Supercritical CO2 and ultrasonic combined machining system and machine tool

Abstract

The utility model discloses a supercritical CO2 and ultrasonic combined machining system and a machine tool. The system comprises a supercritical CO2 supply system connected with a first control valve; the supercritical CO2 control module is electrically connected with the first control valve; the supercritical CO2 control module is also electrically connected with the supercritical CO2 supply unit; the ultrasonic machining control module comprises an ultrasonic control module, the ultrasonic control module is electrically connected with the ultrasonic machining device, and the ultrasonic control module is further electrically connected with the supercritical CO2 control module so as to control the process parameters of the supercritical CO2 to be dynamically adjusted within a preset range along with the ultrasonic parameters according to the corresponding relation between the process parameters of the supercritical CO2 and the ultrasonic parameters. Through combination of supercritical CO2 and ultrasound, the spraying effect of the supercritical CO2 is improved, the machining effect and machining quality are ensured, and the machining efficiency and precision are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of cutting processing, in particular to a supercritical CO2 and ultrasonic composite processing system and a machine tool. Background Art

[0002] Difficult-to-process materials such as high-strength steel, high-temperature alloys and titanium alloys usually have advantages such as high strength, corrosion resistance, oxidation resistance and excellent high-temperature performance, and are widely used in key equipment in important fields such as aerospace, nuclear energy and military industry. However, while meeting the requirements of high-performance use, due to the difficulty of material processing, it will lead to a series of problems such as severe tool wear, reduced life, high cutting zone temperature, reduced workpiece surface processing quality and large processing residual stress. Traditional pouring cutting fluid processing can no longer solve these problems. In addition, the cutting fluid contains mineral oil and various chemical additives. Large-scale use will harm the environment and the health of operators, and the treatment of waste liquid will increase production costs. Therefore, it is necessary to study a cutting method that can solve the cutting problems of difficult-to-process materials. Traditional pouring cutting fluid processing can no longer solve these problems. In addition, the cutting fluid contains mineral oil and various chemical additives. Large-scale use will harm the environment and the health of operators, and the treatment of waste liquid will increase production costs. In recent years, supercritical CO2 has been widely used in the field of extraction due to its green and non-toxic nature, and it has also been applied to the field of mechanical processing. In order to ensure the cooling effect, a large amount of supercritical CO2 needs to be consumed, resulting in certain waste and low cooling efficiency.

[0003] Ultrasonic machining technology can not only improve the surface roughness of the cutting surface and enhance machining accuracy, but also reduce cutting resistance and extend the life of the tool. Therefore, ultrasonic machining is widely used. Utility Model Content

[0004] The utility model provides a supercritical CO2 and ultrasonic composite machining system, which can realize cutting of difficult-to-machine materials, is environmentally friendly, has good cooling effect, can improve machining surface roughness, improve machining burr problems, and improve machining accuracy and efficiency.

[0005] According to one aspect of the utility model, a supercritical CO2 and ultrasonic composite processing system is provided, the supercritical CO2 and ultrasonic composite processing system comprising: a supercritical CO2 supply unit connected to a first control valve;

[0006] A supercritical CO2 control module, electrically connected to the first control valve; the supercritical CO2 control module is also electrically connected to the supercritical CO2 supply unit;

[0007] Ultrasonic machining device;

[0008] An ultrasonic machining control module includes an ultrasonic control module, which is electrically connected to the ultrasonic machining device and is also electrically connected to the supercritical CO2 control module, so as to control the process parameters of the supercritical CO2 to dynamically adjust within a preset range following the ultrasonic parameters according to the correspondence between the process parameters of the supercritical CO2 and the ultrasonic parameters of the ultrasonic machining device; the ultrasonic parameters include the ultrasonic vibration frequency f and the ultrasonic amplitude A of the ultrasonic machining device, and the process parameters of the supercritical CO2 include the supercritical CO2 pressure P.

[0009] Optionally, the correspondence between the supercritical CO2 pressure P and the ultrasonic vibration frequency f is: when the ultrasonic vibration frequency f is within a first preset ultrasonic vibration frequency range, the ultrasonic vibration frequency f is negatively correlated with the supercritical CO2 pressure P; when the ultrasonic vibration frequency f is within a second preset ultrasonic vibration frequency range, the ultrasonic vibration frequency f is positively correlated with the supercritical CO2 pressure P, and any value within the first preset ultrasonic vibration frequency range is smaller than any value within the second preset ultrasonic vibration frequency range.

[0010] Optionally, the correspondence between the supercritical CO2 pressure P and the ultrasonic amplitude A is: when the ultrasonic amplitude A is within a first preset ultrasonic amplitude range, the ultrasonic amplitude A is negatively correlated with the supercritical CO2 pressure P; when the ultrasonic amplitude A is within a second preset ultrasonic amplitude range, the ultrasonic amplitude A is positively correlated with the supercritical CO2 pressure P, and any value within the first preset ultrasonic amplitude range is smaller than any value within the second preset ultrasonic amplitude range.

[0011] Optionally, the supercritical CO2 control module controls the supercritical CO2 pressure within a preset pressure range, the ultrasonic control module controls the ultrasonic amplitude within a preset ultrasonic amplitude range, and the ultrasonic control module also controls the ultrasonic vibration frequency within a preset ultrasonic vibration frequency range. The preset pressure range is P≥8MPa, the preset ultrasonic amplitude range is A≥0.5μm, and the preset ultrasonic vibration frequency is 16KHz≤f≤50KHz.

[0012] Optionally, the supercritical CO2 supply unit includes: a CO2 supply unit, a pressurization heating unit, a first temperature monitoring unit and a first pressure monitoring unit;

[0013] The boost heating unit is connected to the CO2 supply unit, the first temperature monitoring unit and the first pressure monitoring unit are arranged on the output pipeline of the boost heating unit, and the boost heating unit, the first temperature monitoring unit and the first pressure monitoring unit are all electrically connected to the supercritical CO2 control module.

[0014] Optionally, it further includes a compressed air supply unit, which is connected to the first boost unit of the boost heating unit through a first control valve.

[0015] Optionally, the compressed air supply unit is also connected to the ultrasonic machining device through a second control valve and a one-way valve; and the ultrasonic machining control module also includes a spindle control module, the spindle control module is electrically connected to the supercritical CO2 control module, and the second control valve is also electrically connected to the supercritical CO2 control module.

[0016] Optionally, it further comprises a micro-lubrication supply unit, the micro-lubrication supply unit is connected to the output pipeline of the supercritical CO2 supply unit, and the micro-lubrication supply unit is also electrically connected to the supercritical CO2 control module;

[0017] The supercritical CO2 control module is further configured to control the pressure of the lubricating oil output by the minimal lubrication supply unit to be greater than the pressure of the supercritical CO2.

[0018] Optionally, the minimal lubrication supply unit includes a lubricating oil storage tank, a second boosting unit and a second pressure monitoring unit which are connected in sequence, and the second boosting unit and the second pressure monitoring unit are both electrically connected to the supercritical CO2 control module.

[0019] Optionally, the ultrasonic machining device includes: a tool parameter monitoring unit and an ultrasonic generator; wherein the tool parameter monitoring unit and the ultrasonic generator are both electrically connected to the ultrasonic control module to feed back ultrasonic parameters to the ultrasonic control module.

[0020] Optionally, it also includes a second temperature monitoring unit; the second temperature monitoring unit is arranged on the output pipeline of the supercritical CO2 supply unit, and the second temperature monitoring unit is also electrically connected to the supercritical CO2 control module.

[0021] Optionally, the supercritical CO2 supply unit is connected to the ultrasonic machining device via a third control valve.

[0022] Optionally, it also includes a pressure relief valve and a fourth pressure monitoring unit, wherein the pressure relief valve and the fourth pressure monitoring unit are both arranged on the pipeline connecting the third control valve and the ultrasonic machining device, and are both electrically connected to the supercritical CO2 control module, and the spindle control module of the ultrasonic machining control module is electrically connected to the supercritical CO2 control module.

[0023] According to another aspect of the utility model, a machine tool is provided, comprising the above-mentioned supercritical CO2 and ultrasonic composite machining system.

[0024] The technical solution of the embodiment of the utility model provides a supercritical CO2 and ultrasonic composite processing system, which includes: a supercritical CO2 supply system connected to a first control valve to provide supercritical CO2 to a cutting processing area; a supercritical CO2 control module electrically connected to the first control valve to control the start or close of the first control valve; the supercritical CO2 control module is also electrically connected to the supercritical CO2 supply system to control the process parameters of supercritical CO2; an ultrasonic processing control module is electrically connected to an ultrasonic processing device to control the ultrasonic processing device; the ultrasonic processing control module includes an ultrasonic control module, the ultrasonic control module is electrically connected to the ultrasonic processing device to obtain ultrasonic parameters, and the ultrasonic control module is also electrically connected to the supercritical CO2 control module to control the process parameters of supercritical CO2 to dynamically adjust according to the correspondence between the process parameters of supercritical CO2 and the ultrasonic parameters of the ultrasonic processing device. It can be seen that by using supercritical CO2 to cool the processing area, it is green, environmentally friendly and pollution-free, with good cooling effect, and can effectively reduce the temperature of the cutting area. And through ultrasonic high-frequency vibration, it can also improve the surface roughness and burr problems of the processing. And by controlling the process parameters of supercritical CO2 and dynamically adjusting according to the correspondence between the process parameters of supercritical CO2 and ultrasonic parameters, the injection effect of supercritical CO2 is improved, thereby ensuring the processing effect and processing quality, improving processing efficiency and precision, and effectively reducing costs.

