Single station glass lens molding process
By increasing the number of die-casting cycles and adjusting the temperature and pressure in a single-station molding equipment, the problems of excessive preform deformation and gas retention were solved, thus achieving standardization of lens surface shape and improving production applicability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- 安徽光智科技有限公司
- Filing Date
- 2023-06-13
- Publication Date
- 2026-06-05
AI Technical Summary
In the die-casting process, the deformation of the preform in a single-station molding equipment is too large, resulting in the lens surface not meeting the standards. In addition, the small difference between the curvature of the mold surface and the preform causes gas retention and exhaust problems.
In a single-station molding equipment, step S4 is added, repeating step S3 by setting the number of die castings, adjusting the temperature and pressure to improve the shape variation of the preform, ensuring that the lens surface meets the standard, and improving the gas retention and venting issues.
It improves the production applicability of single-station molding equipment, enabling the production of different lens models to be adjusted in one chamber, ensuring that the lens surface shape meets the standard, and solving the problems of excessive deformation and gas retention.
Smart Images
Figure CN116768454B_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of glass lens molding processes, and more specifically to single-station glass lens molding processes. Background Technology
[0002] Glass lens molding is a technique that involves first heating and softening glass material to a certain degree, then applying pressure to a high-precision mold to shape it into a lens of a specified form. Typically, the die-casting process for a pre-formed lens (blank) involves three steps: preheating, die-casting, and cooling. Preheating refers to heating the pre-formed material above its glass transition temperature. Die-casting involves pressing the preheated pre-formed material through a mold of a specific shape to obtain the pre-set shape. Cooling refers to cooling the die-cast lens using a heat exchange method.
[0003] Currently, lens molding equipment is divided into two types: single-station and multi-stage. Single-station molding equipment uses a die-casting method where the four processes of venting, preheating, die-casting, and cooling are completed within a single cavity. Multi-stage equipment, on the other hand, employs a collaborative approach, with preheating, die-casting, and cooling processes performed in multiple cavities. Compared to multi-stage equipment, single-station die-casting equipment uses fewer cavities, has a simpler structure, is easier to maintain and adjust, and can simultaneously produce multiple lens models.
[0004] In the actual trial die casting process using a single-station molding equipment, if the deformation of the preform is too large (generally, for preform spheres 200 with a diameter greater than 20mm, the deviation R between the center thickness TH1 and the standard thickness TH2 of the glass lens 400 formed after trial die casting exceeds 0.02mm, it is considered that the deformation of the preform is too large), the resistance generated by the deformation during a single die casting process will cause the preform to not fit firmly with the mold surface, ultimately resulting in the pressed lens surface not meeting the standard. Furthermore, if the difference between the curvature of the mold surface and the curvature of the preform is too small (refer to...), Figure 3 During a single die casting process, the preform is compressed, reducing its volume. Since the mold surface lacks sufficient curvature to accommodate this change, gas can easily accumulate (see reference). Figure 4 (Air was not expelled between the glass lens 400 and the mold 300), which led to the air venting problem. Summary of the Invention
[0005] In view of the problems existing in the background art, the purpose of this disclosure is to provide a single-station glass lens molding process, which can improve the problem of excessive deformation of the preform, thereby enabling the surface shape of the lens pressed by trial pressing to meet the standard.
[0006] Another objective of this disclosure is to provide a single-station glass lens molding process that can complete the adjustment of the preform deformation during the testing process in just one chamber, facilitating the testing of different lens models and thus improving the applicability of production.
[0007] Another object of this disclosure is to provide a single-station glass lens molding process that can improve the gas retention and venting problems caused by the curvature of the mold surface being too small relative to the curvature of the preform.
[0008] Therefore, the single-station glass lens molding process includes the following steps: S1, venting: Pre-shaped small balls are placed into the mold and assembled, then placed into the working chamber of the single-station molding machine. The single-station molding machine is turned on, and the working chamber is evacuated by a vacuum pump on the vacuum line. Nitrogen is then introduced into the working chamber through a nitrogen pump on the nitrogen line to fill the working chamber with nitrogen and maintain a positive pressure. S2, preheating: The mold is preheated by a heating element located inside the same working chamber. When the preheating reaches the first heating temperature, the mold is kept warm for a predetermined time. S3, die casting: After the predetermined holding time is reached, the heating element stops holding the mold and the mold is allowed to self-heat. Then, after cooling, open the air inlet valve of the cylinder of the single-station molding press in the same working chamber to inflate the cylinder to the first pressure value. The cylinder drives the die-casting head to press down the pre-shaped ball. When the die-casting head descends to the first height, continue to press down the die-casting head while opening the air outlet valve of the cylinder and reducing the opening of the air inlet valve of the cylinder, so that the pressure of the cylinder drops to the second pressure value. When the mold temperature drops to the second heating temperature, the pressing down of the die-casting head stops, the air inlet valve of the cylinder is closed and the cylinder is reset. S4, repeat step S3 according to the set number of die-casting times. S5, cool, let the mold cool naturally in the same working chamber to obtain the molded glass lens.
