Potassium titanyl phosphate crystal growth furnace and control method thereof

Abstract

The invention belongs to the technical field of crystal growth, and particularly discloses a potassium titanyl phosphate crystal growing furnace and a control method thereof.The method comprises the steps that a seed crystal rotating rod is driven by a direct-current motor to achieve constant rotation, and the perpendicularity of the seed crystal rotating rod is dynamically corrected through a ball structure in a connecting base; the precise lifting of the seed crystal rotating rod is realized by utilizing gear meshing transmission and screw rod adjusting functions in the lifting device; the temperature distribution in the furnace barrel is monitored in real time through a temperature sensor, and the heating power is adjusted by combining a PLC control system and based on a PID algorithm so as to maintain the solution uniformity; adjusting the rotating speed of the direct-current motor according to a voltage signal output by the potentiometer to ensure that the rotating speed of the seed crystal rotating rod is matched with the pulling rate; the invention aims to solve the problems that in the prior art, the vertical precision of a seed crystal rotating rod is difficult to guarantee during crystal growth, the pulling process is unstable, and the solution uniformity is difficult to maintain in a high-temperature environment.

Description

Technical Field

[0001] This invention relates to the field of crystal growth technology, specifically to a potassium oxytitanium phosphate crystal growth furnace and its control method. Background Technology

[0002] In the growth of potassium titanium phosphate (KTiOPO4, or KTP) crystals, the core technical challenge lies in achieving precise vertical control of the seed crystal rotor during continuous rotation and stirring, while ensuring the stability and accuracy of the pulling process. This issue involves the selection of the flux system and the maintenance of solution homogeneity in the flux method. However, the seed crystal remaining stationary relative to the solution may lead to uneven nucleation distribution, affecting crystal quality. Furthermore, the KH2PO4-K2HPO4-TiO2 system has a high water content at high temperatures, which easily leads to liquid overflow due to evaporation, increasing operational complexity.

[0003] Application number CN86100393 discloses a process and apparatus for growing potassium titanate phosphate crystals using a flux method. KPO3 and K4P2O7 are used as fluxes, and the raw materials are melted by heating with an electric furnace wire before cooling and growth. However, this method does not propose specific measures to ensure vertical accuracy, and the seed crystal spindle relies on manual, experience-based operation during the pulling process. This may lead to unstable crystal growth conditions due to human factors, thus affecting crystal performance.

[0004] Ultimately, in practice, the design and control of the pulling device have a significant impact on the crystal growth results. If the pulling speed or rotational accuracy cannot meet the requirements, it may lead to uneven stress distribution or increased defects within the crystal. Furthermore, it raises the technical training requirements for operators, increasing the barrier to entry for process implementation. This complex issue permeates the entire process, from seed crystal placement and solution homogeneity maintenance to crystal pulling, involving multiple interactions between mechanical design, temperature control, and manual operation, directly affecting the growth efficiency and quality of KTP crystals. Summary of the Invention

[0005] This invention provides a potassium oxytitanium phosphate crystal growth furnace and its control method, aiming to solve the problems in the prior art of difficulty in ensuring the vertical accuracy of the seed crystal rotor during crystal growth, instability in the pulling process, and difficulty in maintaining solution uniformity under high temperature environment.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A method for controlling a potassium oxytitanium phosphate crystal growth furnace includes: driving a seed crystal rotor to achieve constant rotation via a DC motor, and dynamically correcting the perpendicularity of the seed crystal rotor through a ball bearing structure in the connecting seat; achieving precise lifting of the seed crystal rotor using gear meshing transmission and screw adjustment functions in the lifting device; monitoring the temperature distribution inside the furnace in real time using a temperature sensor, and adjusting the heating power based on a PLC control system and PID algorithm to maintain solution homogeneity; adjusting the DC motor speed according to the voltage signal output by the potentiometer to ensure that the rotation speed of the seed crystal rotor matches the lifting rate; displaying current process parameters and recording key data on an LCD display; placing a platinum crucible between multiple layers of insulation material and achieving temperature gradient control through heating with electric heating wires; and finally generating a complete crystal growth log for subsequent analysis and optimization.

[0007] In one aspect of this disclosure, the step of achieving constant rotation of the seed crystal rotor by driving it with a DC motor and dynamically correcting the perpendicularity of the seed crystal rotor through a ball bearing structure in the connecting seat includes: The DC motor is fixed to the cross arm of the machine body. The seed crystal rotating rod is clamped by the upper and lower connecting blocks in the connecting seat. Multiple balls are embedded in the connecting seat to reduce friction. Adjusting bolts are inserted into the through holes of the upper and lower connecting blocks. The clamping force of the connecting seat on the seed crystal rotor is changed by adjusting the tightness of the bolts. After the DC motor is started, the seed crystal rotor maintains stable rotation under the support of the ball bearings, while the ball bearing structure dynamically compensates for the radial offset of the seed crystal rotor. If the verticality deviation of the seed crystal rotor exceeds the preset threshold, its position is readjusted by adjusting the bolt.

