A manufacturing method of a light-transmitting bronze mirror

Abstract

The present invention discloses a method for manufacturing a light-transmitting bronze mirror, which includes drawing a three-dimensional model of the bronze mirror using 3D modeling software, and integrally printing a wax mold of the bronze mirror using a 3D printer; manufacturing a mirror blank using a precision plaster mold casting process; manufacturing a casting blank of the mirror body; cleaning the casting blank; and polishing the mirror body. The above manufacturing method includes steps such as wax mold manufacturing, mirror blank manufacturing, mirror body casting, casting blank cleaning, and mirror body polishing. By combining 3D printing and precision plaster mold casting processes, and then using a green alloy material with excellent casting performance as the material for the bronze mirror, the crystallization interval is controlled within 100 °C, laying a foundation for fluid filling and the density of the casting, further improving the density of the mirror body casting. Finally, after processing such as casting blank cleaning and mirror body polishing of the casting blank of the mirror body, the obtained light-transmitting bronze mirror has excellent reflection effect and clear light-transmitting effect.

Description

Technical Field

[0001] The present invention relates to the technical field of bronze mirror manufacturing, and particularly to a manufacturing method of a light-transmitting bronze mirror. Background Art

[0002] Bronze mirrors were daily utensils used by ancient Chinese people to look at their faces and for decoration. They were regarded as precious items among bronze wares and were popular in China for thousands of years. Their development can be divided into several stages such as the early stage, the popular stage, the peak stage, the mid-decline stage, the prosperous stage, and the decline stage. After the popularization of glass mirrors in the Qing Dynasty, they withdrew from the historical stage. The basic structure of a bronze mirror is that the front side is highly polished and the back side is decorated with patterns. In the Western Han Dynasty, a miraculous bronze mirror was created. In the light reflected by it, the patterns on the back of the mirror would appear, as if the light penetrated from behind the mirror, so it was called a light-transmitting mirror. In history, there were some documents recording the light-transmitting mirror, but they only recorded the phenomenon. The reason for this phenomenon was only slightly mentioned in Volume 19 of "Dream Pool Essays" by the Song Dynasty scientist Shen Kuo. "There is a light-transmitting mirror in the world. There are inscriptions on the back of the mirror, a total of twenty characters. The characters are extremely ancient and cannot be read. When the mirror is used to receive sunlight, the inscriptions on the back and the twenty characters are all projected onto the wall of the room clearly. Some people have explored its principle and believe that when casting, the thinner parts cool first, and only the parts with the inscriptions on the back are slightly thicker and cool later, and the copper shrinks more. Although the inscriptions are on the back, there are faint traces on the front side of the mirror, so they appear in the light. After my observation, the principle is indeed like this." However, the manufacturing method of the light-transmitting mirror is basically lost. In the 1980s, a few domestic researchers studied the mechanism of the light-transmitting mirror and used the pottery mold casting process to replicate bronze mirrors with light-transmitting effects.

[0003] Patent CN93108885.2 discloses a bronze mirror and its preparation method, including steps such as mold making, smelting, casting, mirror opening, light-transmitting treatment, and gilding, etc.; the formula of the bronze mirror is 65 - 80wt% of Cu, 15 - 27wt% of Sn, 1 - 5wt% of Pb, and 0.01 - 0.05wt% of Zn; it can achieve the "light-transmitting" effect. Patent CN92244010.7 discloses a light-transmitting bronze mirror, on the front side of the mirror body of the bronze mirror, there is a concave image similar to the pattern on the back of the mirror or a concave image different from the back of the mirror. When in use, it can maintain a certain angle with the light source, and the similar pattern on the back of the bronze mirror can be reflected through light reflection. However, these methods have the following deficiencies: First, they all adopt the ancient pottery mold casting process, with a long production cycle and numerous and complex processes. They cannot meet the contemporary market requirements in terms of production efficiency, product quality, production cost, etc.; second, the bronze mirror material is a lead-containing copper alloy, which cannot meet the basic requirements of environmental protection; third, the crystallization interval of the bronze mirror material is too wide, and some even reach more than 400°C, showing a serious paste-like solidification mode during casting, resulting in shrinkage porosity in the casting, which is very unfavorable for the surface polishing of the bronze mirror and is prone to polishing scratches and holes, affecting the surface brightness and reflection effect. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides a method for manufacturing a light-transmitting bronze mirror. A green alloy material with excellent casting performance is used as the bronze mirror material. The structure of the bronze mirror is designed, the curvature of the front surface of the mirror is controlled, the decorative pattern structure and distribution on the back surface of the bronze mirror are scientifically arranged, and it is cast and formed under vacuum pressure conditions by the plaster mold precision casting process. The mirror surface is polished by the profiling polishing technology, thereby obtaining an excellent reflection effect and a clear light-transmitting effect.

