A chalcogenide glass molding die and a molding method

Abstract

This invention relates to the field of optical component molding technology, and discloses a chalcogenide glass molding die, comprising a mold sleeve, an upper mold, and a lower mold. The upper and lower molds are fitted into the mold sleeve, with the upper mold positioned above the lower mold. The length and width of the upper mold are equal to the length and width of the lower mold. The length of the upper mold is L, where L = L 热 -2d-2c-2k; The width of the upper mold is D, D = D 热 -2d-2c-2k, k≥10mm; the height of the upper mold is h, h≥H; this molding die can better ensure the thickness deviation accuracy of chalcogenide glass molding and reduce the material loss rate. A chalcogenide glass molding method is also disclosed.

Description

Technical Field

[0001] This invention relates to the field of optical component molding technology, and in particular to a chalcogenide glass molding die and molding method. Background Technology

[0002] Chalcogenide glass is a novel infrared material with excellent infrared transmittance in the 3–5 μm and 8–14 μm wavelength ranges. Its low temperature coefficient of refractive index meets the requirements of athermal optical design and exhibits excellent achromatic performance. As an amorphous material, chalcogenide glass, similar to plastics, gradually decreases in viscosity during heating until it reaches its optimal viscosity range, allowing for precise molding to a shape provided by a mold. In other words, chalcogenide glass is suitable for the preparation of medium to large-sized optical lens preforms. However, molding with molds can result in excessive thickness deviations in the finished product. Current solutions involve surface grinding of the finished product to meet usage requirements, adding an extra step that reduces production efficiency and wastes material.

[0003] CN201510507167 discloses a molding die and molding method for chalcogenide glass. The die is a combined structure, including an upper mold core, a lower mold core, and a sleeve. The upper and lower mold cores are located inside the sleeve, and the lower end face of the upper mold core and the upper end face of the lower mold core are aspherical surfaces. The cavity formed between them is used to accommodate the chalcogenide glass to be molded. The upper and lower mold cores respectively include a surface pressing area, an annular groove area, an end face positioning area, and a radial positioning area. The four areas are arranged sequentially from the center outward. The annular groove area is located outside the outer circular area of ​​the chalcogenide glass and is used to release excess material from the chalcogenide glass during the molding process.

[0004] Therefore, the technical problem that this invention needs to solve is: how to better ensure the thickness deviation accuracy of chalcogenide glass molding and reduce the material loss rate. Summary of the Invention

[0005] The main objective of this invention is to provide a chalcogenide glass molding die, which designs the height of the upper die according to a corresponding height formula, thereby reducing the probability of the upper die tilting during molding, thus reducing the thickness deviation of the chalcogenide glass after molding and ensuring the thickness deviation accuracy of the chalcogenide glass molding.

[0006] In addition, a method for molding chalcogenide glass is also provided.

[0007] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0008] A chalcogenide glass molding die includes a mold sleeve, an upper mold, and a lower mold. The upper and lower molds are fitted into the mold sleeve, with the upper mold positioned above the lower mold. The length and width of the upper mold are equal to the length and width of the lower mold. The length of the upper mold is L, where L = L热 -2d-2c-2k; The width of the upper mold is D, D = D 热 -2d-2c-2k, k≥10mm;

[0009] The height of the upper mold is h, where h ≥ H;

[0010]

[0011] Where: L 热 D is the length of the external heating cavity; 热 d is the width of the external heating cavity; d is the thickness of the mold sleeve; k is the gap between the mold sleeve and the external heating cavity; H is the minimum height required for the upper mold; A is an empirical coefficient; X is the length or width of the upper mold; Δ is the thickness deviation accuracy required for making chalcogenide glass; θ is the maximum angle that the upper mold can shift in the mold sleeve; C is the gap between the upper mold and the mold sleeve.

[0012] Preferably, the value of A ranges from 1.1 to 1.3; the value of cosθ ranges from 0.95 to 1; and the value of C ranges from 0.03 to 0.05 mm.

[0013] Preferably, the length and width of the upper mold are equal.

[0014] Preferably, when H is greater than the height of the external heating cavity, then k1 = k + n, where k is the previously used k value, and n ≥ 5mm. The new upper mold length and width are obtained through k1, and then... The new H is calculated until H is less than the height of the external heating cavity.

