Air pressure control system and method for plasma cutting equipment

Abstract

The invention provides an air pressure control system and method for plasma cutting equipment, and the system comprises a parameter obtaining module which is used for obtaining set cutting process parameters; the control module is used for determining the target cutting air pressure corresponding to the set cutting process parameters according to the mapping relation between the pre-stored cutting process parameters and the cutting air pressure; a proportional valve control signal is generated according to the target cutting air pressure; the proportional valve module is used for controlling the output cutting air pressure based on the proportional valve control signal; and the gas output module is used for outputting gas outwards under the control of the proportional valve module. The proportional valve of the cutting equipment is automatically adjusted according to the cutting process parameters, automatic control over the cutting air pressure is achieved, and the cutting quality is improved.

Description

Technical Field

[0001] The present application relates to the technical field of plasma cutting equipment, and in particular to a plasma cutting equipment air pressure control system and method. Background Art

[0002] The principle of plasma cutting equipment is to apply high voltage between the electrode and the workpiece to excite gas (such as argon, nitrogen, oxygen, etc.) to form plasma. Plasma has high energy and temperature and can quickly melt metal. Plasma cutting equipment is used in different cutting processes, and different cutting pressures need to be adjusted. To adjust the cutting pressure, you need to manually adjust the external pressure regulating valve or manually adjust the pressure of the proportional valve. These two solutions are time-consuming and there is a problem of forgetting to adjust the pressure when switching cutting processes. The manually adjusted proportional valve may also be inconsistent with the actual required cutting pressure, resulting in arc interruption or poor cutting quality during the cutting process.

[0003] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present application, and therefore may include information that does not constitute prior art known to ordinary technicians in the field. Summary of the invention

[0004] In response to the problems in the prior art, the purpose of this application is to provide a plasma cutting equipment air pressure control system and method, which automatically adjusts the proportional valve of the cutting equipment according to the cutting process parameters, realizes automatic control of the cutting air pressure, and improves the cutting quality.

[0005] The present application embodiment provides a plasma cutting equipment air pressure control system, comprising:

[0006] A parameter acquisition module is used to acquire and set cutting process parameters;

[0007] A control module, for determining a target cutting pressure corresponding to the set cutting process parameters according to a pre-stored mapping relationship between the cutting process parameters and the cutting pressure; and generating a proportional valve control signal according to the target cutting pressure; and

[0008] A proportional valve module, used for controlling the output cutting gas pressure based on a proportional valve control signal;

[0009] The gas output module is used to output gas to the outside under the control of the proportional valve module.

[0010] In some embodiments, the cutting process parameters include one or more of an output current value, a cutting method, a type of material to be cut, and a thickness of the material to be cut.

[0011] In some embodiments, the proportional valve module is also used to obtain the actual cutting gas pressure;

[0012] The control module is used to generate a proportional valve control signal according to the difference between the actual cutting gas pressure and the target cutting gas pressure.

[0013] In some embodiments, the control module generates a proportional valve control signal based on a proportional-integral algorithm according to a difference between the actual cutting gas pressure and the target cutting gas pressure.

[0014] In some embodiments, it also includes:

[0015] The amplification module is used to amplify the proportional valve control signal into a control signal within the control voltage range of the proportional valve module and input the control signal into the proportional valve module.

[0016] In some embodiments, the parameter acquisition module is further used to display and set cutting process parameters.

[0017] In some embodiments, a communication module is also included, which is used to send the set cutting process parameters acquired by the parameter acquisition module to the control module.

[0018] In some embodiments, a gas input module is further included for inputting external gas into the proportional valve module.

[0019] The present application also provides a method for controlling the air pressure of a plasma cutting device. The method adopts the air pressure control system of the plasma cutting device described above, and includes the following steps:

[0020] Get and set cutting process parameters;

[0021] According to the pre-stored mapping relationship between the cutting process parameters and the cutting gas pressure, the target cutting gas pressure corresponding to the set cutting process parameters is determined;

[0022] Generate proportional valve control signal according to target cutting air pressure;

[0023] The output cutting gas pressure is controlled based on the proportional valve control signal.