[0005] The present invention is realized by adopting the following technical solutions:

[0006] A method for manufacturing a light-transmitting bronze mirror, comprising the following steps:

[0007] S1: Wax pattern making:

[0008] Use 3D modeling software to draw a three-dimensional model of the bronze mirror, and use a 3D printer to print out the bronze mirror wax pattern as a whole;

[0009] S2: Mirror blank making:

[0010] Use the plaster mold precision casting process to make the mirror blank;

[0011] S3: Mirror body pouring:

[0012] Put the alloy material into the graphite crucible of the vacuum induction furnace, first evacuate to 5 - 15 Pa, then fill with pure argon to 1 - 1.1 atm. When the metal charge is melted, adjust the temperature to 880 - 910 °C, start the electromagnetic stirring function, and keep stirring for 1.5 - 2.5 min to obtain the metal liquid; wherein, the alloy material includes the following components by weight percentage: 22 - 25% tin, 0.2 - 1.0% gallium, 1 - 4% zinc, 0.3 - 3% germanium, 0.03 - 0.2% neodymium, 0.1 - 0.5% ruthenium, 0.02 - 0.15% boron, and the rest is copper and inevitable impurity elements;

[0013] In this step, by designing the alloy composition, the crystallization interval is controlled within 100 °C, laying a foundation for fluid filling and the density of the casting; and the material does not contain toxic and harmful elements, has a melting point lower than 835 °C, and does not contain alloy elements that react chemically with the plaster mold material, so it is suitable for forming by the plaster mold precision casting process.

[0014] At the same time, put the mirror blank of the plaster mold into the casting chamber, evacuate to 30 - 60 Pa, then inject the metal liquid into the mirror blank of the plaster mold. After 20 - 50 s of pouring, start the pressurizing device, and maintain a gas pressure of 2 - 3 atm on the metal liquid surface to make the metal liquid crystallize and solidify under pressure, improving the density of the mirror body casting to obtain the mirror body casting blank;

[0015] In this step, the plaster mold precision casting process is adopted to ensure the fineness of the surface and patterns of the bronze mirror. The casting process plan of the bronze mirror is designed to obtain a bronze mirror casting with sound structure, clear outline and delicate surface;

[0016] S4: Cleaning the casting blank;

[0017] S5: Grinding and polishing the mirror body.

[0018] Furthermore, in step S1, the structure of the three-dimensional model of the bronze mirror is as follows:

[0019] The mirror body is a perfect circle, and the mirror surface is slightly convex; the surface of the front of the mirror body is bright (that is, there are no patterns on the front of the mirror body and the surface is bright); the back of the mirror body is provided with a decorative pattern with a convex-concave-convex structure partition (that is, the back of the mirror body adopts a combination of concave and convex), and the convex ring area of the decorative pattern is provided with an intaglio pattern carved downward, and the concave ring area of the decorative pattern is provided with a relief pattern upward.

[0020] In this step, the overall design of the bronze mirror structure is carried out to make the curvature radius of the front and the decorative pattern on the back coordinate and cooperate, forming macroscopic stress and micro-area casting stress inside the casting, and promoting the generation of microscopic concave and convex effects on the front of the bronze mirror after grinding and polishing.

[0021] Furthermore, the diameter of the mirror body is 70 - 150 mm, the protruding height of the center of the mirror surface of the mirror body is 0.65 - 0.95 mm higher than the edge of the mirror surface, and the curvature radius of the mirror surface of the mirror body is 850 - 3200 mm; the wall thickness of the mirror body corresponding to the intaglio pattern is 0.3 - 0.5 mm; the protruding height of the relief pattern is 1 - 2 mm.

[0022] Furthermore, in step S1, the wax mold of the bronze mirror is blue wax or purple wax; the 3D printer prints the wax mold of the bronze mirror based on the FDM principle; the set step size of the 3D printer is 0.02 - 0.03 mm. Using this method, high-quality wax molds can be stably produced, ensuring the external contour dimensions and delicate patterns of the bronze mirror, and steam dewaxing can be used. After roasting, there is no residual ash in the mold, and the casting surface quality is good.

