CN114685033B - Method for molding by obtaining a calibration curve of temperature - Google Patents
Method for molding by obtaining a calibration curve of temperature Download PDFInfo
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- CN114685033B CN114685033B CN202210351013.8A CN202210351013A CN114685033B CN 114685033 B CN114685033 B CN 114685033B CN 202210351013 A CN202210351013 A CN 202210351013A CN 114685033 B CN114685033 B CN 114685033B
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- 238000000034 method Methods 0.000 title claims abstract description 63
- 238000000465 moulding Methods 0.000 title claims abstract description 22
- 238000011088 calibration curve Methods 0.000 title description 3
- 238000010438 heat treatment Methods 0.000 claims abstract description 34
- 239000002994 raw material Substances 0.000 claims abstract description 19
- 238000001816 cooling Methods 0.000 claims abstract description 18
- 238000003825 pressing Methods 0.000 claims abstract description 17
- 230000003287 optical effect Effects 0.000 claims abstract description 14
- 230000008569 process Effects 0.000 claims abstract description 12
- 238000000137 annealing Methods 0.000 claims abstract description 10
- 238000003475 lamination Methods 0.000 claims abstract description 8
- 230000009477 glass transition Effects 0.000 claims abstract description 4
- 238000004321 preservation Methods 0.000 claims abstract description 4
- 239000000463 material Substances 0.000 claims description 26
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 16
- 229910052710 silicon Inorganic materials 0.000 claims description 16
- 239000010703 silicon Substances 0.000 claims description 16
- 238000000576 coating method Methods 0.000 claims description 9
- 238000009413 insulation Methods 0.000 claims description 9
- 239000011248 coating agent Substances 0.000 claims description 8
- 239000010453 quartz Substances 0.000 claims description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 6
- 238000007723 die pressing method Methods 0.000 claims description 3
- 238000005485 electric heating Methods 0.000 claims description 3
- 239000011521 glass Substances 0.000 abstract description 26
- 238000000748 compression moulding Methods 0.000 description 30
- 230000008859 change Effects 0.000 description 21
- 238000010586 diagram Methods 0.000 description 12
- 239000010935 stainless steel Substances 0.000 description 9
- 229910001220 stainless steel Inorganic materials 0.000 description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 239000000758 substrate Substances 0.000 description 4
- 230000005856 abnormality Effects 0.000 description 3
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 238000004422 calculation algorithm Methods 0.000 description 2
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- 238000001514 detection method Methods 0.000 description 2
- 229910021389 graphene Inorganic materials 0.000 description 2
- 238000003384 imaging method Methods 0.000 description 2
- 238000003754 machining Methods 0.000 description 2
- 229910021421 monocrystalline silicon Inorganic materials 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000002210 silicon-based material Substances 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
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- 239000005388 borosilicate glass Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
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- 239000002131 composite material Substances 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
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- FBMUYWXYWIZLNE-UHFFFAOYSA-N nickel phosphide Chemical compound [Ni]=P#[Ni] FBMUYWXYWIZLNE-UHFFFAOYSA-N 0.000 description 1
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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
- C03B11/12—Cooling, heating, or insulating the plunger, the mould, or the glass-pressing machine; cooling or heating of the glass in the mould
- C03B11/122—Heating
-
- 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
- C03B11/16—Gearing or controlling mechanisms specially adapted for glass presses
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B25/00—Annealing glass products
- C03B25/02—Annealing glass products in a discontinuous way
Abstract
The invention provides a molding method of an optical lens, comprising the following steps: preheating and heating: the motor drives the lower die carrying the lens raw material to rise, the upper die is heated by voltage, and when the temperature rises to the target temperature, the upper die is continuously heated; raising the lower mold, heating the lower mold by voltage, and transferring heat to the lens raw material when the temperature is raised to a certain degree, so that the temperature of the lens raw material is raised to the glass transition temperature (Tg) or above; and (3) heat preservation and lamination step: the lower die motor continuously drives the lower die to ascend and simultaneously carries the lens raw material to displace, so that the lens raw material contacts the upper die, and the pressing process is completed; and (3) cooling and blanking: carrying out slow annealing treatment, and carrying out primary annealing treatment on the formed lens in a forming die so as to release internal stress; the annealed molded lens was taken out of the mold and placed on a cooling plate to be cooled individually to room temperature. And stable molding quality and glass quality are obtained by controlling the actual temperature of the mold.