[0008] In one aspect of this disclosure, the step of precisely lifting the seed crystal screw by utilizing the gear meshing transmission and screw adjustment function in the lifting device includes: The two gears are respectively mounted on the screw and the mechanical crank, and the two gears achieve synchronous movement through meshing transmission; The outer surface of the screw is machined with standard threads, and the cross arm is provided with a screw hole that matches the screw thread. The cross arm is screwed to the screw through the screw hole. When the mechanical crank is turned, the screw moves axially, driving the cross arm to move up and down, thereby lifting the seed crystal screw. The lifting rate is determined by the gear ratio design. If the lifting rate needs to be adjusted, the gears with different gear ratios are replaced or the rotation speed of the mechanical crank is changed.

[0009] In one aspect of this disclosure, the step of monitoring the temperature distribution inside the furnace in real time using a temperature sensor, and adjusting the heating power based on a PLC control system and a PID algorithm to maintain solution homogeneity includes: A temperature sensor is installed inside the furnace barrel near the platinum crucible to collect temperature data inside the furnace barrel in real time. The collected temperature data is transmitted to the PLC control system, which then calculates the heating power requirement based on the preset temperature curve. The platinum crucible is heated by an electric heating wire, the input power of which is adjusted by a PLC control system. If the temperature detected by the temperature sensor deviates from the preset range, the PLC control system will automatically adjust the heating power of the heating element.

[0010] In one aspect of this disclosure, the step of adjusting the DC motor speed according to the voltage signal output by the potentiometer to ensure that the rotational speed of the seed crystal rotor matches the pulling rate includes: Connect the potentiometer electrically to the DC motor and change its output voltage by rotating the potentiometer knob; The voltage signal output by the potentiometer is processed by the amplifier circuit and then transmitted to the DC motor to control the speed of the DC motor. The LCD display is electrically connected to the potentiometer to display the voltage value output by the potentiometer and the actual speed of the DC motor in real time. If the rotation speed of the seed crystal rotor does not match the lifting rate, the speed of the DC motor can be changed by adjusting the potentiometer knob.

[0011] In one aspect of this disclosure, the step of displaying current process parameters and recording key data via a liquid crystal display includes: The LCD display is mounted on the machine body and electrically connected to the PLC control system. The LCD display shows in real time the temperature data collected by the temperature sensor, the voltage signal output by the potentiometer, the speed of the DC motor, and the lifting rate of the lifting device. The PLC control system stores the data displayed on the LCD screen in the built-in storage module to form a complete record of process parameters. If the process parameters exceed the preset range, the LCD screen will issue an alarm.

[0012] In one aspect of this disclosure, the step of placing the platinum crucible between multiple layers of insulation material and controlling the temperature gradient by heating with an electric heating wire includes: The platinum crucible is placed horizontally on a liftable base plate, which is connected to the machine body via a slide rail. The platinum crucible is wrapped with a first insulation material layer, an electric heating wire, and a second insulation material layer in sequence. The first and second insulation material layers are made of high-temperature resistant ceramic fiber material, and the heating wire is connected to the PLC control system via a power cord. The PLC control system adjusts the heating power of the heating element based on the signal fed back from the temperature sensor.

[0013] In one aspect of this disclosure, the step of finally generating a complete crystal growth log for subsequent analysis and optimization includes: The process parameters recorded on the liquid crystal display are transmitted to an external storage device through a communication interface to form a crystal growth log; The crystal growth log includes temperature change curves, DC motor speed records, pull-up rate data, and changes in potentiometer output voltage. By analyzing the crystal growth log, the temperature stability, the rotation accuracy of the seed crystal rotor, and the matching degree of the pulling rate during the crystal growth process are evaluated. If the crystal growth results do not meet expectations, adjust the process parameters based on the data in the crystal growth log.

