Crucible melting electrode opening control method

Abstract

The invention discloses a method for controlling the opening degree of a crucible melting electrode, which is used for performing segmented management on the life cycle of the electrode and collecting the consumption speed of the electrode in each cycle. And processing the collected data to obtain the historical speed of electrode consumption in different periods. When the crucible is melted, the historical speed of the corresponding period is used, the speed of the electrode is actively set, and the electrode is slowly closed. The closing distance counteracts the opening distance generated by combustion consumption of the electrode, and dynamic stability of the opening degree of the electrode is achieved. According to the consumption characteristics of the electrodes, the speed setting adopts a composite speed setting form of speed and PWM waves, and the contradiction between the speed and the stability is balanced. On the basis of CCD control, the speed of the electrode is actively set, errors caused by combustion consumption are counteracted, and the opening degree of the electrode is controlled more accurately and stably, and fluctuation is smaller.

Description

Technical Field

[0001] This invention relates to the field of quartz crucible melting and manufacturing, and specifically to a method for controlling the opening degree of the melting electrode in a crucible. Background Technology

[0002] Currently, quartz crucibles are primarily manufactured using a high-temperature electric arc method to melt rotating quartz blanks. The electric arc is typically generated by three graphite electrodes. The distance between the electrode tips determines the arc length; different arc lengths result in different high-temperature zones. If the opening and closing distances of each crucible in a batch are inconsistent, the melted crucibles will exhibit variations in wall thickness or irregular roundness. Therefore, precise control of the electrode opening and closing distances is crucial during the melting process.

[0003] Currently, electrode opening and closing control is generally implemented by a servo system. When not discharging, the servo system can precisely control the opening and closing distance. However, during electrode discharge, even when the servo motor is stationary, the electrode distance increases due to electrode combustion and consumption. The closed-loop control system of the servo unit cannot recognize this change, thus distorting the electrode opening and closing control. Furthermore, the rate of electrode consumption varies constantly due to differences in purging processes, electrode quality, and discharge time, and cannot be compensated for by simple unit-time errors.

[0004] To address the distortion in electrode opening and closing control, a CCD device (camera device) is added to provide real-time feedback of the actual current opening and closing value to the servo control system. The servo system compares the feedback value with the set value to correct the output, ensuring consistency between the actual and set values.

[0005] The control method described above, which adds a CCD device, compensates for errors only after they are detected. This is a passive control method, which suffers from lag and frequent fluctuations. To improve control accuracy and reduce fluctuations, a new control method is needed. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a method for controlling the opening degree of the melting electrode in a crucible. Based on CCD control, the electrode is actively speed-matched to offset the error caused by combustion consumption, making the electrode opening degree control more precise, more stable, and with less fluctuation.

[0007] The technical solution of this invention is: a method for controlling the opening degree of a crucible melting electrode, the specific steps of which are as follows:

[0008] Step S1: Divide the electrode's life cycle into several control cycles;

[0009] Step S2: Based on the crucible model, collect the consumption rate of the most recent 5 sets corresponding to the control cycle; after excluding abnormal fluctuations, average the data to obtain the historical consumption rate.

[0010] (1)

[0011] in, For historical consumption rate, arrive The consumption rate for the last 5 times;

[0012] Using PWM waves, the output is periodically matched to the speed; where the PWM wave coefficient is the proportion of the output time in one control cycle; (2)

[0013] in, For PWM waveform coefficients, For the speed output time, The duration of one control cycle;

[0014] In PWM wave composite speed matching, the actual speed of the speed matching is calculated using historical consumption speed and PWM wave coefficient.

[0015] (3)

[0016] in, This is the actual speed output. Historical consumption rate;

[0017] Step S3: Output speed using the actual speed ratio. By combining PWM waves, the electrodes are slowly closed, achieving a dynamic balance between electrode consumption and electrode closure.

[0018] Furthermore, in step S4, if an error is detected between the actual value and the set value during the control process, the servo system calculates the current consumption rate after quickly correcting the positioning.

[0019] (4)

[0020] in, The current consumption rate, For the distance consumed, This refers to the arc initiation discharge time;

[0021] Then, after updating the actual pace speed using the current consumption speed, output control is performed to correct any possible errors.

[0022] (5)

[0023] in, This is the actual speed output. The current consumption rate, These are the PWM waveform coefficients.

[0024] Furthermore, in step S5, when the current crucible melting ends, the current electrode consumption rate is calculated using formula (4), and the historical consumption rate is calculated using formula (1). This is to update the data for the next control operation.

[0025] Furthermore, in step S1, the electrode's lifespan is divided into 4-6 cycles. Smaller crucible sizes result in more lifespan segments, while larger crucible sizes result in fewer lifespan segments.

[0026] The beneficial effect of this invention is that it provides a method for controlling the opening degree of the melting electrode in a crucible.

[0027] 1. Segment the electrode's lifespan and collect the electrode consumption rate for each cycle. Process the collected data to obtain the historical consumption rate of the electrode for different cycles.