[0023] Furthermore, in step S2, the plaster mold precision casting process includes the following steps:

[0024] The gypsum casting powder is formulated into a gypsum slurry, and then the gypsum slurry is poured into the bronze mirror wax pattern by using the vertical casting process. Among them, the gating system is set as a stepped type, and the cross-sectional areas of the sprue and the ingate are set in the ratio of 1.1 - 1.5:1, which is beneficial to blocking the slag that may be brought in by the molten metal. The ingate adopts a circular runner and is connected at an angle of 15 - 30° with the tangent of the edge of the bronze mirror wax pattern, so that the molten metal enters the cavity smoothly. At the same time, a fillet with a radius of R2 - 4mm is set at the inner connection to prevent tensile cracks from occurring at the root of the ingate when the casting shrinks.

[0025] Further, the gypsum casting powder comprises the following components in weight percentages: 10 - 20wt% zircon powder, 30 - 40wt% quartz powder, 20 - 30wt% cristobalite powder, and the rest is gypsum powder. In this step, the ordinary gypsum casting powder is modified to solve the problems of the traditional process of casting with pottery molds, such as numerous production processes, too long production cycle, multiple loose pieces need to be set for complex patterns, poor dimensional accuracy, poor air permeability, resulting in poor surface quality of the casting. At the same time, the gypsum mold has good replicability, simple production, and easy cleaning, but there are problems such as poor thermal conductivity, poor thermal stability, and low roasting strength. And the mirror body alloy has a relatively wide crystallization interval compared with other copper alloys, and has a greater tendency to produce shrinkage porosity and composition segregation. By modifying the gypsum casting powder and adding 10 - 20% zircon powder, the heat storage coefficient and thermal conductivity of the mold are enhanced, which is beneficial to the density and surface finish of the bronze mirror casting. Among them, the gypsum powder is traditional hydrated calcium sulfate.

[0026] Further, the gypsum slurry is prepared by mixing the gypsum casting powder and a boric acid aqueous solution with a concentration of 1.5 - 3.5% in a mass ratio of 100:(36 - 40). In this step, a boric acid aqueous solution with a concentration of 1.5 - 3.5% is used to prepare the gypsum slurry to increase the strength of the gypsum mold and reduce the probability of sand holes in the casting. Preferably, the mass ratio of the gypsum casting powder to the boric acid aqueous solution is 100:(37 - 39).

[0027] Further, in step S3, the total content of inevitable impurity elements does not exceed 0.1wt%.

[0028] Further, in step S4, the cleaning of the casting blank includes the following steps:

[0029] After pouring, the mirror body casting blank is cooled to below 60 - 100°C, the mold is loosened by a vibrator, the casting is taken out, the adhered gypsum mold is washed clean with a high-pressure water gun, and the gating system is cut off by a cutting machine to obtain an unpolished mirror body.

[0030] Further, in step S5, the grinding and polishing of the mirror body includes the following steps:

[0031] Use a grinding wheel to grind off the residual runner and flash areas, use wire brushes and palm brushes to polish the back of the mirror body, then clamp the mirror body on the fixed fixture of an automatic pressure grinding machine with the mirror surface facing downwards.

[0032] Manufacture a corresponding concave mold according to the required mirror surface curvature radius (i.e., the mirror surface curvature radius is 850 - 3200 mm). Mount the mold on the grinding fixture, with its center aligned with the center of the grinding disk, and keep the concave surface facing upwards.

[0033] Adjust the position of the mirror body to make its center coincide with the center of the concave mold. Set the rotational speed of the mold to 100 - 150 rpm, set the rotational speed of the mirror body to 20 - 40 rpm, and set the pressure to 50 - 100 N. Paste sandpaper or polishing cloth on the concave mold in order from coarse to fine, add water to the surface of the mold, and wet-grind the surface of the mirror body in sequence until the mirror surface achieves a highly shiny effect.