[0014] In another aspect, this disclosure also relates to a control system for a potassium oxytitanium phosphate crystal growth furnace, the system comprising: The rotation control module is configured to achieve constant rotation by driving the seed crystal rotor with a DC motor and to dynamically correct the perpendicularity of the seed crystal rotor through the ball bearing structure in the connecting seat. The lifting adjustment module is configured to achieve the precise lifting of the seed crystal screw by utilizing the gear meshing transmission and screw adjustment function in the lifting device; The temperature management module is configured to monitor the temperature distribution inside the furnace barrel in real time through a temperature sensor, and adjust the heating power based on a PLC control system and a PID algorithm to maintain solution uniformity. The speed matching module is configured to adjust the DC motor speed according to the voltage signal output by the potentiometer to ensure that the rotation speed of the seed crystal rotor matches the lifting rate. The data display module is configured to display the current process parameters and record key data via an LCD display; The thermal environment optimization module is configured to achieve temperature gradient control by placing the platinum crucible between multiple layers of insulation material and heating it with an electric heating wire. The log generation module is configured to ultimately generate a complete crystal growth log for subsequent analysis and optimization steps.

[0015] In another aspect of this disclosure, this disclosure also relates to a potassium oxytitanium phosphate crystal growth furnace, including a growth furnace body, wherein the growth furnace body is provided with the aforementioned potassium oxytitanium phosphate crystal growth furnace control system, and the growth furnace body is used to implement the aforementioned potassium oxytitanium phosphate crystal growth furnace control method.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a control method for a potassium titanium phosphate crystal growth furnace. A DC motor drives a seed crystal rotor to achieve constant rotation, and a ball bearing structure in the connecting seat dynamically corrects the verticality of the rotor, effectively solving the problem of inconsistent vertical accuracy of the seed crystal rotor during long-term operation in existing technologies. The ball bearing structure not only significantly reduces friction but also compensates for radial offset in real time, ensuring the seed crystal rotor maintains a high-precision vertical state, thus avoiding tilting and stress concentration during crystal growth and improving the integrity of the crystal structure. Secondly, the precise lifting of the seed crystal rotor is achieved through gear meshing and screw adjustment in the lifting device. The gear ratio design allows for flexible adjustment of the lifting rate, and combined with the stable operation of the mechanical crank, significantly improves the controllability and repeatability of the lifting process, reducing instability caused by human intervention. Furthermore, a temperature sensor monitors the temperature distribution inside the furnace in real time, and a PLC control system dynamically adjusts the heating power to ensure the solution remains uniform in a high-temperature environment, preventing uneven crystal nucleation or defect formation caused by local temperature fluctuations. A potentiometer adjusts the DC motor speed based on the output voltage signal, precisely matching the seed crystal rotor speed with the pulling rate to optimize crystal growth kinetics. An LCD display shows and records key process parameters in real time, facilitating operator monitoring and timely adjustments, enhancing process transparency and operational safety. A platinum crucible is placed between multiple layers of insulation material, and precise temperature gradient control is achieved through heating with electric heating wires, effectively reducing heat loss and maintaining a stable thermal environment. The resulting crystal growth log provides detailed data support for subsequent process analysis and optimization, comprehensively improving the growth efficiency, quality consistency, and process repeatability of potassium titanium phosphate crystals. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a flowchart of a potassium oxytitanium phosphate crystal growth furnace and its control method according to the present invention. Detailed Implementation

[0019] The present invention will be further described below with reference to embodiments. These embodiments are merely some, not all, of the embodiments described. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the protection scope of the present invention.

[0020] Please see Figure 1As shown, this embodiment discloses a potassium oxytitanium phosphate crystal growth furnace and its control method; In this embodiment, the growth furnace body mainly includes: a frame, a seed crystal rotor, a DC motor, a connecting base, a lifting device, a temperature sensor, a PLC control system, a potentiometer, a liquid crystal display, a platinum crucible, multi-layer insulation material, and heating wires; the specific arrangement and interaction of the above components are described below: The main body is the basic structure of the entire crystal growth furnace, and its horizontal arm is used to fix the DC motor and the lifting device. The DC motor is mounted on one side of the cross arm of the machine body and is fixedly connected to the cross arm by bolts; The output shaft of the DC motor is directly connected to one end of the seed crystal rotor to achieve power transmission.

[0021] The other end of the seed crystal rotor passes through the connecting seat and extends into the furnace barrel to support the seed crystal and complete the rotation and lifting actions during the crystal growth process.

[0022] The connecting seat is located below the cross arm. It has an upper connecting block and a lower connecting block on its upper and lower parts, respectively. An adjusting bolt is inserted through a through hole between the upper and lower connecting blocks. The tightness of the adjusting bolt can change the clamping force of the connecting seat on the seed crystal rotor.

[0023] Multiple balls are embedded in the connector, and the balls are distributed around the radial direction of the seed crystal rotor. This reduces friction and dynamically corrects the perpendicularity of the seed crystal rotor when it rotates.

[0024] When the seed crystal rotor deviates radially due to long-term operation, the ball bearing structure can compensate for its position.