[0024] In some embodiments, generating a proportional valve control signal according to a target cutting gas pressure includes the following steps:

[0025] Get the actual cutting gas pressure output from the gas output module;

[0026] Determine whether the difference between the actual cutting gas pressure and the target cutting gas pressure is greater than or equal to a preset minimum difference threshold;

[0027] If yes, a proportional valve control signal is generated based on a proportional-integral algorithm according to the difference between the actual cutting gas pressure and the target cutting gas pressure;

[0028] Otherwise, stop the cutting gas pressure adjustment process.

[0029] The plasma cutting equipment air pressure control system and method provided in this application have the following advantages:

[0030] By adopting the plasma cutting equipment control system and method of the present application, the proportional valve of the cutting equipment is automatically adjusted according to the cutting process parameters, the automatic control of the cutting gas pressure is realized, the gas pressure adjustment speed is improved, thereby improving the cutting efficiency, improving the accuracy of the gas pressure adjustment, being able to adapt to the requirements of various cutting processes, avoiding interrupted arcs during the cutting process, thereby improving the cutting quality. By adopting this system, there is no need for the staff to manually determine the cutting gas pressure, nor is there a need for the staff to manually adjust the proportional valve, which reduces the threshold for use by the staff. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings.

[0032] Figure 1 It is a structural block diagram of a plasma cutting equipment air pressure control system according to an embodiment of the present application;

[0033] Figure 2 It is a detailed structural schematic diagram of a gas pressure control system of a plasma cutting device according to an embodiment of the present application;

[0034] Figure 3 is a flow chart of a method for controlling air pressure of plasma cutting equipment according to an embodiment of the present application;

[0035] Figure 4 This is a flow chart of generating a proportional valve control signal according to an embodiment of the present application.

[0036] Reference numerals:

[0037] M100-parameter acquisition module; M200-control module; M300-proportional valve module; M400-gas output module; M500-communication module; M600-amplification module; M700-gas input module. DETAILED DESCRIPTION

[0038] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this application will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. In the figures, the same reference numerals represent the same or similar structures, and thus their repeated description will be omitted. "or" and "or" in the specification may both mean "and" or "or".

[0039] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that when the terms "consisting of" and / or "comprising" are used in this specification, the presence of the features, integers, steps, operations, elements and / or parts can be determined, but the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups is not excluded. At the same time, when used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0040] Plasma cutting equipment is a kind of equipment that uses the high temperature generated by plasma to cut metal and other materials. Its working principle is that the gas in the cutting gun is ionized into positive and negative charged ions and electrons under the action of high-frequency arc to form plasma. The plasma is accelerated under the action of the electric field to form a high-energy density plasma beam, which is ejected through the nozzle. When the plasma beam contacts the surface of the workpiece, it instantly heats the metal to a molten state, and uses its high-speed airflow to blow away the molten metal, thereby achieving cutting. The output gas pressure of the plasma cutting equipment has many important effects on the cutting effect. When the air pressure is insufficient, the ejection speed of the plasma arc is weakened, which will lead to a decrease in cutting ability and difficulty in cutting through thicker materials. When the air pressure is too high, the excessive airflow will blow away the concentrated arc column, disperse the energy of the arc column, and weaken the cutting intensity of the plasma arc, which will also affect the cutting effect and fail to achieve the ideal cutting depth and speed.