[0034] In this step, use profiling technology to mechanically grind the surface of the bronze mirror to ensure a smooth and consistent surface curvature, high efficiency, and environmental friendliness.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] The manufacturing method of the light-transmitting bronze mirror of the present invention includes steps such as wax pattern making, mirror blank making, mirror body casting, casting blank cleaning, and mirror body grinding and polishing. It combines 3D printing and plaster mold precision casting processes, and then uses a green alloy material with excellent casting performance as the bronze mirror material, controlling the crystallization interval within 100 °C to lay a foundation for fluid filling and casting density, further improving the density of the mirror body casting. Finally, after treating the mirror body casting blank such as casting blank cleaning and mirror body grinding and polishing, the obtained light-transmitting bronze mirror has excellent reflection effect and clear light-transmitting effect.

[0037] The manufacturing method of the light-transmitting bronze mirror of the present invention controls the crystallization interval within 100 °C by designing the alloy composition to lay a foundation for fluid filling and casting density; conducts an overall design of the bronze mirror structure to make the curvature radius of the front and the decorative pattern on the back coordinate and cooperate, forming macroscopic stress and micro-area casting stress inside the casting to promote the generation of microscopic unevenness on the front of the bronze mirror after grinding and polishing; uses the plaster mold precision casting process to ensure the fineness of the bronze mirror surface and patterns, designs the casting process plan of the bronze mirror to obtain a bronze mirror casting with sound structure, clear contour, and delicate surface; uses profiling technology to mechanically grind the surface of the bronze mirror to ensure a smooth and consistent surface curvature, high efficiency, and environmental friendliness. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic structural diagram of the cross-section of the mirror body of the bronze mirror wax pattern in Embodiment 1.

[0039] In the figure: 10, intaglio pattern; 20, relief pattern. Specific embodiments

[0040] Next, in combination with specific embodiments, the present invention will be further described. It should be noted that, on the premise of non-conflict, the following-described embodiments or technical features can be arbitrarily combined with each other to form new embodiments.

[0041] Embodiment 1

[0042] A method for manufacturing a light-transmitting bronze mirror includes the following steps:

[0043] S1: Wax pattern making:

[0044] Use 3D modeling software to draw a three-dimensional model of the bronze mirror. Use purple wax as the raw material, set the step size to 0.025 mm, and use a 3D printer based on the FDM principle to print out the bronze mirror wax pattern as a whole;

[0045] Among them, the structure of the three-dimensional model of the bronze mirror is as follows: for easy access and reflection, the mirror body is set as a regular circle with a diameter of 100 mm. The mirror surface is slightly convex, and it is controlled that the center of the mirror surface is 0.8 mm higher than the edge of the mirror surface. The radius of curvature of the mirror surface is 1560 mm. There are no patterns on the front of the mirror body, and the surface is bright; on the back of the mirror body, decorative patterns are set. In an uneven combination manner, a convex-concave-convex structural partition is set. An intaglio pattern 10 is set in the convex ring area with downward engraving, and the wall thickness of the mirror body corresponding to the intaglio is controlled to be 0.4 mm. A relief pattern 20 is set in the concave ring area with upward protrusion, and the height of the relief is controlled to be 1.5 mm to obtain the bronze mirror wax pattern, as Figure 1 shown;

[0046] S2: Mirror blank making:

[0047] Prepare the gypsum casting powder into a gypsum slurry, and then use the vertical pouring process to pour the gypsum slurry into the bronze mirror wax pattern. Among them, the gating system is set as a stepped type, and the cross-sectional areas of the sprue and the ingate are set in a ratio of 1.2:1, which is beneficial to blocking the slag that may be brought in by the molten metal; the ingate uses a circular gate and is connected at an angle of 20° to the tangent of the edge of the bronze mirror wax pattern, so that the molten metal enters the cavity smoothly. At the same time, an R3 mm fillet transition is set at the inner connection to prevent tensile cracks from occurring at the root of the ingate when the casting shrinks.

[0048] Among them, the gypsum casting powder includes the following components in weight percentage: 15 wt% zircon powder, 32 wt% quartz powder, 25 wt% cristobalite powder, and the rest is gypsum powder.

[0049] The gypsum slurry is prepared by mixing the gypsum casting powder and a boric acid aqueous solution with a concentration of 2.5% in a mass ratio of 100:38.