[0025] For example, the ball structure contains six circumferentially distributed tungsten carbide balls, each ball abutting against the surface of the seed crystal rotor by spring preload; when the seed crystal rotor deviates radially, the balls on the deviated side are squeezed to generate a reverse elastic force, pushing the seed crystal rotor to reset, thus achieving dynamic compensation; In some optional embodiments, the ball structure includes six circumferentially distributed tungsten carbide balls, each ball being preloaded by a compression spring with an initial preload force of 5-20 N, and installed in a ball groove; when the seed crystal rotor deviates radially, the ball on the deviated side is squeezed to generate a reverse elastic force, pushing the seed crystal rotor to reset, thus achieving dynamic compensation.

[0026] If the verticality deviation of the seed crystal rotor exceeds the preset threshold, the clamping state of the connecting seat is readjusted by adjusting the bolts, thereby correcting the position of the seed crystal rotor.

[0027] For example, if the verticality deviation of the seed crystal rotor exceeds 0.5° as monitored in real time by a laser goniometer, its position can be readjusted by adjusting the bolts.

[0028] The lifting device includes two gears, a screw, and a mechanical crank. The two gears are respectively mounted on the screw and the mechanical crank, and the two gears achieve synchronous movement through meshing transmission. The outer surface of the screw is machined with standard threads, and the cross arm has a threaded hole that matches the screw thread. The screw is screwed to the cross arm through the threaded hole.

[0029] The mechanical crank is located on one side of the machine body. By manually rotating the mechanical crank, the screw moves axially, thereby pushing the horizontal arm up and down to achieve precise lifting of the seed crystal screw.

[0030] The lifting speed is determined by the gear ratio. If the lifting speed needs to be adjusted, it can be achieved by replacing the gears with different gear ratios or changing the rotation speed of the mechanical crank.

[0031] In practice, the design of the lifting device ensures that the seed crystal rotor can rise steadily and controllably during crystal growth.

[0032] A temperature sensor is installed inside the furnace barrel near the platinum crucible to collect real-time temperature data. The sensor is connected to a PLC control system via a signal line, transmitting the collected temperature data. The PLC calculates the heating power requirement based on a preset temperature curve and maintains solution homogeneity by controlling the input power of the heating element.

[0033] For example, the PLC control system calculates the heating power requirement based on a preset temperature curve, which is: heating to 800°C at a rate of 5°C / min, holding at that temperature for 4 hours, and then cooling to 600°C at a rate of 2°C / min. The heating wire is wound around the perimeter of the platinum crucible, and its two ends are connected to the PLC control system via power cords. The heating power of the heating wire is adjusted by the PLC control system. If the temperature detected by the temperature sensor deviates from the preset range, the PLC control system will automatically adjust the heating power of the heating wire to restore the temperature to the target value.

[0034] In addition, the platinum crucible is wrapped with a first insulation material layer, an electric heating wire, and a second insulation material layer in sequence. The first and second insulation material layers are made of high-temperature resistant ceramic fiber material, which has low thermal conductivity and high heat resistance, and can effectively reduce heat loss and maintain the temperature gradient inside the furnace.

[0035] The solution remains uniform during crystal growth through the coordinated operation of temperature sensors and a PLC control system.

[0036] The potentiometer is electrically connected to the DC motor, and its output voltage is changed by rotating the potentiometer knob. The voltage signal output by the potentiometer is processed by an amplification circuit and then transmitted to the DC motor to control its speed. An LCD display is electrically connected to the potentiometer, showing the output voltage value and the actual speed of the DC motor in real time. In actual operation, if the rotation speed of the seed crystal rotor does not match the lifting rate, the speed of the DC motor can be adjusted by changing the potentiometer knob, thus achieving precise adjustment of the seed crystal rotor's rotation speed.

[0037] For example: ensure that the ratio of the rotation speed of the seed crystal rotor to the pulling rate is 1:10, with an allowable deviation of ±5%; if the deviation exceeds the limit, adjust the DC motor speed by adjusting the potentiometer knob.

[0038] The LCD display is also electrically connected to the PLC control system to display current process parameters and record key data. The LCD displays real-time temperature data collected by the temperature sensor, voltage signals output by the potentiometer, DC motor speed, and lifting rate of the lifting device. The PLC control system stores the data displayed on the LCD in its built-in storage module, forming a complete record of process parameters. If the process parameters exceed the preset range, the LCD will issue an alarm to remind the operator to make timely adjustments.