Description
Technical Field
The present invention relates to a molding method of an optical lens. And more particularly to a method of molding by obtaining a calibration curve of temperature.
Background
Glass molding techniques are widely used in a variety of applications. Glass materials have the characteristics of higher refractive index, high deformation resistance, low expansion, high imaging quality and the like, and are attracting attention in the field of micro-electromechanical systems. At present, the mold design for the micro lens array is single in material, and cannot meet the application requirements of the mold forming technology for the ultra-thick micro lens array.
The prior art solution is to investigate the effect of the selection of mold materials on the microlens array molding technique. At present, as the general micro-lens array lens is thinner and the micro-structure unit depth is shallower, the areas of the upper mold core and the lower mold core can be enlarged in the aspect of traditional mold design, so that the side edge of the lens is not restrained by the sleeve in the compression molding process, and the lens thickness is only controlled. After the compression molding is finished, the lens is cut to obtain the lens meeting the requirements, so that the whole set of die (comprising the upper die core, the lower die core and the sleeve) is made of a single material. At present, for a thin single-sided microlens array, a heat-resistant stainless steel material (only special materials are plated on the surfaces of an upper mold core and a lower mold core, and a sleeve is made of heat-resistant stainless steel) is adopted for the whole mold, or a hard alloy material is adopted for the whole mold. The hard alloy die has the advantages of high heat transfer speed, small thermal expansion coefficient and good high-temperature service performance due to the self material, but is limited by the current processing method of superhard materials, and can only be used for processing large-scale simple optical structures such as aspheric lenses, and has no ultra-precise processing means on micro-nano optical structures such as microarrays, and cannot meet the precision requirements required by relatively precise microlens array dies.
While the heat-resistant stainless steel die can be used for precisely machining the micro-nano optical structure, the material characteristics such as easy oxidation and the like are difficult to use for machining the ultra-precise die, meanwhile, for an ultra-thick micro lens array, the lens is thicker, the lens is not suitable for integral cutting, the array unit is deeper, the micro lens array forming difficulty is increased, and the forming condition is more severe. The side edge of the lens is required to be in contact with the sleeve, the material flow in the X and Y directions of the lens is limited, the overall size in the X and Y directions is ensured, meanwhile, the filling in the Z direction is promoted to be more complete, and the shape accuracy of the lens array is ensured. However, the glass material softened at high temperature under the action of vertical pressure is tightly attached to the heat-resistant stainless steel sleeve, and because the heat expansion coefficient of the heat-resistant stainless steel is larger than that of the glass, the shrinkage of the heat-resistant stainless steel is larger than that of the glass during cooling, and at the moment, the lens formed by cooling and solidifying can be extruded and cracked by the heat-resistant stainless steel sleeve, so that the die combination of the core and the sleeve of the single heat-resistant stainless steel material cannot meet the requirement.
The method provided in prior art CN111763001a includes utilizing a multiple material composite mold for high precision glass molding. The mold comprises two mold cores, wherein the two mold cores are an upper mold core and a lower mold core respectively, the mold cores comprise a substrate and a coating, the substrate is made of heat-resistant stainless steel, the coating is made of nickel phosphide, and the coating is coated on one side of the two mold cores opposite to each other; the inner sleeve is made of a material with a thermal expansion coefficient smaller than that of a processed glass material and that of a substrate, the substrate comprises a protruding part and a limiting part, the protruding part stretches into the inner sleeve and is attached to the inner wall of the inner sleeve at normal temperature at a mold pressing temperature while leaving a gap, and the limiting part is used for contacting and limiting with the end face of the inner sleeve; the outer sleeve is made of the same material as the base, the outer sleeve is sleeved on the outer sides of the upper mold core, the lower mold core and the inner sleeve at the same time, a gap is reserved between the outer sleeve and the inner sleeve, and the limiting part is attached to the inner wall of the outer sleeve. The prior art method further comprises the steps of: polishing the plurality of array preforms and the one flat plate preform, respectively; cleaning the plurality of array preforms and the flat plate preform respectively; placing a plurality of array preforms in a plurality of grooves of a lower die core respectively; placing a flat preform over a plurality of array preforms; assembling a die, and placing the die into a molding press for vacuumizing; heating the mold to enable the temperature to reach an annealing point of the glass; applying pressure to the array preform and the flat plate preform to form the array lens; cooling the array lens; the array lens is removed from the mold. However, the prior art approach is a solution provided from the standpoint of changing the mold material or how to avoid micro-bubbles in the lens array. The use of different mold materials allows a microlens array to be obtained that meets the requirements from a finished product perspective, but multiple mold materials increase production costs. In the prior art, no technical proposal is provided for maintaining the main flow die material as much as possible and obtaining the microlens array meeting the requirements on the basis of maintaining the existing die pressing device as much as possible.
