A metal growth tank and method for preparing a high retroreflective microprism mold

Abstract

The application discloses a metal growth tank for preparing high retroreflective micro-prism molds and a method thereof; the metal growth tank body is provided with a water inlet pipe and a water outlet pipe between the tank body and a filter, a tank liquid circulating system is used for circulating the tank liquid into the filter through the water inlet pipe and then into the metal growth tank body through the water outlet pipe; an anode titanium basket is arranged on one side of the metal growth tank body and connected with an anode of a direct current power supply; an eccentric wheel connecting rod linear reciprocating motion mechanism is arranged on the other side of the metal growth tank body and connected with a cathode of the direct current power supply, a cathode stainless steel plate is arranged on the eccentric wheel connecting rod linear reciprocating motion mechanism, and the eccentric wheel connecting rod linear reciprocating motion mechanism drives the cathode stainless steel plate to move left and right; an electric heating device is arranged in the metal growth tank body and electrically connected with a temperature control device; the application solves the problem of the uniformity of the thickness of the nickel plating layer in four directions, solves the problem of the thickness control of the micro-prism nickel plate at the edge, and provides conditions for later welding and plate splicing.

Description

Technical Field

[0001] This invention belongs to the field of microprism fabrication technology, specifically relating to a metal growth tank and method for fabricating a high retroreflective microprism mold. Background Technology

[0002] Under typical DC electroforming conditions, electroformed nickel only yields a relatively rough surface with low retroreflective properties. The microprism reflective film, composed of a pyramidal array on the order of tens of micrometers, cannot be further machined or polished. In the electroforming tank, nickel ions are unevenly distributed in the solution due to incomplete circulation, resulting in inconsistent thickness of the anode after electroplating. The reflective film requires a working mold with a very high retroreflective coefficient, meaning a high-reflective microprism nickel plate must be obtained immediately after electroforming, while ensuring uniform nickel plating thickness in all four directions.

[0003] Therefore, it is necessary to improve the traditional electroforming tank so that the nickel plated layer of the high retroreflective microprism nickel plate welded to the stainless steel hanger has a uniform thickness in all four directions, and at the same time, the process can be combined to obtain a nickel plate with high retroreflective microprism. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a metal growth tank and method for preparing a high retroreflective microprism mold.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] In a first aspect, the present invention provides a metal growth tank for preparing a high retroreflective microprism mold, comprising a metal growth tank body, a DC power supply, a tank liquid circulation system, an anode titanium basket, a cathode stainless steel plate, a filter, an electric heating device, a temperature control device, and an eccentric wheel connecting rod linear reciprocating motion mechanism.

[0007] The metal growth tank and the filter are provided with an inlet pipe and an outlet pipe. The tank liquid circulation system allows the tank liquid in the metal growth tank to enter the filter through the inlet pipe and then be sprayed back into the metal growth tank through the outlet pipe.

[0008] The anode titanium basket is disposed on one side of the metal growth tank and is connected to the anode of the DC power supply; a sulfur-containing nickel ball is placed in the anode titanium basket to serve as the anode;

[0009] The eccentric wheel and connecting rod linear reciprocating motion mechanism is located on the other side of the metal growth tank, and one end of the eccentric wheel and connecting rod linear reciprocating motion mechanism is connected to the cathode of the DC power supply.

[0010] The cathode stainless steel plate is mounted on an eccentric wheel and connecting rod linear reciprocating motion mechanism, which drives the cathode stainless steel plate to move left and right along the metal growth tank; the cathode stainless steel plate is used to place the microprism nickel plate.

[0011] The electric heating device is installed inside the metal growth tank and is electrically connected to the temperature control device. The electric heating device keeps the tank solution at a constant temperature for electroplating.

[0012] Preferably, the eccentric wheel and connecting rod linear reciprocating motion mechanism includes a motor, an eccentric disc, a connecting rod, and a conductive copper rod;

[0013] The output shaft of the motor is connected to the center of one side of the eccentric disk; one end of the connecting rod is hinged to the other side of the eccentric disk, and the other end of the connecting rod is hinged to one end of the conductive copper rod; the other end of the conductive copper rod is connected to the cathode of the DC power supply; the cathode stainless steel plate is mounted on the conductive copper rod. When the motor rotates, it drives the eccentric disk to rotate, causing one end of the connecting rod to perform circular motion, and the other end of the connecting rod to drive the conductive copper rod to perform reciprocating linear motion.