[0039] The platinum crucible is horizontally placed on a height-adjustable base plate, which is connected to the machine body via a slide rail for easy height adjustment. The platinum crucible is surrounded by a first insulation layer, a heating wire, and a second insulation layer. Both layers are made of high-temperature resistant ceramic fiber material, exhibiting low thermal conductivity and high heat resistance, effectively reducing heat loss. The heating wire is connected to a PLC control system via a power cord. The PLC system adjusts the heating power of the heating wire based on signals from a temperature sensor. Through the insulation provided by the first and second insulation layers, and the heating effect of the heating wire, a stable temperature gradient is formed inside the platinum crucible, providing an ideal thermal environment for crystal growth.

[0040] The crystal growth log is generated by a log generation module, which is electrically connected to the LCD and PLC control system. The process parameters recorded on the LCD are transmitted to an external storage device via a communication interface, forming the crystal growth log. The crystal growth log includes temperature change curves, DC motor speed records, pull-up rate data, and potentiometer output voltage changes. By analyzing the crystal growth log, the temperature stability during crystal growth, the rotation accuracy of the seed crystal rotor, and the matching degree of the pull-up rate are evaluated. If the crystal growth result does not meet expectations, the process parameters are adjusted based on the data in the crystal growth log. The generation and analysis of the crystal growth log provide a basis for optimizing subsequent crystal growth processes.

[0041] In this embodiment, the connection and positional relationships between the various components are clearly described, and the collaborative process of each component to achieve crystal growth is explained in detail. A DC motor drives the seed crystal rotor to achieve constant rotation, and the perpendicularity of the seed crystal rotor is dynamically corrected by the ball bearing structure in the connecting seat. Precise lifting of the seed crystal rotor is achieved using gear meshing transmission and screw adjustment functions in the lifting device. Temperature sensors monitor the temperature distribution within the furnace in real time, and a PLC control system adjusts the heating power based on a PID algorithm to maintain solution homogeneity. The DC motor speed is adjusted according to the voltage signal output by the potentiometer to ensure that the rotational speed of the seed crystal rotor matches the lifting rate. Current process parameters are displayed and key data is recorded on an LCD screen. A platinum crucible is placed between multiple layers of insulation material and heated by an electric heating wire to achieve temperature gradient control. Finally, a complete crystal growth log is generated for subsequent analysis and optimization. The specific implementation methods of the above steps have been described in detail in this embodiment to ensure that those skilled in the art can implement this technology according to the contents of the specification.

[0042] The PID algorithm is configured as follows:

[0043] in,

[0044] This refers to the output of the controller, which is the heating power that the PLC calculates and needs to apply to the heating element. This refers to the current time; This refers to the current error value, which is the difference between the set value and the actual measured value. The set value is the target temperature at time t on the preset temperature curve; the actual measured value is the actual temperature inside the furnace collected in real time by the temperature sensor. This refers to the control output and the current error. Proportional control is used to react immediately to the current state of the system. The larger the error, the stronger the control effect, thereby quickly reducing the error.

[0045] It refers to proportional gain, which is an adjustable coefficient that determines the strength of the proportional effect.

[0046] If the current furnace temperature suddenly drops below the target temperature, the proportional term will immediately increase the heating power proportionally in an attempt to bring the temperature back to the target value.

[0047] This means that the control output is proportional to the cumulative amount of error over time, i.e., the integral of the error. Its function is to eliminate steady-state error. Even if the proportional term cannot completely eliminate small errors, the integral term will continuously accumulate this error value over time, thereby gradually increasing the control effect until the error is completely eliminated.

[0048] This refers to the integral gain, which is also an adjustable coefficient. in, Configured as:

[0049] in, It is the integration time, indicating how fast the integration process takes place.

[0050] It refers to the sum of all error values ​​from time 0 to the current time t. Its function is to ensure the long-term accuracy of temperature during the long-term isothermal stage of crystal growth (such as being at 800℃ for 4 hours). If there is a small and continuous temperature deviation in the system, the integral term will continue to act and eventually completely correct this deviation, ensuring the long-term accuracy of temperature.

[0051] This refers to the rate of change of the control output relative to the error, i.e., the derivative of the error. Its function is to predict future error trends and apply control in advance. It can suppress system oscillations and improve system stability. When the error begins to decrease rapidly, the derivative term will reduce the control output in advance to prevent the system from overshooting the target value due to inertia.

[0052] This refers to the differential gain, which is an adjustable coefficient. Configured as:

[0053] in, It is the differential time, representing the intensity of the differential action.

[0054] This refers to the rate of change of the error, that is, the rate of change of the current error relative to time. Its function is to sense the rate of temperature change during the heating or cooling phase (such as a change rate of 5℃ / min). If the temperature rises too quickly, it will reduce the heating power in advance to make the heating process more stable and avoid temperature overshoot, which is crucial for the thermal environment stability of crystal growth.