[0009] The beneficial effects of this disclosure are as follows: Compared with the die casting method used in the single-station molding equipment in the background technology, which completes the four processes of degassing, preheating, die casting and cooling in a single cavity, the single-station glass lens molding process of this application adds step S4. By repeating step S3 according to the set number of die castings, the problem that the original one-time die casting cannot accurately replicate the surface shape on the mold is solved. The set number of die castings can be adjusted as needed, thereby improving the excessive deformation of the preform and making the surface shape of the lens pressed by trial pressing meet the standard.
[0010] Compared with the multi-stage molding equipment that uses multiple chambers to complete the molding process of glass lens production, the single-station glass lens molding process of this application can complete the adjustment of the preform deformation during the test pressing process in only one chamber, which is convenient for testing different types of lenses and thus improves the applicability of production. Attached Figure Description
[0011] Figure 1 This is a schematic diagram of a single-station glass lens molding process.
[0012] Figure 2 This is a schematic diagram of the working principle of a single-station glass lens molding machine, in which the die-casting head is located at the initial height.
[0013] Figure 3 This is a schematic diagram showing the positions of the pre-shaped spheres and the mold before molding.
[0014] Figure 4 This is a schematic diagram showing the positions of the molded glass lens, the mold, and the die-casting head, with the center thickness indicated.
[0015] The reference numerals in the attached figures are explained as follows:
[0016] 100 Single-Station Molding Machine P1 First Pressure Value
[0017] 1. Working chamber P2 second pressure value
[0018] 11 heating components N die casting times
[0019] 12 sleeve H0 initial height
[0020] 2 Vacuum line H1 first height
[0021] 21 Vacuum Pump TH1 Center Thickness
[0022] 3. Nitrogen pipeline TH2 standard thickness
[0023] 31 Nitrogen pump R deviation
[0024] 4-cylinder D1 first tolerance range
[0025] 5 die-casting head D2 second range
[0026] 6. Control station D3, third range
[0027] T1 First heating temperature 200 pre-shaped small sphere
[0028] T2 Second Heating Temperature 300 Mold
[0029] t Insulation time 400 glass lens Detailed Implementation
[0030] The accompanying drawings illustrate embodiments of this disclosure, and it will be understood that the disclosed embodiments are merely examples of this disclosure, which can be implemented in various forms. Therefore, the specific details disclosed herein should not be construed as limiting, but are intended only as the basis for the claims and as an illustrative basis to teach those skilled in the art how to implement this disclosure in various ways.
[0031] Reference Figure 1 and Figure 2 The single-station glass lens molding process includes the following steps: S1, venting: pre-shaped small balls 200 are placed into mold 300 and assembled. The mold is then placed into the working chamber 1 of the single-station molding machine 100. The single-station molding machine 100 is turned on, and the working chamber 1 is evacuated via vacuum pump 21 on vacuum line 2. Nitrogen is then introduced into the working chamber 1 via nitrogen pump 31 on nitrogen line 3 to fill the working chamber 1 with nitrogen and maintain a positive pressure. S2, preheating: mold 300 is preheated via heating component 11 located inside the same working chamber 1. When the preheating reaches the first heating temperature T1, mold 300 is kept warm for a predetermined time t. S3, die casting: after the predetermined time t is reached, heating component 11 stops keeping warm and mold 300 is allowed to self-heat. Then, after cooling, the air inlet valve of cylinder 4 of the single-station molding press 100 in the same working chamber 1 is opened to inflate cylinder 4 to the first pressure value P1. Cylinder 4 drives the die-casting head 5 to press down the pre-shaped small ball 200. When the die-casting head 5 descends to the first height H1, the operation of pressing down the die-casting head 5 is maintained while the air outlet valve of cylinder 4 is opened and the opening of the air inlet valve of cylinder 4 is reduced, so that the pressure of cylinder 4 drops to the second pressure value P2. When the temperature of mold 300 drops to the second heating temperature T2, the pressing down of die-casting head 5 stops, the air inlet valve of cylinder 4 is closed and cylinder 4 is reset. S4, repeat step S3 according to the set number of die-casting times N. S5, cool down, let mold 300 cool naturally in the same working chamber 1 to obtain the molded glass lens 400.
[0032] Compared with the die-casting method used in the single-station molding equipment in the background technology, which completes the four processes of degassing, preheating, die-casting and cooling in a single cavity, the single-station glass lens molding process of this application adds step S4. By repeating step S3 according to the set number of die-casting times N, the problem that the original one-time die-casting molding cannot accurately replicate the surface shape on the mold is solved. The set number of die-casting times N can be adjusted as needed, thereby improving the excessive deformation of the preform and making the surface shape of the lens pressed in the trial press meet the standard.