[0014] Preferably, the motor is connected to a frequency converter to achieve adjustable motor speed, resulting in low-speed rotation. A frequency converter device is installed on the motor's power supply line.

[0015] Preferably, pulley sets are provided at the bottom of both ends of the conductive copper rod, and the bottom of the pulley sets is located on the metal growth tank.

[0016] Preferably, the top of the cathode stainless steel plate is provided with a hook, and the cathode stainless steel plate is installed on the eccentric wheel connecting rod linear reciprocating motion mechanism through the hook.

[0017] Preferably, a support is provided on one side of the metal growth tank. The support is an insulating woolen support, and a conductive copper flat iron is installed on the support. One end of the conductive copper flat iron is connected to the anode of the DC power supply. The anode titanium basket is installed on the conductive copper flat iron.

[0018] Secondly, the present invention provides a method for preparing a high retroreflective microprism mold using a metal growth tank, the method comprising the following steps:

[0019] Step S1: Preparation of bath solution

[0020] Step S1-1: Calculate the volume of each drug according to the volume of the metal growth tank, clean the metal growth tank, add deionized water to the metal growth tank to make up half the volume of the metal growth tank, and raise the temperature to 30℃-40℃.

[0021] Step S1-2: Open the filter to circulate and stir the deionized water, and slowly add 500-650 g / L nickel aminosulfonate and 15 g / L nickel chloride to the metal growth tank while stirring.

[0022] Step S1-3: Dissolve 30g / L boric acid in metering buffer and 90℃ deionized water, then slowly pour the solution into the metal growth tank and circulate and stir to raise the temperature of the solution to 50℃.

[0023] Steps S1-4: Sample and analyze the solution composition, and adjust the pH of the bath solution with nickel aminosulfonate to make the pH of the bath solution between 3.8 and 4;

[0024] Steps S1-5: Add sodium dodecyl sulfate and saccharin. The volume concentration of sodium dodecyl sulfate is 0.05-1 g / L, and the concentration of saccharin is 0.1-1 g / L.

[0025] Steps S1-6: Use an electric heating device and a temperature control device to maintain the temperature of the bath solution at 50°C;

[0026] Step S2: Bath treatment to remove organic impurities; with fewer impurities in the bath, the purity of the electroplated nickel is higher, the replicated nickel plate prism structure is more complete, and the brightness is higher.

[0027] Step S3: Preparation of the cathode stainless steel plate

[0028] Step S3-1: Prepare a 1.1m*1.65m stainless steel mirror panel with a thickness of 5MM. Polish one side with a 200-grit fine polishing wheel and wipe the other side clean with alcohol. Stick 5cm wide double-sided tape around the edges of the surface, and then cover it with another 5cm wide tape that is resistant to high temperature and acid and alkali to seal the edges.

[0029] Step S3-2: Laser weld the four sides of the microprism nickel plate to the stainless steel mirror panel obtained in step S3-1;

[0030] Step S3-3: Use a 1 cm thick piece of high-temperature resistant and acid-alkali resistant tape to stick around the microprism nickel plate to adjust the uniformity of the coating thickness from top to bottom and left to right.

[0031] Step S3-4: Check the surface of the cathode stainless steel plate obtained in step S3-3 for contamination.

[0032] Step S3-5: Install the cathode stainless steel plate with the microprism nickel plate on the eccentric wheel connecting rod linear reciprocating motion mechanism.

[0033] Step S4: Preparation of the high retroreflection microprism mold;

[0034] Step S4-1 Electroforming in the bath: Control the bath temperature at 49-50℃, pH 3.8-4.0, stress 0-4, and pre-adjust the current to 350A with a current density of 2.5A / dM. 2 Electroplating for 0.5 hours, then adjusting the current to 400A for electroplating, the thickness of the nickel plating layer is directly proportional to the electroplating time;

[0035] Step S4-2: Take the plate: Use two cups of 5000ML 50-60℃ warm water to thoroughly wet the entire cathode stainless steel plate, and then use an air gun to dry the water.

[0036] Step S4-3 Demolding: Slowly separate the mother plate and the daughter plate (i.e., the plating layer formed after electroplating the microprism nickel plate and the mother plate). Observe whether there are water stains and plating solution contamination around the daughter plate. If so, rinse with pure water in time and let it air dry naturally. Use a cutting machine to cut off the edge of the ineffective plating layer around the nickel plate. Finally, seal the edges with film and tape.