[0055] Therefore, the PID algorithm integrates the rapid response of the proportional gain, the precise elimination of residual errors by the integral gain, and the predictive and stabilizing effects of the derivative gain, thereby achieving high-precision and high-stability control of the furnace temperature. This is achieved by adjusting... , as well as These three parameters enable the system to achieve optimal control, ensure solution homogeneity, and provide an ideal thermal environment for the growth of high-quality crystals.

[0056] To enable those skilled in the art to fully understand and implement this invention, the specific implementation principle of this invention is further explained below in conjunction with a specific application scenario.

[0057] First, place the machine body on a stable workbench, ensuring its horizontal arm is level. The DC motor is bolted to one side of the horizontal arm, its output shaft directly connected to one end of the seed crystal rotor. The other end of the seed crystal rotor extends into the furnace barrel through a connecting seat. Multiple ball bearings are embedded in the connecting seat, distributed radially around the seed crystal rotor to reduce friction during rotation. When the seed crystal rotor experiences radial displacement due to prolonged operation, the ball bearing structure dynamically compensates for its position. If the verticality deviation of the seed crystal rotor exceeds a preset threshold, the clamping state is readjusted by adjusting the adjusting bolts at the top and bottom of the connecting seat, thereby correcting the position of the seed crystal rotor. This design ensures that the seed crystal rotor maintains a stable vertical position throughout the crystal growth process.

[0058] Subsequently, a lifting device is installed to achieve precise lifting of the seed crystal rotor. Two gears are respectively mounted on the screw and the mechanical crank, and the two gears achieve synchronous movement through meshing transmission. The outer surface of the screw is machined with standard threads, and the cross arm has a threaded hole that matches the screw thread. The screw is screwed to the cross arm through the threaded hole. The mechanical crank is located on one side of the machine body. By manually rotating the mechanical crank, the screw moves axially, thereby pushing the cross arm up and down to achieve the lifting of the seed crystal rotor. The lifting rate is determined by the gear ratio. If it is necessary to adjust the lifting rate, it can be achieved by replacing the gears with different gear ratios or changing the rotation speed of the mechanical crank. This design ensures that the seed crystal rotor can rise smoothly and controllably during crystal growth.

[0059] Next, a temperature sensor is installed inside the furnace near the platinum crucible to collect real-time temperature data. The temperature sensor is connected to the PLC control system via a signal line, transmitting the collected temperature data. The PLC control system calculates the heating power requirement based on a preset temperature curve and maintains solution homogeneity by controlling the input power of the heating wire. The heating wire is wound around the platinum crucible, with its two ends connected to the PLC control system via power lines. The heating power of the heating wire is adjusted by the PLC control system. If the temperature detected by the temperature sensor deviates from the preset range, the PLC control system automatically adjusts the heating power of the heating wire to restore the temperature to the target value. Furthermore, the platinum crucible is sequentially wrapped with a first insulation layer, a heating wire, and a second insulation layer. Both insulation layers are made of high-temperature resistant ceramic fiber material, which has low thermal conductivity and high heat resistance, effectively reducing heat loss and maintaining the temperature gradient inside the furnace. Through the coordinated operation of the temperature sensor and the PLC control system, the homogeneity of the solution is ensured during crystal growth.

[0060] In actual operation, the potentiometer is electrically connected to the DC motor, and its output voltage is changed by rotating the potentiometer knob. The voltage signal output by the potentiometer is processed by the amplification circuit and then transmitted to the DC motor to control its speed. The LCD display is electrically connected to the potentiometer, displaying the voltage value output by the potentiometer and the actual speed of the DC motor in real time. If the rotation speed of the seed crystal rotor does not match the lifting rate, the speed of the DC motor is changed by adjusting the potentiometer knob, thereby achieving precise adjustment of the seed crystal rotor's rotation speed. The LCD display is also electrically connected to the PLC control system to display current process parameters and record key data. The LCD display shows in real time the temperature data collected by the temperature sensor, the voltage signal output by the potentiometer, the speed of the DC motor, and the lifting rate of the lifting device. The PLC control system stores the data displayed on the LCD display in its built-in storage module, forming a complete record of process parameters. If the process parameters exceed the preset range, the LCD display issues an alarm to remind the operator to make timely adjustments.