[0033] Compared with the multi-stage molding equipment that uses multiple chambers to complete the molding process of glass lens production, the single-station glass lens molding process of this application can complete the adjustment of the preform deformation during the test pressing process in only one chamber, which is convenient for testing different types of lenses and thus improves the applicability of production.
[0034] Reference Figure 2The initial height H0 is the height of the die-casting head 5 from the upper surface of the mold 300 before it begins to press down. In one example, when the die-casting head 5 is at the first height H1, it is not in contact with the pre-formed sphere 200. In another example, when the die-casting head 5 is at the first height H1, it has already contacted the pre-formed sphere 200 and caused deformation of the pre-formed sphere 200. In one example, in step S3, the first heating temperature T1 is 200-600℃.
[0035] In one example, in step S3, the second heating temperature T2 is 170-550°C.
[0036] In one example, in step S3, the first pressure value P1 is 15-30 PSI.
[0037] In one example, in step S3, the second pressure value P2 is 13-28 PSI.
[0038] In one example, in step S3, the predetermined heat preservation time t is 20-120s.
[0039] In one example, in step S3, the first height H1 is 12-18 mm.
[0040] In one example, in step S4, the number of die-casting cycles N is set to 1-3.
[0041] In step S4, the number of die-casting cycles N is determined by the number of glass lenses 400 produced from the trial die-casting. The determination process is as follows:
[0042] Initially set the number of die-casting cycles N, and then perform steps S1 to S5 according to the initially set number of die-casting cycles N.
[0043] The center thickness TH1 of the 400mm glass lens formed after die casting was measured during the pressure test.
[0044] Determine the deviation R between the measured center thickness TH1 and the standard thickness TH2;
[0045] If the deviation R is within the first tolerance range D1, then the initially set number of die-casting times N is appropriate.
[0046] If the measured center thickness TH1 is greater than the standard thickness TH2 and the deviation R exceeds the first tolerance range D1, then the glass lens 400 formed after the trial die casting is not properly pressed. Further determination is needed: is the deviation R within the second range D2, which is larger than the first tolerance range D1, or within the third range D3, which is larger than the second range D2? If the deviation R is within the second range D2, then the initially set number of die castings N is maintained, but the temperature and pressure are increased. If the deviation is within the third range D3, then only one more die casting is added to the initially set number of die castings N. It should be noted that adding only one more die casting to the initially set number of die castings N means adding one more die casting without adjusting the pressure and temperature.
[0047] If the measured center thickness TH1 is less than the standard thickness TH2 and the deviation exceeds the first tolerance range D1, the glass lens 400 formed after the test pressing is over-pressed. Further determine whether the deviation R is in the second range D2, which is larger than the first tolerance range D1, or in the third range D3, which is larger than the second range D2. If the deviation R is in the second range D2, maintain the previously set number of pressing N but reduce the temperature and pressure. If the deviation R is in the third range D3, reduce the number of pressing N by one.
[0048] Repeat the die-casting test according to the number of die-castings N, temperature and pressure determined in the previous step, until the number of die-castings N, temperature and pressure that meet the first tolerance range D1 are determined.
[0049] The background technology mentions that if the difference between the curvature of the mold surface and the curvature of the preform is too small, it will cause venting problems during a single die casting. The single-station glass lens molding process of this application repeats step S3 according to the set number of die castings N. The temperature and pressure of the die casting number N are flexibly adjusted according to the size of the preform deformation (i.e., the deviation R between the measured center thickness TH1 and the standard thickness TH2), so that the preform can be more easily compressed and filled along the curvature of the mold surface, thereby improving the gas retention and venting problems.
[0050] In one example, the first tolerance range D1 is ±0.02 mm;
[0051] In one example, the second range D2 is ±0.04 mm;
[0052] In one example, the third range D3 is ±0.06 mm.
[0053] In one example, increasing / decreasing the temperature means increasing / decreasing the first heating temperature T1 by 1-2°C;
[0054] In one example, the increase / decrease pressure value is to increase / decrease the first pressure value P1 by 1-2 PSI.
[0055] In one example, the heating component 11 is a heating coil wound around the outside of the sleeve 12, and the mold 300 is partially placed inside the sleeve 12.
[0056] Reference Figure 2 The control station is communicatively connected to the inlet and outlet valves of the vacuum pump 21, the nitrogen pump 31, and the cylinder 4. In some embodiments, the control station is a PLC control station.
[0057] Several exemplary embodiments have been described in detail above, but this document is not intended to limit itself to the explicitly disclosed combinations. Therefore, unless otherwise stated, the various features disclosed herein can be combined to form several other combinations, which are not shown for simplicity.