[0050] S3: Mirror body pouring:

[0051] Put the alloy material into the graphite crucible of the vacuum induction furnace. First, evacuate to 10 Pa, and then fill with pure argon to 1.03 atm. When the metal charge is completely melted, adjust the temperature to 890 °C, start the electromagnetic stirring function, and keep stirring for 2 min to obtain the molten metal. Among them, the alloy material includes the following components by weight percentage: 25% tin, 0.35% gallium, 2% zinc, 0.3% germanium, 0.1% neodymium, 0.15% ruthenium, 0.075% boron, and the rest is copper and inevitable impurity elements;

[0052] At the same time, load the mirror blank of the gypsum mold into the casting chamber, evacuate to 40 Pa, and then pour the molten metal into the mirror blank of the gypsum mold. After 30 s of pouring, start the pressurizing device, and maintain a gas pressure of 2.5 atm on the molten metal surface to make the molten metal crystallize and solidify under pressure to obtain the mirror blank casting;

[0053] S4: Cleaning of the casting blank;

[0054] After pouring, cool the mirror blank casting to below 80 °C, use a vibrator to loosen the mold, take out the casting, wash the adhered gypsum mold clean with a high-pressure water gun, and use a cutting machine to cut off the gating system to obtain an unpolished mirror body.

[0055] S5: Grinding and polishing of the mirror body:

[0056] Use a grinding wheel to grind off areas such as the runner residue and flash, use tools such as a wire brush and a palm brush to brighten the back of the mirror body, and then clamp the mirror body on the fixed fixture of the automatic pressure grinding machine, keeping the mirror surface facing down;

[0057] Make a corresponding concave mold according to the required mirror surface curvature radius, install the mold on the grinding fixture plate, and make the center coincide with the center of the grinding plate, keeping the concave surface facing up;

[0058] Adjust the position of the mirror body to make the center of the mirror body coincide with the center of the concave mold; set the mold rotation speed to 120 rpm, set the mirror body rotation speed to 30 rpm, set the pressure to 75 N, paste sandpaper or polishing cloth on the concave mold in order from coarse to fine, and add water to the surface of the mold, and wet-grind the surface of the mirror body in turn until the mirror surface reaches a highly shiny effect.

[0059] Performance test and results:

[0060] (1) Detected by a differential thermal analyzer, the liquidus point of the alloy is 803 °C, which is suitable for forming by the gypsum mold precision casting process;

[0061] (2) Align the mirror surface with the light source, and irradiate the reflected light onto the backing plate, and the pattern on the back of the mirror can be clearly reflected.

[0062] Example 2

[0063] A method for manufacturing a light-transmitting bronze mirror includes the following steps:

[0064] S1: Wax pattern making:

[0065] Use 3D modeling software to draw a three-dimensional model of the bronze mirror. Use purple wax as the raw material, set the step size to 0.02 mm, and use a 3D printer based on the FDM principle to print out the wax pattern of the bronze mirror as a whole;

[0066] Among them, the structure of the three-dimensional model of the bronze mirror is: set the mirror body as a perfect circle with a diameter of 70 mm, the mirror surface is slightly convex, control the center of the mirror surface to be 0.65 mm higher than the edge of the mirror surface, the radius of curvature of the mirror surface is 850 mm, there are no decorative patterns on the front of the mirror body, and the surface is bright; on the back of the mirror body, set decorative patterns, adopt a combination of concave and convex, set a convex-concave-convex structure partition, set intaglio patterns carved downward in the convex ring area, control the wall thickness of the mirror body corresponding to the intaglio to be 0.3 mm, set raised patterns upward in the concave ring area, control the height of the raised patterns to be 1.0 mm, and obtain the wax pattern of the bronze mirror;

[0067] S2: Mirror blank making:

[0068] Prepare gypsum slurry by mixing gypsum casting powder. Then, adopt the vertical pouring process to pour the gypsum slurry into the wax pattern of the bronze mirror. Among them, the gating system is set as a stepped type, and the cross-sectional areas of the sprue and the ingate are set in the ratio of 1.5:1, which is beneficial to blocking the slag that may be brought in by the molten metal; the ingate adopts a circular gate and is connected at an angle of 30° to the tangent of the edge of the wax pattern of the bronze mirror, so that the molten metal enters the cavity smoothly. At the same time, set a fillet transition of R2 mm at the inner connection to prevent tensile cracks from occurring at the root of the ingate when the casting shrinks.

[0069] Among them, the gypsum casting powder includes the following components in weight percentage: 10 wt% zircon powder, 40 wt% quartz powder, 20 wt% cristobalite powder, and the rest is gypsum powder.

[0070] The gypsum slurry is prepared by mixing gypsum casting powder and boric acid aqueous solution with a concentration of 3.5% in a mass ratio of 100:39.