Disclosure of Invention
The invention aims to provide a mould pressing method of an optical lens, in particular to a mould pressing method which is used for heating a mould of the optical lens according to different heating conditions in the mould pressing process, so that the optical lens with stable mould pressing quality is obtained on the basis of maintaining the service life of the mould and meeting the technological requirements.
The invention provides a molding method of an optical lens, comprising the following steps: preheating and heating: the motor drives the lower die carrying the lens raw material to rise, the upper die is heated by voltage, and when the temperature rises to the target temperature, the upper die is continuously heated; raising the lower mold, heating the lower mold by voltage, and transferring heat to the lens raw material when the temperature is raised to a certain degree, so that the temperature of the lens raw material is raised to the glass transition temperature (Tg) or above; and (3) heat preservation and lamination step: the lower die motor continuously drives the lower die to ascend and simultaneously carries the lens raw material to displace, so that the lens raw material contacts the upper die, and the pressing process is completed; and (3) cooling and blanking: carrying out slow annealing treatment, and carrying out primary annealing treatment on the formed lens in a forming die so as to release internal stress; taking the annealed molded lens out of the molding die, and placing the molded lens on a cooling disc to be independently cooled to room temperature; a step of taking out the mold, wherein the cooled compression molding product is separated from the upper mold and the lower mold; the upper die and the lower die are silicon dies plated with graphene-like coatings, and the upper die and the lower die are respectively subjected to the preheating and heating step, the heat-preserving and pressing step and the cooling and blanking step by using proportional-differential integral (PID) control voltage; the upper die and the lower die are respectively subjected to temperature detection, and the temperature calibration procedure is finished under the condition that the temperature difference is smaller than 1; when the temperature difference is greater than or equal to 1, the upper and lower dies are heated to the preheating temperature by adjusting the heating parameters of the upper and lower dies, respectively, and the upper and lower dies are controlled, respectively.
In one aspect of the molding method, the top seat is used for fixing the upper mold, and the top seat further comprises an upper mold frame, a quartz heat insulation positioning sheet, an observation window, a positioning hole or a positioning column and fixing equipment; the base is used for fixing the lower die and comprises a positioning column or a positioning hole matched with the positioning hole or the positioning column on the top base, a quartz heat insulation positioning sheet, an electric heating connector, a lower die frame which is in mirror symmetry with the upper die frame and fixing equipment; and the silicon mold cores are arranged at the positions corresponding to the centers of the upper mold and the lower mold.
In another aspect of the molding method of the present invention, the conductance G of the mold core and the temperature T satisfy the following relationship:therein E, T 0 C is a calibration coefficient related to the mold core and is a fitting parameter; likewise, the core temperature +.>And in the calibration process, the C value is calibrated according to the temperature of the mold core, and a corresponding relation formula of the conductance G and the temperature T is obtained.