[0061] The platinum crucible is horizontally placed on a height-adjustable base plate, which is connected to the machine body via a slide rail for easy height adjustment. The platinum crucible is surrounded by a first insulation layer, a heating wire, and a second insulation layer. Both layers are made of high-temperature resistant ceramic fiber material, exhibiting low thermal conductivity and high heat resistance, effectively reducing heat loss. The heating wire is connected to a PLC control system via a power cord. The PLC system adjusts the heating power of the heating wire based on signals from a temperature sensor. Through the insulation provided by the first and second insulation layers, and the heating effect of the heating wire, a stable temperature gradient is formed inside the platinum crucible, providing an ideal thermal environment for crystal growth.

[0062] Finally, the crystal growth log is generated by a log generation module, which is electrically connected to the LCD and PLC control system. The process parameters recorded on the LCD are transmitted to an external storage device via a communication interface, forming the crystal growth log. The crystal growth log includes temperature change curves, DC motor speed records, pull-up rate data, and potentiometer output voltage changes. By analyzing the crystal growth log, the temperature stability during crystal growth, the rotation accuracy of the seed crystal rotor, and the matching degree of the pull-up rate are evaluated. If the crystal growth result does not meet expectations, the process parameters are adjusted based on the data in the crystal growth log. The generation and analysis of the crystal growth log provide a basis for optimizing subsequent crystal growth processes.

[0063] It should be noted that the growth furnace body in this embodiment is prior art, and the specific structure is based on the prior art with application number CN201110220827.X, which will not be described in detail here.

[0064] In the description of this invention, it should be understood that the terms "coaxial," "bottom," "one end," "top," "middle," "other end," "upper," "side," "top," "inner," "front," "center," "both ends," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0065] Furthermore, the terms “first,” “second,” “third,” and “fourth” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as “first,” “second,” “third,” or “fourth” may explicitly or implicitly include at least one of those features.

[0066] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixing," "screw connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0067] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for controlling a potassium oxytitanium phosphate crystal growth furnace, characterized in that, include: A constant rotation of the seed crystal rotor is achieved by driving it with a DC motor, and the perpendicularity of the seed crystal rotor is dynamically corrected by the ball bearing structure in the connecting seat. The precise lifting of the seed crystal screw is achieved by utilizing the gear meshing transmission and screw adjustment function in the lifting device; The temperature distribution inside the furnace is monitored in real time by a temperature sensor, and the heating power is adjusted based on a PLC control system and a PID algorithm to maintain the uniformity of the solution. Adjust the DC motor speed according to the voltage signal output by the potentiometer to ensure that the rotation speed of the seed crystal rotor matches the pulling rate; The current process parameters are displayed on the LCD screen and key data is recorded. The platinum crucible is placed between multiple layers of insulation material, and the temperature gradient is controlled by heating with an electric heating wire. A complete crystal growth log is finally generated for subsequent analysis and optimization.

2. The method for controlling a potassium oxytitanium phosphate crystal growth furnace according to claim 1, characterized in that: The step of achieving constant rotation of the seed crystal rotor by driving it with a DC motor and dynamically correcting the perpendicularity of the seed crystal rotor through the ball bearing structure in the connecting seat includes: The DC motor is fixed to the cross arm of the machine body. The seed crystal rotating rod is clamped by the upper and lower connecting blocks in the connecting seat. Multiple balls are embedded in the connecting seat to reduce friction. Adjusting bolts are inserted into the through holes of the upper and lower connecting blocks. The clamping force of the connecting seat on the seed crystal rotor is changed by adjusting the tightness of the bolts. After the DC motor is started, the seed crystal rotor maintains stable rotation under the support of the ball bearings, while the ball bearing structure dynamically compensates for the radial offset of the seed crystal rotor. If the verticality deviation of the seed crystal rotor exceeds the preset threshold, its position is readjusted by adjusting the bolt.

3. The method for controlling a potassium oxytitanium phosphate crystal growth furnace according to claim 1, characterized in that: The step of precisely lifting the seed crystal rotor by utilizing the gear meshing transmission and screw adjustment function in the lifting device includes: The two gears are respectively mounted on the screw and the mechanical crank, and the two gears achieve synchronous movement through meshing transmission; The outer surface of the screw is machined with standard threads, and the cross arm is provided with a screw hole that matches the screw thread. The cross arm is screwed to the screw through the screw hole. When the mechanical crank is turned, the screw moves axially, driving the cross arm to move up and down, thereby lifting the seed crystal screw. The lifting rate is determined by the gear ratio design. If the lifting rate needs to be adjusted, the gears with different gear ratios are replaced or the rotation speed of the mechanical crank is changed.

