glass surface, the optical glass has a thickness of 2mm, a surface roughness of Ra3.2μm, and a flatness of 0.01mm.

[0054] It is worth noting that the optical glass model is H-K9L, and the metal substrate is a titanium alloy substrate with a grade of TC4.

[0055] The thermal expansion coefficient of K9 glass is 7.1×10 -6 / K, the thermal expansion coefficient of TC4 titanium alloy is 8.6×10 -6 / K, the thermal expansion coefficients of the two are relatively close, and the dimensional stability when the temperature changes is similar. Therefore, when the two are used in combination, the risk of internal stress and deformation caused by the difference in thermal expansion coefficients is relatively low.

[0056] In summary, the present invention optimizes the parts layout and adopts the optical glass bottom-placed parts assembly method, which effectively avoids the phenomenon of glass edge debonding and cracking due to stress release during the sintering process; by optimizing the sintering method and sintering procedure, it ensures that the sintering is firm while ensuring that the surface quality of the optical glass meets the use requirements, thereby improving the sintering quality of the optical glass and the metal substrate.

[0057] The sintering method of the optical-mechanical integrated lightweight reflector of the present invention is described below with reference to specific embodiments.

[0058] Example 1

[0059] This embodiment provides a sintering method for an optical-mechanical integrated lightweight reflector.

[0060] like Figure 1 , 5 As shown, the special-shaped integrated lightweight reflector has a right triangle cross-section, the lengths of the two right-angled sides are 20.6 mm and 18.6 mm respectively, one of the acute angles is 48°, and the total length of the part is 100 mm; the metal matrix material is titanium alloy, and the glass grade is K9 optical glass.

[0061] The processing includes the following steps:

[0062] S1. Processing of titanium alloy substrate: ensure the flatness of the sintered surface is 0.01mm and the surface roughness is Ra1.6um;

[0063] S2. Processing of optical glass: ensure flatness 0.01mm, parallelism 0.05mm, thickness 2.5±0.1mm, roughness Ra1.6um, no large sand holes (sand holes with a diameter less than 0.5mm are allowed) and large scratches (scratches with a length less than 15mm and a width less than 0.07mm are allowed);

[0064] S3, Sintering of optical glass and substrate:

[0065] Before sintering the metal matrix and the optical glass, wipe the metal body and the processed optical glass with absorbent cotton dipped in ether to remove surface dust and ensure that the metal body and the optical glass fit tightly;

[0066] according to Figure 3 The order shown is to place the fire blanket on the refractory bricks, place the optical glass on the fire blanket, and finally place the metal substrate on the fire blanket;

[0067] Sintering is carried out as follows:

[0068] Step 1, place the optical glass bottom-mounted parts assembly into a sealing furnace, raise the temperature in the sealing furnace from room temperature 25°C to 620±5°C, and control the heating time to be 10 hours;

[0069] Step 2: Maintain a constant temperature of 620±5℃ for 5h;

[0070] Step 3: After the parts assembly is cooled down to below 40°C in the furnace, the parts assembly is taken out;

[0071] After inspection, it is found that there are no bubbles between the glass and the metal, the glass has no cracks, and the sintered layer has a uniform color; proceed to step S4;

[0072] S4. Eliminate marks on the glass surface: Manually operate and grind the parts with diamond abrasive on a flat single-axis machine. Measure the thickness of the glass layer while grinding. At the same time, observe whether the marks on the glass surface are eliminated. Figure 6 .

[0073] Comparative Example 1

[0074] This embodiment provides a sintering method for an optical-mechanical integrated lightweight reflector.

[0075] The dimensions and materials of each component are the same as those in Example 1.

[0076] The processing process is basically the same as that of Example 1, except that in step S3, the parts are arranged as follows: from top to bottom, optical glass, metal substrate, fire blanket and refractory bricks, that is, glass is placed on top.

[0077] After sintering was completed and cooled to below 40°C, the parts were taken out and inspection revealed that the glass edges were debonding and internal cracks had occurred.

[0078] Comparative Example 2

[0079] This embodiment provides a sintering method for an optical-mechanical integrated lightweight reflector.

[0080] The dimensions and materials of each component are the same as those in Example 1.

