A control system of horizontal numerical control turning and milling combined machine tool

Abstract

The application provides a control system of a horizontal numerical control turning and milling combined machine tool, the machine tool comprising a rack, a workpiece clamping assembly arranged on the rack, a tool rest seat horizontally and slidably arranged on the rack, a sliding frame slidably arranged with the tool rest seat, a tool holder rotatably arranged on the sliding frame and used for mounting a tool, and a driving motor used for driving the tool holder to rotate; the control system comprises a controller, a vibration detection unit arranged on the tool holder and used for detecting a vibration value of the tool holder, and a current detection unit connected with the driving motor and used for detecting a motor current of the driving motor; the controller is configured to calculate a weighted comprehensive wear index based on the motor current detected by the current detection unit and the vibration value detected by the vibration detection unit, and dynamically adjust a cutting speed and a feed rate based on the weighted comprehensive wear index, so as to ensure the machining precision of a product.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of machine tool processing, in particular to a control system of a horizontal numerical control turning and milling combined machine tool. BACKGROUND

[0002] In numerical control processing, tool wear will directly affect the processing quality and equipment safety. At present, cutting force, vibration, current, acoustic emission and other sensors are commonly used for monitoring. However, a single sensor is susceptible to infection and difficult to comprehensively reflect the tool wear state under complex working conditions. The motor current signal is susceptible to power grid fluctuations and sensor system errors, and it is difficult to accurately capture the small wear changes when the cutting amount is small. As for the vibration signal, it is affected by the machine tool structure vibration, uneven workpiece material interference, and different batches of workpieces, which lead to signal fluctuations and misjudgment of wear degree. Therefore, accurately determining the tool wear degree is an urgent problem for those skilled in the art.

[0003] In the existing processing technology, first, the process designer determines the specific cutting speed and feed amount in advance according to the workpiece material, workpiece structure and tool, and then inputs the control system of the machine tool to realize automatic processing. As for tool wear, the machine tool will only issue an alarm prompt to the operator to replace the tool when severe wear is reached. After the tool enters the stable wear stage, the cutting edge of the tool gradually becomes blunt, and the actual cutting parameters of the tool change, thereby affecting the processing precision. Therefore, when processing batch workpieces, the same process parameters are used for processing due to the difference in tool wear, which directly affects the product quality.

[0004] Therefore, it is necessary to improve the control system of the existing horizontal numerical control turning and milling combined machine tool to improve the processing precision of the product. SUMMARY

[0005] The main purpose of the present application is to provide a control system of a horizontal numerical control turning and milling combined machine tool, which can automatically adjust the cutting speed and feed amount according to the wear degree of the tool, thereby ensuring the processing precision of the product.

[0006] In order to achieve the above purpose, in the first aspect, the present application provides a control system of a horizontal numerical control turning and milling combined machine tool, the machine tool comprising a machine frame, a workpiece clamping assembly arranged on the machine frame, a tool holder seat horizontally slidingly arranged on the machine frame, a sliding frame slidingly arranged with the tool holder seat, a tool holder rotatingly arranged on the sliding frame and used for mounting a tool, and a driving motor driving the tool holder to rotate.

[0007] The control system comprises a controller, a vibration detection unit arranged on the tool holder for detecting vibration values thereof, a current detection unit connected with the driving motor and used for detecting motor currents thereof, the controller is configured to calculate a weighted comprehensive wear index based on the motor currents detected by the current detection unit and the vibration values detected by the vibration detection unit, and dynamically adjust the cutting speed and the feed amount based on the weighted comprehensive wear index.

[0008] Optionally, the weighted comprehensive wear index wherein I is a current cutting current average value, I0 is a new tool standard current value, V is a current vibration effective value, and V0 is a new tool standard vibration value, and are weight coefficients.