[0015] Meanwhile, a method for molding chalcogenide glass is also provided, including the following steps:

[0016] Step 1: Place the chalcogenide glass into a molding die, and press it after the chalcogenide glass has softened;

[0017] Step 2: After molding, anneal and cool to obtain the finished chalcogenide glass;

[0018] The molding die is the molding die described above;

[0019] Step 1 is carried out in an environment of 240–380℃.

[0020] Preferably, before step 1, the surface of the molding die is cleaned with alcohol and a release agent is evenly sprayed onto the surface of the molding die.

[0021] Preferably, the molding pressure is 0.2–0.8 MPa; the holding time is 10–80 min; and the number of molding cycles is 1–10.

[0022] Preferably, the specific operation of step 1 is as follows: put the chalcogenide glass into the molding die, then put the molding die into the forming machine, heat the bottom plate of the forming machine to 150-210°C, introduce nitrogen gas, continue to heat the bottom plate, and after the chalcogenide glass softens, it is formed.

[0023] Preferably, the annealing process in step 2 is as follows: first, heat the chalcogenide glass to 100-500°C and hold it at that temperature for 2-6 hours. After holding, allow it to cool naturally to room temperature.

[0024] It should be noted that the above parameters are set according to the softening point and specifications of different chalcogenide glass grades. For example, when the chalcogenide glass grade is VlG06 and the specifications are D25.4*3.4mm, the molding is carried out at 240℃, the molding pressure is 0.4Mpa, the holding time is 30min, the molding number is 4 times, the annealing heating temperature is 175℃, and the holding time is 4h.

[0025] Compared with existing technologies, this solution has the following advantages:

[0026] The molding die in this solution determines the size of the upper die based on the size of the external heating chamber, thereby enabling the molding die to press larger sizes of chalcogenide glass and improving production efficiency; secondly, it further... The formula calculates the minimum height of the upper mold. Based on the calculated minimum height and the height of the external heating cavity, the height of the upper mold is determined. Then, based on the dimensions of the upper mold, the corresponding mold sleeve and lower mold dimensions are designed. By designing the molding die in this way, the probability of the upper mold tilting or shifting during molding can be reduced, thereby reducing the thickness deviation of the chalcogenide glass after molding. This improves the thickness deviation accuracy of the chalcogenide glass, eliminating the need for an additional grinding process to adjust the thickness deviation of the chalcogenide glass, increasing production efficiency, and reducing material loss. Attached Figure Description

[0027] Figure 1 This is a cross-sectional view of the molding die in Example 1;

[0028] Figure 2 This is a schematic diagram of the CAD simulation of Example 1. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application shown herein can generally be arranged and designed in various different configurations.

[0030] Example 1

[0031] refer to Figure 1-2 A chalcogenide glass molding die includes a mold sleeve 1, an upper mold 2, and a lower mold 3. The upper mold 2 and the lower mold 3 are fitted into the mold sleeve 1, with the upper mold 2 positioned above the lower mold 3. The length and width of the upper mold 2 are equal to the length and width of the lower mold 3. The length of the upper mold 2 is L, where L = L 热 -2d-2c-2k; The width of the upper mold 2 is D, D = D 热 -2d-2c-2k, k≥10mm;

[0032] The height of the upper mold 2 is h, where h ≥ H;

[0033]

[0034] Where: L 热 D is the length of the external heating cavity; 热 d is the width of the external heating cavity; d is the thickness of the mold sleeve 1; k is the gap between the mold sleeve 1 and the external heating cavity; H is the minimum height required for the upper mold 2; A is an empirical coefficient; X is the length or width of the upper mold 2; Δ is the thickness deviation accuracy required for making chalcogenide glass; θ is the maximum angle that the upper mold 2 can deviate in the mold sleeve 1; C is the gap between the upper mold 2 and the mold sleeve 1.

