Quartz crucible manufacturing device and automatic feeding method for manufacturing quartz crucible

Abstract

The invention relates to an automatic feeding method for manufacturing a quartz crucible and a quartz crucible manufacturing device. The automatic feeding structure comprises a fixed frame, a feeder vertical driving mechanism and a feeder horizontal driving mechanism which are arranged on the fixed frame, and at least two groups of feeding mechanisms; all the feeding mechanisms can work in a time-sharing manner under gas purging of the corresponding gas purging pipes to continuously feed quartz sand contained in the corresponding quartz sand feeders into the containing cavity for forming through the quartz sand feeding pipes, so that the feeding mechanism can adapt to feeding of quartz crucibles with different sizes and specifications; the automatic degree of feeding is improved, the possibility of pollution caused by a traditional feeding mode can be reduced, the quartz sand feeding efficiency is improved, the production cost of quartz crucibles is effectively reduced, and the product quality of the quartz crucibles is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of crucible manufacturing, and particularly to a quartz crucible manufacturing device and an automatic feeding method for manufacturing quartz crucibles. Background Art

[0002] With the booming development of the new energy and semiconductor industries, large-size monocrystalline silicon wafers have become increasingly important in both the photovoltaic and semiconductor fields. Quartz crucibles are essential products for manufacturing large-size silicon wafers and are often in short supply due to the booming photovoltaic and semiconductor markets. Quartz crucibles are products made from natural or synthetic quartz sand through a series of processes such as melting, cutting, and cleaning.

[0003] As one of the most important links in the manufacturing process of quartz crucibles, how to avoid impurity contamination throughout the entire process has become an important issue in quartz crucible manufacturing. Currently, the traditional manual feeding method greatly increases the possibility of impurity contamination.

[0004] Currently, the main cost source of domestic quartz crucibles is quartz sand. Therefore, it is crucial to save quartz sand during the manufacturing process of quartz crucibles, and saving quartz sand has become the most effective way to reduce costs. Summary of the Invention

[0005] The purpose of the present invention is to provide a quartz crucible manufacturing device and an automatic feeding method for manufacturing quartz crucibles, so as to improve the degree of automation of feeding and reduce the possibility of contamination caused by the traditional feeding method.

[0006] According to some embodiments, the present invention provides a quartz crucible manufacturing device, comprising: a melting mold structure, comprising a melting mold body, a melting mold horizontal driving mechanism and a melting mold rotating mechanism, the melting mold body having a holding cavity for holding the quartz sand, the melting mold horizontal driving mechanism being used to drive the melting mold body to move horizontally to a material receiving process position, the melting mold rotating mechanism being used to drive the melting mold body to rotate at a set process speed; an automatic feeding structure, comprising a fixed frame, a feeder vertical driving mechanism and a feeder horizontal driving mechanism arranged on the fixed frame, and at least two groups of feeding mechanisms, each group of the feeding mechanisms The mechanism includes a quartz sand feeder, a quartz sand feeding pipe connected to the quartz sand feeder, and a gas purge pipe connected to the quartz sand feeding pipe. The feeder vertical drive mechanism is used to drive the feeding mechanism to move vertically, and the feeder horizontal drive mechanism is used to drive the feeding mechanism to move horizontally, so as to move the discharge port of the quartz sand feeding pipe to the feeding process position in the accommodating cavity. All the feeding mechanisms can work in a time-sharing manner under the gas purge of the corresponding gas purge pipe to continuously feed the quartz sand contained in the corresponding quartz sand feeder into the accommodating cavity through the quartz sand feeding pipe for molding. The purity of the quartz sand contained in different quartz sand feeders is different.

[0007] According to other embodiments, the present invention further provides an automatic feeding method for manufacturing a quartz crucible, using the quartz crucible manufacturing device of the present invention, the method comprising the following steps: before the quartz sand feeding starts, the melting mold body is driven to move horizontally to a material receiving process position by the melting mold horizontal driving mechanism, and the melting mold body is driven to rotate at a set process speed by the melting mold rotating mechanism; the feeding mechanism is driven to move by the feeder vertical driving mechanism and the feeder horizontal driving mechanism respectively, and the discharge port of the quartz sand feeding pipe is moved to the feeding position in the accommodating cavity; material process position; control all the feeding mechanisms to work in time sharing, and under the gas purge of the corresponding gas purge pipe, continuously feed the quartz sand of the corresponding target weight contained in the corresponding quartz sand feeder into the said accommodating cavity through the quartz sand feeding pipe for molding, wherein at least two layers of quartz sand with increasing quartz sand purity are formed in sequence along the inner side of the melting mold body facing the axis of the melting mold body; after the quartz sand feeding and molding is completed, the feeding mechanism is driven to move by the vertical driving mechanism of the feeder and the horizontal driving mechanism of the feeder respectively, and the discharge port of the quartz sand feeding pipe is moved away from the said accommodating cavity.

[0008] In some embodiments, when a material cut-off valve is provided between each of the quartz sand feeders and the corresponding quartz sand feed pipes, and each set of the feeding mechanisms further includes a weighing sensor, the step of controlling all the feeding mechanisms to work in a time-sharing manner and continuously discharging the corresponding target weight of quartz sand contained in the corresponding quartz sand feeder into the accommodation cavity through the quartz sand feed pipe under the gas purge of the corresponding gas purge pipe further includes the following steps: controlling the corresponding material cut-off valve to open according to a feeding control signal; and controlling the corresponding material cut-off valve to close when the weight of the discharged quartz sand sensed by the weighing sensor reaches the target weight.

[0009] With the above technical solution, by adding an automatic feeding structure, it is possible to adapt to the feeding of quartz crucibles of different sizes and specifications, improve the automation degree of feeding, reduce the possibility of pollution caused by the traditional feeding method, improve the feeding efficiency of quartz sand, effectively reduce the production cost of quartz crucibles, and improve the product quality of quartz crucibles. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0011] Figure 1 is a main cross-sectional view of a quartz crucible manufacturing device according to an embodiment of the present invention;

[0012] Figure 2 is a side cross-sectional view of a quartz crucible manufacturing device according to an embodiment of the present invention;

[0013] Figure 3 is a flowchart of an automatic feeding method for manufacturing a quartz crucible according to an embodiment of the present invention.

[0014] Description of the Reference Numerals:

[0015] 1. Melting die body; 101. Accommodation cavity; 109. Axis;

[0016] 2. Melting die rotating mechanism; 3. Melting die horizontal driving mechanism;

[0017] 4. Gas purge pipe; 5. Quartz sand feed pipe;

[0018] 51. First vertical section; 52. Bending section; 53. Second vertical section; 59. Discharge port;

[0019] 6. Weighing sensor; 7. Quartz sand feeder; 71. Material cut-off valve;

[0020] 8. Fixed frame; 81. Vertical beam; 82. Cross beam;

[0021] 9. Feeder vertical drive mechanism; 10. Feeder horizontal drive mechanism. Detailed implementation manners

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0023] An embodiment of the present invention provides a quartz crucible manufacturing device.

[0024] Please refer to Figures 1 to 2 together, where Figure 1 is the main view cross-sectional schematic diagram of the quartz crucible manufacturing device according to an embodiment of the present invention; Figure 2 is the side view cross-sectional schematic diagram of the quartz crucible manufacturing device according to an embodiment of the present invention. For the convenience of description, in the following embodiments, the horizontal direction may be the X-axis or Y-axis direction in the Cartesian coordinate system, and the vertical direction is the Z-axis direction in the Cartesian coordinate system.

[0025] As Figures 1 to 2 shown, the quartz crucible manufacturing device described in this embodiment includes: a melting die structure and an automatic feeding structure.

[0026] Specifically, the melting die structure includes a melting die body 1, a melting die rotating mechanism 2, and a melting die horizontal driving mechanism 3. The melting die body 1 has a receiving cavity 101 for receiving the quartz sand to be put in. The melting die horizontal driving mechanism 3 is used to drive the melting die body 1 to horizontally move to the material receiving process position. The melting die horizontal driving mechanism 3 is also used to drive the melting die body 1 to horizontally move to the process position where the crucible melting and the crucible taking can be completed. The melting die rotating mechanism 2 is used to drive the melting die body 1 to rotate at a set process speed, so that the quartz sand put into the receiving cavity 101 forms a quartz sand crucible blank under the action of rotational centrifugal force. The ways for the melting die body 1 to achieve fixation, movement, and rotation can refer to the existing implementation ways, which will not be elaborated here.

[0027] Specifically, the automatic feeding structure includes a fixed frame 8, a vertical driving mechanism 9 of the feeder and a horizontal driving mechanism 10 of the feeder arranged on the fixed frame 8, and at least two groups of feeding mechanisms. Each group of the feeding mechanisms includes a quartz sand feeder 7, a quartz sand feeding pipe 5 connected to the quartz sand feeder 7, and a gas purging pipe 4 connected to the quartz sand feeding pipe 5. The vertical driving mechanism 9 of the feeder is used to drive the feeding mechanism to move vertically, and the horizontal driving mechanism 10 of the feeder is used to drive the feeding mechanism to move horizontally. Through the cooperation of the vertical driving mechanism 9 of the feeder and the horizontal driving mechanism 10 of the feeder, the discharge port 59 of the quartz sand feeding pipe 5 is moved to the feeding process position in the accommodation cavity 101.

[0028] The fixed frame 8 can be fixed in the area outside the outer periphery of the melting mold body 1. The vertical driving mechanism 9 of the feeder is arranged on the vertical beam 81 of the fixed frame 8, and both the quartz sand feeder 7 and the horizontal driving mechanism 10 of the feeder are arranged on the cross beam 82 of the fixed frame 8. The quartz sand feeding pipe 5 has a first vertical section 51 connected to the quartz sand feeder 7, a bent section 52 connecting the first vertical section 51 and bending away from the vertical beam 82 of the fixed frame 8, and a second vertical section 53 connecting the bent section 52 and extending away from the quartz sand feeder 7, so as to facilitate the discharge port 59 located in the second vertical section 53 to extend into the accommodation cavity 101.

[0029] The structure of the automatic feeding structure is simple, can adapt to the feeding of quartz crucibles with different size specifications, reduce the possibility of pollution caused by the traditional feeding method, improve the efficiency of quartz sand feeding, effectively reduce the production cost of quartz crucibles, and improve the product quality of quartz crucibles.

[0030] All the feeding mechanisms can work at different times, and under the gas purging of the corresponding gas purging pipe 4, the quartz sand contained in the corresponding quartz sand feeder 7 is continuously put into the accommodation cavity 101 through the quartz sand feeding pipe 5 for molding; among them, the purity of the quartz sand contained in different quartz sand feeders 7 is different. Before the quartz sand feeding starts, the feeding mechanism is driven to move respectively through the vertical driving mechanism 9 of the feeder and the horizontal driving mechanism 10 of the feeder, so that the discharge port 59 of the quartz sand feeding pipe 5 is moved to the feeding process position in the accommodation cavity 101; after the quartz sand feeding and molding are completed, the feeding mechanism is driven to move respectively through the vertical driving mechanism 9 of the feeder and the horizontal driving mechanism 10 of the feeder, so that the discharge port 59 of the quartz sand feeding pipe 5 is moved away from the accommodation cavity 101 (for example, back to the original position).

[0031] In some embodiments, when the melting die rotating mechanism 2 drives the melting die body 1 to rotate at a set process speed, the axis 109 of the melting die body 1 is parallel to the vertical direction Y. Compared with the traditional inclined feeding of the melting die body, the amount of quartz sand scattered during the feeding process is greatly reduced in this embodiment.

[0032] In some embodiments, the quartz sand feeding pipe 5 feeds quartz sand in a direction perpendicular to the bottom surface of the inner wall of the melting die body 1, and the discharge port 59 of the quartz sand feeding pipe 5 extends into the accommodation cavity 101. Further, the distance between the discharge port 59 of the quartz sand feeding pipe 5 and the bottom surface of the inner wall of the melting die body 1 is a preset distance (the preset distance is greater than the thickness of the quartz sand crucible blank to be formed), so that the discharge port 59 of the quartz sand feeding pipe 5 can extend into the accommodation cavity 101 as much as possible, reducing the amount of quartz sand scattered during the feeding process.

[0033] In some embodiments, each quartz sand feeder 7 contains quartz sand of a corresponding target weight. The required target weight of quartz sand can be pre-weighed and placed into the corresponding quartz sand feeder 7. When the discharge port 59 of the quartz sand feeding pipe 5 is moved to the feeding process position in the accommodation cavity 101, the quartz sand of the corresponding target weight is directly fed continuously, and the tungsten quartz sand in the corresponding quartz sand feeder 7 is then fed completely; switch to the next quartz sand feeder 7 to start feeding.

[0034] In some embodiments, a material cut-off valve 12 is provided between each quartz sand feeder 7 and the corresponding quartz sand feeding pipe 5 for controlling the opening and closing of the feeding. The corresponding material cut-off valve 12 can be controlled to open by a feeding control signal for continuous feeding of quartz sand, and the corresponding material cut-off valve 12 is controlled to close after the feeding is completed; switch to the next quartz sand feeder 7 to start feeding. The material cut-off valve 12 can also control the amount of the fed material.

[0035] In some embodiments, a solenoid valve is provided between each gas purge pipe 4 and the corresponding quartz sand feeding pipe 5 for controlling the opening and closing of the gas purge. The solenoid valve can also control the amount of the purge gas.

[0036] In some embodiments, each set of the feeding mechanisms further includes a weighing sensor 6 for sensing the weight of the quartz sand fed by the corresponding quartz sand feeder 7. The automatic feeding structure further includes a controller (not shown) for controlling the corresponding material cut-off valve 71 to open according to a feeding control signal, and for controlling the corresponding material cut-off valve 71 to close when the weight of the fed quartz sand sensed by the weighing sensor 6 reaches the target weight.

[0037] In some embodiments, all the feeding mechanisms are arranged side by side and can be moved simultaneously.

[0038] The figure shows two sets of feeding mechanisms, which are arranged side by side and can be moved simultaneously. According to the process ratio of the quartz layer required for the quartz crucible, the outer-layer quartz sand and the inner-layer quartz sand are respectively fed. Specifically, the material cut-off valve 71 of the quartz sand feeder 7 containing the outer-layer quartz sand is opened (it can be opened according to the set valve opening) for continuous feeding, and the corresponding gas purge pipe 4 blows air simultaneously until the feeding of the outer-layer quartz sand is completed (until the corresponding weighing sensor 6 reaches the set target weight value); during the feeding, corresponding forming tools such as forming rods or forming plates can be used to form the corresponding quartz sand layer. A feeding mechanism containing the inner-layer quartz sand completes the feeding of the inner-layer quartz sand according to the same process. Among them, the purity of the outer-layer quartz sand is less than the purity of the inner-layer quartz sand. According to the process ratio of the quartz layer required for the quartz crucible, three sets of feeding mechanisms or more can also be set. For a three-layer or more process formula, the above feeding process is also executed. Specifically, multiple quartz sand layers are sequentially formed along the inner side surface of the melting mold body towards the axis of the melting mold body, and the purity of the quartz sand in the multiple quartz sand layers increases sequentially.

[0039] Based on the same inventive concept, the present invention also provides an automatic feeding method for manufacturing a quartz crucible.

[0040] Please refer to Figure 3 , which is a flowchart of the automatic feeding method for manufacturing a quartz crucible according to an embodiment of the present invention. As Figure 3 shown, the automatic feeding method for manufacturing a quartz crucible in this embodiment uses the quartz crucible manufacturing device described in the present invention Figures 1 to 2 . The method includes the following steps: S1. Before the start of quartz sand feeding, drive the melting mold body to move horizontally to the material receiving process position through the melting mold horizontal drive mechanism, and drive the melting mold body to rotate at a set process speed through the melting mold rotation mechanism; S2. Drive the feeding mechanism to move respectively through the feeder vertical drive mechanism and the feeder horizontal drive mechanism, and move the discharge port of the quartz sand feeding pipe to the feeding process position in the accommodation cavity; S3. Control all the feeding mechanisms to work at different times, and continuously feed the corresponding target weight of quartz sand in the corresponding quartz sand feeder into the accommodation cavity through the quartz sand feeding pipe under the gas purge of the corresponding gas purge pipe for forming; and S4. After the completion of quartz sand feeding and forming, drive the feeding mechanism to move respectively through the feeder vertical drive mechanism and the feeder horizontal drive mechanism, and move the discharge port of the quartz sand feeding pipe away from the accommodation cavity. Among them, at least two quartz sand layers with sequentially increasing quartz sand purity are sequentially formed along the inner side surface of the melting mold body towards the axis of the melting mold body.

[0041] In some embodiments, when a material shut-off valve 71 is provided between each of the quartz sand feeders 7 and the corresponding quartz sand feeding pipe 5, and each group of the feeding mechanism also includes a weighing sensor 6, the step S3 also includes the following steps: controlling the corresponding material shut-off valve 71 to open according to a feeding control signal; and controlling the corresponding material shut-off valve 51 to close when the weight of the fed quartz sand sensed by the weighing sensor 6 reaches the target weight.

[0042] The above-mentioned embodiment of the present invention, by adding an automatic feeding structure including a fixed frame, a vertical driving mechanism of the feeder and a horizontal driving mechanism of the feeder arranged on the fixed frame, and at least two groups of feeding mechanisms, all of the feeding mechanisms can work in time-sharing mode under the gas purge of the corresponding gas purge pipe to continuously feed the quartz sand contained in the corresponding quartz sand feeder into the accommodating cavity through the quartz sand feeding pipe for forming. It can adapt to the feeding of quartz crucibles of different sizes and specifications. Improving the degree of automation of feeding can reduce the possibility of pollution caused by traditional feeding methods, improve the efficiency of quartz sand feeding, effectively reduce the production cost of quartz crucibles, and improve the product quality of quartz crucibles.

[0043] It should be noted that the terms "including" and "having" and their variations involved in the document of the present invention are intended to cover non-exclusive inclusions. The terms "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence, unless the context clearly indicates, and it should be understood that the data used in this way can be interchanged under appropriate circumstances. The term "one or more" depends at least in part on the context, and can be used to describe features, structures or characteristics in a singular sense, or can be used to describe features, structures or combinations of features in a plural sense. The term "based on" can be understood as not necessarily intended to express a set of exclusive factors, but can alternatively, also at least in part depending on the context, allow the presence of other factors that are not necessarily explicitly described. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict. In addition, in the above description, the description of well-known components and technologies is omitted to avoid unnecessary confusion of the concept of the present invention. In the above embodiments, each embodiment focuses on the differences from other embodiments, and the same / similar parts between the embodiments can be referred to each other.

[0044] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A quartz crucible manufacturing device, characterized in that, include: The melting mold structure includes a melting mold body, a melting mold horizontal driving mechanism and a melting mold rotating mechanism, wherein the melting mold body has a receiving cavity for receiving the put quartz sand, the melting mold horizontal driving mechanism is used to drive the melting mold body to move horizontally to a material receiving process position, and the melting mold rotating mechanism is used to drive the melting mold body to rotate according to a set process speed; The automatic feeding structure comprises a fixed frame, a feeder vertical driving mechanism and a feeder horizontal driving mechanism arranged on the fixed frame, and at least two groups of feeding mechanisms, each group of the feeding mechanisms comprises a quartz sand feeder, a quartz sand feeding pipe connected to the quartz sand feeder, and a gas purge pipe connected to the quartz sand feeding pipe, the feeder vertical driving mechanism is used to drive the feeding mechanism to move vertically, and the feeder horizontal driving mechanism is used to drive the feeding mechanism to move horizontally, so as to move the discharge port of the quartz sand feeding pipe to the feeding process position in the accommodating cavity, all the feeding mechanisms can work in time-sharing mode under the gas purge of the corresponding gas purge pipe to continuously feed the quartz sand contained in the corresponding quartz sand feeder through the quartz sand feeding pipe into the accommodating cavity for molding, and the purity of the quartz sand contained in different quartz sand feeders is different.

2. The quartz crucible manufacturing apparatus according to claim 1, wherein When the melting mold rotating mechanism drives the melting mold body to rotate according to a set process speed, the axis of the melting mold body is parallel to the vertical direction.

3. The quartz crucible manufacturing apparatus according to claim 1 or 2, wherein The quartz sand feeding pipe feeds quartz sand in a direction perpendicular to the bottom surface of the inner wall of the melting mold body, and the discharge port of the quartz sand feeding pipe extends into the accommodating cavity.

4. The quartz crucible manufacturing apparatus according to claim 1, wherein The fixed frame is fixed to the area outside the periphery of the melting mold body, the vertical drive mechanism of the feeder is arranged on the vertical beam of the fixed frame, and the quartz sand feeder and the horizontal drive mechanism of the feeder are both arranged on the cross beam of the fixed frame; the quartz sand feeding pipe has a first vertical section connected to the quartz sand feeder, a bent section connected to the first vertical section and bent in the direction away from the vertical beam of the fixed frame, and a second vertical section connected to the bent section and extending in the direction away from the quartz sand feeder.

5. The quartz crucible manufacturing apparatus according to claim 1, characterized in that, All the feeding mechanisms are arranged in parallel and can be moved simultaneously.

6. The quartz crucible manufacturing apparatus according to claim 1, characterized in that, Each of the quartz sand feeders contains quartz sand of a corresponding target weight.

7. The quartz crucible manufacturing apparatus according to claim 1, characterized in that, A material stop valve is arranged between each of the quartz sand feeders and the corresponding quartz sand feeding pipe to control the opening and closing of the feeding; an electromagnetic valve is arranged between each of the gas purge pipes and the corresponding quartz sand feeding pipe to control the opening and closing of the gas purge.

8. The quartz crucible manufacturing apparatus according to claim 7, wherein, Each group of the feeding mechanisms also includes a weighing sensor for sensing the weight of the quartz sand fed by the corresponding quartz sand feeder; The automatic feeding structure also includes a controller for controlling the opening of the corresponding material stop valve according to the feeding control signal, and for controlling the closing of the corresponding material stop valve when the weight of the quartz sand fed sensed by the weighing sensor reaches the target weight.

9. An automatic feeding method for manufacturing a quartz crucible, characterized in that, Using the quartz crucible manufacturing device according to any one of claims 1 to 8, the method comprises the following steps: Before the quartz sand feeding starts, the melting mold body is horizontally driven to the material receiving process position by the melting mold horizontal driving mechanism, and the melting mold body is driven to rotate at a set process speed by the melting mold rotating mechanism; The feeding mechanism is driven to move by the feeding device vertical driving mechanism and the feeding device horizontal driving mechanism respectively, and the discharge port of the quartz sand feeding pipe is moved to the feeding process position in the accommodating cavity; Control all the feeding mechanisms to work in a time-sharing manner, and continuously feed the corresponding target weight of quartz sand in the corresponding quartz sand feeder into the accommodating cavity through the quartz sand feeding pipe under the gas purge of the corresponding gas purge pipe to form a shape. Among them, at least two quartz sand layers with gradually increasing quartz sand purity are formed along the inner side surface of the melting mold body towards the axis of the melting mold body; After the quartz sand feeding and forming are completed, the feeding mechanism is driven to move by the feeding device vertical driving mechanism and the feeding device horizontal driving mechanism respectively, and the discharge port of the quartz sand feeding pipe is moved away from the accommodating cavity.

10. The automatic feeding method for manufacturing a quartz crucible according to claim 9, characterized in that, When a material cut-off valve is provided between each quartz sand feeder and the corresponding quartz sand feeding pipe, and each set of feeding mechanisms further includes a weighing sensor, the step of controlling all the feeding mechanisms to work in a time-sharing manner and continuously feeding the corresponding target weight of quartz sand in the corresponding quartz sand feeder into the accommodating cavity through the quartz sand feeding pipe under the gas purge of the corresponding gas purge pipe to form a shape further includes the following steps: Controlling the corresponding material cut-off valve to open according to the feeding control signal; and When the weight of the fed quartz sand sensed by the weighing sensor reaches the target weight, controlling the corresponding material cut-off valve to close.

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