[0041] like Figure 1 As shown, the present application provides a plasma cutting equipment air pressure control system, comprising:

[0042] The parameter acquisition module M100 is used to acquire and set cutting process parameters; in this embodiment, the cutting process parameters include one or more of the output current value, the cutting method, the type of material to be cut, and the thickness of the material to be cut;

[0043] The control module M200 is used to determine the target cutting pressure corresponding to the set cutting process parameters according to the pre-stored mapping relationship between the cutting process parameters and the cutting pressure; and to generate a proportional valve control signal according to the target cutting pressure; the control module M200 can be implemented by a micro control unit, which executes the program in the memory in advance to realize the control function; and

[0044] Proportional valve module M300, used to control the output cutting air pressure based on the proportional valve control signal; the proportional valve is a common pneumatic control component that can achieve precise control of the air pressure of the pneumatic system to meet high-precision control requirements;

[0045] The gas output module M400 is used to output gas to the outside under the control of the proportional valve module; the gas output module M400 is a component that outputs the gas passing through the proportional valve to the outside of the welding gun.

[0046] By adopting the plasma cutting equipment control system of the present application, the proportional valve of the cutting equipment is automatically adjusted according to the cutting process parameters, the automatic control of the cutting gas pressure is realized, the gas pressure adjustment speed is improved, thereby improving the cutting efficiency, improving the accuracy of the gas pressure adjustment, being able to adapt to the requirements of various cutting processes, avoiding the interruption of the arc during the cutting process, thereby improving the cutting quality. By adopting this system, there is no need for the staff to manually determine the size of the cutting gas pressure, nor is there a need for the staff to manually adjust the proportional valve, which reduces the use threshold for the staff. The control system can be integrated into the plasma cutting equipment, the parameter acquisition module M100 is set on the housing of the plasma cutting equipment, the control module M200, the proportional valve module M300 and the gas output module M400 are set in the housing, and the control module M200 can be integrated into the control MCU of the plasma cutting equipment, or set in a separate MCU.

[0047] As mentioned above, the cutting process parameters may include the output current value. When the cutting process parameters are changed, the proportional valve module needs to be adjusted accordingly. Among them, when the output current value is large, the plasma arc energy is large, and a higher cutting gas pressure is required to ensure the stability of the plasma arc. The higher gas pressure can make the plasma arc energy more concentrated and the injection force stronger, thereby matching the larger output current, which is conducive to improving the cutting speed and quality. On the contrary, when the output current value is small, the arc energy is relatively weak, and a smaller cutting gas pressure is required to maintain the stable combustion of the plasma arc.

[0048] Cutting process parameters may include cutting methods. Different cutting methods have different requirements for cutting gas pressure. For example, contact cutting requires lower gas pressure to maintain arc balance. If the gas pressure is too high, the arc may become unstable or even extinguished, affecting the normal cutting process. Transferred arc cutting requires higher cutting gas pressure to ensure the straightness and energy concentration of the plasma arc to achieve efficient cutting.

[0049] The cutting process parameters may include the type of material to be cut. For example, when cutting carbon steel, stainless steel, and aluminum alloy, the corresponding cutting gas pressure requirements are different. Setting the cutting gas pressure to a gas pressure value suitable for a specific material is conducive to obtaining better cutting quality.

[0050] The cutting process parameters may include the thickness of the material to be cut. For example, when the material to be cut is thicker, the cutting difficulty is correspondingly greater, requiring greater cutting energy and a stronger plasma arc to penetrate the material, and therefore, a higher cutting pressure is required. When the thickness of the cutting material is thinner, cutting is relatively easy, and excessive cutting pressure is not required. Lower cutting pressure can make the plasma arc softer, reduce the impact force on the material, and prevent excessive deformation and burrs.

[0051] In this embodiment, the staff can pre-establish the mapping relationship between the cutting process parameters and the cutting pressure and store it in the memory. The cutting process parameters include parameters of m dimensions (m≥1), each parameter includes n optional values ​​(n>1), and the optional values ​​of the parameters of m dimensions are respectively combined to obtain m×n parameter combinations, and a preset cutting pressure value is set corresponding to each parameter combination, that is, m×n values ​​corresponding to the m×n parameter combinations can be obtained and stored as a mapping table. Here, the number of optional values ​​of the parameters of each dimension is n as an example for explanation. In other embodiments, the number of optional values ​​of the parameters of each dimension can also be different, for example, the output current is divided into n1 gears, the cutting mode is set to n2 types, the type of material to be cut is divided into n3 types, and the cutting thickness is divided into n4 levels. And after forming multiple parameter combinations, some parameter combinations that will not be used can be deleted. For example, for a specific cutting mode, its output current needs to meet or exceed the current threshold I1, then the combination of the thickness of the material and the output current less than the current threshold I1 is deleted. Therefore, when setting the mapping table of parameter combinations and preset cutting pressures, the optional values ​​of the parameters based on each dimension are freely combined. After obtaining multiple parameter combinations, the parameter combinations are screened according to the preset parameter relationship conditions, and the parameter combinations that do not meet the parameter relationship conditions are removed, and the preset cutting pressure values ​​are set for the remaining parameter combination relationships. The preset parameter relationship conditions include, for example, for a specific cutting method, its output current is greater than or equal to the current threshold I1; for materials with a thickness greater than the thickness threshold T1, its output current is greater than or equal to the current threshold I2; when the material to be cut is copper, its output current is greater than or equal to the current threshold I3; when the material to be cut is tungsten, its output current is less than or equal to the current threshold I4, etc. Alternatively, when setting the parameter combination, the staff can directly select several commonly used parameter combinations based on experience, and only set the preset cutting pressure values ​​for these commonly used parameter combinations.

[0052] The preset cutting air pressure value may be an empirical value set by the staff, and the cutting effect may be verified by experiments. After the control module M200 obtains the set cutting process parameters, the control module M200 searches the mapping table to find which parameter combination in the mapping table corresponds to the set cutting process parameters, and then uses the preset cutting air pressure value corresponding to the parameter combination as the target cutting air pressure.

[0053] In this embodiment, the proportional valve module M300 is also used to obtain the actual cutting pressure output by the gas output module M400, wherein the proportional valve module M300 can determine the actual cutting pressure output according to the valve scale after the valve is adjusted, or determine the actual cutting pressure by reading the barometer. The actual cutting pressure is the cutting pressure collected during the actual operation of the plasma cutting equipment. The control module M200 is used to generate a proportional valve control signal according to the difference between the actual cutting pressure and the target cutting pressure. Among them, the control module M200 generates a proportional valve control signal based on a proportional integral algorithm according to the difference between the actual cutting pressure and the target cutting pressure. When calculating the proportional valve control signal, the difference between the target cutting pressure and the actual cutting pressure is used as the error to be reduced, and the proportional valve control signal is used as the control amount. By adjusting the appropriate proportional integral coefficient, the actual cutting pressure is adjusted to the target cutting pressure at an appropriate speed, and finally the actual cutting pressure reaches the value of the target cutting pressure. When the absolute value of the difference between the actual cutting pressure and the target cutting pressure is less than the preset minimum difference threshold, it is considered that the actual cutting pressure has been adjusted to the target cutting pressure, and the proportional valve module M300 is stopped from being adjusted to keep the output pressure stable.

[0054] like Figure 2 As shown, since the magnitude of the proportional valve control signal generated by the control module M200 may not reach the value required to drive the proportional valve module M300 to adjust, the plasma cutting equipment control system also includes an amplifier module M600, which is used to amplify the proportional valve control signal into a control signal within the control voltage range of the proportional valve module M300 and input it to the proportional valve module. The amplifier module M600 may include, for example, an amplifier circuit composed of an operational amplifier, a transistor amplifier circuit, and other circuit structures.