[0071] S3: Mirror body pouring:

[0072] Put the alloy material into the graphite crucible of the vacuum induction furnace, first evacuate to 5 Pa, and then fill with pure argon to 1.0 atm. When the metal charge is melted completely, adjust the temperature to 900 °C, start the electromagnetic stirring function, and keep stirring for 1.5 min to obtain molten metal; among them, the alloy material includes the following components in weight percentage: 22% tin, 0.2% gallium, 1% zinc, 3% germanium, 0.03% neodymium, 0.1% ruthenium, 0.02% boron, and the rest is copper and inevitable impurity elements;

[0073] Meanwhile, place the mirror blank of the gypsum mold into the casting chamber, evacuate to 30 Pa, then pour the molten metal into the mirror blank of the gypsum mold. After 20 s of pouring, start the pressurizing device, maintain a gas pressure of 2.0 atm on the surface of the molten metal, and make the molten metal crystallize and solidify under pressure to obtain a mirror blank casting;

[0074] S4: Cleaning of the casting blank;

[0075] After pouring, cool the mirror blank casting to below 100 °C, use a vibrator to loosen the mold, take out the casting, rinse the adhered gypsum mold clean with a high-pressure water gun, and use a cutting machine to cut off the gating system to obtain an unpolished mirror body.

[0076] S5: Grinding and polishing of the mirror body:

[0077] Use a grinding wheel to grind off areas such as the runner residue and flash, use tools such as wire brushes and palm brushes to polish the back of the mirror body, and then clamp the mirror body on the fixed fixture of an automatic pressure grinding machine with the mirror surface facing down;

[0078] Make a corresponding concave mold according to the required mirror surface curvature radius, install the mold on the grinding fixture plate, and make the center coincide with the center of the grinding plate, with the concave surface facing up;

[0079] Adjust the position of the mirror body to make the center of the mirror body coincide with the center of the concave mold; set the mold rotation speed to 100 rpm, set the mirror body rotation speed to 40 rpm, set the pressure to 50 N, paste sandpaper or polishing cloth on the concave mold in order from coarse to fine, add water to the surface of the mold, and wet-grind the surface of the mirror body in turn until the mirror surface reaches a highly shiny effect.

[0080] Performance testing and results:

[0081] (1) Detected by a differential thermal analyzer, the liquidus point of the alloy is 806 °C, which is suitable for forming by the precision casting process of gypsum mold;

[0082] (2) Align the mirror surface with the light source and shine the reflected light onto the backing plate, and the pattern on the back of the mirror can be clearly reflected.

[0083] Example 3

[0084] A method for making a light-transmitting bronze mirror includes the following steps:

[0085] S1: Wax pattern making:

[0086] Use 3D modeling software to draw a three-dimensional model of the bronze mirror, use purple wax as the raw material, set the step size to 0.03 mm, and use a 3D printer based on the FDM principle to print out the bronze mirror wax pattern as a whole;

[0087] Among them, the structure of the three-dimensional model of the bronze mirror is as follows: The mirror body is set as a perfect circle with a diameter of 150 mm. The mirror surface is slightly convex, with the center of the mirror surface being 0.95 mm higher than the edge of the mirror surface. The radius of curvature of the mirror surface is 3200 mm. There are no decorative patterns on the front of the mirror body, and the surface is shiny; on the back of the mirror body, decorative patterns are set, using a combination of concave and convex methods, with a structural partition of convex-concave-convex. Intaglio patterns are set by downward engraving in the convex ring area, and the wall thickness of the mirror body corresponding to the intaglio is controlled to be 0.5 mm. Relief patterns are set upward in the concave ring area, and the height of the relief is controlled to be 2.0 mm to obtain the wax pattern of the bronze mirror.

[0088] S2: Mirror blank production:

[0089] The gypsum casting powder is formulated into a gypsum slurry, and then the gypsum slurry is poured into the wax pattern of the bronze mirror by using the vertical casting process. Among them, the gating system is set as a stepped type, and the cross-sectional areas of the sprue and the ingate are set in a ratio of 1.1:1, which is beneficial to blocking the slag that may be brought in by the molten metal; the ingate adopts a circular runner and is connected at an angle of 15° to the tangent of the edge of the wax pattern of the bronze mirror, so that the molten metal enters the cavity smoothly. At the same time, a fillet with a radius of R4 mm is set at the inner connection to prevent tensile cracks from occurring at the root of the ingate when the casting shrinks.