[0037] Preferably, the specific steps for the bath treatment in step S2 to remove organic impurities are as follows:

[0038] Step S2-1: Remove organic impurities, add 1 g / L potassium permanganate, and stir for 1-2 hours; add coconut shell activated carbon granules to the filter, filter for 12 hours, replace the coconut shell activated carbon filter element, and filter for 12 hours; adjust the pH of the solution to 3.8-4.0.

[0039] Step S2-2: Replace the PP filter element, use a corrugated plate as the cathode, and perform electrolytic purification treatment with a low current density. The cathode current density is 0.05-0.5 A / dm³. 2 The cumulative electrolysis charge is at least 1 A·h / L;

[0040] Step S2-3: After the bath treatment is completed, check the stress and whether the Hall effect tank is normal.

[0041] Preferably, in step S3, when inspecting the cathode stainless steel plate obtained in steps S3-4 to check for surface contamination, the cleaning steps for the plate if contamination is found are as follows:

[0042] Cleaning: Place the large board into a cleaning tank filled with cleaning solution and clean for one minute; after taking it out, thoroughly clean the tape side of the large board with deionized pure water, then rinse it all over with a shower head; then rinse it all over with a fine stream of water 3 times; finally, rinse it all over with a shower head.

[0043] Passivation: Immerse the large plate in the passivation tank for one minute. The passivation solution is potassium dichromate with a concentration of 25g / L. After taking it out, thoroughly clean the tape side of the large plate with pure water. Then rinse the front of the large plate with a shower head from all directions. Rinse it three times with a fine water jet from all directions. Finally, rinse it with a shower head from all directions.

[0044] This invention has the following beneficial effects: It utilizes a bath circulation system to create circulation within the metal growth tank. The bath is sprayed from the bottom of the tank and, combined with an eccentric wheel and connecting rod linear reciprocating motion mechanism, the motor rotates, driving the connecting rod to rotate circumferentially, which in turn drives the conductive copper rod to reciprocate linearly, thereby moving the cathode stainless steel plate left and right. This solves the problem of uneven nickel ion distribution in the bath due to incomplete circulation in ordinary electroforming tanks, resulting in inconsistent anode thickness after electroplating. It also solves the problem of uniform nickel plating thickness in four directions, thus resolving the difficulty of controlling the edge thickness of microprism nickel plates and providing conditions for subsequent welding and assembly. Attached Figure Description

[0045] Figure 1 This is a top view of the metal growth tank described in this invention;

[0046] Figure 2 This is a side view of the metal growth tank described in this invention;

[0047] Figure 3 This is a front view of the metal growth tank described in this invention;

[0048] Figure 4 This is a schematic diagram of the cathode stainless steel plate in the metal growth tank of the present invention.

[0049] Figure 5 This is a schematic diagram of the linear reciprocating motion mechanism of the eccentric wheel connecting rod in the metal growth tank according to the present invention;

[0050] Figure 6 This is a schematic diagram of the anode titanium basket in the metal growth tank of the present invention;

[0051] Figure 7 for Figure 2 Enlarged view of point A in the middle;

[0052] Figure 8 This is a schematic diagram of the structure of the corrugated board described in this invention.

[0053] In the diagram: 1. Metal growth tank; 2. Secondary tank; 3. DC power supply; 4. Filter; 5. Inlet pipe; 6. Outlet pipe; 7. Motor; 8. Eccentric disc; 9. Connecting rod; 10. Conductive copper rod; 11. Conductive copper flat iron; 12. Anode titanium basket; 13. Cathode stainless steel plate; 14. Hook; 15. Electric heating device; 16. Temperature control device; 17. Pulley block; 18. Support; 19. Corrugated board. Detailed Implementation

[0054] The present invention will be further described below with reference to embodiments, but these embodiments are not intended to limit the scope of the invention.

[0055] like Figure 1-8 As shown, a metal growth tank for preparing a high retroreflective microprism mold includes a metal growth tank body 1, a DC power supply 3, a secondary tank 2, a tank liquid circulation system, an anode titanium basket 12, a cathode stainless steel plate 13, a filter 4, an electric heating device 15, a temperature control device 16, and an eccentric wheel connecting rod linear reciprocating motion mechanism.

