CN116639866A - Non-isothermal step-by-step hot pressing method and step-by-step hot pressing device - Google Patents
Non-isothermal step-by-step hot pressing method and step-by-step hot pressing device Download PDFInfo
- Publication number
- CN116639866A CN116639866A CN202310556789.8A CN202310556789A CN116639866A CN 116639866 A CN116639866 A CN 116639866A CN 202310556789 A CN202310556789 A CN 202310556789A CN 116639866 A CN116639866 A CN 116639866A
- Authority
- CN
- China
- Prior art keywords
- hot pressing
- die
- forming station
- heating
- lower die
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000007731 hot pressing Methods 0.000 title claims abstract description 53
- 238000000034 method Methods 0.000 title claims abstract description 35
- 239000011521 glass Substances 0.000 claims abstract description 91
- 238000010438 heat treatment Methods 0.000 claims abstract description 84
- 238000013519 translation Methods 0.000 claims abstract description 70
- 238000001816 cooling Methods 0.000 claims abstract description 40
- 239000011261 inert gas Substances 0.000 claims abstract description 5
- 230000005484 gravity Effects 0.000 claims description 54
- 238000011065 in-situ storage Methods 0.000 claims description 16
- 238000009826 distribution Methods 0.000 claims description 11
- 230000008569 process Effects 0.000 claims description 11
- 238000000465 moulding Methods 0.000 claims description 9
- 238000012545 processing Methods 0.000 description 10
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- 239000000919 ceramic Substances 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 7
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 5
- 229910052802 copper Inorganic materials 0.000 description 5
- 239000010949 copper Substances 0.000 description 5
- 238000006073 displacement reaction Methods 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 230000009471 action Effects 0.000 description 3
- 238000000137 annealing Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 3
- 230000001965 increasing effect Effects 0.000 description 3
- 238000011068 loading method Methods 0.000 description 3
- 238000004321 preservation Methods 0.000 description 3
- 238000003825 pressing Methods 0.000 description 3
- 229910052581 Si3N4 Inorganic materials 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000003486 chemical etching Methods 0.000 description 2
- 238000000609 electron-beam lithography Methods 0.000 description 2
- 230000003028 elevating effect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000005350 fused silica glass Substances 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 238000002164 ion-beam lithography Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000003801 milling Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000005304 optical glass Substances 0.000 description 2
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 2
- 229910052721 tungsten Inorganic materials 0.000 description 2
- 239000010937 tungsten Substances 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000002860 competitive effect Effects 0.000 description 1
- 239000000112 cooling gas Substances 0.000 description 1
- 239000000110 cooling liquid Substances 0.000 description 1
- 230000007123 defense Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000013307 optical fiber Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000010076 replication Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B11/00—Pressing molten glass or performed glass reheated to equivalent low viscosity without blowing
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B11/00—Pressing molten glass or performed glass reheated to equivalent low viscosity without blowing
- C03B11/05—Pressing molten glass or performed glass reheated to equivalent low viscosity without blowing in machines with reciprocating moulds
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B23/00—Re-forming shaped glass
- C03B23/0013—Re-forming shaped glass by pressing
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
- Y02P40/57—Improving the yield, e-g- reduction of reject rates
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)
Abstract
The application belongs to the technical field of glass hot pressing, and particularly relates to a non-isothermal step-type hot pressing method and a step-type hot pressing device. The non-isothermal step-by-step hot pressing method comprises the following steps: heating, wherein the translation stage drives one of the lower dies to be positioned at a forming station; heating the upper mold to a first predetermined temperature using a first heating assembly and heating the lower mold and glass element at the forming station to a second predetermined temperature using a second heating assembly in a vacuum environment or an inert gas environment; hot pressing, wherein the lifting platform drives the translation platform to move upwards so as to enable a lower die positioned at the forming station to be matched with an upper die, and the imprinting force of the force application structure is loaded on the lower die; cooling, reducing the temperature of the upper mold and the lower mold at the forming station at a predetermined cooling rate to anneal the microstructure replicated glass element; and demolding, wherein the lifting platform drives the translation platform to descend so as to enable the lower die to unload the imprinting force of the force application structure. The application can improve the hot pressing efficiency of the glass element.
Description
Technical Field
The application belongs to the technical field of glass hot pressing, and particularly relates to a non-isothermal step-type hot pressing method and a step-type hot pressing device.
Background
Glass micro-optical elements such as micro-lens arrays, fresnel lenses, transmission gratings, diffraction optical elements and the like are increasingly demanded in the fields of aerospace, national defense safety, green energy sources, space sensing, laser radiation, optical fiber communication, biomedical treatment, consumer electronics and the like, and the efficient low-cost manufacturing technology for pertinently developing high-quality glass micro-optical elements is an important direction of competitive development at home and abroad.