In yet another aspect of the molding process of the present invention, a stepwise power ramp-up heating is employed, the duration of each step being used to establish steady state conditions to obtain a more reliable correlation between temperature and conductance values (I/V); based on the thermoelectric properties of the graphene coated silicon die to observe changes in the temperature and electrical properties of the system, for example, increase by 10 to 110 watts every 5 minutes, then decrease by 20 to 10 watts every 10 minutes; the duration of each step is used to establish steady state conditions to obtain a more reliable correlation between temperature and conductance values (I/V); the empirical formula for the conductance temperature is: the resistivity r of intrinsic silicon at temperatures above 400K is proportional to exp (Eg/kT), where Eg (about 1.1 eV) is the silicon bandgap and K (about 8.7X10) -5 eV/° K) is a boltzmann constant. The unit of the temperature T is K; matching the curves by adding a proportionality constant kc, the formula is:
conductance value=1/(kc·exp (Eg/kT))=1/kc·exp (12,643/(t+273)) curve shift; by changing the band gap Eg and the proportionality constant kc, curve fitting is performed when eg=0.52 and kc=0.0003.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below. It will be apparent to those skilled in the art that the drawings in the following description are merely examples of the invention and that other drawings may be derived from them without undue burden to those skilled in the art.
FIG. 1 is a schematic diagram showing a pressing step in the compression molding method of the present invention.
FIG. 2 is a graph showing the temperature change in the compression molding method of the present invention.
Fig. 3 (a) -3 (e) are graphs showing the relationship between different parameters using a stepwise power boost heating method in the compression molding method of the present invention.
Fig. 4 is a schematic diagram showing the steps of the preheating stage of temperature change in the compression molding method of the present invention.
Fig. 5 is a schematic diagram showing the steps of the temperature change thermal insulation lamination stage in the compression molding method of the present invention.
FIG. 6 is a schematic diagram showing the step of maintaining the press-fit position in the temperature-varying cooling stage of the compression molding method of the present invention.
Fig. 7 is a schematic diagram showing the steps of the blanking stage from the temperature change to the end of the cooling stage in the compression molding method of the present invention.
FIG. 8 is a flow chart showing the temperature calibration steps in the compression molding method of the present invention.
FIG. 9 is a graph showing the temperature relationship of the conductance corresponding to different values of C in the temperature calibration step in the compression molding method of the present invention.
FIG. 10 is a graph of calculated temperature for a normally life mold core in a compression molding process of the present invention.
Fig. 11 is a model calculation temperature chart of lifetime abnormality in the compression molding method of the present invention.
FIG. 12 is a graph showing the relationship between the addition of a coefficient matching mathematical model and an actual value curve in the heating step of the compression molding method of the present invention.
FIG. 13 is a graph showing the fit of the parameters after the adjustment of the heating step in the compression molding method of the present invention.
Detailed Description
Specific embodiments of the present invention will now be described with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention.
FIG. 1 is a schematic diagram showing a pressing step in the compression molding method of the present invention. In the heating step, the glass product to be pressed, for example, glass beads 103, is placed on the lower mold 102, and the type of glass that can be used is not particularly limited, and known glass can be selected and used according to the application. Examples thereof include optical glasses such as borosilicate glass, silicate glass, phosphoric acid glass, and lanthanoid glass.
A motor (not shown) drives the lower mold 102 to rise, heats the upper mold 101 by voltage, and continuously heats the upper mold 101 when the temperature rises to a target temperature; as the distance between the upper mold 101 and the lower mold 102 is reduced, the upper mold 101 is heated by a voltage, which is brought by the change of the distance, when the temperature rises to a target temperature, the lower mold 102 is heated by a voltage, and when the temperature increases to a certain extent, heat is transferred to the glass ball 103, so that the temperature of the glass ball 103 rises to a glass transition temperature (Tg) or higher; a pressing step, wherein a motor of the lower die 102 continuously drives the lower die 102 to ascend, and meanwhile, the glass ball 103 is carried to displace, so that the glass ball 103 contacts the upper die 101, and the pressing process is completed; annealing and cooling, namely performing slow annealing treatment, and performing primary annealing treatment on the formed lens in a forming die so as to release internal stress; taking the annealed molded lens out of the molding die, and placing the molded lens on a cooling disc to be independently cooled to room temperature; and a mold-taking step of taking out the cooled compression molded product from the upper mold 101 and the lower mold 102.