[0025] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present utility model, nor are they intended to limit the scope of the present utility model. Other features of the present utility model will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 It is a structural principle block diagram of a supercritical CO2 and ultrasonic composite processing system provided in an embodiment of the utility model;

[0028] Figure 2 It is a principle structure block diagram of another supercritical CO2 and ultrasonic composite processing system provided in an embodiment of the utility model;

[0029] Figure 3It is a principle structure block diagram of another supercritical CO2 and ultrasonic composite processing system provided in an embodiment of the utility model;

[0030] Figure 4 It is a principle structure block diagram of another supercritical CO2 and ultrasonic composite processing system provided in an embodiment of the utility model;

[0031] Figure 5 It is a principle structure block diagram of another supercritical CO2 and ultrasonic composite processing system provided in an embodiment of the utility model;

[0032] Figure 6 It is a principle structure block diagram of another supercritical CO2 and ultrasonic composite processing system provided in the embodiments of the present application;

[0033] Figure 7 It is a principle structure block diagram of another supercritical CO2 and ultrasonic composite processing system provided in the embodiments of the present application;

[0034] Figure 8 It is a principle structure block diagram of another supercritical CO2 and ultrasonic composite processing system provided in the embodiments of the present application;

[0035] Fig. 9 It is a principle structure block diagram of another supercritical CO2 and ultrasonic composite processing system provided in the embodiments of the present application;

[0036] Fig.10 It is a flow chart of a control method of a supercritical CO2 and ultrasonic composite processing system provided in an embodiment of the present application.

[0037] Fig.11 It is a schematic diagram of the overall process of a supercritical CO2 and ultrasonic composite processing system provided in an embodiment of the utility model;

[0038] Fig.12 It is a flow chart of parameter adjustment of a supercritical CO2 and ultrasonic composite machining system provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0040] It should be noted that the terms "first", "second", etc. in the specification and claims of the utility model and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the utility model described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0041] Figure 1 This is a principle structure diagram of a supercritical CO2 and ultrasonic composite processing system provided in the embodiment of the present application. Figure 1 The supercritical CO2 and ultrasonic composite processing system comprises: a supercritical CO2 supply unit 10, a control module 20 and an ultrasonic processing device 30; wherein the control module 20 is electrically connected to the supercritical CO2 supply unit, and is used to control the supercritical CO2 supply unit to provide supercritical CO2 to the processing area, and control the process parameters of the supercritical CO2 of the supercritical CO2 supply unit; the control module is electrically connected to the ultrasonic processing device to obtain the ultrasonic parameters of the ultrasonic processing device, and is used to control the ultrasonic processing device to provide ultrasonic vibration;

[0042] The control module 20 is configured to: according to the correspondence between the process parameters of supercritical CO2 and the ultrasonic parameters, control the process parameters of supercritical CO2 to dynamically adjust within a preset range following the ultrasonic parameters, the process parameters of supercritical CO2 include supercritical CO2 pressure P, and the ultrasonic parameters include ultrasonic amplitude A and ultrasonic vibration frequency f.

[0043] Among them, the end of the output pipeline of the supercritical CO2 supply unit 10 can be connected to the ultrasonic processing device 30, so as to provide supercritical CO2 to the processing area through the internal cooling channel of the ultrasonic processing device 30. Specifically, after passing through the internal cooling channel of the ultrasonic processing device, it is necessary to finally provide supercritical CO2 to the processing area through the cooling channel in the internal cooling tool holder or the internal cooling tool to form internal cooling. Of course, the supercritical CO2 supply unit can also be directly connected to the nozzle of the external device to provide supercritical CO2 to the processing area, forming external cooling. That is, during external cooling, supercritical CO2 does not pass through the cooling channel of the ultrasonic processing device. This part is no different from the prior art, so it will not be expanded in detail. The following description takes internal cooling as an example, unless otherwise specified.

[0044] Exemplarily, the ultrasonic machining device 30 is used to provide ultrasonic vibration, and realizes cutting processing of the workpiece to be machined according to the supercritical CO2 provided by the supercritical CO2 supply unit 10 in combination with ultrasound. Among them, the workpiece to be machined can be difficult-to-machine materials such as high-strength steel, high-temperature alloys and titanium alloys. The ultrasonic machining device 30 may include a spindle, an ultrasonic generator, a transmitting unit, an ultrasonic toolholder and a tool arranged on the spindle (it is also possible to install the transducer part in the spindle and connect it to the spindle using a precision toolholder). Furthermore, the transmitting unit can be installed inside the spindle, or directly installed at the front end of the spindle, and of course, it can also be installed on the spindle housing through a clamp, that is, it is externally mounted on the spindle housing, and after the ultrasonic transmitting unit receives the ultrasonic signal of the ultrasonic generator, it is transmitted to the receiving unit of the ultrasonic toolholder by wired or wireless means, thereby realizing the transmission of the ultrasonic signal, and the ultrasonic signal can cause the ultrasonic toolholder to generate ultrasonic vibration, thereby ultrasonically machining the workpiece to be machined.

[0045] The supercritical CO2 supply unit 10 is used to provide supercritical CO2. The supercritical CO2 supply unit 10 outputs supercritical CO2 by heating and pressurizing low-temperature and low-pressure CO2 so that the low-temperature and low-pressure CO2 enters a supercritical state through heating and pressurization, thereby obtaining supercritical CO2.

[0046] The control module 20 may be a controller such as a numerical control system or a PLC, and may be configured according to actual conditions, and is not specifically limited here.

[0047] The supercritical CO2 pressure can be obtained by setting a pressure detection unit on the pipeline between the supercritical CO2 supply unit and the ultrasonic processing device. The control module 20 obtains the ultrasonic parameters from the ultrasonic processing device 30, and then the control module controls the supercritical CO2 process parameters of the supercritical CO2 supply unit 10 according to the aforementioned ultrasonic parameters. Specifically, the ultrasonic parameters include the ultrasonic vibration frequency fed back by the ultrasonic generator to the control module 20, and also include the ultrasonic amplitude detected by the tool parameter monitoring unit by setting a tool parameter monitoring unit at the tool end.

[0048] Exemplarily, the control module is electrically connected to the ultrasonic generator and the tool parameter monitoring unit, and the ultrasonic generator and the tool parameter monitoring unit feed back the ultrasonic parameters to the control module, so that the control module adjusts the supercritical CO2 pressure of the supercritical CO2 supply unit according to the corresponding relationship between the process parameters of the supercritical CO2 and the ultrasonic parameters. In addition, the control module is electrically connected to the ultrasonic generator and is also used to control the start or stop of the ultrasonic generator to control whether it outputs an ultrasonic signal to the transmitting unit.

[0049] The control module 20 is also used to control the adjustment of the ultrasonic parameters of the ultrasonic machining device 30 to control the ultrasonic parameters within a preset range.

[0050] The control module 20 is electrically connected to the ultrasonic machining device 30 and is also used to control the start or stop of the ultrasonic machining device 30, including air blowing, tool changing, etc.

[0051] As for the correspondence between supercritical process parameters and ultrasonic parameters, due to the existence of acoustic resistance between the tool and the workpiece during ultrasonic-assisted processing, a large amount of heat will be generated during ultrasonic vibration, and the tool and the chips will be separated periodically during ultrasonic-assisted processing, and heat will be taken away during the periodic separation. Therefore, when the amplitude is constant, in the early stage, as the ultrasonic vibration frequency increases, the tool and the workpiece are separated periodically, and the heat taken away by the periodic separation is greater than the heat generated by the ultrasonic and tool workpiece acoustic resistance, so it is beneficial to reduce the amount of carbon dioxide injection, that is, a higher supercritical CO2 pressure is not required to meet the cooling requirements. However, as the ultrasonic vibration frequency continues to increase, the heat generated by the ultrasonic and tool workpiece acoustic resistance increases sharply and is greater than the heat taken away by the periodic separation. At this time, the amount of carbon dioxide injection needs to be increased, that is, a relatively higher supercritical CO2 pressure is required to meet the cooling requirements and ensure the stability of ultrasonic processing.