[0009] Optionally, the cutting speed is adjusted based on the weighted comprehensive wear index wherein is an adjusted cutting speed at the Kth moment, is an initial cutting speed, is a speed adjustment coefficient, is a normal threshold value of the weighted comprehensive wear index of the tool, is the weighted comprehensive wear index of the tool at the Kth moment.

[0010] Optionally, the feed amount is adjusted based on the weighted comprehensive wear index wherein is an adjusted feed amount at the Kth moment, is an initial feed amount, is a feed adjustment coefficient.

[0011] Optionally, the vibration detection unit is a piezoelectric acceleration sensor.

[0012] Optionally, the current detection unit is a Hall current sensor.

[0013] Optionally, further comprising an alarm electrically connected with the controller, when the calculated weighted comprehensive wear index is greater than 0.6, the controller controls the alarm to alarm and controls the machine tool to stop.

[0014] Optionally, the workpiece clamping assembly comprises a first mounting frame fixedly arranged on the machine frame, a multi-jaw chuck rotatably arranged on the first mounting frame, a first motor driving the multi-jaw chuck to rotate, a sliding frame slidably arranged on the machine frame through a first linear track, and a first driving mechanism driving the sliding frame to slide.

[0015] Optionally, the sliding frame is slidably arranged on the tool seat in an inclined manner from top to bottom through a second linear track, and the sliding frame is driven to slide by a second driving mechanism.

[0016] Optionally, the tool holder comprises a tool holder body, a plurality of tool mounting dies evenly distributed on the tool holder body with the rotation center as the center, and the tool is fixedly arranged on the tool mounting die through a fastener.

[0017] The control system of the horizontal numerical control turning and milling combined machine tool has the beneficial effects that the weighted comprehensive wear index is calculated by combining the motor current and the vibration value, two signal values which are easy to obtain and have strong anti-interference, and the current cutting speed and the feed amount are dynamically adjusted according to the weighted comprehensive wear index, so that when batch machining workpieces are performed, the control system of the machine tool can automatically and dynamically adjust according to the wear degree of the tool, thereby ensuring the quality of each batch of products, and the degree of automation is high. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings, which form a part of the present application, are intended to provide further understanding of the present application, and to make apparent the other features, objectives, and advantages of the present application. The illustrative embodiments of the present application and their description serve the purpose of explanations and are not only intended to limit the present application. In the drawings:

[0019] Figure 1 is a schematic diagram of a machine tool Figure One ;

[0020] Figure 2 is a schematic diagram of a machine tool Figure Two .

[0021] Wherein: 1, rack; 2, tool holder seat; 3, sliding frame; 4, tool holder; 5, driving motor; 6, multi-jaw chuck; 7, center; 8, mounting die. DETAILED DESCRIPTION

[0022] In order to enable personnel in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor should fall within the scope of protection of the present application.

[0023] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0024] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0025] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0026] In addition, the term "multiple" should mean two or more.

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] like Figures 1-2 As shown, a control system for a horizontal CNC milling and turning machine tool is disclosed. The machine tool includes a frame 1, a workpiece clamping assembly disposed on the frame 1, a tool holder 2 horizontally slidably disposed on the frame 1, a sliding frame 3 slidably disposed with respect to the tool holder 2, a tool holder 4 rotatably disposed on the sliding frame 3 and used for mounting tools, and a drive motor 5 for driving the tool holder 4 to rotate.

[0029] The system also includes an alarm electrically connected to the controller. When the calculated weighted comprehensive wear index is greater than 0.6, the controller activates the alarm and stops the machine tool. The normal threshold weighted comprehensive wear index is ≤0.3, indicating slight tool wear that does not require adjustment. The warning threshold is a weighted comprehensive wear index greater than 0.3 and ≤0.6, indicating stable tool wear that requires fine-tuning of machining parameters. When the critical threshold (weighted comprehensive wear index greater than 0.6) is reached, the tool is approaching severe wear and needs to be replaced. At this point, the alarm sounds, and the controller stops the machine tool, waiting for the operator to replace the tool before restarting, thus ensuring product quality.