The top seat is used for fixing an upper die (not shown in the figure), and further comprises an upper die frame, a quartz heat insulation positioning sheet, an observation window, a positioning hole or a positioning column, and fixing equipment such as a fixing screw and the like. The base is used for fixing a lower die (not shown in the figure) and comprises a positioning column or a positioning hole matched with a positioning hole or a positioning column on the top base, a quartz heat insulation positioning sheet, an electric heating connector, a lower die frame which is in mirror symmetry with an upper die frame, and fixing equipment such as a fixing screw and the like. And a silicon mold core is arranged at the corresponding position of the centers of the upper mold and the lower mold.
The upper die 101 and the lower die 102 are both single crystal silicon materials commonly available in the market, and when externally subjected to forces greater than the single crystal silicon material can withstand at that temperature, i.e., yield stress. Yield strength or yield stress is a property of a material and is the stress corresponding to the yield point at which the material begins to plastically deform.
The glass molded body produced by the production method can be used as various optical elements such as an imaging lens for a digital camera or the like, an optical pickup lens for a DVD or the like, and a coupling lens for optical communication. Further, the glass preform can be used as a glass preform for manufacturing various optical elements by a reheat press method.
FIG. 2 is a graph showing the temperature change in the compression molding method of the present invention. In the present compression molding method, the temperature change of the upper and lower molds is divided into three parts as a whole as shown in fig. 2: a preheating stage, a heat-preserving lamination stage and a cooling stage. Wherein the preheating stage is to stabilize the temperature for a period of time (40 s) from the beginning of heating to the preset temperature, and then enter the thermal insulation lamination stage; in the heat preservation and lamination stage, the temperature is stable and unchanged, the lower die is raised, and raw materials are laminated to generate a product; the cooling stage can be divided into two stages, namely a stage of maintaining the pressing position and a blanking stage. And (3) maintaining the pressing position stage, keeping the positions of the upper die and the lower die unchanged, and controlling the temperature of the upper die and the lower die to drop. And in the blanking stage, nitrogen is filled, the temperature is rapidly reduced, and simultaneously, the lower die and the product are lowered to a blanking position, so that blanking and next feeding are prepared.
There is a certain degree of instability due to the various measurement methods based. It is therefore necessary to take temperature readings from multiple pathways. And collecting temperature data of different input powers and resistance data of the heating element by heating the graphene-like coating silicon die, and simultaneously obtaining temperature readings of the thermocouple so as to analyze the conductive characteristics of the graphene-like coating silicon die. To obtain more accurate temperature readings, each power setting will be maintained for 300 seconds, it is desirable to be able to establish an isothermal state on the heating unit, thereby eliminating thermal losses and conduction problems of the thermocouple.
According to the graphene-like coating silicon die heating method in the die pressing method, a step-by-step power increasing heating mode is adopted to observe the change of the temperature and the electrical characteristics of the system, for example, 10-110 watts are increased every 5 minutes, and then 20-10 watts are reduced every 10 minutes; the duration of each step is used to establish steady state conditions to obtain a more reliable correlation between temperature and conductance values (I/V); finally, based on the thermoelectric property of the graphene coating silicon mode, the theoretical mathematical model of the intrinsic silicon resistivity property at high temperature is proved to be identical with the actual value, and an empirical formula of the conductivity temperature is established.
Fig. 3 (a) -3 (e) are graphs showing the relationship between different parameters using a stepwise power boost heating method in the compression molding method of the present invention. Wherein fig. 3 (a) is a power setting diagram; FIG. 3 (b) is a voltage current output graph; FIG. 3 (c) is a graph of voltage-current IV;
FIG. 3 (d) is a correlation diagram of temperature curves; fig. 3 (e) is a conductance converter temperature profile calibrated by a thermocouple. The resistivity r of intrinsic silicon at temperatures above 400K is proportional to exp (Eg/kT), where Eg (about 1.1 eV) is the silicon bandgap and K (about 8.7X10) -5 eV/° K) is a boltzmann constant. The unit of temperature T is K. Matching the curves by adding a proportionality constant kc, the formula is:
conductivity value=1/(kc·exp (Eg/kT))=1/kc·exp (12,643/(t+273))
But the curve is offset as shown in fig. 12. FIG. 12 is a graph showing the relationship between the addition of a coefficient matching mathematical model and an actual value curve in the heating step of the compression molding method of the present invention.