[0035] The heating chamber is located inside the forming machine. The specific design process for the upper mold 2 is as follows: First, determine the dimensions of the heating chamber and the required thickness tolerance accuracy for the produced chalcogenide glass. In this embodiment, the dimensions of the heating chamber (length × width × height) are 237mm × 237mm × 100mm, the required thickness tolerance accuracy for the produced chalcogenide glass is 0.2mm, k is 10mm, cosθ≈1, C=0.05mm, A is 1.2, and d=50mm. Therefore, the length L of the upper mold 2 is L=237-2×50-2×0.05-2×10=116.9mm, the width D=237-2×50-2×0.05-2×10=116.9mm, and the minimum height of the upper mold 2 is… Therefore, the dimensions (length × width × height) of the upper mold 2 are 117mm × 117mm × 70.14mm;

[0036] It should be noted that the thickness of the mold sleeve 1 and the thickness of the lower mold 3 are determined according to design experience. They can be appropriately modified according to the size of the overall molding die, the forming pressure and other parameters, without affecting the design of the upper mold 2. The height h of the upper mold 2 can also be greater than H, but it is necessary to ensure that h is less than the height of the external heating cavity.

[0037] The dimensions of the upper mold were input into the CAD software for simulation. The upper mold was then rotated in the CAD software to its maximum offset angle within mold sleeve 1. The thickness deviation of the chalcogenide glass was measured to be 0.17 mm. Figure 2As shown, it can be seen that designing a molding die using the method of this application can effectively reduce the thickness deviation of chalcogenide glass during the molding process and reduce the material loss rate. Moreover, by designing a molding die using this method, it is only necessary to substitute conventional parameters into the corresponding formula to obtain the overall dimensions of the upper die, which can improve the design efficiency of workers and thus improve production efficiency.

[0038] Preferably, the value of A ranges from 1.1 to 1.3; the value of cosθ ranges from 0.95 to 1; and the value of C ranges from 0.03 to 0.05 mm.

[0039] In this embodiment, the value of A is 1.2, but the value of A can also be adjusted according to the actual processing conditions; the value of C is 0.05mm, where C is the gap between the upper mold 2 and the mold sleeve 1, and an appropriate value is selected within the range according to production requirements; since the gap between the mold sleeve 1 and the upper mold 2 is small, the angle θ is generally less than 1°. Therefore, in order to better use the minimum height formula for calculation, the value of cosθ is 1. With the guarantee of the empirical coefficient A, the influence of cosθ on the minimum height formula can be greatly reduced.

[0040] Preferably, the length and width of the upper mold 2 are equal.

[0041] In this embodiment, since the height of the upper mold 2 is calculated by substituting the length and width of the upper mold 2 into the minimum height formula and taking the maximum value, the minimum height has only one value when the length and width of the upper mold 2 are equal. Moreover, when the length and width are equal, larger chalcogenide glass can be produced. The chalcogenide glass can then be cut to obtain chalcogenide glass of the required specifications, thereby improving production efficiency.

[0042] Preferably, when H is greater than the height of the external heating cavity, then k1 = k + n, where k is the previously used k value, and n ≥ 5mm. The new length and width of the upper mold 2 are obtained through k1, and then... The new H is calculated until H is less than the height of the external heating cavity.

[0043] When calculating the minimum height, the calculated minimum height may exceed the height of the external heating cavity, preventing the mold from being placed inside. Therefore, it is necessary to first compare the minimum height with the height of the external heating cavity. If H is greater than the height of the external heating cavity, the length and width of the upper mold 2 are recalculated. A new k value is obtained by adding an n value to the previous k value. In this embodiment, the n value is 10mm, but other values ​​can be used according to actual needs. The new minimum height value is then calculated until the minimum height is less than the height of the external heating cavity, thus meeting the usage requirements of the molding die.

[0044] Example 2

[0045] A method for molding chalcogenide glass includes the following steps:

[0046] The chalcogenide glass used in this embodiment is VIG06 (equivalent to IG6 in Germany), with dimensions (length × width × height) of 100mm × 100mm × 10mm. Before step 1, the surface of the molding die is cleaned with alcohol. After cleaning, boron nitride release agent is evenly sprayed onto the surface of the molding die. During the spraying process, it is important to ensure that the corners of the die are evenly coated with boron nitride release agent to prevent the chalcogenide glass from breaking. After spraying, let it stand for 10 minutes.