[0055] In this embodiment, the parameter acquisition module M100 is also used to display the set cutting process parameters. The staff can input the set cutting process parameters through the parameter acquisition module M100, and can view the set cutting process parameters, modify some or all of the cutting process parameters through the parameter acquisition module M100. The parameter acquisition module M100 may include, for example, a touch screen, or may include a display screen and an input keyboard, or other components that can display parameters and support users to set and modify parameters. The parameter acquisition module M100 may provide options for several preset parameter combinations, which are provided to the user in the form of buttons or lists in the user interface for the user to choose, or may directly provide selection options for cutting process parameters of various dimensions, or the user may directly input cutting process parameters of various dimensions. After acquiring the set cutting process parameters, the control module M200 may also determine whether the set cutting process parameters meet the preset parameter conditions according to the preset parameter relationship conditions. If not, the user is prompted to modify them. The preset parameter relationship conditions include, for example, for a specific cutting method, the output current is greater than or equal to the current threshold I1; for materials with a thickness greater than the thickness threshold T1, the output current is greater than or equal to the current threshold I2; when the material to be cut is copper, the output current is greater than or equal to the current threshold I3; when the material to be cut is tungsten, the output current is less than or equal to the current threshold I4, etc. When the user sets or selects incorrectly, the user can be prompted to make changes in time by displaying an error message.

[0056] like Figure 2 As shown, the plasma cutting equipment control system also includes a communication module M500, which is used to send the set cutting process parameters obtained by the parameter acquisition module M100 to the control module M200. The communication module M500 can be a wired communication module, or a wireless communication module such as Bluetooth, WIFI, etc. Figure 2 As shown, the plasma cutting equipment control system also includes a gas input module M700, which is used to input external gas to the proportional valve module M300. The gas input module M700 is mainly responsible for providing stable, continuous and required gas to the plasma cutting equipment to generate a plasma arc for cutting, and its components include, for example, a gas source (common gas sources include compressed air, nitrogen, argon, etc.), a gas regulating valve, etc.

[0057] like Figure 3 As shown, the embodiment of the present application also provides a plasma cutting equipment air pressure control method, using the above-mentioned plasma cutting equipment air pressure control system, the plasma cutting equipment air pressure control method includes the following steps:

[0058] S100: obtaining and setting cutting process parameters; in this embodiment, the cutting process parameters include one or more of an output current value, a cutting method, a type of material to be cut, and a thickness of the material to be cut;

[0059] S200: determining a target cutting gas pressure corresponding to the set cutting process parameters according to a pre-stored mapping relationship between the cutting process parameters and the cutting gas pressure;

[0060] In this embodiment, the pre-stored mapping relationship between the cutting process parameters and the cutting gas pressure is a mapping table of parameter combinations of cutting process parameters in multiple dimensions and cutting gas pressure values. The mapping table is stored in a memory, and the control module reads the mapping table, performs a table lookup based on the set cutting process parameters, and obtains the preset cutting gas pressure in the mapping table as the target cutting gas pressure;

[0061] S300: Generate a proportional valve control signal according to the target cutting air pressure;

[0062] Specifically, the control module generates a proportional valve control signal according to the difference between the actual cutting air pressure and the target cutting air pressure fed back by the proportional valve module, so as to adjust the actual cutting air pressure to the target cutting air pressure;

[0063] S400: Control the output cutting gas pressure based on the proportional valve control signal.

[0064] By adopting the gas pressure control method of the plasma cutting equipment, the proportional valve of the cutting equipment is automatically adjusted according to the cutting process parameters, the automatic control of the cutting gas pressure is realized, the gas pressure adjustment speed is improved, thereby improving the cutting efficiency, improving the accuracy of the gas pressure adjustment, being able to adapt to the requirements of various cutting processes, avoiding arc interruption during the cutting process, thereby improving the cutting quality. By adopting this system, there is no need for the staff to manually determine the cutting gas pressure, nor is there a need for the staff to manually adjust the proportional valve, which reduces the threshold for use by the staff. This control method can be deployed in the plasma cutting equipment, and the control process can be realized by the control MCU of the plasma cutting equipment, or it can be set in a separate MCU to realize the control process.

[0065] like Figure 4 As shown, the step S300: generating a proportional valve control signal according to the target cutting air pressure includes the following steps:

[0066] S310: Acquire the actual cutting gas pressure outputted from the gas output module;

[0067] S320: Determine whether the difference between the actual cutting gas pressure and the target cutting gas pressure is greater than or equal to a preset minimum difference threshold;

[0068] If yes, S330: generating a proportional valve control signal based on a proportional-integral algorithm according to the difference between the actual cutting pressure and the target cutting pressure;

[0069] Otherwise, it is considered that the actual cutting gas pressure has been adjusted to the target cutting gas pressure, and the actual cutting gas pressure value is kept unchanged, S340: the cutting gas pressure adjustment process is stopped.

[0070] The above content is a further detailed description of the present application in combination with specific preferred implementation methods, and it cannot be determined that the specific implementation of the present application is limited to these descriptions. For ordinary technicians in the technical field to which the present application belongs, several simple deductions or substitutions can be made without departing from the concept of the present application, which should be deemed to fall within the scope of protection of the present application.

Claims

1. A plasma cutting equipment air pressure control system, characterized in that: include: A parameter acquisition module is used to acquire and set cutting process parameters; A control module, used for determining the target cutting gas pressure corresponding to the set cutting process parameters according to the pre-stored mapping relationship between the cutting process parameters and the cutting gas pressure; and generating a proportional valve control signal according to the target cutting air pressure; as well as A proportional valve module, used for controlling the output cutting gas pressure based on the proportional valve control signal; The gas output module is used to output gas to the outside under the control of the proportional valve module.

2. The plasma cutting equipment air pressure control system according to claim 1, characterized in that: The cutting process parameters include one or more of an output current value, a cutting method, a type of material to be cut, and a thickness of the material to be cut.

3. The plasma cutting equipment air pressure control system according to claim 1, characterized in that: The proportional valve module is also used to obtain the actual cutting gas pressure; The control module is used to generate a proportional valve control signal according to the difference between the actual cutting gas pressure and the target cutting gas pressure.

4. The plasma cutting equipment air pressure control system according to claim 3, characterized in that: The control module generates the proportional valve control signal based on a proportional-integral algorithm according to the difference between the actual cutting gas pressure and the target cutting gas pressure.

5. The plasma cutting equipment air pressure control system according to claim 1, characterized in that: Also includes: The amplification module is used to amplify the proportional valve control signal into a control signal within the control voltage range of the proportional valve module and input the control signal into the proportional valve module.

6. The plasma cutting equipment air pressure control system according to claim 1, characterized in that: The parameter acquisition module is also used to display the set cutting process parameters.

7. The plasma cutting equipment air pressure control system according to claim 1, characterized in that: It also includes a communication module, which is used to send the set cutting process parameters acquired by the parameter acquisition module to the control module.

8. The plasma cutting equipment air pressure control system according to claim 1, characterized in that: It also includes a gas input module for inputting external gas into the proportional valve module.

9. A method for controlling air pressure of plasma cutting equipment, characterized in that: Using the plasma cutting equipment air pressure control system according to any one of claims 1 to 8, the method comprises the following steps: Get and set cutting process parameters; Determining the target cutting gas pressure corresponding to the set cutting process parameters according to the pre-stored mapping relationship between the cutting process parameters and the cutting gas pressure; generating a proportional valve control signal according to the target cutting air pressure; The output cutting gas pressure is controlled based on the proportional valve control signal.

10. The plasma cutting equipment air pressure control method according to claim 9, characterized in that: Generating a proportional valve control signal according to the target cutting air pressure comprises the following steps: Obtaining the actual cutting gas pressure outputted from the gas output module; Determining whether the absolute value of the difference between the actual cutting gas pressure and the target cutting gas pressure is greater than or equal to a preset minimum difference threshold; The proportional valve control signal is generated based on a proportional-integral algorithm according to a difference between the actual cutting gas pressure and the target cutting gas pressure.

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