The bandgap may be lower provided that the silicon is not intrinsic or contaminated during processing. By changing the band gap Eg and the proportionality constant kc, curve fitting is performed when eg=0.52 and kc=0.0003, as shown in fig. 13. FIG. 13 is a graph showing the fit of the parameters after the adjustment of the heating step in the compression molding method of the present invention.
Fig. 4 is a schematic diagram showing the steps of the preheating stage of temperature change in the compression molding method of the present invention. Wherein the upper and lower dies are heated to the preheat temperature respectively using proportional-differential integral (PID) control voltages, respectively.
Fig. 5 is a schematic diagram showing the steps of the temperature change thermal insulation lamination stage in the compression molding method of the present invention. Wherein, the lower mould that bears raw materials glass ball is driven by the base and rises, gradually with the last mould contact on the footstock. The upper and lower dies are heated to the preheat temperature separately using proportional-differential integral (PID) control voltages, respectively.
FIG. 6 is a schematic diagram showing the step of maintaining the press-fit position in the temperature-varying cooling stage of the compression molding method of the present invention. Wherein, the base keeps the position unchanged after rising to a certain height, and the upper and lower dies respectively press the raw material glass balls; the upper and lower modes are cooled using proportional-differential integral (PID) control voltages, respectively.
Fig. 7 is a schematic diagram showing the steps of the blanking stage from the temperature change to the end of the cooling stage in the compression molding method of the present invention. The base drives the lower die and the product to descend to the blanking position, the temperature is reduced in a nitrogen filling mode, and the upper die and the lower die are powered off.
FIG. 8 is a flow chart showing the temperature calibration steps in the compression molding method of the present invention. The upper die and the lower die are respectively subjected to temperature detection, and the temperature calibration procedure is finished under the condition that the temperature difference is smaller than 1; when the temperature difference is greater than or equal to 1, the upper and lower dies are heated to the preheating temperature by adjusting the heating parameters of the upper and lower dies, respectively, and the upper and lower dies are controlled, respectively.
According to experimental data fitting, the conductance G and the temperature T of the mold core accord with the following relation:therein E, T 0 And C is a calibration coefficient related to the mold core for fitting parameters.
Also, when the die core conductance is known, the die core temperature can be obtained
When the temperature is calibrated, the C value is calibrated according to the temperature of the mold core, a corresponding relation formula of the conductance G and the temperature T is obtained, and the flow is shown in figure 8.
FIG. 9 is a graph showing the temperature relationship of the conductance corresponding to different values of C in the temperature calibration step in the compression molding method of the present invention.
The conductance is relatively stable when the mold core is operating stably. The reason is that the temperature change of the mold core is relatively slow, the conductance also gradually changes along with the temperature, and the jitter does not occur. When the conductance G of the mould core shakes, the signal is the signal with the service life being prolonged. The film on the surface of the mold core is worn, damaged and peeled off, or the surface is provided with impurities, foreign matters, oxidization and the like.
Fig. 10 is a graph showing calculated temperature of a mold core having a normal life in the compression molding method of the present invention, the mold core calculating temperature T calculated from conductance G instead of the detected temperature. The temperature is slowly varying and relatively stable.
Fig. 11 is a graph of a model calculated temperature of lifetime abnormality in the compression molding method of the present invention, the mold core calculated temperature of lifetime abnormality being also a temperature T calculated from the conductance G. As shown in fig. 11, the temperature may shake, in this example, only one, two, three or four individual shakes may be generated in the initial stage, and the operation may be continued for a period of time, and frequent shakes such as those shown in the figure may not be used.
The mould pressing method provided by the invention is that the upper mould and the lower mould are independently heated when the temperature rises to the calibrated temperature through observing the temperature change curve; simultaneously heating the upper die and the lower die to 500 ℃ for example; a calibration method for obtaining a temperature curve through a temperature change curve; in addition, the distance between the die and the die core is regulated, the temperature change is brought along with the change of the distance, a temperature change curve is drawn through an algorithm, and the integral temperature change curve is obtained by combining the front temperature change and the rear temperature change; in order to optimize the process parameters of the molding process. Judging the service life of the die through a temperature control curve of the die, wherein the service life can be generally 90%; and calibrating the die by a temperature and temperature control algorithm, thereby obtaining the calibration of the service life of the die, particularly a silicon die. The experimental procedure was consistent and the data obtained was fitted back. Obtaining the final temperature of temperature control by controlling the temperature of the die; and the stable molding quality and glass quality are obtained by controlling the actual temperature of the mold, so that the problem in the prior art, namely the problem that the molding quality is unstable under the condition of unstable temperature, and the glass quality is unstable, is solved.