Claims
1. A single-station glass lens molding process, characterized in that, It consists of the following steps: S1, exhaust, put the pre-shaped small ball (200) into the mold (300) and assemble it. Then put it into the working chamber (1) of the single-station molding machine (100). Turn on the single-station molding machine (100), and after the vacuum pump (21) on the vacuum pipeline (2) evacuates the working chamber (1), nitrogen is introduced into the working chamber (1) through the nitrogen pump (31) on the nitrogen pipeline (3) to achieve the working chamber (1) being filled with nitrogen and maintaining a positive pressure. The surface of the mold (300) is a downward concave arc shape. S2, preheating, the mold (300) is preheated by the heating component (11) located inside the same working chamber (1). When the preheating reaches the first heating temperature (T1), the mold (300) is heat-preserved for a predetermined time (t). S3, Die Casting: After the predetermined holding time (t) is reached, the heating component (11) stops holding the temperature and allows the mold (300) to cool naturally. Open the air inlet valve of the cylinder (4) of the single-station molding press (100) in the same working chamber (1) and inflate the cylinder (4) to the first pressure value (P1). The cylinder (4) drives the die-casting head (5) to press down the pre-shaped small ball (200), wherein the lower surface of the die-casting head (5) is a plane; When the die-casting head (5) descends to the first height (H1), the operation of pressing down the die-casting head (5) continues while the air outlet valve of the cylinder (4) is opened and the air inlet valve of the cylinder (4) is reduced, so that the pressure of the cylinder (4) drops to the second pressure value (P2) until the temperature of the mold (300) drops to the second heating temperature (T2), the pressing down of the die-casting head (5) stops, the air inlet valve of the cylinder (4) is closed and the cylinder (4) is reset; S4, repeat step S3 according to the set number of die-casting times (N); S5, Cooling: The mold (300) is naturally cooled in the same working cavity (1) to obtain the molded glass lens (400). in, In step S3, the first pressure value (P1) is 15-30 PSI and / or the second pressure value (P2) is 13-28 PSI; In step S4, the number of die-casting cycles (N) is determined by the number of glass lenses (400) produced from the die-casting trials. The determination process is as follows: Initially set the number of die-casting cycles (N), and perform steps S1 to S5 according to the initially set number of die-casting cycles (N). The center thickness (TH1) of the glass lens (400) formed after the pressure test and die casting was measured. Determine the deviation (R) between the measured center thickness (TH1) and the standard thickness (TH2); If the deviation (R) is within the first tolerance range (D1), then the initially set number of die castings (N) is appropriate; If the measured center thickness (TH1) is greater than the standard thickness (TH2) and the deviation (R) exceeds the first tolerance range (D1), then the glass lens (400) formed after the trial die casting is not pressed in place. Further determination is made whether the deviation (R) is in the second range (D2) which is larger than the first tolerance range (D1) or in the third range (D3) which is larger than the second range (D2). If the deviation (R) is in the second range (D2), then the initial die casting number (N) is maintained but the temperature and pressure are increased. If the deviation is in the third range (D3), then only one more die casting is added to the initial die casting number (N). If the measured center thickness (TH1) is less than the standard thickness (TH2) and the deviation exceeds the first tolerance range (D1), the glass lens (400) formed after the test pressing is over-pressed. Further determination is made whether the deviation (R) is in the second range (D2) which is larger than the first tolerance range (D1) or in the third range (D3) which is larger than the second range (D2). If the deviation (R) is in the second range (D2), the number of pressings (N) initially set before the pressure is maintained, but the temperature and pressure are reduced. If the deviation (R) is in the third range (D3), the number of pressings is reduced by one from the initially set number of pressings (N). Repeat the die-casting test according to the number of die-castings (N), temperature and pressure determined in the previous step until the number of die-castings (N), temperature and pressure that meet the first tolerance range (D1) are determined. The first tolerance range (D1) is ±0.02mm; The second range (D2) is ±0.04 mm; The third range (D3) is ±0.06 mm.
2. The single-station glass lens molding process according to claim 1, characterized in that, In step S3, the first heating temperature (T1) is 200-600℃ and / or the second heating temperature (T2) is 170-550℃.
3. The single-station glass lens molding process according to claim 1, characterized in that, In step S3, the predetermined heat preservation time (t) is 20-120s.
4. The single-station glass lens molding process according to claim 1, characterized in that, In step S3, the first height (H1) is 12-18 mm.
5. The single-station glass lens molding process according to claim 1, characterized in that, Increasing / decreasing the temperature involves raising / lowering the first heating temperature (T1) by 1-2℃; Increasing / decreasing the pressure value increases / decreases the first pressure value (P1) by 1-2 PSI.
6. The single-station glass lens molding process according to claim 1, characterized in that, The heating component (11) is a heating coil wound around the outside of the sleeve (12), and the mold (300) is partially placed in the sleeve (12).