[0056] A water inlet pipe 5 and a water outlet pipe 6 are provided between the metal growth tank 1 and the filter 4. The bottom of the metal growth tank 1 is provided with a row of φ10mm fine holes, all of which are connected to the water inlet pipe 5. The filter 4 contains 8 PP filter elements. The tank solution circulation system allows the tank solution in the metal growth tank 1 to enter the filter 4 through the water inlet pipe 5, and then circulate back into the metal growth tank 1 through the water outlet pipe 6. The tank solution is sprayed out through a row of fine holes on the water outlet pipe 6 at the bottom of the metal growth tank 1, achieving the effect of circulation, stirring and filtration. The auxiliary tank 2 is set on one side of the metal growth tank 1 and is connected to the metal growth tank 1. It is used to add chemicals and reaction aids.

[0057] The anode titanium basket 12 is set on one side of the metal growth tank 1. The metal growth tank 1 has a support 18 on one side. The support 18 is an insulating woolen support. A conductive copper flat iron 11 is installed on the support 18. One end of the conductive copper flat iron 11 is connected to the anode of the DC power supply through a cable. The top of the anode titanium basket 12 is provided with a hook. Multiple anode titanium baskets 12 are installed on the conductive copper flat iron 11 along the length of the conductive copper flat iron 11 through the hook. A sulfur-containing nickel ball is placed in the anode titanium basket 12 to serve as the anode.

[0058] An eccentric wheel and connecting rod linear reciprocating motion mechanism is installed on the metal growth tank 1. One end of the eccentric wheel and connecting rod linear reciprocating motion mechanism is connected to the cathode of a DC power supply. The eccentric connecting rod linear reciprocating motion mechanism includes a motor 7, an eccentric disk 8, a connecting rod 9, and a conductive copper rod 10. The output shaft of the motor 7 is connected to the center of one side of the eccentric disk 8. One end of the connecting rod 9 is hinged to the other side of the eccentric disk 8, and the other end of the connecting rod 9 is hinged to one end of the conductive copper rod 10. The other end of the conductive copper rod 10 is connected to the cathode of the DC power supply via a cable. Both ends of the conductive copper rod 10 are equipped with pulley groups 17, the bottom of which is set on the metal growth tank. The conductive copper rod 10 is positioned opposite to the anode titanium basket. The motor 7 is a low-speed motor, or the motor is connected to a frequency converter to achieve adjustable motor speed and low-speed rotation.

[0059] The top of the cathode stainless steel plate 13 is provided with a hook 14. The cathode stainless steel plate 13 is installed on the conductive copper rod 10 of the eccentric wheel connecting rod linear reciprocating motion mechanism through the hook 14. The hook is made of 5mm thick copper flat iron bent. When the motor rotates, it drives one end of the connecting rod to rotate in a circle. Both ends of the connecting rod are hinged, thereby driving the conductive copper rod to perform linear reciprocating motion, thereby driving the anode stainless steel plate to move left and right. The cathode stainless steel plate 13 is used to place the microprism nickel plate.

[0060] An electric heating device 15 is installed inside the metal growth tank 1 and is electrically connected to a temperature control device 16. The temperature control device 16 is electrically connected to a temperature control probe, and the temperature is displayed on the temperature display of the temperature control device. The electric heating device 15 keeps the bath solution at a constant temperature for electroplating.

[0061] A method for preparing a high retroreflective microprism mold, characterized in that the method includes the following steps:

[0062] Step S1: Preparation of bath solution

[0063] Based on the content of each component in the solution and the volume of the metal growth tank, the volume of each reagent is calculated as follows:

[0064] Step S1-1: Clean the metal growth tank 1, add 1 / 2 volume of deionized water to the metal growth tank 1, and raise the temperature to 30℃-40℃.

[0065] Step S1-2: Open filter 4 to circulate and stir the solution, and slowly add 500-650 g / L nickel aminosulfonate and 15 g / L nickel chloride to metal growth tank 1 while stirring.

[0066] Step S1-3: Dissolve 30g / L boric acid in metering buffer and 90℃ deionized water, then slowly pour the solution into the metal growth tank 1, and circulate and stir to raise the temperature of the solution to 50℃.