[0052] When the ultrasonic vibration frequency is constant, in the early stage, as the ultrasonic amplitude gradually increases, the tool and the workpiece are separated periodically, and the heat taken away by the periodic separation is greater than the heat generated by the ultrasonic and tool workpiece acoustic resistance, which is conducive to reducing the amount of carbon dioxide injection, that is, the cooling demand can be met without a higher supercritical CO2 pressure. However, as the ultrasonic amplitude continues to increase, the heat generated by the ultrasonic and tool workpiece acoustic resistance increases sharply and is greater than the heat taken away by the periodic separation. At this time, the amount of carbon dioxide injection needs to be increased, that is, a relatively higher supercritical CO2 pressure is required to meet the cooling demand and ensure the stability of ultrasonic machining.

[0053] Optionally, the control module 20 is also configured to: when the ultrasonic amplitude A is controlled to remain unchanged, when the ultrasonic vibration frequency f is within a first preset ultrasonic vibration frequency range, the ultrasonic vibration frequency f is negatively correlated with the supercritical CO2 pressure P; when the ultrasonic vibration frequency f is within a second preset ultrasonic vibration frequency range, the ultrasonic vibration frequency f is positively correlated with the supercritical CO2 pressure P, and any value within the first preset ultrasonic vibration frequency range is smaller than any value within the second preset ultrasonic vibration frequency range.

[0054] The first preset ultrasonic vibration frequency range is 16KHz≤f<30KHz, and the second preset ultrasonic vibration frequency range is 30KHz≤f≤50KHz.

[0055] Moreover, when 16KHz≤f<30KHz, 8MPa<P≤15MPa, and f is negatively correlated with P; when 30KHz≤f≤50KHz, P≥8MPa, and f is positively correlated with P.

[0056] Optionally, the control module is further configured to: control the ultrasonic amplitude A to remain unchanged, and the ultrasonic vibration frequency to be a first preset ultrasonic vibration frequency f1, the supercritical CO2 pressure to be a first preset pressure P1, and the first preset ultrasonic vibration frequency is negatively correlated with the first preset pressure.

[0057] The first preset ultrasonic vibration frequency f1 satisfies: 16≤f1<30KHz, and the first preset pressure P1 satisfies: 8MPa<P1≤15MPa. It should be noted that the values ​​of the first preset ultrasonic vibration frequency and the first preset pressure can be set according to actual conditions and are not specifically limited here.

[0058] Optionally, the control module is further configured to: control the ultrasonic amplitude A to remain unchanged, and the ultrasonic vibration frequency to be a second preset ultrasonic vibration frequency f2, the supercritical CO2 pressure to be a second preset pressure P2, and the second preset ultrasonic vibration frequency is positively correlated with the second preset pressure.

[0059] The second preset ultrasonic vibration frequency f2 satisfies: 30KHz≤f2≤50KHz, and the second preset pressure P2 satisfies: P2≥8MPa. It should be noted that the values ​​of the second preset ultrasonic vibration frequency and the second preset pressure can be set according to actual conditions and are not specifically limited here.

[0060] Optionally, the control module 20 is further configured to: when the ultrasonic vibration frequency f is controlled to remain unchanged, when the ultrasonic amplitude A is within a first preset ultrasonic amplitude range, the ultrasonic amplitude A is negatively correlated with the supercritical CO2 pressure P; when the ultrasonic amplitude A is within a second preset ultrasonic amplitude range, the ultrasonic amplitude A is positively correlated with the supercritical CO2 pressure P, and any value within the first preset ultrasonic amplitude range is smaller than any value within the second preset ultrasonic amplitude range.

[0061] The first preset ultrasonic amplitude range is 0.5-10 μm, and the second preset ultrasonic amplitude range is greater than 10 μm.

[0062] Moreover, when 0.5μm≤A<10μm, 8MPa<P≤15MPa, and A and P are negatively correlated; when A≥10μm, P≥8MPa, and A and P are positively correlated.

[0063] Optionally, the control module is configured to: control the ultrasonic vibration frequency f to remain unchanged, and the ultrasonic amplitude to be a first preset ultrasonic amplitude A1, the supercritical CO2 pressure to be a first preset pressure P1, and the first preset ultrasonic amplitude A1 is negatively correlated with the first preset pressure P1.

[0064] The first preset ultrasonic amplitude A1 satisfies: 0.5 μm ≤ A1 < 10 μm, and the first preset pressure P1 satisfies: 8 MPa < P1 ≤ 15 MPa. It should be noted that the values ​​of the first preset ultrasonic amplitude and the first preset pressure can be set according to actual conditions and are not specifically limited here.

[0065] Optionally, the control module is configured to: control the ultrasonic vibration frequency f to remain unchanged, and the ultrasonic amplitude to be a second preset ultrasonic amplitude A2, the supercritical CO2 pressure to be a second preset pressure P2, and the second preset ultrasonic amplitude A2 is positively correlated with the first preset pressure P2.

[0066] The second preset ultrasonic amplitude A2 satisfies: A2 ≥ 10 μm, and the second preset pressure P2 satisfies: P2 ≥ 8 MPa. It should be noted that the values ​​of the second preset ultrasonic amplitude and the second preset pressure can be set according to actual conditions and are not specifically limited here.

[0067] It should be noted that the value ranges of the first preset ultrasonic vibration frequency, the second preset ultrasonic vibration frequency, the first preset ultrasonic amplitude, the second preset ultrasonic amplitude, the first preset pressure, and the second preset pressure are only exemplary descriptions, which can be set according to actual conditions and are not specifically limited here. Other value ranges can also be set. For example, when the ultrasonic amplitude A is controlled to remain unchanged, the value ranges of the ultrasonic vibration frequency f and the corresponding supercritical CO2 pressure P can be set according to Table 1; when the ultrasonic vibration frequency f is controlled to remain unchanged, the value ranges of the ultrasonic amplitude A and the corresponding supercritical CO2 pressure P can be set according to Table 2.

[0068] Table 1 Values ​​between ultrasonic vibration frequency f and supercritical CO2 pressure P

[0069] Serial number Ultrasonic vibration frequency f / KHz <![CDATA[Supercritical CO2 pressure P / MPa]]> 1 16-20 12-15 2 20-30 8-12 3 30-40 8-15 4 40-50 ≥15

[0070] Table 2 Values ​​between ultrasonic amplitude A and supercritical CO2 pressure P

[0071] Serial number Ultrasonic amplitude A / μm <![CDATA[Supercritical CO2 pressure P / MPa]]> 1 0.5-5 12-15 2 5-10 8-12 3 10-20 8-15 4 ≥20 ≥15

[0072] Optionally, the control module is further configured to: control the supercritical CO2 pressure P within a preset pressure range, control the ultrasonic amplitude A within a preset amplitude range, and control the ultrasonic vibration frequency f within a preset vibration frequency range.

[0073] For example, the preset pressure range may be greater than or equal to 8 MPa, the preset amplitude range may be greater than or equal to 0.5 micrometers, and the preset vibration frequency range may be 16-50 KHz. The lower limit of the supercritical CO2 pressure is 7.31 MPa. Since the flow in the pipeline will cause certain losses, the lower limit of the preset pressure range is limited in this application to be slightly higher than the supercritical lower limit.

[0074] In the technical solution of this embodiment, the implementation process of the supercritical CO2 and ultrasonic composite processing system is as follows: Figure 1 When the workpiece to be processed needs to be cut, the workpiece to be processed is fixed in the processing area. The control module 20 controls the supercritical CO2 supply unit 10 to provide supercritical CO2 to the processing area, and controls the ultrasonic processing device 30 to start ultrasonic processing. The control module 20 obtains the ultrasonic amplitude from the ultrasonic processing device 30, and dynamically adjusts the supercritical CO2 pressure of the supercritical CO2 supply unit 10 according to the corresponding relationship between the process parameters of supercritical CO2 and the ultrasonic parameters, so that it follows the dynamic adjustment of the ultrasonic parameters.

[0075] By combining supercritical CO2 with ultrasound, green cutting of difficult-to-process materials can be achieved. In the early stage of increasing ultrasonic parameters, ultrasonic vibration causes the tool and chips to separate periodically and take away most of the heat. At this time, the injection amount of supercritical CO2 can be reduced. As the ultrasonic parameters continue to increase, the heat taken away by the periodic separation is less than the heat generated by acoustic resistance, and the injection amount of supercritical CO2 needs to be increased. Therefore, there is a correlation between ultrasonic parameters and supercritical parameters. Through the relationship between the two, the supercritical parameters can be reasonably adjusted to improve the injection effect of supercritical CO2, ensure the processing effect and processing quality, improve processing efficiency and precision, and effectively reduce costs. In addition, by using supercritical CO2, it is green, environmentally friendly and pollution-free, with good cooling effect, which can effectively reduce the temperature of the cutting area, and through ultrasonic processing, it can also improve the surface roughness and processing burr problems.