Ultra-precision grinding, micro-milling, laser direct writing, ion beam lithography, electron beam lithography, chemical etching and precision hot stamping are the main manufacturing methods of glass micro-optical elements. Because of the high brittleness and low fracture toughness of the optical glass material, the problems of serious cutter abrasion, subsurface damage of elements, lower processing efficiency and the like exist in ultra-precise grinding and micro-milling; the laser direct writing has the problems of poor processing surface quality, surface component change and the like; ion beam lithography and electron beam lithography have extremely low processing efficiency, and are difficult to process complex curved surface structures; the chemical etching needs to use strong acid substances, and is dangerous.
The precise hot stamping has the advantages of cross micro-nano scale manufacturing, net forming, higher manufacturing efficiency, low cost, green environmental protection and the like, and the surface replication fidelity is high, so that the combination of the ultra-precise die micro-nano manufacturing technology is expected to realize the high-quality and low-cost green manufacturing of the glass micro-optical element.
However, the existing glass hot pressing is carried out by single-mode single-hole processing, namely, one processing flow can only process one piece of glass, so that the molding efficiency is low.
Disclosure of Invention
The embodiment of the application aims to provide a non-isothermal step-by-step hot pressing method, which aims to solve the problem of how to improve the molding efficiency of glass elements.
In order to achieve the above purpose, the application adopts the following technical scheme:
in a first aspect, a non-isothermal step-wise hot pressing method is provided for molding a glass element positioned at a forming station, the non-isothermal step-wise hot pressing method comprising the steps of:
preparing an upper die which is positioned at the forming station and provided with a microstructure, a lower die carrying the glass element, a translation table for driving the lower die to move, a lifting table and a force application structure connected with the upper die, wherein the translation table is positioned below the upper die, a plurality of lower dies are linearly and alternately arranged on the translation table, and the lifting table is used for driving the translation table to ascend or descend;
heating, wherein the translation stage drives one of the lower dies to be positioned at the forming station; heating the upper mold to a first predetermined temperature using a first heating assembly and heating the lower mold and the glass element at the forming station to a second predetermined temperature using a second heating assembly in a vacuum environment or an inert gas environment;
hot pressing, wherein the lifting platform drives the translation platform to move upwards so as to enable the lower die at the forming station to be matched with the upper die, and the imprinting force of the force application structure is loaded on the lower die so as to enable the glass element to copy the microstructure;
cooling, reducing the temperature of the upper mold and the lower mold at the forming station at a predetermined cooling rate to anneal the glass element replicated with the microstructure;
demoulding, wherein the lifting platform drives the translation platform to descend so as to enable the lower mould to unload the imprinting force of the force application structure;
and the translation stage drives each lower die to be sequentially positioned at the forming station, and the heating step, the hot pressing step, the cooling step and the demolding step are repeated.
In a second aspect, there is provided a step-press apparatus having a forming station and for performing the non-isothermal step-press method, the step-press apparatus comprising:
the die structure comprises an upper die, a translation table, a lower die and a lifting table, wherein the upper die is positioned at the forming station and provided with a microstructure, the translation table is positioned below the upper die, the lower die is positioned at the translation table and is used for bearing glass elements, the lifting table is connected with the translation table, the lower die is provided with a plurality of dies, each die is sequentially and linearly arranged at the translation table, and the translation table is used for driving each lower die to be sequentially positioned at the forming station;
a heating structure including a first heating assembly connected to and used for heating the upper mold and a second heating assembly connected to and used for heating the lower mold; and
and the force application structure is arranged on the forming station in a sliding manner along the vertical direction and is connected with the upper die, the lifting platform drives the translation platform to lift so as to enable the lower die positioned on the forming station to be clamped with the upper die, and the imprinting force of the force application structure is loaded on the lower die so as to enable the glass element to replicate the microstructure.
The application has the beneficial effects that: the non-isothermal step-by-step hot pressing method comprises heating, hot pressing, cooling and demolding, wherein a plurality of lower molds are arranged on a translation table, and each lower mold and an upper mold are sequentially subjected to mold clamping and hot pressing, so that a plurality of glass elements can be formed in one processing process, microstructures on the upper mold are sequentially copied to the glass elements, and the molding efficiency is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments or exemplary technical descriptions will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained according to these drawings without inventive effort for a person of ordinary skill in the art.
FIG. 1 is a flow chart of a non-isothermal stepwise hot pressing method provided by an embodiment of the present application;
FIG. 2 is a schematic diagram of the variation of temperature, pressure and displacement of the upper and lower dies in the non-isothermal stepwise hot pressing process of FIG. 1;
FIG. 3 is a schematic perspective view of a step hot press according to another embodiment of the present application;
FIG. 4 is an exploded schematic view of the step press of FIG. 3;
fig. 5 is a schematic front view of the mold structure and force applying structure of fig. 3.