[0067] Steps S1-4: Sample and analyze the solution composition, and adjust the pH of the bath solution with nickel aminosulfonate to make the pH of the bath solution between 3.8 and 4;

[0068] Steps S1-5: Add sodium dodecyl sulfate and saccharin. The volume concentration of sodium dodecyl sulfate is 0.05-1 g / L, and the concentration of saccharin is 0.1-1 g / L.

[0069] Steps S1-6: Use electric heating device 15, temperature probe, and temperature control device 16 to maintain the bath temperature at 50°C;

[0070] Step S2: Tank solution treatment:

[0071] Step S2-1: Remove organic impurities, add 1g / L potassium permanganate, and stir for 1-2 hours; add coconut shell activated carbon granules to filter 4, filter for 12 hours, replace the coconut shell activated carbon filter element and filter for 12 hours; adjust the pH of the solution to 3.8-4.0 by adding aminosulfonic acid.

[0072] Step S2-2: Replace the PP filter element. Use corrugated plate 19 as the cathode. Corrugated plate 19 is made of 1.5mm thick stainless steel sheet bent at a 45° angle to the horizontal. The stainless steel sheet must be smooth, flat, acid and alkali resistant, and resistant to electroplating solution corrosion. The top of the corrugated plate is made of 4mm thick stainless steel sheet bent and hung on a conductive copper rod for low-current-density electrolytic purification treatment. The cathode current density is 0.05-0.5A / dm³. 2 The cumulative electrolysis charge is at least 1 A·h / L;

[0073] Step S2-3: After the bath treatment is completed, check the stress and whether the Hall effect tank is normal;

[0074] Step S3: Preparation of the cathode stainless steel plate

[0075] Step S3-1: Prepare a 1.1m*1.65m stainless steel mirror panel with a 5mm diameter. Polish one side with a 200-grit fine polishing wheel and wipe the other side clean with alcohol. Attach the surface with 5cm wide double-sided tape, and then cover it with another 5cm wide high-temperature and acid-alkali resistant tape. Seal the edges with double-sided tape and high-temperature and acid-alkali resistant tape as well.

[0076] Step S3-2: Laser weld the four sides of the microprism nickel plate to the stainless steel mirror panel obtained in step S3-1;

[0077] Step S3-3: Use a 1 cm high temperature resistant and acid and alkali resistant tape to stick around the microprism nickel plate to adjust the thickness of the coating to be uniform from top to bottom and left to right, so as to obtain the cathode stainless steel plate.

[0078] Step S3-4: Inspect the cathode stainless steel plate obtained in step S3-3 for surface contamination. Use an LED warm-light retroreflective flashlight to observe the shadows on the plate surface, the uniformity of brightness, and any contamination. If contamination is found, the cleaning steps for the plate are as follows:

[0079] Cleaning: Place the large board into a cleaning tank filled with cleaning solution and clean for one minute; after taking it out, thoroughly clean the tape side of the large board with deionized pure water, and then rinse it all over with a shower head; then rinse it three times from left to right and from top to bottom with a fine water jet; finally, rinse it all over with a shower head.

[0080] Passivation: Immerse the large plate in the passivation tank for one minute. The passivation solution is potassium dichromate with a concentration of 25g / L. After taking it out, thoroughly clean the tape side of the large plate with pure water. Then rinse the front of the large plate with a shower head from all directions. Next, rinse it three times with a fine water jet from left to right and from top to bottom. Finally, rinse it with a shower head from all directions.

[0081] Step S3-5: Install the cathode stainless steel plate with the nickel plate on the eccentric wheel connecting rod linear reciprocating motion mechanism.

[0082] Step S4: Preparation of the high retroreflection microprism mold;

[0083] Step S4-1 Electroforming in the bath: Control the bath temperature at 49-50℃, pH 3.8-4.0, stress 0-4, and pre-adjust the current to 350A with a current density of 2.5A / dM. 2 Electroplating for 0.5 hours, then adjusting the current to 400A for electroplating, the thickness of the nickel plating layer is directly proportional to the electroplating time;

[0084] Step S4-2: Take the plate: Use two cups of 5000ML 50-60℃ warm water to rinse the cathode stainless steel plate from top to bottom and from left to right, and then use an air gun to dry the water.