[0090] Among them, the gypsum casting powder includes the following components in weight percentage: 20 wt% zircon powder, 30 wt% quartz powder, 20 wt% cristobalite powder, and the rest is gypsum powder.

[0091] The gypsum slurry is prepared by mixing the gypsum casting powder and a boric acid aqueous solution with a concentration of 1.5% in a mass ratio of 100:37.

[0092] S3: Mirror body casting:

[0093] The alloy material is placed in the graphite crucible of the vacuum induction furnace. First, it is evacuated to 15 Pa, and then filled with pure argon to 1.1 atm. When the metal charge is completely melted, the temperature is adjusted to 910 °C, and the electromagnetic stirring function is started and stirred for 2.5 min to obtain the molten metal; among them, the alloy material includes the following components in weight percentage: 24% tin, 0.3% gallium, 3% zinc, 0.5% germanium, 0.05% neodymium, 0.2% ruthenium, 0.05% boron, and the rest is copper and inevitable impurity elements;

[0094] At the same time, the mirror blank of the gypsum mold is loaded into the casting chamber, evacuated to 60 Pa, and then the molten metal is injected into the mirror blank of the gypsum mold. After 50 s of pouring, the pressurizing device is started, and a gas pressure of 3.0 atm is maintained on the molten metal surface to make the molten metal crystallize and solidify under pressure to obtain the mirror body casting blank;

[0095] S4: Casting blank cleaning;

[0096] After casting, the mirror blank is cooled to below 60°C. The mold is loosened using a vibrator, the casting is removed, and the adhered plaster mold is washed clean with a high-pressure water gun. The gating system is cut off using a cutting machine to obtain an unpolished mirror body.

[0097] S5: Grinding and polishing of the mirror body:

[0098] Use a grinding wheel to grind off areas such as the residual runner and flash. Use tools such as wire brushes and palm brushes to brighten the back of the mirror body. Then, clamp the mirror body on the fixed fixture of an automatic pressure grinding machine with the mirror surface facing down.

[0099] Make a corresponding concave mold according to the required mirror surface curvature radius. The mold is installed on the grinding chuck, and the center coincides with the center of the grinding disc, with the concave surface facing up.

[0100] Adjust the position of the mirror body to make the center of the mirror body coincide with the center of the concave mold. Set the rotational speed of the mold to 150 rpm, the rotational speed of the mirror body to 20 rpm, and the pressure to 100 N. Paste sandpaper or polishing cloth on the concave mold in order from coarse to fine, add water to the surface of the mold, and wet-grind the surface of the mirror body in sequence until the mirror surface achieves a highly shiny effect.

[0101] Performance testing and results:

[0102] (1) Detected by a differential thermal analyzer, the liquidus point of the alloy is 813°C, which is suitable for forming by the plaster mold precision casting process.

[0103] (2) Align the mirror surface with a light source and shine the reflected light onto the backing plate, and the pattern on the back of the mirror can be clearly reflected.

[0104] The above embodiments are only the preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention fall within the scope of protection required by the present invention.

Claims

1. A method for manufacturing a light-transmitting bronze mirror, characterized in that, It includes the following steps: S1: Wax pattern making: Use 3D modeling software to draw a three-dimensional model of the bronze mirror, and use a 3D printer to print out the wax pattern of the bronze mirror as a whole; S2: Mirror blank making: Use the precision casting process of gypsum mold to make the mirror blank; S3: Mirror body pouring: Put the alloy material into the graphite crucible of the vacuum induction furnace, first evacuate to 5-15 Pa, then fill with pure argon to 1-1.1 atm. When the metal charge is melted, adjust the temperature to 880-910 °C, start the electromagnetic stirring function, and keep stirring for 1.5-2.5 min to obtain the molten metal; among them, the alloy material includes the following components by weight percentage: 22-25% tin, 0.2-1.0% gallium, 1-4% zinc, 0.3-3% germanium, 0.03-0.2% neodymium, 0.1-0.5% ruthenium, 0.02-0.15% boron, and the rest is copper and inevitable impurity elements; At the same time, put the mirror blank of the gypsum mold into the casting chamber, evacuate to 30-60 Pa, then inject the molten metal into the mirror blank of the gypsum mold. After pouring is completed, after 20-50 s, start the pressurizing device, and maintain a gas pressure of 2-3 atm on the molten metal surface to make the molten metal crystallize and solidify under pressure to obtain the mirror body casting blank; S4: Cleaning of the casting blank; S5: Grinding and polishing of the mirror body.