4. The method for controlling a potassium oxytitanium phosphate crystal growth furnace according to claim 1, characterized in that: The step of monitoring the temperature distribution inside the furnace in real time using a temperature sensor, and adjusting the heating power based on a PLC control system and a PID algorithm to maintain solution homogeneity includes: A temperature sensor is installed inside the furnace barrel near the platinum crucible to collect temperature data inside the furnace barrel in real time. The collected temperature data is transmitted to the PLC control system, which then calculates the heating power requirement based on the preset temperature curve. The platinum crucible is heated by an electric heating wire, the input power of which is adjusted by a PLC control system. If the temperature detected by the temperature sensor deviates from the preset range, the PLC control system will automatically adjust the heating power of the heating element.

5. The method for controlling a potassium oxytitanium phosphate crystal growth furnace according to claim 1, characterized in that: The step of adjusting the DC motor speed according to the voltage signal output by the potentiometer to ensure that the rotation speed of the seed crystal rotor matches the pulling rate includes: Connect the potentiometer electrically to the DC motor and change its output voltage by rotating the potentiometer knob; The voltage signal output by the potentiometer is processed by the amplifier circuit and then transmitted to the DC motor to control the speed of the DC motor. The LCD display is electrically connected to the potentiometer to display the voltage value output by the potentiometer and the actual speed of the DC motor in real time. If the rotation speed of the seed crystal rotor does not match the lifting rate, the speed of the DC motor can be changed by adjusting the potentiometer knob.

6. The method for controlling a potassium oxytitanium phosphate crystal growth furnace according to claim 1, characterized in that: The step of displaying the current process parameters and recording key data via a liquid crystal display includes: The LCD display is mounted on the machine body and electrically connected to the PLC control system. The LCD display shows in real time the temperature data collected by the temperature sensor, the voltage signal output by the potentiometer, the speed of the DC motor, and the lifting rate of the lifting device. The PLC control system stores the data displayed on the LCD screen in the built-in storage module to form a complete record of process parameters. If the process parameters exceed the preset range, the LCD screen will issue an alarm.

7. The method for controlling a potassium oxytitanium phosphate crystal growth furnace according to claim 1, characterized in that: The step of placing the platinum crucible between multiple layers of insulation material and controlling the temperature gradient by heating with an electric heating wire includes: The platinum crucible is placed horizontally on a liftable base plate, which is connected to the machine body via a slide rail. The platinum crucible is wrapped with a first insulation material layer, an electric heating wire, and a second insulation material layer in sequence. The first and second insulation material layers are made of high-temperature resistant ceramic fiber material, and the heating wire is connected to the PLC control system via a power cord. The PLC control system adjusts the heating power of the heating element based on the signal fed back from the temperature sensor.

8. The method for controlling a potassium oxytitanium phosphate crystal growth furnace according to claim 1, characterized in that: The final step of generating a complete crystal growth log for subsequent analysis and optimization includes: The process parameters recorded on the liquid crystal display are transmitted to an external storage device through a communication interface to form a crystal growth log; The crystal growth log includes temperature change curves, DC motor speed records, pull-up rate data, and changes in potentiometer output voltage. By analyzing the crystal growth log, the temperature stability, the rotation accuracy of the seed crystal rotor, and the matching degree of the pulling rate during the crystal growth process are evaluated. If the crystal growth results do not meet expectations, adjust the process parameters based on the data in the crystal growth log.

9. The method for controlling a potassium titanium phosphate crystal growth furnace according to claim 1, characterized in that: The control method is implemented through a control system for a potassium oxytitanium phosphate crystal growth furnace, the system comprising: The rotation control module is configured to achieve constant rotation by driving the seed crystal rotor with a DC motor and to dynamically correct the perpendicularity of the seed crystal rotor through the ball bearing structure in the connecting seat. The lifting adjustment module is configured to achieve the precise lifting of the seed crystal screw by utilizing the gear meshing transmission and screw adjustment function in the lifting device; The temperature management module is configured to monitor the temperature distribution inside the furnace barrel in real time through a temperature sensor, and adjust the heating power based on a PLC control system and a PID algorithm to maintain solution uniformity. The speed matching module is configured to adjust the DC motor speed according to the voltage signal output by the potentiometer to ensure that the rotation speed of the seed crystal rotor matches the lifting rate. The data display module is configured to display the current process parameters and record key data via an LCD display; The thermal environment optimization module is configured to achieve temperature gradient control by placing the platinum crucible between multiple layers of insulation material and heating it with an electric heating wire. The log generation module is configured to ultimately generate a complete crystal growth log for subsequent analysis and optimization steps.

10. A potassium titanium phosphate crystal growth furnace, characterized in that: The invention includes a growth furnace body and a control system for a potassium oxytitanium phosphate crystal growth furnace as described in claim 9, wherein the growth furnace body is used to implement a control method for a potassium oxytitanium phosphate crystal growth furnace as described in claims 1-8.

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