[0085] Step S4-3 Demolding: Pry open the large plate from one corner and slowly separate the mother plate and daughter plate from left to right. Observe whether there are water stains and plating solution contamination around the daughter plate. If so, rinse with pure water and let it air dry. Use a cutting machine to cut off the ineffective plating layer around the nickel plate. Finally, seal the edges with film and tape.

[0086] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. However, the above description is merely a specific embodiment of the present invention, and the technical features of the present invention are not limited thereto. Any other embodiments derived by those skilled in the art without departing from the technical solution of the present invention should be covered within the patent scope of the present invention.

Claims

1. A metal growth slot for making a high retroreflective microprismatic mold, characterized by, The metal growth tank body (1), a direct current power supply (3), a tank liquid circulating system, an anode titanium basket (12), a cathode stainless steel plate (13), a filter (4), an electric heating device (15), a temperature control device (16), an eccentric wheel connecting rod linear reciprocating mechanism; The metal growth tank body (1) and the filter (4) are provided with a water inlet pipe (5) and a water outlet pipe (6), the tank liquid circulating system makes the tank liquid in the metal growth tank body (1) enter the filter (4) through the water inlet pipe (5), and then is sprayed and circulated to the metal growth tank body (1) through the water outlet pipe (6), the water outlet pipe (6) is arranged at the bottom of the metal growth tank body (1), a row of fine holes are arranged on the water outlet pipe (6), and the tank liquid in the water outlet pipe (6) is sprayed out from the fine holes; The anode titanium basket (12) is arranged on one side in the metal growth tank body (1), and the anode titanium basket (12) is connected with the anode of the direct current power supply (3); The eccentric wheel connecting rod linear reciprocating mechanism is arranged on the other side of the metal growth tank body (1), one end of the eccentric wheel connecting rod linear reciprocating mechanism is connected with the cathode of the direct current power supply (3), The cathode stainless steel plate (13) is installed on the eccentric wheel connecting rod linear reciprocating mechanism, the eccentric wheel connecting rod linear reciprocating mechanism drives the cathode stainless steel plate (13) to move left and right along the metal growth tank body (1), and the cathode stainless steel plate (13) is used for placing a micro-prism nickel plate; The electric heating device (15) is arranged in the metal growth tank body (1) and is electrically connected with the temperature control device (16), and the electric heating device (15) makes the tank liquid constant-temperature electroplating; The eccentric wheel connecting rod linear reciprocating mechanism comprises a conductive copper rod (10), the cathode stainless steel plate (13) is installed on the conductive copper rod (10), and pulley blocks (17) are arranged at the bottoms of two ends of the conductive copper rod (10) and are arranged on the metal growth tank body (1).

2. The metal growth tank for making a high retroreflective microprism mold according to claim 1, wherein The eccentric wheel connecting rod linear reciprocating mechanism comprises a motor (7), an eccentric disc (8) and a connecting rod (9); One end of the connecting rod (9) is hingedly connected to the other side of the eccentric disc (8), the other end of the connecting rod (9) is hingedly connected to one end of the conductive copper rod (10), and the other end of the conductive copper rod (10) is connected with the cathode of the direct current power supply (3).

3. The metal growth slot for making a high retroreflective microprismatic mold according to claim 2, wherein The motor (7) is connected with a frequency converter, the speed of the motor can be adjusted, and low-speed rotation is formed.

4. The metal growth tank for making a high retroreflective microprism mold according to claim 1, wherein A hook (14) is arranged at the top of the cathode stainless steel plate (13), and the cathode stainless steel plate (13) is installed on the eccentric wheel connecting rod linear reciprocating mechanism through the hook (14).

5. The metal growth tank for making a high retroreflective microprism mold according to claim 1, wherein One side of the metal growth tank body is provided with a support (18), the support (18) is an insulating wool support, a conductive copper flat iron (11) is installed on the support (18), one end of the conductive copper flat iron (11) is connected with the anode of the direct current power supply (3), and the anode titanium basket (12) is installed on the conductive copper flat iron (11).