Wherein, each reference sign in the figure:
100. a step-by-step hot press device; 101. a hot-pressing box body; 102. a vacuum chamber; 20. a force application structure; 21. a first stage gravity unit; 22. a second stage gravity unit; 23. a guide post; 30. a mold structure; 31. an upper die; 32. a lower die; 52. a translation stage; 51. a lifting table; 53. a sliding platform; 41. a temperature distribution in-situ observation structure; 42. a shape profile in-situ observation structure; 211. a first slide plate; 212. a first weight; 221. a second slide plate; 222. a second weight; 24. a pressure ball; 60. a heating structure; 61. a first heating assembly; 62. a second heating assembly; 200. a glass element; 63. guide posts and guide sleeves; 421. an XZ displacement stage; 422. an XY inclined table; 423. an XYR displacement table;
Detailed Description
The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.
It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly or indirectly connected to the other element. The orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", etc. are based on the orientation or positional relationship shown in the drawings, are for convenience of description only, and are not intended to indicate or imply that the apparatus or element in question must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the application, and the specific meaning of the terms described above will be understood by those of ordinary skill in the art as appropriate. The terms "first," "second," and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features. The meaning of "a plurality of" is two or more, unless specifically defined otherwise.
Referring to fig. 1-2, a non-isothermal step-wise hot press method is provided for hot press forming a glass element 200, where the glass element 200 is an optical glass element 200, such as BK7, and the glass element 200 is located at a forming station. The non-isothermal step-by-step hot pressing method comprises the following steps:
referring to fig. 3 to 5, S1: heating; the upper mold 31, the lower mold 32, the translation stage 52, the lifting stage 51, the force application structure 20, the first heating component 61 and the second heating component 62 are prepared, the upper mold 31 is connected with the force application structure 20 and is located at a forming station and is provided with a microstructure, the lower mold 32 is provided with a glass element 200 and is connected with the translation stage 52, and the translation stage 52 is used for driving the lower mold 32 to horizontally move so that the lower mold 32 is located right below the upper mold 31. The lifting table 51 can drive the translation table 52 to move upward to contract the upper mold 31 and the lower mold 32, or drive the translation table 52 to move downward to disengage the lower mold 32 from the upper mold 31. The plurality of lower molds 32 are linearly and intermittently arranged along the horizontal movement direction of the translation stage 52; the translation stage 52 drives one of the lower dies 32 to be positioned at the forming station; in a vacuum environment or an inert gas environment, the upper mold 31 is heated to a first predetermined temperature using the first heating assembly 61, which may be higher than the glass element 200 transition temperature of the glass element 200 and maintain the temperature of the upper mold 31 at the first predetermined temperature, the lower mold 32 and the glass element 200 at the forming station are heated to a second predetermined temperature using the second heating assembly 62, which may be not higher than the glass element 200 transition temperature, and the temperature of the lower mold 32 is maintained at the second predetermined temperature. It will be appreciated that the upper mold 31, the lower mold 32, the translation stage 52, the lift stage 51, the force application structure 20, the first heating assembly 61, and the second heating assembly 62 are all located within the vacuum chamber 102 of the autoclave body 101, and that the vacuum chamber 102 may be evacuated or filled with an inert gas.
S2: the hot pressing, the lifting table 51 drives the translation table 52 to move upwards, so that the lower mold 32 at the forming station is clamped with the upper mold 31, the upper surface of the glass element 200 is abutted against the microstructure, the upper mold 31 softens the upper surface of the glass element 200 through heat conduction, and the imprinting force of the force application structure 20 is loaded on the lower mold 32, so that the upper surface of the glass element 200 replicates the microstructure.
S3: and cooling, wherein the temperature of the upper mold 31 and the lower mold 32 at the forming station is lowered at a predetermined cooling rate to anneal the glass member 200 on which the microstructure is replicated. In the cooling step, the heating power of the first heating element 61 may be reduced so that the temperature of the glass member 200 is slowly lowered, and the cooling rate may be 20 degrees/min or 50 degrees/min, which may be selected according to the actual situation, without limitation.
S4: demolding, wherein the lifting platform 51 drives the translation platform 52 to descend so that the lower mold 32 unloads the imprinting force of the force application structure 20;
referring to fig. 3 to 5, the translation stage 52 drives each lower mold 32 to be sequentially located at the forming station, and sequentially repeats the heating step, the hot pressing step, the cooling step and the demolding step, so that the processing of the multiple glass elements 200 can be realized in one forming process, and the processing efficiency of the glass elements 200 is improved.
Referring to fig. 3 to 5, it can be understood that the upper mold 31 is cooled first, so as to avoid the excessive stress of the microstructure on the glass element 200, and simultaneously maintain the upper mold 31 at a certain temperature, so as to facilitate the heating of the next molding and improve the heating efficiency and the molding efficiency.