Reference herein to "one embodiment," "an embodiment," or "one or more embodiments" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Furthermore, it is noted that the word examples "in one embodiment" herein do not necessarily all refer to the same embodiment.
The above description is only for the purpose of illustrating the technical solution of the present invention, and any person skilled in the art may modify and change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, the protection scope of the invention should be considered as the scope of the claims. The invention has been described above with reference to examples. However, other embodiments than the above described are equally possible within the scope of the disclosure. The different features and steps of the invention may be combined in other ways than those described. The scope of the invention is limited only by the appended claims. More generally, one of ordinary skill in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the teachings of the present invention are used.
Claims (4)
1. A method for calibrating temperature of an upper die and a lower die for optical lens die pressing comprises the following steps:
the motor drives the lower die carrying the lens raw material to rise, the temperature reading of the thermocouple is obtained, and the temperature calibration procedure is started;
heating the upper die and the lower die in a step-by-step power increasing mode by controlling voltage through proportional-derivative integral (PID);
respectively detecting the temperature of the upper die and the lower die, respectively heating the upper die and the lower die to a preheating temperature by respectively adjusting heating parameters of the upper die and the lower die under the condition that the temperature difference is more than or equal to 1 ℃, and respectively controlling the upper die and the lower die; ending the temperature calibration procedure when the temperature difference is less than 1 ℃;
and heating the graphene-like coating silicon die in a step-by-step power increasing mode to obtain an empirical formula: the conductance G and the temperature T of the upper die and the lower die accord with the following relation:wherein T is 0 273, the die temperature is obtained given the conductance of the upper and lower dies>E is band gap E g The Boltzmann constant k, C is a proportionality constant, and E and C are calibration coefficients associated with the mold core.
2. A method of molding using the method of temperature calibration as in claim 1, comprising:
preheating and heating: the motor drives the lower die carrying the lens raw material to ascend; heating the upper die and the lower die in a step-by-step power increasing mode; obtaining a thermocouple temperature reading; heating the upper die and the lower die by increasing the power step by step, and passing through an upper die and lower die conductivity-temperature relation formulaObtaining a calculated temperature; wherein T is 0 273; judging the service life of the die by calculating a temperature curve graph;
and (3) heat preservation and lamination step: after the temperature has been increased to a certain level and stabilized for a period of time, heat is transferred to the lens material, and the temperature of the lens material is raised to the glass transition temperature T g The above-mentioned steps are carried out,
the motor continues to drive the lower die carrying the lens raw material to ascend and simultaneously carry the lens raw material to displace, so that the lens raw material contacts the upper die, and the pressing process is completed;
and (3) cooling and blanking: heating the upper die and the lower die through proportional-differential integral PID control voltage, carrying out slow annealing treatment on the lens raw material, and carrying out primary annealing treatment on the formed lens in the forming die so as to release internal stress; the annealed molded lens was taken out of the mold and placed on a cooling plate to be cooled individually to room temperature.
3. The molding method of claim 2, wherein a top base is used for fixing the upper mold, and the top base further comprises an upper mold frame, a quartz heat insulation positioning sheet, an observation window, a positioning hole or a positioning column and fixing equipment; the base is used for fixing the lower die and comprises a positioning column or a positioning hole matched with the positioning hole or the positioning column on the top base, a quartz heat insulation positioning sheet, an electric heating connector, a lower die frame which is in mirror symmetry with an upper die frame and fixing equipment.
4. The molding process of claim 2, wherein the duration of each power in the stepwise power ramp-up heating is used to establish steady state conditions to achieve a more reliable correlation between temperature and conductance values.