[0028] 2. During the melting of the crucible, the historical speed corresponding to the cycle is used to actively speed-match the electrodes and slowly close them. The closing distance offsets the opening distance caused by electrode combustion and consumption, thus achieving dynamic stability of the electrode opening.

[0029] 3. Based on the consumption characteristics of the electrodes, the speed matching adopts a composite speed matching form of speed plus PWM wave, which balances the contradiction between speed and stability.

[0030] This application, based on CCD control, actively speeds the electrodes to offset errors caused by combustion consumption, making electrode opening control more precise, more stable, and with less fluctuation. Attached Figure Description

[0031] Figure 1 A control flowchart for the crucible melting electrode opening control method;

[0032] Figure 2 This is a schematic diagram of the electrode opening.

[0033] Figure 3 This is a schematic diagram of a PWM wave.

[0034] In the diagram: 1 represents the electrode, and 2 represents the electrode consumption portion. Detailed Implementation

[0035] The present invention will now be further described with reference to the accompanying drawings.

[0036] The electrode opening control process, such as Figure 1 As shown.

[0037] In step S1, the electrode's lifespan is generally divided into 4-6 cycles. Smaller crucible sizes result in more lifespan segments, while larger crucible sizes result in fewer lifespan segments.

[0038] In step S2, based on the crucible model, collect the consumption rate for the most recent 5 sets corresponding to each cycle. After excluding data with abnormal fluctuations, average the data to obtain the historical consumption rate. The calculation formula is as follows:

[0039]

[0040] in, For historical consumption rate, arrive This represents the consumption rate over the last 5 times.

[0041] To avoid excessively low speeds and servo system instability, a PWM wave is used, with the output time periodically matched to the speed. The PWM wave coefficient represents the proportion of the output time within one control cycle (see...). Figure 3 Formula 2 is as follows:

[0042]

[0043] in, For PWM waveform coefficients, For the speed output time, The time of one control cycle.

[0044] In PWM wave composite speed matching, the actual speed of the speed matching is calculated using historical consumption speed and PWM wave coefficients, as shown in Formula 3 below:

[0045]

[0046] in, This is the actual speed output. For historical consumption rate, These are the PWM waveform coefficients.

[0047] In step S3, output speed using the actual pace. By combining PWM waves, the electrodes are slowly closed, achieving a dynamic balance between electrode consumption and electrode closure.

[0048] In step S4, if an error is detected between the actual value and the set value during the control process, the servo system quickly corrects the positioning and calculates the current consumption rate. The calculation formula is as follows:

[0049]

[0050] in, The current consumption rate, The distance after consumption (see) Figure 2 , (Initial distance) This refers to the arc ignition discharge time.

[0051] After updating the actual pace using the current consumption speed, output control is then implemented. This corrects for potential errors, and the calculation formula is as follows:

[0052]

[0053] in, This is the actual speed output. The current consumption rate, These are the PWM waveform coefficients.

[0054] In step S5, once the crucible melting is complete, use Formula 4 to calculate the electrode consumption rate for this current operation, and use Formula 1 to calculate the historical consumption rate. This is to update the data for the next control operation.

[0055] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for controlling the opening degree of a crucible melting electrode, characterized in that, The specific steps are as follows: Step S1: Divide the electrode's life cycle into several control cycles; Step S2: Based on the crucible model, collect the consumption rate of the most recent 5 sets corresponding to the control cycle; after excluding abnormal fluctuations, average the data to obtain the historical consumption rate. （1） in, For historical consumption rate, arrive The consumption rate for the last 5 times; Using PWM waves, the output is periodically matched to the speed; where the PWM wave coefficient is the proportion of the output time in one control cycle; (2) in, For PWM waveform coefficients, For the speed output time, The duration of one control cycle; In PWM wave composite speed matching, the actual speed of the speed matching is calculated using historical consumption speed and PWM wave coefficient. （3） in, This is the actual speed output. Historical consumption rate; Step S3: Output speed using the actual speed ratio. By combining PWM waves, the electrodes are slowly closed, achieving a dynamic balance between electrode consumption and electrode closure.

2. The method for controlling the opening degree of a crucible melting electrode according to claim 1, characterized in that: Step S4: If an error is detected between the actual value and the set value during the control process, the servo system will quickly correct the positioning and calculate the current consumption rate. （4） in, The current consumption rate, For the distance consumed, This refers to the arc initiation discharge time; Then, after updating the actual pace speed using the current consumption speed, output control is performed to correct any possible errors. （5） in, This is the actual speed output. The current consumption rate, These are the PWM waveform coefficients.

3. The method for controlling the opening degree of a crucible melting electrode according to claim 1, characterized in that: Step S5: When the crucible melting ends, use formula (4) to calculate the electrode consumption rate for this time, and use formula (1) to calculate the historical consumption rate. This is to update the data for the next control operation.

4. The method for controlling the opening degree of a crucible melting electrode according to claim 1, characterized in that: In step S1, the life cycle of the electrode is divided into 4-6 cycles.

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