Referring to fig. 3 to 5, the non-isothermal step-by-step hot pressing method provided in the present embodiment includes heating, hot pressing, cooling and demolding, and by disposing a plurality of lower molds 32 on the translation stage 52, and sequentially closing and hot pressing each lower mold 32 with the upper mold 31, a plurality of glass elements 200 can be formed in one processing process, so that the microstructure on the upper mold 31 is sequentially copied onto the glass elements 200, and molding efficiency is improved.
It will be appreciated that the lower die 32, which is not in the forming station, may be preheated first so that after it is moved to the forming station, the heating time may be shortened to improve the molding efficiency.
Alternatively, in the S2 hot pressing step, the upper mold 31 and the lower mold 32 are held and maintained for a certain time under the force application structure 20 so that the upper surface of the glass member 200 sufficiently replicates the microstructure.
Referring to fig. 3-5, in some embodiments, the first predetermined temperature is greater than the second predetermined temperature. Alternatively, the glass softening point temperature of BK7 may be 550 degrees, the first predetermined temperature may be 600 degrees, and the second predetermined temperature may be 520 degrees.
At the beginning of the hot pressing step S2, the lift table 51 drives the translation table 52 to rise so that a gap of 0.5mm is left between the upper surface of the glass element 200 and the lower surface of the upper mold 31. The vacuum pump starts to operate until the gas pressure in the vacuum chamber 102 is lower than 1Pa. When the system is stabilized, the first heating component 61 and the second heating component 62 are used for heating the upper die 31 and the lower die 32 respectively, alternatively, the first heating component 61 and the second heating component 62 can be ceramic heating plates, and the ceramic heating plates can be used for rapidly heating the upper die 31 and the lower die 32 and monitoring the heating temperature of the upper die 31 and the lower die 31 in real time through thermocouples embedded in the lower die 32 and the upper die 31. When the temperature of the upper die 31 approaches the target imprinting temperature T B (first predetermined temperature), the lower die 32 temperature reaches the preheating temperature T P (second predetermined temperature), and T P ＜T B The heating power is adjusted to make the temperatures of the upper and lower dies 32 respectively constant at T P And T B And maintained for a while, the uniformity of the temperature distribution of the upper mold 31 and the lower mold 32 is improved, and since the first predetermined temperature is greater than the second predetermined temperature, the upper mold 31 can soften the upper surface of the glass element 200 while the temperature of the other portion of the glass element 200 is lower when the upper surface of the glass element 200 contacts the upper mold 31, reducing the temperature difference variation of the glass element 200 at the time of the subsequent cooling annealing, thereby reducing the internal stress of the glass element 200.
Referring to fig. 1-2, in some embodiments, the force application structure 20 includes a first stage gravity unit 21 slidably disposed in a vertical direction at the forming station and connected to the upper mold 31, and a second stage gravity unit 22 slidably disposed in a vertical direction at the forming station; the hot pressing step comprises the following steps:
s21: the lifting table 51 drives the lower mold 32 to move upward a first distance so that the first stage gravity unit 21 is loaded on the lower mold 32 and the upper mold 31 softens the upper surface of the glass member 200; the elevating table 51 moves upward to keep the glass member 200 in contact with the upper mold 31 and to realize the loading of the imprinting force of the first stage gravity unit 21, and the superficial upper surface of the glass member 200 is rapidly heated and softened due to the higher surface temperature of the upper mold 31, while the temperature of the lower layer under the glass member 200 is kept consistent with the lower mold 32, which is advantageous for controlling the internal stress of the glass member 200.
S22: the lifting table 51 drives the lower mold 32 to move upwards for a second distance, so that the first stage gravity unit 21 and the second stage gravity unit 22 are loaded on the lower mold 32, and the glass element 200 in a viscoelastic state gradually fills the groove of the microstructure under the action of the first stage gravity unit 21 and the second stage gravity unit 22, so that the glass element 200 replicates the microstructure.
Alternatively, the first distance may be 1mm, 3mm or 5mm.
Alternatively, the second distance may be 1mm, 3mm or 5mm.
It will be appreciated that the first stage gravity unit 21 and the second stage gravity unit 22 apply the pressing force to the glass member 200 by their own gravity, no additional driver is required, and the force application process is smooth and reliable.
Referring to fig. 3 to 5, in the optional cooling step, the upper mold 31 is provided with an upper cooling block, the lower mold 32 is provided with a lower cooling block, the upper cooling block and the lower cooling block are provided with cooling channels, and the cooling rates of the upper mold 31 and the lower mold 32 can be adjusted by adjusting the flow rate of the cooling liquid or the cooling gas in the cooling channels.