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Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4058729A (en) * | 1975-11-14 | 1977-11-15 | Arden Sher | Pyroelectric apparatus including effectively intrinsic semiconductor for converting radiant energy into electric energy |
| DE4018213A1 (en) * | 1990-06-07 | 1991-12-12 | Manfred Dr Ing Markworth | Temp. measuring head for extruded, pressed or rolled semi-products - has contact-free cooled unit with sensors through which area around semi-product is sucked |
| JP2005008513A (en) * | 2003-05-26 | 2005-01-13 | Hoya Corp | Press-molding apparatus, press-molding method and method of producing optical element |
| JP2009096711A (en) * | 2007-09-25 | 2009-05-07 | Hoya Corp | Molding die, method for producing glass molding using the molding die and method for producing optical element |
| US8228159B1 (en) * | 2007-10-19 | 2012-07-24 | University Of Central Florida Research Foundation, Inc. | Nanocomposite semiconducting material with reduced resistivity |
| JP2016059164A (en) * | 2014-09-09 | 2016-04-21 | 株式会社日立製作所 | Inspection method of solar cell module |
| CN109264978A (en) * | 2017-07-18 | 2019-01-25 | 香港理工大学 | Micro-embossing device and method applied to precision glass microscopic optical structure |
| CN109384372A (en) * | 2017-08-09 | 2019-02-26 | 香港理工大学 | A kind of optical element mould pressing method based on class graphene Electric radiant Heating Film |
| WO2019178678A1 (en) * | 2018-03-19 | 2019-09-26 | Terra Firma Innovations Inc. | Photovoltaic microcell array with multi-stage concentrating optics |
| CN113651522A (en) * | 2021-09-14 | 2021-11-16 | 李莉华 | Non-isothermal glass molding method |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20020009602A1 (en) * | 2000-03-13 | 2002-01-24 | Hoya Corporation | Method and apparatus of fabricating glass molded article, method of fabricating glass substrate, and information recording medium |
| US8021135B2 (en) * | 2007-06-08 | 2011-09-20 | Sabic Innovative Plastics Ip B.V. | Mold apparatus for forming polymer and method |
-
2022
- 2022-04-02 CN CN202210351013.8A patent/CN114685033B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4058729A (en) * | 1975-11-14 | 1977-11-15 | Arden Sher | Pyroelectric apparatus including effectively intrinsic semiconductor for converting radiant energy into electric energy |
| DE4018213A1 (en) * | 1990-06-07 | 1991-12-12 | Manfred Dr Ing Markworth | Temp. measuring head for extruded, pressed or rolled semi-products - has contact-free cooled unit with sensors through which area around semi-product is sucked |
| JP2005008513A (en) * | 2003-05-26 | 2005-01-13 | Hoya Corp | Press-molding apparatus, press-molding method and method of producing optical element |
| JP2009096711A (en) * | 2007-09-25 | 2009-05-07 | Hoya Corp | Molding die, method for producing glass molding using the molding die and method for producing optical element |
| US8228159B1 (en) * | 2007-10-19 | 2012-07-24 | University Of Central Florida Research Foundation, Inc. | Nanocomposite semiconducting material with reduced resistivity |
| JP2016059164A (en) * | 2014-09-09 | 2016-04-21 | 株式会社日立製作所 | Inspection method of solar cell module |
| CN109264978A (en) * | 2017-07-18 | 2019-01-25 | 香港理工大学 | Micro-embossing device and method applied to precision glass microscopic optical structure |
| CN109384372A (en) * | 2017-08-09 | 2019-02-26 | 香港理工大学 | A kind of optical element mould pressing method based on class graphene Electric radiant Heating Film |
| WO2019178678A1 (en) * | 2018-03-19 | 2019-09-26 | Terra Firma Innovations Inc. | Photovoltaic microcell array with multi-stage concentrating optics |
| CN113651522A (en) * | 2021-09-14 | 2021-11-16 | 李莉华 | Non-isothermal glass molding method |
Non-Patent Citations (2)
| Title |
|---|
| Lin, YY ; Li, LH.Optimization Design And Experiment Of Parameters For Non-Isothermal Glass Molding Process.《SEVENTH ASIA PACIFIC CONFERENCE ON OPTICS MANUFACTURE》.2022,第12166卷全文. * |
| 张洪润主编.《传感器技术大全.上册》.北京：北京航空航天大学出版社,2007,第278页第2段. * |
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