[0081] The processing process is basically the same as that of Example 1, except that the sintering temperature in step S3 is 700°C.

[0082] After sintering is completed and cooled to below 40°C, the parts are taken out. The imprint on the glass surface is too deep and cannot be completely eliminated after grinding and polishing.

[0083] Comparative Example 3

[0084] This embodiment provides a sintering method for an optical-mechanical integrated lightweight reflector.

[0085] The dimensions and materials of each component are the same as those in Example 1.

[0086] The processing process is basically the same as that of Example 1, except that the sintering temperature in step S3 is 500°C.

[0087] After sintering is completed and cooled to below 40°C, the parts are taken out and the glass can still move.

[0088] It can be seen from Example 1 and Comparative Example 1 that, compared with the sintering method of optical glass on top, the optical glass bottom-mounted parts assembly can effectively avoid debonding at the glass edge and internal cracks; it can be seen from Example 1 and Comparative Example 2 that too high a sintering temperature will cause the reflector glass to ultimately fail to meet the use requirements; it can be seen from Example 1 and Comparative Example 3 that too low a sintering temperature will cause the glass and titanium alloy to be unable to sinter together.

[0089] In summary, the present invention optimizes the parts layout and adopts the optical glass bottom-placed parts assembly method, which effectively avoids the phenomenon of glass edge debonding and cracking due to stress release during the sintering process; by optimizing the sintering method and sintering procedure, it ensures that the sintering is firm while ensuring that the surface quality of the optical glass meets the use requirements, thereby improving the sintering quality of the optical glass and the metal substrate.

[0090] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A sintering method for a special-shaped optical-mechanical integrated lightweight reflector, characterized in that: Before the metal substrate and the optical glass are sintered, the parts layout is designed to form an optical glass bottom-mounted parts group: from top to bottom, they are the metal substrate, optical glass, fire blanket and refractory bricks.

2. The sintering method according to claim 1, characterized in that: The sintering process is carried out in a sealing furnace, and the sintering process is as follows: Step 1, place the optical glass bottom-mounted parts assembly into a sealing furnace, raise the temperature in the sealing furnace from room temperature 25°C to 620±5°C, and control the heating time to be 10 to 12 hours; Step 2: Maintain a constant temperature of 620±5℃ for 5-6h; Step 3: After the parts assembly is cooled to below 40°C in the furnace, take out the parts assembly and inspect whether it is qualified.

3. The sintering method according to claim 1, characterized in that: Before the metal substrate and the optical glass are combined into a parts assembly, the metal substrate needs to be machined and the optical glass needs to be processed.

4. The sintering method according to claim 3, characterized in that: The machining technical requirements for the metal substrate are: flatness 0.01 mm, surface roughness Ra 1.6 μm.

5. The sintering method according to claim 3, characterized in that: The technical requirements for the optical glass processing are: flatness 0.01mm, parallelism 0.05mm, thickness 2.5±0.1mm, surface roughness Ra1.6um, no sand holes with a diameter greater than 0.5mm and scratches with a length greater than 15mm and a width greater than 0.07mm.

6. The sintering method according to claim 1, characterized in that: Before the metal substrate and the optical glass are assembled into a parts assembly, the sintering surface of the metal substrate and the surface of the optical glass need to be treated.

7. The sintering method according to claim 6, characterized in that: The specific process of the surface treatment is: sandblasting the machined sintered surface of the metal substrate with a dry sandblasting machine to remove stains on the sintered surface; and wiping the sintered surface of the metal substrate and the processed optical glass with ether to remove surface dust.

8. The sintering method according to claim 7, characterized in that: The width dimension of the optical glass is 2 mm ± 0.2 mm larger than the width dimension of the sintered surface of the metal substrate, and the length dimension is 0.5 mm ± 0.1 mm larger than the width dimension of the sintered surface of the metal substrate.

9. The sintering method according to claim 2, characterized in that: After sintering is completed and passed inspection, the surface of the optical glass is ground to eliminate the imprint on the glass surface, and then transferred to the subsequent polishing process for further processing.

10. The sintering method according to claim 1, characterized in that: The optical glass model is H-K9L, and the metal substrate is a titanium alloy substrate with a brand name of TC4.

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