[0047] Step 1: Place the chalcogenide glass into a molding die, and press it after the chalcogenide glass has softened;

[0048] The specific operation of step 1 is as follows: First, put the lower mold into the mold sleeve, then put the chalcogenide glass into the mold sleeve. After fixing the lower mold to the mold sleeve with fasteners, put in the upper mold; then put the assembled molding die into the forming machine. The bottom plate of the forming machine starts to heat, thereby heating the molding die. When the bottom plate heats to 160°C, nitrogen gas is introduced into the forming machine to prevent the chalcogenide glass from oxidizing during the heating process; the temperature of the molding die is heated to 240°C to soften the chalcogenide glass, and the chalcogenide glass is formed by compressed air. The forming pressure is 0.4 MPa, and the holding time is 30 minutes. After completing one forming, the same method is used to form the chalcogenide glass 4 times.

[0049] The molding die is the molding die described in Example 1;

[0050] Step 2: After molding, anneal and cool to obtain the finished chalcogenide glass;

[0051] Step 2 is as follows: After the molding is completed, the chalcogenide glass is visually inspected to check for cracks, folds, damage, etc. If there are no problems with the appearance, the chalcogenide glass is heated to 175°C and kept at that temperature for 4 hours. After the temperature is kept at that temperature, it is naturally cooled to room temperature to complete the annealing process and finally the finished chalcogenide glass is obtained.

[0052] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A chalcogenide glass compression mold comprising a mold jacket, an upper mold, and a lower mold; the upper and lower molds being nested in the mold jacket with the upper mold above the lower mold; the length and width of the upper mold being equal to the length and width of the lower mold; characterized in that, The length of the upper die is L, L = L 热 - 2d - 2c - 2k; the width of the upper die is D, D = D 热 - 2d - 2c - 2k, k≥10mm; The height of the upper die is h, and h≥H; ； Where: L 热 D represents the length of the external heating cavity, in mm. 热 d is the width of the external heating cavity, in mm; d is the thickness of the mold sleeve, in mm; k is the gap between the mold sleeve and the external heating cavity, in mm; H is the minimum height required for the upper mold, in mm; A is an empirical coefficient. This refers to the length or width of the upper mold, in mm. The required thickness tolerance for the manufacture of chalcogenide glasses, expressed in mm; This represents the maximum angle that the upper mold can shift within the mold sleeve, in degrees. This represents the gap between the upper mold and the mold sleeve, in mm.

2. The chalcogenide glass molding die of claim 1, wherein, A is in the range of 1.1 to 1.3; A is in the range of 1.1 to 1.3; A is in the range of 1.1 to 1.3; 3. The chalcogenide glass molding die of claim 1, wherein, The length of the upper die is equal to the width.

4. The chalcogenide glass molding die of claim 1, wherein, When greater than the height of the peripheral heating cavity, then k1 = k + n, k is the last adopted k value, n≥5mm, the new upper die length and width are obtained through k1, and then the new is calculated through , until is less than the height of the peripheral heating cavity.

5. A method of molding a chalcogenide glass, characterized by, The method comprises the following steps: Step 1: placing the chalcogenide glass into a die pressing mold, and pressing the chalcogenide glass after softening; Step 2: annealing and cooling after pressing to obtain finished chalcogenide glass; The die pressing mold is the die pressing mold according to any one of claims 1-4; The step 1 is performed in an environment with a temperature of 240-380 ℃.

6. The chalcogenide glass molding method according to claim 5, wherein Before the step 1, the surface of the die pressing mold is cleaned with alcohol, and a release agent is uniformly sprayed on the surface of the die pressing mold.

7. The chalcogenide glass molding method according to claim 5, wherein The pressing pressure is 0.2-0.8 MPa, the pressure maintaining time is 10-80 min, and the pressing times are 1-10.

8. The chalcogenide glass molding method according to claim 5, wherein The specific operation of the step 1 is: placing the chalcogenide glass into the die pressing mold, then placing the die pressing mold into a pressing machine, heating the bottom plate of the pressing machine to 150-210 ℃, then introducing nitrogen, continuing to heat the bottom plate, and pressing the chalcogenide glass after softening.

9. The chalcogenide glass stamping method of claim 5, wherein, The specific operation of annealing in the step 2 is: first heating the chalcogenide glass to 100-500 ℃ and maintaining for 2-6 h, and then naturally cooling to room temperature after the maintaining.

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