Referring to fig. 3-5, in some embodiments, the demolding step includes the steps of:
s31: the lifting table 51 drives the translation table 52 to move downward by the second distance so that the lower mold 32 unloads the imprint force of the second stage gravity unit 22; while maintaining the pressing force of the first stage gravity unit 21 to make F 3 Is applied to the surface of the glass member 200, and prevents the microstructure of the glass member 200 from being relaxed in a low viscosity state, thereby causing deformation and breakage of the surface of the glass member 200. It will be appreciated that after the upper mold 31 and the lower mold 32 are clamped for a period of time, the heating power of the first heating assembly 61 and the flow rate of nitrogen in the upper cooling block are adjusted to beThe temperature slowly drops. And during the annealing process, the lifting platform 51 drives the translation platform 52 to move downwards, so that the unloading of the second-stage gravity unit 22 is realized.
S32: the lifting table 51 drives the translation table 52 to continue to move downward by the first distance so that the lower mold 32 unloads the imprint force of the first stage gravity unit 21 and the upper mold 31 and the lower mold 32 remain in a mold-closed state; when the temperature of the upper mold 31 reaches TF, the lifting table 51 drives the translation table 52 to continue to move downward, so that the unloading of the first-stage gravity unit 21 is realized, the gravity loading imprinting force between the upper mold 31 and the lower mold 32 is reduced to 0N, but the upper mold 31 and the lower mold 32 remain in contact, so that the microstructure of the glass element 200 remains unchanged in shape. At the same time, the heating power of the ceramic heating plate of the first heating assembly 61 is further reduced and the flow rate of nitrogen in the upper cooling block is increased, increasing the cooling rate thereof.
S33: the lifting table 51 drives the translation table 52 to continue to move downward to separate the upper die 31 and the lower die 32. That is, when the temperature of the upper mold 31 and the glass element 200 is lowered to T4, the pressure is unloaded, and the elevating table 51 moves downward, so that the glass element 200 is completely separated from the upper mold 31, and the lower mold 32 is completely separated from the upper mold 31.
Referring to fig. 3-5, in some embodiments, in step S31, the upper mold 31 and the glass element 200 are cooled at a first cooling rate; in the step S32, the upper mold 31 and the glass element 200 are cooled at a second cooling rate, which is greater than the first cooling rate, and the first cooling rate mainly causes the glass element 200 to be in an annealed state, and the second cooling rate mainly achieves rapid cooling of the glass element 200.
In some embodiments, in the heating step of S1, the upper mold 31 and the lower mold 32 are respectively kept at the first predetermined temperature and the second predetermined temperature for a predetermined time, and the predetermined time may be 1min, 3min or 5min, which is selected according to practical situations, but is not limited herein.
Referring to fig. 3-5, nitrogen is introduced into the vacuum chamber 102 after forming all glass elements 200 in the same batch, and the heating power of the ceramic heating plate of the second heating assembly 62 is further reduced, and the nitrogen flow rate of the lower cooling block is increased, so as to accelerate the cooling of each lower mold 32 and each glass element 200. When the temperature of each lower mold 32 is lowered to 200 ℃, each lower mold 32 is kept at a constant temperature, the vacuum chamber 102 is opened, and each glass element 200 is taken out for quality inspection. Therefore, the non-isothermal step-by-step hot pressing method can shorten the forming period by reducing the heat preservation, contact and pressure maintaining time, accelerating the temperature rise and reduction rate, improving the demoulding temperature and avoiding the repeated taking/placing of the glass element 200 materials, thereby improving the manufacturing efficiency.
Referring to FIG. 2, during the hot pressing of the glass element 200, at time t B At this time, the temperature of the upper die 31 or the lower die 32 is heated to T B I.e. a first predetermined temperature, t B To t 2 Heat preservation is carried out, at t D At time, the imprint force gradually increases until the first stage gravity unit 21 and the second stage gravity unit 22 are all loaded, at t E To t 3 Pressure maintaining is carried out, t 3 To t F Annealing is performed and the second stage gravity unit 22 is unloaded, and the temperatures of the upper mold 31 and the lower mold are lowered to T F . At t F By t4, the first stage gravity unit 21 is unloaded and rapidly cooled.
Referring to fig. 3 to 5, the present application further provides a step-type hot pressing apparatus 100, where the step-type hot pressing apparatus 100 is used for implementing the non-isothermal step-type hot pressing method, and the implementation steps of the method refer to the above embodiments, and since the step-type hot pressing apparatus 100 adopts all the technical solutions of all the embodiments, all the beneficial effects brought by the technical solutions of the embodiments are also provided, and are not repeated herein.
Referring to fig. 3 to 5, in some embodiments, the step-type hot press apparatus 100 includes: the mold structure 30, the heating structure 60, and the force application structure 20.