6. A method of making a high retroreflective microprism mold using the metal growth cell of any one of claims 1-5, characterized in that, The method comprises the following steps: Step S1: tank liquid preparation Step S1-1: Calculate the volume of each medicine according to the volume of the metal growth tank, clean the metal growth tank (1), add 1 / 2 of the volume of deionized water to the metal growth tank (1), and heat the temperature to 30-40℃; Step S1-2: Open the filter to circulate and stir the deionized water, slowly add 500-650g / L nickel sulfamate and 15g / L nickel chloride to the metal growth tank (1) and stir; Step S1-3: Dissolve the measured buffer 30g / L boric acid and 90℃ deionized water, slowly pour into the tank solution of the metal growth tank (1), and circulate and stir to make the tank solution temperature rise to 50℃; Step S1-4: Take sample analysis of solution composition, adjust the PH value of the tank solution with nickel sulfamate, and make the tank solution PH at 3.8-4; Step S1-5: Add sodium dodecyl sulfate, saccharin, the volume concentration of sodium dodecyl sulfate is 0.05-1g / L, and the concentration of saccharin is 0.1-1g / L; Step S1-6: Use the electric heating device (15) and the temperature control device (16) to keep the tank solution temperature at 50℃; Step S2: Tank solution treatment, remove organic impurities; Step S3: Preparation of cathode stainless steel large plate Step S3-1: Prepare a 5mm thick stainless steel 1.1m*1.65m mirror plate, polish one side with a 200-mesh fine polishing disc, and wipe the other side clean with alcohol; The surface of the four edges is pasted with 5cm wide double-sided tape, and then covered with a layer of 5cm wide tape that is resistant to high temperature and acid and alkali to seal the edge; Step S3-2: Use laser welding to weld the micro-prism nickel plate to the stainless steel mirror plate obtained in step S3-1 on the four sides; Step S3-3: Paste a one-centimeter acid and alkali resistant tape around the micro-prism nickel plate to adjust the thickness of the coating evenly up and down and left and right; Step S3-4: Check whether the surface of the cathode stainless steel large plate obtained in step S3-3 is contaminated; Step S3-5: Install the cathode stainless steel large plate with the micro-prism nickel plate on the eccentric wheel connecting rod linear reciprocating mechanism; Step S4: Preparation of high retroreflective micro-prism mold; Step S4-1: Under the groove electroforming: the temperature of the tank liquid is controlled at 49-50℃, PH 3.8-4.0, stress 0-4, the current is pre-adjusted to 350A, the current density is 2.5A / dM 2 , electroplating 0.5 hours, then the current is adjusted to 400A for electroplating; Step S4-2 Take the plate: Use 2 cups of 5000ML 50-60℃ warm water to fully spray the cathode stainless steel large plate, and use an air gun to blow the water dry; Step S4-3 Demolding: Slowly separate the mother plate and the daughter plate, observe whether there is water stain and tank solution contamination around the daughter plate, and if so, wash it with pure water and dry naturally; Use a cutting machine to cut off the ineffective coating around the nickel plate; Finally, seal the edge with film and tape.

7. The method of claim 6, wherein the mold for high retroreflective microprisms is prepared by, The specific steps of Step S2, tank solution treatment, removal of organic impurities, are as follows: Step S2-1: Remove organic impurities, add 1g / L potassium permanganate, stir for 1-2 hours; Add coconut shell activated carbon particles to the filter (4), filter for 12 hours, replace the coconut shell activated carbon filter element and filter for 12 hours; Adjust the tank solution PH to 3.8-4.0; Step S2-2: replace the PP filter element, use corrugated board as the cathode, and perform small current density electrolytic purification treatment, the cathode current density is 0.05-0.5 A / dm 2 , and the cumulative power-on amount of electrolysis is at least 1 A·h / L; Step S2-3: After the tank solution treatment is completed, detect the stress and whether the Hall tank is normal.

8. The method of claim 6, wherein the mold for high retroreflective microprisms is prepared by the steps of: When checking the cathode stainless steel large plate obtained in step S3-4 in step S3, if the surface is contaminated, the steps for cleaning the large plate are as follows: Cleaning: put the large plate into the cleaning tank filled with cleaning solution for one minute; after taking out, clean the large plate tape surface thoroughly with deionized water, then rinse it with shower in all directions; then rinse it with fine water column in all directions for 3 times; finally, rinse it with shower in all directions. Passivation: put the large plate into the passivation tank for one minute, and the passivation solution is potassium dichromate with a concentration of 25 g / L; after taking out, clean the large plate tape surface thoroughly with pure water, then rinse the front surface of the large plate with shower in all directions; then rinse it with fine water column in all directions for 3 times; finally, rinse it with shower in all directions.

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