[0076] Figure 2 It is a principle structure block diagram of another supercritical CO2 and ultrasonic composite machining system provided in the embodiment of the present application. On the basis of the above embodiment, the ultrasonic machining device may include a spindle 31 and an ultrasonic generator 32, and the supercritical CO2 supply unit 10 is connected to the spindle 31 of the ultrasonic machining device, and supercritical CO2 is sprayed through the cooling channel on the spindle 31 for cooling. In the technical solution of this embodiment, the implementation process of the supercritical CO2 and ultrasonic composite machining system is as follows: Figure 2When it is necessary to cut the workpiece to be processed, the workpiece to be processed is fixed in the processing area. The control module 20 controls the supercritical CO2 supply unit 10 to provide supercritical CO2 to the processing area through the spindle 31, and controls the ultrasonic generator 32 to provide an ultrasonic signal to the transmitting unit on the spindle 31. The control module 20 obtains the ultrasonic vibration frequency from the ultrasonic generator 32, and the ultrasonic amplitude from the tool parameter monitoring unit, and dynamically adjusts the supercritical CO2 pressure of the supercritical CO2 supply unit 10 according to the corresponding relationship between the process parameters of supercritical CO2 and the ultrasonic parameters, so that it can be dynamically adjusted with the ultrasonic parameters, which is beneficial to improve the injection effect of supercritical CO2, thereby ensuring the processing effect and processing quality, improving the processing efficiency and precision, and effectively reducing costs.

[0077] Figure 3 This is a schematic diagram of another supercritical CO2 and ultrasonic composite processing system provided in the embodiments of the present application. Figure 3 The control module 20 may include a supercritical CO2 control module 22 and an ultrasonic processing control module 21. The supercritical CO2 control module 21 is electrically connected to the supercritical CO2 supply unit 10 to control the process parameters of the supercritical CO2. The ultrasonic processing control module 20 includes an ultrasonic control module 211. The ultrasonic control module 211 is electrically connected to the ultrasonic processing device 20 to obtain ultrasonic parameters. The ultrasonic control module 211 is also electrically connected to the supercritical CO2 control module 22 to control the process parameters of the supercritical CO2 of the supercritical CO2 supply unit to dynamically adjust with the ultrasonic parameters within a preset range according to the corresponding relationship between the process parameters of the supercritical CO2 and the ultrasonic parameters of the ultrasonic processing device. The process parameters of supercritical CO2 include supercritical CO2 pressure, and the ultrasonic parameters include ultrasonic amplitude and ultrasonic vibration frequency.

[0078] By combining supercritical CO2 with ultrasound, green cutting of difficult-to-process materials can be achieved. By using supercritical CO2, it is green, environmentally friendly and pollution-free, with good cooling effect, and can effectively reduce the temperature of the cutting zone. Ultrasonic processing can also improve the surface roughness and burr problems. And by controlling the process parameters of supercritical CO2 according to the correspondence between the process parameters of supercritical CO2 and the ultrasonic parameters, the ultrasonic parameters are dynamically adjusted to improve the injection effect of supercritical CO2, thereby ensuring the processing effect and processing quality, improving processing efficiency and precision, and effectively reducing costs. And the automatic control of the supercritical CO2 and ultrasonic composite processing system is realized through communication between the control modules.

[0079] Among them, the supercritical CO2 control module 22 and the ultrasonic machining control module 21 can be controllers such as single chip microcomputers, which can be set according to actual conditions and are not specifically limited here. The ultrasonic machining control module also includes other modules, such as the spindle control module mentioned later, which will be explained in detail later.

[0080] Figure 4 This is a principle structure diagram of another supercritical CO2 and ultrasonic composite processing system provided in the embodiment of the present application. Figure 3 Based on the examples, see Figure 4 , the supercritical CO2 supply unit can be connected to the third control valve 40 before outputting supercritical CO2 to the processing area, and the supercritical CO2 control module can also be electrically connected to the third control valve 40 to control the start or close of the third control valve 40, thereby controlling the supercritical CO2 supply unit to output supercritical CO2 to the processing area. Moreover, the supercritical CO2 supply unit 10 can also be connected to the ultrasonic processing device through the third control valve 40, and the ultrasonic processing device sprays supercritical CO2 to the cutting processing area through its cooling channel, that is, forming internal cooling. Of course, other modules can also control the opening and closing of the third control valve 40, such as the spindle control module of the ultrasonic processing control system 21. When supercritical CO2 is needed, the spindle control module controls the third control valve to open, and the supercritical CO2 supply unit inputs supercritical CO2 to the ultrasonic processing device through the third control valve, thereby cooling the processing area. The following text is explained by taking the supercritical CO2 control module being electrically connected to the third control valve 40 as an example. Among them, the third control valve 40 can be a switch control valve.

[0081] Figure 5 : is a principle structure block diagram of another supercritical CO2 and ultrasonic composite machining system provided in an embodiment of the present application (in this figure, the electrical connection is set as a dotted line to distinguish it from the pipeline connection). Figure 5The supercritical CO2 supply unit 10 includes: a CO2 supply unit 11, a first pressurizing unit 12, a heating unit 13, a third temperature monitoring unit 14, a first temperature monitoring unit 16, a third pressure monitoring unit 15 and a first pressure monitoring unit 17; the third temperature monitoring unit 14 and the third pressure monitoring unit 15 are respectively connected to the CO2 supply unit 11 to monitor the temperature and pressure of CO2 in the CO2 supply unit 11; the first pressurizing unit 12 and the heating unit 13 are connected to the CO2 supply unit 11 in sequence to pressurize and heat CO2 respectively; the first temperature monitoring unit 16 and the first pressure monitoring unit 17 are arranged on the pipeline connecting the heating unit 13 and the third control valve 40 to monitor the temperature and pressure of the supercritical CO2 after pressurization and heating, and the first pressurizing unit 12, the heating unit 13, the first temperature monitoring unit 16, the first pressure monitoring unit 17, the second temperature monitoring unit 14 and the second pressure monitoring unit 15 are all electrically connected to the supercritical CO2 control module 22 to control the process parameters of the output supercritical CO2. The third temperature monitoring unit 14 and the third pressure monitoring unit 15 may be omitted.

[0082] Among them, the CO2 supply unit 11 is used to provide low-temperature and low-pressure CO2 to the first boosting unit 12. The CO2 supply unit 11 is connected to the first boosting unit 12, and the low-temperature and low-pressure CO2 is pressurized to a certain pressure value (such as above 7.31MPa) through the first boosting unit 12 to obtain high-pressure CO2, and then transported to the heating unit 13 through a pipeline for heating. The heating unit 13 heats the low-temperature and high-pressure CO2 to a certain temperature (such as above 31.7°C), that is, after pressurization and heating, the low-pressure CO2 enters a supercritical state, thereby obtaining supercritical CO2, and transporting it to the ultrasonic machining device 30 through the third control valve 40. Of course, under the premise of ensuring that the supercritical CO2 output by the supercritical CO2 supply unit meets the preset requirements, the order of the first boosting unit and the heating unit can be interchanged, that is, heating first and then pressurizing, or pressurizing first and then heating, or both.

[0083] Among them, the supercritical CO2 control module 22 is used to control the process parameters of the supercritical CO2 output by the supercritical CO2 supply unit 10. Specifically, the third temperature monitoring unit 14 and the third pressure monitoring unit 15 are respectively connected to the CO2 supply unit 11 to monitor the temperature and pressure of the low-temperature and low-pressure CO2 in the CO2 supply unit 11, and send the detection information to the supercritical CO2 control module 22. The first temperature monitoring unit 16 and the first pressure monitoring unit 17 are arranged on the pipeline connecting the heating unit 13 and the third control valve 40, and are used to monitor the pressure and temperature after being pressurized by the first supercharging unit 12 and heated by the heating unit 13, and send the above monitoring information to the supercritical CO2 control module 22. The supercritical CO2 control module 22 is used to monitor the temperature and pressure of the CO2 in the CO2 supply unit 11 in real time according to the temperature and pressure data sent by the third temperature monitoring unit 14 and the third pressure monitoring unit 15, and the temperature and pressure data sent by the first temperature monitoring unit 16 and the first pressure monitoring unit 17 respectively monitor the temperature and pressure of the supercritical CO2 after being pressurized and heated by the first supercharging unit and the heating unit 13 in real time. When the pressure and temperature of the CO 2 heated by the heating unit 13 reach the set target pressure and target temperature, the supercritical CO 2 control module 22 controls the first boosting unit 12 and the heating unit 13 to stop working.

[0084] The supercritical CO 2 control module 22 is connected to the first pressurizing unit 12 and the heating unit 13 in sequence, and is used to control the start or shut down of the first pressurizing unit 12 and the heating unit 13 .