Referring to fig. 3 to 5, the mold structure 30 includes an upper mold 31 located at a forming station and provided with a microstructure, a translation stage 52 located below the upper mold 31, a lower mold 32 located at the translation stage 52 and carrying a glass element 200, and a lifting stage 51 connected to the translation stage 52, where the lower mold 32 is provided in plurality, each mold is sequentially and linearly arranged at the translation stage 52, and the translation stage 52 is used for driving each lower mold 32 to be sequentially located at the forming station; the translation stage 52 can drive the lower die 32 to slide in the horizontal direction, and the lifting stage 51 is provided with a linear encoder to accurately control the lifting or lowering distance of the lifting stage 51.
Referring to fig. 3 to 5, the translation stage 52 and the lifting stage 51 are both located on a sliding platform 53, the sliding platform 53 drives the translation stage 52 and the lifting stage 51 to move horizontally by the principle of a ball screw, two ends of the translation stage 52 are connected to the sliding stage by two guide post and guide sleeves 63, and the lifting stage 51 is located between the two guide post and guide sleeves 63.
Referring to fig. 3 to 5, the heating structure 60 includes a first heating assembly 61 connected to and used for heating the upper mold 31 and a second heating assembly 62 connected to and used for heating the lower mold 32; it will be appreciated that the first heating assembly 61 and the second heating assembly 62 are identical in structural layout. The first heating assembly 61 or the second heating assembly 62 includes two silicon nitride ceramic heating plates, a copper plate, a tungsten plate, and a fused silica plate. The silicon nitride ceramic heating plate has excellent high-temperature oxidation resistance, high durability and high heating power, but has the problem of uneven surface temperature distribution. Because copper has high thermal conductivity, heat can be quickly transferred from the ceramic heating plate to the copper plate, and finally uniform temperature distribution is obtained on the surface of the copper plate. And moreover, the fused quartz plate with extremely low heat conductivity is arranged below the copper plate for heat preservation, so that heat loss can be reduced. On the other hand, the copper-clad plate is covered by the high-strength tungsten plate, so that bending deformation of the copper-clad plate under the action of concentrated force is avoided. The first heating component 61 or the second heating component 62 is used for carrying out the sectional temperature control heating test, the heating rate can reach 500 ℃/min, the highest temperature can reach 1000 ℃, the temperature control precision is 0.5 ℃, the temperature uniformity is +/-3 ℃, and the repeatability is excellent.
Referring to fig. 3 to 5, the force application structure 20 is slidably disposed at the forming station along the vertical direction and connected to the upper mold 31, the lifting table 51 drives the translation table 52 to lift, so that the lower mold 32 at the forming station closes the upper mold 31, and the imprinting force of the force application structure 20 is applied to the lower mold 32, so that the glass element 200 replicates the microstructure.
Referring to fig. 3 to 5, in some embodiments, the step-type hot press apparatus 100 further includes a support frame disposed at the forming station, and the force application structure 20 includes a first stage gravity unit 21 slidably connected to the support frame in a vertical direction and connected to the upper mold 31, and a second stage gravity unit 22 slidably connected to the support frame in a vertical direction, where the second stage gravity unit 22 is located above the first stage gravity unit 21.
Referring to fig. 3 to 5, the first stage gravity unit 21 and the second stage gravity unit 22 are similar in structure and each include weights, and the pressing force and the holding force can be precisely controlled by adjusting the gravity of the weights. The theoretical error can be controlled within 1mN by adopting the F1 grade weight. The moving resolution of the lifting table 51 can reach 50nm, the precision of the linear encoder can reach 5nm, and the precise loading of the vertical displacement is realized by using a fuzzy PID control algorithm, so that the actions of hot pressing, pressure maintaining, demoulding and the like are completed.
Referring to fig. 3 to 5, optionally, the support frame includes a plurality of guide posts 23 arranged in a vertical direction, the first stage gravity unit 21 includes a first weight 212 and a first sliding plate 211, the second stage gravity unit 22 includes a second weight 222 and a second sliding plate 221, the first sliding plate 211 and the second sliding plate 221 are slidably connected to the guide posts 23, and the second sliding plate 221 is located above the first sliding plate 211.
Referring to fig. 3 to 5, optionally, a pressure ball 24 is disposed at the lower end of the second stage gravity unit 22, and the pressure ball 24 is connected to an end surface of the second weight 222, so that the point-to-face contact between the first stage gravity unit 21 and the second stage gravity unit 22 is maintained by the pressure ball 24, which is beneficial to making the stamping force of the first stage gravity unit 21 and the stamping force of the second stage gravity unit 22 collinear along the vertical direction, and improving the hot pressing precision of the glass element 200.
Referring to fig. 3 to 5, it can be understood that the lifting table 51 drives the translation table 52 to move upwards until the corresponding lower mold 32 lifts the upper mold 31 upwards, the first stage gravity unit 21 slides upwards along the guide posts 23, so that the imprinting force of the first stage gravity unit 21 is completely applied to the glass element 200, the lifting table 51 continues to drive the translation table 52 to lift until the first sliding plate 211 abuts against the pressure ball 24 and lifts the second stage gravity unit 22 upwards, and the second stage gravity unit 22 slides upwards along the guide posts 23, so that the imprinting forces of the first stage gravity unit 21 and the second stage gravity unit 22 are completely applied to the glass element 200.