[0030] However, the above simple adjustments alone are insufficient for precise control of product quality. This is because, during CNC machine tool operation, the operator is not a process engineer and cannot adjust the control parameters in real time based on the degree of tool wear, i.e., real-time dynamic adjustment is not possible. Therefore, the control system of this invention includes a controller, a vibration detection unit mounted on the tool holder 4 for detecting its vibration value, and a current detection unit connected to the drive motor 5 for detecting its motor current. The controller is configured to calculate a weighted comprehensive wear index based on the motor current detected by the current detection unit and the vibration value detected by the vibration detection unit, and dynamically adjust the cutting speed and feed rate based on the weighted comprehensive wear index. The vibration detection unit is preferably a piezoelectric accelerometer, and the current detection unit is preferably a Hall current sensor.

[0031] Regarding the weighted composite wear index Where I is the current average cutting current, I0 is the standard current value for the new tool, V is the current effective vibration value, and V0 is the standard vibration value for the new tool. as well as All are weighting coefficients, among which, + =1. When machining materials with high hardness, changes in motor current may be more sensitive to tool wear; in this case, the motor current can be appropriately increased. The value, such as =0.6, =0.4; however, for turning softer materials, the vibration signal may have a more significant impact on tool wear, and can be set to... =0.4, =0.6, therefore, in actual operation, the operator can adjust the processing parameters according to the hardness of the workpiece. as well as Adjustments will be made.

[0032] As for I0 and V0, the motor current I0 and vibration value V0 under the stable state of the new tool are used as the reference, where the stable state is the state when the new tool is in normal turning.

[0033] Adjust the cutting speed based on the weighted comprehensive wear index. ,in Let K be the adjusted cutting speed at time K. The initial cutting speed, For speed adjustment coefficient, This is the normal threshold for the weighted comprehensive wear index of the cutting tool, which is any value within ≤0.3. The operator sets it according to the different processing requirements of the workpiece, such as selecting 0.3; The weighted composite wear index of the tool at time K is related to the speed adjustment coefficient. For lathe tools, the thickness is 0.2-0.3, while for milling cutters, which are more sensitive to speed, the thickness is 0.25-0.35.

[0034] Adjust feed rate based on weighted composite wear index ,in This represents the adjusted feed rate at time k. This is the initial feed rate. For the feed adjustment factor, regarding the feed adjustment factor For lathe tools, the feed rate is 0.15~0.25. Since the feed rate of the milling cutter has a greater impact on vibration, it needs to be adjusted conservatively. Therefore, the feed rate of the milling cutter is 0.1~0.2.

[0035] It should also be noted that max(0,·) means that no adjustment is made when WMI does not exceed the threshold (the coefficient is 0).

[0036] Regarding the structure of the machine tool, the workpiece clamping assembly includes a first mounting bracket fixedly mounted on the frame 1, a multi-jaw chuck 6 rotatably mounted on the first mounting bracket, a first motor driving the multi-jaw chuck 6 to rotate, a movable frame slidably mounted on the frame 1 via a first linear track, and a first drive mechanism driving the movable frame to slide. A center 7 is rotatably mounted on the movable frame. The workpiece is positioned by the cooperation of the center 7 and the multi-jaw chuck 6. At the same time, the multi-jaw chuck 6 is driven to rotate by the first motor, thereby causing the workpiece to rotate during the processing. As for the first drive mechanism, it essentially adjusts the distance between the movable frame and the first mounting bracket in order to match workpieces of different lengths and to facilitate the loading and unloading of workpieces.

[0037] Furthermore, the sliding frame 3 is inclined and slidably arranged with respect to the tool holder from top to bottom via a second linear track. The sliding frame 3 is driven to slide by a second drive mechanism. It should be noted that the inclined sliding arrangement allows for a larger tool holder 4, which can accommodate different tools, thus expanding the machining range of the CNC machine tool. In addition, the second drive mechanism is controlled by a controller. When adjusting the feed rate, the controller controls the second drive mechanism to adjust the sliding frame 3 relative to the tool holder, thereby achieving tool feed rate adjustment. The use of linear guide rails provides higher precision, thus ensuring product quality. It should be noted that the specific structure of the first and second drive mechanisms is not the design focus of this invention. In this invention, the movement is achieved by the cooperation of a lead screw and a screw sleeve. Of course, other drive methods can still be used and are also within the protection scope of this invention.

[0038] Preferably, the tool holder 4 includes a tool holder 4 body and a plurality of tool mounting molds 8 evenly distributed on the tool holder 4 body with its rotation center as the center. The tool is fixedly mounted on the tool mounting mold 8 by fasteners. When replacing the tool, it is connected to the mounting mold 8 by fasteners, which is convenient for disassembly and assembly. Moreover, by matching different mounting molds 8 with different tools, the stability after installation is improved, thereby ensuring the accuracy of vibration detection.

[0039] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A control system for a horizontal CNC turning and milling composite machine tool, characterized in that, The machine tool includes a frame, a workpiece clamping assembly mounted on the frame, a tool holder mounted horizontally on the frame, a sliding frame slidably mounted with respect to the tool holder, a tool holder rotatably mounted on the sliding frame and used for mounting tools, and a drive motor for driving the tool holder to rotate. The control system includes a controller, a vibration detection unit mounted on the tool holder for detecting its vibration value, and a current detection unit connected to the drive motor for detecting its motor current. The controller is configured to calculate a weighted comprehensive wear index based on the motor current detected by the current detection unit and the vibration value detected by the vibration detection unit, and to dynamically adjust the cutting speed and feed rate based on the weighted comprehensive wear index. The weighted comprehensive wear index Where I is the current average cutting current, I0 is the standard current value for the new tool, V is the current effective vibration value, and V0 is the standard vibration value for the new tool. as well as All are weighting coefficients; Adjust the cutting speed based on the weighted comprehensive wear index. ,in Let K be the adjusted cutting speed at time K. The initial cutting speed, For speed adjustment coefficient, The weighted composite wear index of the cutting tool is the normal threshold. The weighted comprehensive wear index of the tool at time K; Adjust feed rate based on weighted composite wear index ,in This represents the adjusted feed rate at time k. This is the initial feed rate. This is the feed adjustment factor.

2. The control system of a horizontal CNC turning and milling composite machine tool as described in claim 1, characterized in that: The vibration detection unit is a piezoelectric accelerometer.

3. The control system of a horizontal CNC turning and milling composite machine tool as described in claim 1, characterized in that: The current detection unit is a Hall current sensor.

4. The control system of a horizontal CNC turning and milling composite machine tool as described in claim 1, characterized in that: It also includes an alarm that is electrically connected to the controller. When the calculated weighted comprehensive wear index is greater than 0.6, the controller controls the alarm to sound and controls the machine tool to stop.

5. The control system of a horizontal CNC turning and milling composite machine tool as described in claim 1, characterized in that: The workpiece clamping assembly includes a first mounting frame fixedly mounted on the frame, a multi-jaw chuck rotatably mounted on the first mounting frame, a first motor driving the multi-jaw chuck to rotate, a movable frame slidably mounted on the frame via a first linear track, and a first driving mechanism driving the movable frame to slide.

6. The control system of a horizontal CNC turning and milling composite machine tool as described in claim 1, characterized in that: The sliding frame is inclined and slidably mounted with respect to the tool holder from top to bottom via a second linear track, and the sliding frame is driven to slide by a second drive mechanism.

7. The control system of a horizontal CNC turning and milling composite machine tool as described in claim 1, characterized in that: The tool holder includes a tool holder body and a plurality of tool mounting molds evenly distributed on the tool holder body with its rotation center as the center. The tools are fixedly mounted on the tool mounting molds by fasteners.

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