[0085] Optionally, continue to refer to Figure 5 The supercritical CO2 and ultrasonic composite machining system further includes a compressed air supply unit 61, which is connected to the first boosting unit 12 through a first control valve 64, and is used to provide compressed air to the first boosting unit 12, thereby driving the first boosting unit 12 to boost the low-temperature and low-pressure CO2 output by the CO2 supply unit. The compressed air supply unit 61 is also connected to the ultrasonic machining device 30 through a second control valve 62 and a one-way valve 63; the second control valve 62 is also electrically connected to the supercritical CO2 control module 22, and the ultrasonic machining control module 21 further includes a spindle control module 212, which is electrically connected to the spindle 31 of the ultrasonic machining device 30, and the spindle control module 212 is electrically connected to the supercritical CO2 control module 22.

[0086] Among them, the second control valve 62 is connected to the compressed air supply unit 61 and the one-way valve 63 respectively, and the one-way valve 63 is connected to the ultrasonic machining device 30. The second control valve 62 is used to control whether the compressed air supply unit 61 supplies compressed air to the ultrasonic machining device 30. The function of the one-way valve is to prevent the supercritical CO2 in the connecting pipeline from entering the pipeline where the compressed air is located. Specifically, when the processing machine tool needs to clean the impurities inside the spindle, the spindle control module 212 sends a signal to the supercritical CO2 control module 22, and the supercritical CO2 control module 22 controls the opening of the third control valve to allow compressed air to clean the spindle. After completing the work, the third control valve is closed, and the compressed air supply unit stops supplying gas to the spindle.

[0087] The supercritical CO2 control module 22 is electrically connected to the second control valve 62 to control the start or close of the second control valve 62. Of course, the second control valve 62 can also be directly electrically connected to the spindle control module 212 of the ultrasonic machining control module 21, so as to directly control the opening or closing of the second control valve 62. The second control valve 62 and the first control valve 64 can be switch control valves.

[0088] Optionally, continue to refer to Figure 5 The ultrasonic machining device 30 includes: a tool parameter monitoring unit 33, a spindle 31, an ultrasonic generator 32, a transmitting unit 35, an ultrasonic tool holder 36 and a tool 34; wherein the tool parameter monitoring unit 33, the ultrasonic generator 32 are electrically connected to the ultrasonic control module 211, so as to feed back the ultrasonic parameters to the ultrasonic control module 211, and the ultrasonic control module 211 is electrically connected to the supercritical CO2 control module 22, so as to control the process parameters of the supercritical CO2 in the supercritical CO2 supply unit 10 according to the corresponding relationship between the process parameters of the supercritical CO2 and the ultrasonic parameters of the ultrasonic machining device. The ultrasonic parameters of the ultrasonic machining device 30 are dynamically adjusted; and the spindle control module 212 is electrically connected to the spindle 31 to control the tool change of the spindle 31. The ultrasonic generator 32 outputs a voltage or current signal to the transmitting unit 35 according to the instruction of the ultrasonic control module 211. The transmitting unit 35 is fixed at the front end of the spindle 31 and forms a wireless transmission with the receiving unit of the ultrasonic tool handle 36. The tool 34 is connected to the spindle 31 through the ultrasonic tool handle 36. The spindle 31 is connected to the third control valve 40 to transport the supercritical CO2 output by the supercritical CO2 supply unit to the cutting machining area through the cooling channel of the spindle 31.

[0089] The third control valve 40 is connected to the spindle 31 and is used to provide supercritical CO2 to the spindle 31. The supercritical CO2 is sprayed to the cutting edge of the tool 34 through the internal cooling channel of the spindle 31 and the spray holes on the ultrasonic tool holder 36 to cool the cutting process.

[0090] Among them, the ultrasonic generator 32 and the tool parameter monitoring unit 33 are electrically connected to the ultrasonic control module 211 for feeding back ultrasonic parameters to the ultrasonic control module 211. Specifically, the tool parameter monitoring unit 33 feeds back ultrasonic amplitude information to the ultrasonic control module 211, and the ultrasonic generator 32 feeds back ultrasonic vibration frequency information to the ultrasonic control module 211.

[0091] Among them, the ultrasonic control module 211 is electrically connected to the ultrasonic generator 32, and is also used to control the adjustment of the ultrasonic parameters of the ultrasonic generator 32 to control ultrasonic parameters such as ultrasonic vibration frequency within a preset range; the tool parameter monitoring unit 33 is electrically connected to the ultrasonic control module 211, and is also used to compare the actual ultrasonic amplitude of the tool 34 with the pre-stored tool ultrasonic amplitude. If there is inconsistency, control the output of an adjustment signal to the ultrasonic generator 32, and the ultrasonic generator 32 outputs a new voltage or current signal to the transmitting unit 33 according to the adjustment signal to adjust the actual ultrasonic amplitude of the tool 36 to make it consistent with the pre-stored tool ultrasonic amplitude.

[0092] Optionally, continue to refer to Figure 5 The supercritical CO2 and ultrasonic composite processing system also includes a second temperature monitoring unit 91; the second temperature monitoring unit 91 is arranged on the pipeline connecting the third control valve 40 and the ultrasonic processing device 30 to monitor the pipeline temperature, and the second temperature monitoring unit 91 is also electrically connected to the supercritical CO2 control module 22.

[0093] Exemplary, reference Figure 5 The second temperature monitoring unit 91 is arranged on the pipeline connecting the third control valve 40 and the main shaft 31, and the second temperature monitoring unit 91 is also electrically connected to the supercritical CO2 control module 22, for monitoring the pipeline temperature, and sending the monitored temperature to the supercritical CO2 control module 22. The advantage of arranging the second temperature monitoring unit 91 between the third control valve 40 and the main shaft 31 is that when using supercritical CO2, due to the good cooling effect of supercritical CO2, if leakage occurs, the temperature in its transmission channel will drop significantly. In order to avoid this situation affecting the processing, the second temperature monitoring unit 91 is arranged between the third control valve 40 and the main shaft 31 to monitor the temperature in real time. Once low temperature occurs, the machine will automatically shut down and stop the supply of supercritical CO2 for troubleshooting.

[0094] Optionally, continue to refer to Figure 5 The supercritical CO2 and ultrasonic composite machining system also includes a pressure relief valve 92 and a fourth pressure monitoring unit 93; the pressure relief valve 92 and the fourth pressure monitoring unit 93 are both arranged on the pipeline connecting the third control valve 40 and the ultrasonic machining device 30, that is, connected to the ultrasonic machining device 30, and are both electrically connected to the supercritical CO2 control module 22, and of course, can also be directly electrically connected to the spindle control module 212.

[0095] Among them, since there is supercritical CO2 in the cooling channel of the spindle, it is in a high-pressure state. When the front end of the spindle needs to change the tool, the internal pressure of the spindle needs to be quickly released before the tool change. Therefore, the supercritical CO2 and ultrasonic composite machining system is also provided with a pressure relief element, which includes a pressure relief valve 92 and a fourth pressure monitoring unit 93. The pressure relief valve 92 and the fourth pressure monitoring unit 93 are respectively arranged between the third control valve 40 and the spindle 31. Among them, the fourth pressure monitoring unit 93 is used to monitor the internal pressure of the spindle 31 in real time. Only when the internal pressure of the spindle is zero, the tool change action can be performed. Among them, the function of the pressure relief valve 92 is to quickly discharge the CO2 gas in the high-pressure state inside the spindle, so that the pressure quickly returns to zero. When the tool needs to be changed, the spindle control module 212 sends a relevant signal to the supercritical CO2 control module 22, and the supercritical CO2 control module 22 controls the pressure relief valve 92 to open. When the fourth pressure monitoring unit 93 feedback pressure is 0, the tool change operation is performed.

[0096] It should be noted that in the supercritical CO2 and ultrasonic composite machining system, the monitoring of temperature and pressure is mainly reflected in the setting of temperature and pressure monitoring after the booster unit (such as the first temperature monitoring unit and the first pressure monitoring unit), and the setting of temperature monitoring before entering the spindle (such as the second temperature monitoring unit and the fourth pressure monitoring unit). There is a certain transmission distance between the supercritical CO2 supply unit and the spindle, so there will be a certain pressure loss and temperature loss. The pressure and temperature at the injection end of the ultrasonic tool handle 36 need to exceed a certain set value (such as the pressure exceeds 7.31MPa to ensure the supercritical state), and when the tool needs to be changed, the pressure must be relieved first. Only when the pressure is zero can the tool be changed, and the temperature in the system is monitored to prevent leakage, so pressure and temperature monitoring are required.

[0097] Exemplarily, the first temperature monitoring unit, the second temperature monitoring unit and the third temperature monitoring unit may be temperature sensors, and the first pressure monitoring unit, the second pressure monitoring unit, the third pressure monitoring unit and the fourth pressure monitoring unit may be pressure sensors.