Referring to fig. 3 to 5, in some embodiments, the step-type hot press apparatus 100 further includes a temperature distribution in-situ observation structure 41 and a shape profile in-situ observation structure 42, wherein the temperature distribution in-situ observation structure 41 and the shape profile in-situ observation structure 42 are respectively located at two sides of the translation stage 52.
Referring to fig. 3 to 5, the temperature distribution in-situ observation structure 41 includes a thermal infrared imager; the shape profile in situ observation structure 42 includes a super depth of field microscope and a CCD camera. The position of the temperature distribution in-situ observation structure 41 or the shape profile in-situ observation structure 42 is adjusted using the Z-slide, XYR-slide, and XY-tilt table 422 to ensure that the camera is just focused on the glass element 200. The temperature distribution in-situ observation structure 41 is used for recording the surface temperatures of the glass element 200, the upper die 31 and the lower die 32 in the hot stamping process, and the measurement accuracy can reach +/-2 ℃. The shape profile in-situ observation structure 42 is used for recording a side video of the glass element 200 in the hot stamping forming process, extracting an edge profile of a microstructure in the video according to a topological structure analysis principle, and obtaining information such as thickness, side profile shape, curvature of the top surface of the microstructure, filling rate and the like of the glass element 200 through image processing, wherein the sampling frequency can reach 30Hz, and the measurement accuracy can reach 0.5 micrometer.
The foregoing is merely an alternative embodiment of the present application and is not intended to limit the present application. Various modifications and variations of the present application will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.
Claims (10)
1. A non-isothermal step-wise hot pressing method for molding a glass element positioned at a forming station, the non-isothermal step-wise hot pressing method comprising the steps of:
preparing an upper die which is positioned at the forming station and provided with a microstructure, a lower die carrying the glass element, a translation table for driving the lower die to move, a lifting table and a force application structure connected with the upper die, wherein the translation table is positioned below the upper die, a plurality of lower dies are linearly and alternately arranged on the translation table, and the lifting table is used for driving the translation table to ascend or descend;
heating, wherein the translation stage drives one of the lower dies to be positioned at the forming station; heating the upper mold to a first predetermined temperature using a first heating assembly and heating the lower mold and the glass element at the forming station to a second predetermined temperature using a second heating assembly in a vacuum environment or an inert gas environment;
hot pressing, wherein the lifting platform drives the translation platform to move upwards so as to enable the lower die at the forming station to be matched with the upper die, and the imprinting force of the force application structure is loaded on the lower die so as to enable the glass element to copy the microstructure;
cooling, reducing the temperature of the upper mold and the lower mold at the forming station at a predetermined cooling rate to anneal the glass element replicated with the microstructure;
demoulding, wherein the lifting platform drives the translation platform to descend so as to enable the lower mould to unload the imprinting force of the force application structure;
and the translation stage drives each lower die to be sequentially positioned at the forming station, and the heating step, the hot pressing step, the cooling step and the demolding step are repeated.
2. The non-isothermal stepwise hot pressing method according to claim 1, wherein: the first predetermined temperature is greater than the second predetermined temperature.
3. The non-isothermal stepwise hot pressing method according to claim 1, wherein: the force application structure comprises a first-stage gravity unit which is arranged at the forming station in a sliding manner along the vertical direction and is connected with the upper die, and a second-stage gravity unit which is arranged at the forming station in a sliding manner along the vertical direction; the hot pressing step comprises the following steps:
s21: the lifting platform drives the lower die to move upwards for a first distance so that the first-stage gravity unit is loaded on the lower die to enable the upper die to soften the upper surface of the glass element;
s22: the lifting table drives the lower die to continue to move upwards for a second distance, so that the first-stage gravity unit and the second-stage gravity unit are both loaded on the lower die, and the glass element replicates the microstructure.
4. A non-isothermal stepwise hot pressing process according to claim 3, wherein: the demolding step comprises the following steps:
s31: the lifting platform drives the translation platform to downwards move the second distance so that the lower die unloads the imprinting force of the second-stage gravity unit;
s32: the lifting platform drives the translation platform to continuously move downwards for the first distance so that the lower die unloads the imprinting force of the first-stage gravity unit, and the upper die and the lower die keep in a die-closing state;
s33: the lifting platform drives the translation platform to continuously move downwards so as to separate the upper die from the lower die.
5. The non-isothermal stepwise hot pressing method according to claim 4, wherein: in the step S31, cooling the upper mold and the glass element at a first cooling rate; in the step S32, the upper mold and the glass element are cooled at a second cooling rate, the second cooling rate being greater than the first cooling rate.