2. The manufacturing method of the light-transmitting bronze mirror according to claim 1, characterized in that, In step S1, the structure of the three-dimensional model of the bronze mirror is: The mirror body is a perfect circle, and the front surface of the mirror is slightly convex; the surface of the front of the mirror body is bright; the back of the mirror body is provided with a decorative pattern with a convex-concave-convex structural partition. The convex ring area of the decorative pattern is provided with a intaglio pattern carved downwards, and the concave ring area of the decorative pattern is provided with a relief pattern upwards.

3. The manufacturing method of the light-transmitting bronze mirror according to claim 2, characterized in that, The diameter of the mirror body is 70-150 mm, the protruding height of the center of the mirror surface of the mirror body is 0.65-0.95 mm higher than the edge of the mirror surface, and the radius of curvature of the mirror surface of the mirror body is 850-3200 mm; the wall thickness of the mirror body corresponding to the intaglio pattern is 0.3-0.5 mm; the protruding height of the relief pattern is 1-2 mm.

4. The manufacturing method of the light-transmitting bronze mirror according to claim 1, characterized in that, In step S1, the wax pattern of the bronze mirror is blue wax or purple wax; the 3D printer prints out the wax pattern of the bronze mirror based on the FDM principle; the set step size of the 3D printer is 0.02-0.03 mm.

5. The manufacturing method of the light-transmitting bronze mirror according to claim 1, characterized in that, In step S2, the precision casting process of the gypsum mold includes the following steps: Prepare the gypsum powder into a gypsum slurry, and then use the vertical pouring process to pour the gypsum slurry into the wax pattern of the bronze mirror. Among them, the gating system is set as a stepped type, and the cross-sectional areas of the sprue and the ingate are set in the ratio of 1.1-1.5:

1. The ingate uses a circular runner and is connected to the tangent of the edge of the wax pattern of the bronze mirror at an angle of 15-30°, and at the same time, a fillet with a radius of R2-4 mm is set at the inner connection for transition.

6. The manufacturing method of the light-transmitting bronze mirror according to claim 5, characterized in that, The gypsum powder includes the following components by weight percentage: 10-20 wt% zircon powder, 30-40 wt% quartz powder, 20-30 wt% cristobalite powder, and the rest is gypsum powder.

7. The manufacturing method of the light-transmitting bronze mirror according to claim 5, characterized in that, The gypsum slurry is prepared by mixing the gypsum powder and boric acid aqueous solution with a concentration of 1.5-3.5% according to a mass ratio of 100:(36-40).

8. The manufacturing method of the light-transmitting bronze mirror according to claim 1, characterized in that, In step S3, the total content of inevitable impurity elements does not exceed 0.1 wt%.

9. The manufacturing method of the light-transmitting bronze mirror according to claim 1, characterized in that, In step S4, the cleaning of the billet includes the following steps: After pouring, the mirror body billet is cooled to below 60-100 °C. The mold is loosened by a vibrator, the casting is taken out, the adhered plaster mold is washed clean with a high-pressure water gun, and the gating system is cut off by a cutting machine to obtain an unpolished mirror body.

10. The manufacturing method of the light-transmitting bronze mirror according to claim 1, characterized in that, In step S5, the grinding and polishing of the mirror body includes the following steps: Use a grinding wheel to grind off the residual riser and flash areas, use wire brushes and palm brushes to brighten the back of the mirror body, and then clamp the mirror body on the fixed fixture of an automatic pressure grinding machine with the mirror surface facing down; Make a corresponding concave mold according to the required mirror surface curvature radius. The mold is installed on the grinding chuck, and the center coincides with the center of the grinding wheel, with the concave surface facing up; Adjust the position of the mirror body to make the center of the mirror body coincide with that of the concave mold; set the rotational speed of the mold to 100-150 rpm, set the rotational speed of the mirror body to 20-40 rpm, set the pressure to 50-100 N, paste sandpaper or polishing cloth on the concave mold in order from coarse to fine, add water to the surface of the mold, and wet-grind the surface of the mirror body in turn until the mirror surface reaches a highly shiny effect.

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