[0098] In the technical solution of this embodiment, the implementation process of the supercritical CO2 and ultrasonic composite processing system is as follows: Figure 5, when cutting processing is required, the workpiece to be processed is installed at the processing position. The CO2 supply unit 11 provides low-temperature and low-pressure CO2 to the first boosting unit 12. The compressed air supply unit 61 is connected to the first boosting unit 12, and is used to provide compressed air to the first boosting unit 12 to drive the first boosting unit 12 to boost. The first boosting unit 12 pressurizes the low-temperature and low-pressure CO2 to a certain pressure value (above 7.31MPa) to obtain high-pressure CO2, and transports it to the heating unit 13 for heating. The heating unit 13 heats the low-temperature and high-pressure CO2 into high-temperature and high-pressure supercritical CO2. And the first temperature monitoring unit 16 and the first pressure monitoring unit 17 are respectively provided on the pipeline connecting the heating unit 13 and the third control valve 40, which are used to monitor the temperature and pressure of the supercritical CO2 at the outlet of the heating unit 13 in real time, and ensure that the temperature and pressure of CO2 reach the set temperature and pressure respectively (the set value is slightly higher than the lower limit of the temperature and pressure in the supercritical state, and is set according to the actual situation). After pressurized heating, the low-temperature and low-pressure CO2 enters a supercritical state, thereby obtaining supercritical CO2, and is delivered to the spindle 31 through the third control valve 40. The spindle control module 212 controls the spindle 31 to spray the supercritical CO2 through the spindle 31 to the processing area; the ultrasonic control module 211 controls the ultrasonic generator 32 to emit an ultrasonic signal, so that the supercritical CO2 and the ultrasonic are combined to achieve cutting processing. In addition, the ultrasonic control module 211 is electrically connected to the ultrasonic generator 32 and the tool parameter monitoring unit 33 to obtain the ultrasonic vibration frequency and ultrasonic amplitude. The ultrasonic control module 211 is also electrically connected to the supercritical CO2 control module 22, so as to control the supercritical CO2 pressure to dynamically adjust with the ultrasonic parameters according to the corresponding relationship between the process parameters of the supercritical CO2 and the ultrasonic parameters, thereby improving the injection effect of the supercritical CO2, ensuring the processing effect and processing quality, improving the processing efficiency and precision, and effectively reducing the cost.

[0099] Figure 6 This is a schematic diagram of another supercritical CO2 and ultrasonic composite processing system provided in the embodiment of the present application. Figure 6The supercritical CO2 and ultrasonic composite machining system also includes a micro-lubrication supply unit 50, which is connected to the output pipeline of the supercritical CO2 supply unit 10, so that the lubricating oil provided by the micro-lubrication supply unit 50 and the supercritical CO2 provided by the supercritical CO2 supply unit 10 are mixed in the output pipeline of the supercritical CO2 supply unit 10, and then the mixture of supercritical CO2 and oil mist is sprayed to the machining area through the internal cooling channel of the spindle 31 of the ultrasonic machining device, which plays a role in cooling and lubrication. Of course, the output pipeline of the supercritical CO2 supply unit 10 can also be directly connected to the external nozzle to spray the mixture of supercritical CO2 and oil mist to the machining area, that is, not through the internal cooling channel of the ultrasonic machining device. The control module 20 is also configured to: control the oil pressure output by the micro-lubrication supply unit 50 to be greater than the supercritical CO2 pressure, and control the output lubricating oil amount.

[0100] The control module 20 is connected to the micro-lubrication supply unit 50 and is also used to control the activation or deactivation of the micro-lubrication supply unit 50 to control whether the micro-lubrication supply unit 50 provides micro-lubricating oil to the output pipeline of the supercritical CO2 supply unit.

[0101] For example, a lubricating oil quantitative supply device can be provided on the output pipeline of the minimal lubrication supply unit 50 to control the amount of lubricating oil mixed with the supercritical CO2. The lubricating oil quantitative supply device can be a mechanical pump, a precision quantitative pump, etc., which can be specifically provided according to actual conditions and is not specifically limited here.

[0102] Specifically, when it is necessary to cut the workpiece to be processed, the workpiece to be processed is fixed in the processing area. The control module 20 controls the supercritical CO2 supply unit 10 to provide supercritical CO2, and controls the micro-lubrication supply unit 50 to provide lubricating oil. Then the mixture of lubricating oil and supercritical CO2 is delivered to the spindle 31. At the same time, the control module 20 controls the ultrasonic generator 32 to output relevant signals to the transmitting unit on the spindle 31, and dynamically adjusts the supercritical CO2 pressure of the supercritical CO2 supply unit 10 according to the corresponding relationship between the process parameters of supercritical CO2 and the ultrasonic parameters according to the feedback ultrasonic vibration frequency and ultrasonic amplitude. At the same time, the oil pressure output by the micro-lubrication supply unit 50 is controlled to be greater than the supercritical CO2 pressure. Therefore, by combining micro-lubrication, supercritical CO2 and ultrasound control, the process parameters, ultrasonic parameters and lubricating oil pressure of supercritical CO2 can be controlled within a reasonable range, which is conducive to improving the injection effect of the cooling lubricating medium, thereby ensuring the processing effect and processing quality, and improving the processing efficiency and precision. In addition, the high-frequency vibration of ultrasound can promote better mixing of supercritical CO2 and lubricating oil, and will not cause excessive oil accumulation in the pipeline due to the low solubility of lubricating oil in supercritical CO2, and eventually form oil droplets to be ejected from the spindle nozzle, thereby achieving efficient internal spraying of supercritical oil and supercritical CO2. When supercritical CO2 is ejected from the nozzle on the ultrasonic tool holder, dry ice blockage may form at the outlet over time, affecting the injection direction of supercritical CO2, and thus affecting the cooling and lubrication effect on the tool. The high-frequency vibration of ultrasound can effectively prevent the accumulation of dry ice and the growth of dry ice, thereby ensuring that the injection direction of supercritical CO2 is not disturbed. In addition, by using supercritical CO2, it is green, environmentally friendly and pollution-free, has a good cooling effect, can effectively reduce the temperature of the cutting area, and by combining ultrasound, it can also improve the surface roughness of the machined surface, improve the problem of machining burrs, reduce machining costs, and improve machining quality and effects.

[0103] Optionally, in order to allow the lubricating oil to be better dissolved in the supercritical CO2, the pressure difference between the oil pressure output by the minimal lubrication supply unit and the supercritical CO2 pressure is greater than a preset pressure difference. The preset pressure difference may be 0.5 MPa. The preset pressure difference may also be other values, which may be set according to actual conditions and are not specifically limited here.

[0104] Figure 7 This is a schematic diagram of another supercritical CO2 and ultrasonic composite processing system provided in the embodiment of the present application. Figure 7The supercritical CO2 and ultrasonic composite machining system also includes a micro-lubrication supply unit 50, which is electrically connected to the control module 20 to control the micro-lubrication supply unit 50 to provide lubricating oil, and the supercritical CO2 supply unit 10 is connected to the output pipeline of the micro-lubrication supply unit 50, so that the lubricating oil provided by the micro-lubrication supply unit 50 and the supercritical CO2 provided by the supercritical CO2 supply unit 10 are mixed in the output pipeline of the micro-lubrication supply unit 50, and then the mixture of supercritical CO2 and oil mist is sprayed to the machining area through the internal cooling channel of the spindle 31, which plays a role in cooling and lubricating. The control module 20 is also configured to: control the lubricating oil pressure output by the micro-lubrication supply unit 50 to be less than the supercritical CO2 pressure, so that the supercritical CO2 can be better mixed with the lubricating oil, and is also used to control the output lubricating oil amount.

[0105] Figure 8 This is a schematic diagram of another supercritical CO2 and ultrasonic composite processing system provided in the embodiment of the present application. Figure 8 The supercritical CO2 and ultrasonic composite machining system also includes a micro-lubrication supply unit 50 and a mixing module 60. The micro-lubrication supply unit 50 and the supercritical CO2 supply unit 10 are both connected to the mixing module 60. The micro-lubrication supply unit 50 is electrically connected to the control module 20 to control the output amount of lubricating oil; the mixing module 60 is also connected to the spindle 31; wherein, the micro-lubrication supply unit 50 is used to provide lubricating oil to the mixing module 60, the supercritical CO2 supply unit 10 is used to provide supercritical CO2 to the mixing module 60, and the mixing module 60 is used to mix the supercritical CO2 with the lubricating oil and then transport it to the spindle 31.

[0106] The control module 20 is connected to the micro-lubrication supply unit 50 and is also used to control the activation or deactivation of the micro-lubrication supply unit 50 to control whether the micro-lubrication supply unit 50 provides micro-lubricating oil to the mixing module 60 and control the output of the lubricating oil.

[0107] Fig. 9 This is a schematic diagram of another supercritical CO2 and ultrasonic composite processing system provided in the embodiment of the present application. Fig. 9The supercritical CO2 and ultrasonic composite machining system also includes a micro-lubrication supply unit 50 and a compressed air supply unit 61. The output end of the micro-lubrication supply unit 50 is connected to the pipeline connecting the supercritical CO2 supply unit 10 and the third control valve 40, that is, connected to the output pipeline of the supercritical CO2 supply unit 10. Since the third control valve 40 is connected to the ultrasonic machining device 30, supercritical CO2 and oil mist are finally ejected from the ultrasonic machining device 30. The micro-lubrication supply unit 50 is also electrically connected to the supercritical CO2 control module 22. The compressed air supply unit 61 is not only connected to the supercritical CO2 supply unit 10, but also connected to the micro-lubrication supply unit 50, so as to drive the booster unit of the micro-lubrication supply unit 50 to ensure that the lubricating oil pressure reaches the set value.

[0108] The minimal lubrication supply unit 50 is used to provide lubricating oil to the output pipeline of the supercritical CO 2 supply unit 10 so that the lubricating oil is mixed with the supercritical CO 2 .

[0109] Specifically, when the system needs oil mixing, the supercritical CO2 control module 22 controls the micro-lubrication supply unit 50 to start working. When the system does not need oil mixing, the micro-lubrication supply unit 50 does not work. It should be noted that whether oil mixing is required can be set according to actual processing requirements. For example, when processing some products in the medical industry, there is a special requirement that oil cannot be present.

[0110] In the technical solution of this embodiment, the implementation process of the supercritical CO2 and ultrasonic composite processing system is as follows: Fig. 9 When cutting processing is required, the workpiece to be processed is installed at the processing position. The supercritical CO2 supply unit 10 provides supercritical CO2, and the micro-lubrication supply unit 50 provides lubricating oil. In the pipeline connecting the supercritical CO2 supply unit 10 and the third control valve 40, supercritical CO2 is mixed with lubricating oil, and then the supercritical CO2 mixed with lubricating oil is provided to the ultrasonic processing device 30 through the third control valve 40. The ultrasonic processing device 30 sprays supercritical CO2 and oil mist mixed with lubricating oil to the cutting processing area through its main axis to achieve cooling and lubrication, and realizes cutting processing of the workpiece to be processed in combination with ultrasound.

[0111] Fig.10 : is a principle structure block diagram of another supercritical CO2 and ultrasonic composite machining system provided in an embodiment of the present application (in this figure, the electrical connection is set as a dotted line to distinguish it from the pipeline connection). Fig.10The minimal lubrication supply unit 50 includes: a lubricating oil storage tank 51, a second boosting unit 52 and a second pressure monitoring unit 53; the lubricating oil storage tank 51 is connected to the output pipeline of the supercritical CO2 supply unit through the second boosting unit 52, so as to input lubricating oil thereto; the second pressure monitoring unit 53 is connected to the output pipeline of the second boosting unit 52 to monitor the lubricating oil pressure after the second boosting unit 52; the second boosting unit 52 and the second pressure monitoring unit 53 are both electrically connected to the supercritical CO2 control module 22.

[0112] Among them, the compressed air supply unit 61 is also connected to the second boosting unit 52, and is used to provide compressed air to the second boosting unit 52 to drive the second boosting unit 52 to boost. Of course, a control valve (not shown in the figure) is set between the second boosting unit and the compressed air supply unit. The control valve is electrically connected to the supercritical CO2 supply unit and has the same function as the second control valve, which will not be expanded in detail here. The lubricating oil is pressurized by the second boosting unit 52. The second pressure monitoring unit 53 is connected to the second boosting unit 52, and is used to monitor the pressure of the pressurized lubricating oil. When the pressure reaches the pressure value set by the system, the second boosting unit 52 stops pressurizing. And the lubricating oil pressurized by the second boosting unit 52 is transported to the output pipeline of the supercritical CO2 supply unit and mixed with the supercritical CO2.

[0113] When supercritical CO2 is mixed with pressurized lubricating oil (i.e., high-pressure lubricating oil), the pressure of the high-pressure lubricating oil needs to be higher than the pressure of the supercritical CO2. For example, the pressure of the lubricating oil is 0.5 MPa higher than the pressure of the supercritical CO2, so that the lubricating oil is more easily dissolved in the supercritical CO2.

[0114] Exemplary, reference Fig.10 The compressed air supply unit 61 is connected to the first boost unit 12 and the second boost unit 72 respectively, and is used to drive the first boost unit 12 and the second boost unit 72 respectively.

[0115] Optionally, continue to refer to Fig.10 The supercritical CO2 and ultrasonic composite processing system also includes a lubricating oil quantitative supply unit 80; one end of the lubricating oil quantitative supply unit 80 is connected to the second boosting unit 72, and the other end is connected to the pipeline connecting the supercritical CO2 supply unit 10 and the third control valve 40.

[0116] When the system needs to use lubricating oil, the amount of lubricating oil used is usually relatively small, so setting up the lubricating oil quantitative supply unit 80 is conducive to accurately controlling the supply amount of lubricating oil, and further conducive to ensuring efficient mixing of lubricating oil and supercritical CO2.

[0117] The lubricating oil quantitative supply unit 80 can be electrically connected to the supercritical CO2 control module 22 to limit the amount of lubricating oil mixed with the supercritical CO2. The oil quantity control range can be 0-100 ml / h, or other numerical ranges, which can be set according to actual conditions and are not specifically limited here.

[0118] The lubricating oil quantitative supply unit 80 may be a mechanical pump or a precision quantitative pump, and may be configured according to actual conditions, and is not specifically limited here.

[0119] In the technical solution of this embodiment, the implementation process of the supercritical CO2 and ultrasonic composite processing system is as follows: Fig.10 When cutting is required, when supercritical CO2 needs to be mixed with a trace amount of lubricating oil, the lubricating oil storage tank 51 is connected to the second boosting unit 52, and the compressed air supply unit 61 is connected to the second boosting unit 52, which is used to provide compressed air to the second boosting unit 52 to drive the second boosting unit 52 to boost. The second boosting unit 52 boosts the pressure to pressurize the lubricating oil. The second pressure monitoring unit 53 is connected to the second boosting unit 52, which is used to monitor the pressure of the pressurized lubricating oil. When the pressure reaches the pressure value set by the system, the second boosting unit 52 stops pressurizing. And the lubricating oil pressurized by the second boosting unit 52 is quantitatively delivered to the output end of the supercritical CO2 supply unit 10 through the lubricating oil quantitative supply unit 80, and mixed with the supercritical CO2. The supercritical CO2 mixed with the lubricating oil is delivered to the spindle 31 through the third control valve 40. The spindle control module 212 controls the spindle 31 to spray supercritical CO2 mixed with lubricating oil and oil mist into the processing area through the cooling channel of the spindle 31 to achieve cooling and lubrication. The ultrasonic control module 211 controls the ultrasonic generator 54 to emit ultrasonic signals, so that the supercritical CO2 mixed with a trace amount of lubricating oil and ultrasound are combined to achieve cutting processing.

[0120] Fig.11 This is a flow chart of a control method for a supercritical CO2 and ultrasonic composite processing system provided in an embodiment of the present application. This embodiment of the present application also provides a control method for a supercritical CO2 and ultrasonic composite processing system, refer to Fig.11 , the method comprises the following steps:

[0121] S110, according to the correspondence between the process parameters of supercritical CO2 and the ultrasonic parameters, controlling the process parameters of supercritical CO2 to dynamically adjust within a preset range following the ultrasonic parameters.

[0122] Among them, the process parameters of supercritical CO2 include supercritical CO2 pressure, and the ultrasonic parameters include ultrasonic amplitude and ultrasonic vibration frequency.

[0123] The control method of the supercritical CO2 and ultrasonic composite processing system is applied to the supercritical CO2 and ultrasonic composite processing system. The supercritical CO2 and ultrasonic composite processing system at least includes a supercritical CO2 supply unit, a control module and an ultrasonic processing device. The supercritical CO2 supply unit is used to provide supercritical CO2 to the processing area. The control module is used to control the process parameters of the supercritical CO2 to dynamically adjust within a preset range following the ultrasonic parameters according to the corresponding relationship between the process parameters of the supercritical CO2 and the ultrasonic parameters.

[0124] Moreover, the control module can also be used to control the process parameters of the supercritical CO2 of the supercritical CO2 supply unit and the ultrasonic parameters of the ultrasonic processing device to remain stable within a preset range, and to control the start or stop of the supercritical CO2 supply unit and the ultrasonic processing device.

[0125] The technical solution of this embodiment provides a control method for a supercritical CO2 and ultrasonic composite processing system, which includes: controlling the process parameters of the supercritical CO2 of the supercritical CO2 supply unit and the ultrasonic parameters of the ultrasonic processing device to remain stable, and according to the corresponding relationship between the process parameters of the supercritical CO2 and the ultrasonic parameters, controlling the process parameters of the supercritical CO2 to dynamically adjust within a preset range following the ultrasonic parameters within a preset range, the process parameters of the supercritical CO2 include the supercritical CO2 pressure, and the ultrasonic parameters include the ultrasonic amplitude and the ultrasonic vibration frequency. It can be seen that by combining supercritical CO2 with ultrasound, green cutting of difficult-to-process materials can be achieved, and by controlling the process parameters of the supercritical CO2 to dynamically adjust following the ultrasonic parameters according to the corresponding relationship between the process parameters of the supercritical CO2 and the ultrasonic parameters, the process parameters of the supercritical CO2 are controlled within a reasonable range, thereby ensuring the processing effect and processing quality, improving the processing efficiency and precision, and effectively reducing costs. In addition, by using supercritical CO2 internal spraying, which is green, environmentally friendly and pollution-free, with good cooling effect, it can effectively reduce the temperature of the cutting area, and through ultrasonic machining, it can also improve the surface roughness of the machining, improve the machining burr problem, and reduce the machining cost.

[0126] Fig.12 Schematic diagram of the overall process of a supercritical CO2 and ultrasonic composite processing system provided in the embodiment of the present application. Fig.12, Under normal processing state (automatic mode, start loading program), the sequence of relevant actions of the processing machine tool is as follows: first start the supercritical CO2 supply unit, let the pressurization and heating system (i.e. the first pressurization unit and the heating unit) pressurize and heat to a reasonable preset value, fix the workpiece to be processed on the operating table of the machine tool, start the machine tool to prepare for processing, and the pressure relief system (i.e. the second pressure monitoring unit) monitors the internal pressure of the spindle. When the pressure signal is zero, the next instruction is allowed to be executed; if the program has a tool change instruction, the tool change action is executed. After the tool is ready, (if the program has an instruction) the ultrasonic control module controls the amplitude debugging action, and then the supercritical CO2 control module controls the supercritical CO2 supply unit to spray supercritical CO2 (the supercritical CO2 control module controls the third control valve to open), and then the part processing program is followed. During the processing, the second temperature monitoring unit can monitor the system temperature in real time. During the processing, the ultrasonic control module collects the ultrasonic vibration frequency of the ultrasonic generator and the ultrasonic amplitude monitoring data of the tool parameter monitoring unit, the supercritical CO2 control module monitors the supercritical CO2 pressure, the ultrasonic control module is electrically connected to the supercritical CO2 control module, and the ultrasonic control module continuously sends instructions to the supercritical CO2 control module to adjust the supercritical CO2 pressure according to the acquired ultrasonic vibration frequency and ultrasonic amplitude, that is, the process parameters of the supercritical CO2 in the supercritical CO2 supply unit are dynamically adjusted within a preset range along with the ultrasonic parameters of the ultrasonic machining device; the above adjustments are continuously circulated during the processing. After the processing procedure of the current tool is completed, when the tool needs to be changed for subsequent processing, the ultrasonic control module controls the ultrasonic generator to be turned off, and at the same time controls the supercritical CO2 supply unit to stop spraying supercritical CO2 through communication with the supercritical CO2 control module, and opens the pressure relief system (i.e., the fourth pressure monitoring unit and the pressure relief valve) until the internal pressure of the spindle is zero, and then performs the tool change, and performs subsequent processing until the part processing is completed.

[0127] An embodiment of the present application also provides a machine tool, which includes the supercritical CO2 and ultrasonic composite machining system provided by any embodiment of the present application.

[0128] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0129] The above specific implementations do not constitute a limitation on the protection scope of the present utility model. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. A supercritical CO2 and ultrasonic composite processing system, characterized in that: include: Supercritical CO2 supply unit; A supercritical CO2 control module, electrically connected to the supercritical CO2 supply unit; Ultrasonic machining device; An ultrasonic machining control module includes an ultrasonic control module, which is electrically connected to the ultrasonic machining device and is also electrically connected to the supercritical CO2 control module, so as to control the process parameters of the supercritical CO2 to dynamically adjust within a preset range following the ultrasonic parameters according to the corresponding relationship between the process parameters of the supercritical CO2 and the ultrasonic parameters of the ultrasonic machining device; the ultrasonic parameters include ultrasonic vibration frequency f and ultrasonic amplitude A, and the process parameters of the supercritical CO2 include supercritical CO2 pressure P.

2. The supercritical CO2 and ultrasonic composite processing system according to claim 1, characterized in that: The corresponding relationship between the supercritical CO2 pressure P and the ultrasonic vibration frequency f is: when the ultrasonic vibration frequency f is within the first preset ultrasonic vibration frequency range, the ultrasonic vibration frequency f is negatively correlated with the supercritical CO2 pressure P; when the ultrasonic vibration frequency f is within the second preset ultrasonic vibration frequency range, the ultrasonic vibration frequency f is positively correlated with the supercritical CO2 pressure P, and any value within the first preset ultrasonic vibration frequency range is smaller than any value within the second preset ultrasonic vibration frequency range.

3. The supercritical CO2 and ultrasonic composite processing system according to claim 1, characterized in that: The corresponding relationship between the supercritical CO2 pressure P and the ultrasonic amplitude A is: when the ultrasonic amplitude A is within the first preset ultrasonic amplitude range, the ultrasonic amplitude A is negatively correlated with the supercritical CO2 pressure P; when the ultrasonic amplitude A is within the second preset ultrasonic amplitude range, the ultrasonic amplitude A is positively correlated with the supercritical CO2 pressure P, and any value within the first preset ultrasonic amplitude range is smaller than any value within the second preset ultrasonic amplitude range.

4. The supercritical CO2 and ultrasonic composite processing system according to claim 1, characterized in that: The supercritical CO2 control module controls the supercritical CO2 pressure within a preset pressure range, the ultrasonic control module controls the ultrasonic amplitude within a preset ultrasonic amplitude range, and the ultrasonic control module also controls the ultrasonic vibration frequency within a preset ultrasonic vibration frequency range. The preset pressure range is P≥8MPa, the preset ultrasonic amplitude range is A≥0.5μm, and the preset ultrasonic vibration frequency is 16KHz≤f≤50KHz.

5. The supercritical CO2 and ultrasonic composite processing system according to claim 1, characterized in that: The supercritical CO2 supply unit includes: a CO2 supply unit, a pressurization heating unit, a first temperature monitoring unit and a first pressure monitoring unit; The boost heating unit is connected to the CO2 supply unit, the first temperature monitoring unit and the first pressure monitoring unit are arranged on the output pipeline of the boost heating unit, and the boost heating unit, the first temperature monitoring unit and the first pressure monitoring unit are all electrically connected to the supercritical CO2 control module.

6. The supercritical CO2 and ultrasonic composite processing system according to claim 5, characterized in that: It also includes a compressed air supply unit, which is connected to the first boost unit in the boost heating unit through a first control valve.

7. The supercritical CO2 and ultrasonic composite processing system according to claim 6, characterized in that: The compressed air supply unit is also connected to the ultrasonic machining device through a second control valve and a one-way valve; and the ultrasonic machining control module also includes a spindle control module, the spindle control module is electrically connected to the supercritical CO2 control module, and the second control valve is also electrically connected to the supercritical CO2 control module.

8. The supercritical CO2 and ultrasonic composite processing system according to claim 1, characterized in that: It also includes a micro-lubrication supply unit, which is connected to the output pipeline of the supercritical CO2 supply unit, and the micro-lubrication supply unit is also electrically connected to the supercritical CO2 control module; The supercritical CO2 control module is further configured to control the pressure of the lubricating oil output by the minimal lubrication supply unit to be greater than the pressure of the supercritical CO2.

9. The supercritical CO2 and ultrasonic composite processing system according to claim 8, characterized in that: The minimal lubrication supply unit includes a lubricating oil storage tank, a second boosting unit and a second pressure monitoring unit which are connected in sequence, and the second boosting unit and the second pressure monitoring unit are both electrically connected to the supercritical CO2 control module.

10. The supercritical CO2 and ultrasonic composite processing system according to claim 1, characterized in that: The ultrasonic machining device comprises: a tool parameter monitoring unit and an ultrasonic generator; wherein the tool parameter monitoring unit and the ultrasonic generator are both electrically connected to the ultrasonic control module.

11. The supercritical CO2 and ultrasonic composite processing system according to claim 1, characterized in that: It also includes a second temperature monitoring unit; the second temperature monitoring unit is arranged on the output pipeline of the supercritical CO2 supply unit, and the second temperature monitoring unit is also electrically connected to the supercritical CO2 control module.

12. The supercritical CO2 and ultrasonic composite processing system according to claim 1, characterized in that: The supercritical CO2 supply unit is connected to the ultrasonic machining device through a third control valve.

13. The supercritical CO2 and ultrasonic composite processing system according to claim 12, characterized in that: It also includes a pressure relief valve and a fourth pressure monitoring unit, which are both arranged on the pipeline connecting the third control valve and the ultrasonic machining device, and are both electrically connected to the supercritical CO2 control module, and the spindle control module of the ultrasonic machining control module is electrically connected to the supercritical CO2 control module.

14. A machine tool, characterized in that: It comprises the supercritical CO2 and ultrasonic composite processing system as described in any one of claims 1 to 13.

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