6. The non-isothermal stepwise hot pressing method according to any of the claims 1-5, wherein: in the heating step, the upper die and the lower die are respectively kept at the first preset temperature and the second preset temperature for a preset time.
7. A step press apparatus having a forming station and adapted to perform the non-isothermal step press method according to any of claims 1-6, wherein the step press apparatus comprises:
the die structure comprises an upper die, a translation table, a lower die and a lifting table, wherein the upper die is positioned at the forming station and provided with a microstructure, the translation table is positioned below the upper die, the lower die is positioned at the translation table and is used for bearing glass elements, the lifting table is connected with the translation table, the lower die is provided with a plurality of dies, each die is sequentially and linearly arranged at the translation table, and the translation table is used for driving each lower die to be sequentially positioned at the forming station;
a heating structure including a first heating assembly connected to and used for heating the upper mold and a second heating assembly connected to and used for heating the lower mold; and
and the force application structure is arranged on the forming station in a sliding manner along the vertical direction and is connected with the upper die, the lifting platform drives the translation platform to lift so as to enable the lower die positioned on the forming station to be clamped with the upper die, and the imprinting force of the force application structure is loaded on the lower die so as to enable the glass element to replicate the microstructure.
8. The step-type hot press apparatus of claim 7, wherein: the step-type hot pressing device further comprises a supporting frame arranged at the forming station, the force application structure comprises a first-stage gravity unit which is connected with the supporting frame in a sliding mode along the vertical direction and connected with the upper die, and a second-stage gravity unit which is connected with the supporting frame in a sliding mode along the vertical direction, and the second-stage gravity unit is located above the first-stage gravity unit.
9. The step-type hot press apparatus of claim 7, wherein: the stepping hot press device further comprises a temperature distribution in-situ observation structure and a shape profile in-situ observation structure, wherein the temperature distribution in-situ observation structure and the shape profile in-situ observation structure are respectively positioned on two sides of the translation table.
10. The step-type hot press apparatus of claim 7, wherein: the stepping hot press device further comprises a hot press box body with a vacuum cavity, and the die structure, the heating structure and the force application structure are all located in the vacuum cavity.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310556789.8A CN116639866A (en) | 2023-05-16 | 2023-05-16 | Non-isothermal step-by-step hot pressing method and step-by-step hot pressing device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310556789.8A CN116639866A (en) | 2023-05-16 | 2023-05-16 | Non-isothermal step-by-step hot pressing method and step-by-step hot pressing device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116639866A true CN116639866A (en) | 2023-08-25 |
Family
ID=87623999
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310556789.8A Pending CN116639866A (en) | 2023-05-16 | 2023-05-16 | Non-isothermal step-by-step hot pressing method and step-by-step hot pressing device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116639866A (en) |
-
2023
- 2023-05-16 CN CN202310556789.8A patent/CN116639866A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5586995B2 (en) | Transfer apparatus and transfer method | |
| CN114573218B (en) | Accurate loading device and accurate loading board are to board hot stamping equipment | |
| CN116639866A (en) | Non-isothermal step-by-step hot pressing method and step-by-step hot pressing device | |
| JP2002293553A (en) | Method for producing optical element, production apparatus and molding raw material of optical element, mold for premolding and lens array of optical element | |
| US5403370A (en) | Glass compression molding apparatus | |
| CN114685033A (en) | Method for moulding by obtaining a calibration curve of temperature | |
| JP4409985B2 (en) | Press molding apparatus, press molding method and molded product | |
| CN117923767A (en) | Stacked hot pressing method and stacked hot pressing device | |
| JP3967146B2 (en) | Optical element molding method | |
| JP2002047016A (en) | Method of manufacturing optical element and its forming device | |
| JPH06122525A (en) | Apparatus for forming optical element, forming method and optical element | |
| CN111792619B (en) | Method for continuously manufacturing micro-nano structure on glass surface in batch | |
| JP2004091281A (en) | Apparatus for manufacturing glass lens | |
| JP4255294B2 (en) | Glass optical element manufacturing method and molding apparatus | |
| JP2003073135A (en) | Method and mold for forming optical element | |
| JP5244575B2 (en) | Optical element manufacturing method | |
| JP2504817B2 (en) | Optical element molding method | |
| JPH04164826A (en) | Apparatus for forming glass lens and production process | |
| JP3883634B2 (en) | Mold for press molding optical elements | |
| JPH11157854A (en) | Method for forming optical element and device therefor | |
| CN106966570B (en) | Method and apparatus for manufacturing optical element | |
| JP2000169159A (en) | Device and process for forming glass element | |
| CN115893816A (en) | Hot reflux forming method and hot pressing device | |
| JP2002104831A (en) | Method of press-forming | |
| JP6667358B2 (en) | Glass substrate generator |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |