Method for detecting cutting capacity of main shaft

Abstract

The invention discloses a method for detecting the cutting capacity of a main shaft, and aims at making judgment and early warning on the real-time cutting capacity and the cutting state of the main shaft, reducing the abnormal risk in the machining process, improving the machining safety and reducing the trial and error cost. The method comprises the main steps that the cutting torque and the torque utilization rate of a main shaft are monitored in real time through a networking monitoring interface, current cutting materials and cutting process parameters are substituted into a formula fitted through a logarithm multiple linear regression mode to calculate the theoretical cutting torque, the actual cutting torque of the main shaft is compared with the theoretical cutting torque, and the cutting torque utilization rate of the main shaft is calculated. The current spindle cutting capacity and cutting state are judged, cutting risk early warning is made in real time according to the detection state, and a user is prompted to adjust current technological parameters in time.

Description

Technical Field

[0001] This invention relates to the field of machining, and more specifically to a method for detecting the cutting capability of a spindle. Background Technology

[0002] Accurate measurement of spindle cutting force is crucial for improving the operating efficiency and machining quality of CNC machine tools. Existing spindle cutting capacity monitoring technologies can be implemented through various methods, including load suspension, three-coordinate force sensor, and vibration sensor methods.

[0003] The load suspension method measures cutting force by applying a certain load to the workpiece or tool and installing sensors on the bar stock or equipment. This method requires an equal load to process the bar stock, which may lead to some waste in actual production. The three-coordinate measuring machine (CMM) force sensor method uses three force sensors installed on the machine tool to measure tangential force, radial force, and spindle power respectively. This method is limited by the accuracy of the sensors. The vibration sensor method uses vibration sensors installed on the machine tool surface to measure the frequency and amplitude of machine tool vibrations during cutting to infer the cutting force. This method does not require changing the cutting conditions and process, but requires reasonable calculation and inference based on actual conditions.

[0004] Although there are many calculation methods used by scholars at home and abroad in the existing formulas for calculating cutting torque, the research on milling torque calculation formulas is still insufficient, and there is a lack of optimal calculation methods for different materials, different tools and different cutting parameters.

[0005] In existing spindle cutting torque monitoring processes, there is no real-time early warning function when the spindle cutting torque exceeds the limit. When the spindle cutting capacity reaches the upper limit or becomes abnormal, the resulting machining risks cannot be known immediately.

[0006] When measuring the spindle cutting torque during actual machining, external sensors are used. This is not only limited by the accuracy of the sensors themselves, but also costly and time-consuming and labor-intensive to install and debug. There is no accurate and reliable calculation formula for the spindle cutting torque in the calculation theory, and the general calculation formula cannot accurately calculate the cutting torque for each material and specific fixed tool. Summary of the Invention

[0007] The purpose of this invention is to address the problems in the prior art by providing a method for detecting spindle cutting capability. Without adding additional sensors, the method accurately calculates the spindle cutting torque based on cutting parameters and workpiece material, and determines the current spindle cutting capability and cutting status in real time. When the cutting status is abnormal, a real-time alarm is issued to reduce the risk of abnormality, maximize the spindle cutting capability, and ensure the spindle's service life.

[0008] To achieve the above objectives, the technical solution adopted by the present invention includes the following steps: The first step is to obtain the real-time spindle torque and calculate the spindle torque utilization rate through the machine tool network interface; The second step is to calculate the actual spindle cutting torque and match it with the actual spindle cutting torque based on the no-load torque corresponding to the current spindle speed. The third step is to calculate the theoretical spindle cutting torque based on the current cutting process parameters, including the cutting material, tool diameter d0, spindle speed n, feed rate F, number of cutting edges Z, and depth of cut a. p and cutting width a e A full-parameter segment cutting torque calculation model was established, and an empirical formula was fitted using logarithmic multiple linear regression. The theoretical spindle cutting torque was calculated by substituting each parameter into the fitted empirical formula. The theoretical spindle torque calculation formula is as follows: ; In addition to supporting common materials such as 6-series aluminum, 7-series aluminum, and 45 steel, it also supports 4Cr13 and Q235; the detailed calculation formula is shown below: 6-series aluminum: ; 7-series aluminum: ; 45 steel: ; 4Cr13: ; Q235: ; In the calculation formulas for the above five materials, each letter has the same meaning. d0 is the tool diameter (mm), a p a is the depth of cut (mm). e Z is the cutting width (mm), n is the number of cutting edges, n is the spindle speed (rpm), and f is the cutting width (mm). z This refers to the feed per tooth. The fourth step is to determine the real-time spindle cutting capability. Based on the current spindle torque utilization rate, the spindle cutting capability under the current parameters is determined in real time. When the spindle cutting capability exceeds the set threshold, an alert is issued, indicating the time of the abnormality and the tool number, prompting the user to adjust the process parameters. Step 5: Determine the real-time spindle cutting status. Compare the current actual spindle cutting torque with the theoretical cutting torque to determine the spindle cutting status under the current process parameters. If the spindle cutting status is abnormal, issue a reminder to prompt the user to adjust the process parameters. Step 6: Print out the real-time spindle torque and spindle torque utilization rate collected during the process to a fixed directory for users to facilitate subsequent data processing and analysis.

[0009] Furthermore, the specific steps for calculating the torque utilization rate based on the spindle model in the first step are as follows: (1) Obtain the current real-time torque of the spindle; (2) Calculate the current spindle torque utilization rate based on the rated power and rated torque of the current spindle in S6 mode; (3) Currently supports the full range of spindles: including 105S, 130S, 150S, 180S and 200S.

[0010] Furthermore, the fourth step of determining the spindle cutting capability is primarily based on the spindle torque utilization rate. The spindle torque utilization rate varies with the current spindle model, machining tools, process parameters, and cutting material. When any condition changes, the spindle torque utilization rate changes, and the spindle cutting capability changes accordingly. The criteria for determining the spindle cutting capability are as follows: when the spindle torque utilization rate is less than the default threshold of 60%, the spindle cutting capability is considered "good"; when the real-time torque utilization rate is between 60% and 80%, the spindle cutting capability is considered "average"; and when the real-time torque utilization rate is between 80% and 100%, the spindle cutting capability is considered "needs optimization."

[0011] Furthermore, the fifth step of judging the spindle cutting state involves comparing the actual cutting torque with the theoretical cutting torque calculated using the aforementioned formula. If the deviation exceeds a set threshold, the current spindle cutting state is considered abnormal, and a real-time alert is issued. The judgment criteria are as follows: when the actual cutting torque deviates from the theoretical cutting torque by more than ±50% for one minute, the current cutting state is considered abnormal, and the system issues a real-time alert, prompting the user to adjust the process parameters.

[0012] Compared with the prior art, the present invention has been optimized in the following aspects: 1. This invention employs logarithmic multiple linear regression to establish functional relationships between various workpiece materials, tool materials, and different cutting parameters, thus expanding upon the shortcomings of existing calculation formulas and clarifying theoretical calculation formulas for spindle cutting torque for five materials (6-series aluminum, 7-series aluminum, 45 steel, 4Cr13, and Q235). Spindle cutting torque can be directly calculated using material and process parameters without the need for actual cutting, improving process development and verification efficiency and reducing trial cutting costs.

[0013] 2. This invention employs a novel data acquisition method: a network monitoring interface to monitor spindle cutting torque, replacing traditional force and vibration sensors. These methods are limited by sensor accuracy, high hardware costs, and stringent personnel requirements. The network monitoring interface method used in this invention requires only a single network cable to acquire data, is simple and easy to operate, saves time and effort, and has low personnel requirements.

[0014] 3. This invention monitors the spindle cutting torque while simultaneously judging and analyzing the spindle cutting capability and cutting status. When the threshold line is exceeded, a real-time prompt is given to the user to make adjustments, thereby reducing cost waste caused by errors during the trial cutting process. Attached Figure Description

[0015] Figure 1 This invention provides a system for evaluating spindle cutting capability; Figure 2 This invention provides the cutting process parameters required for calculating the theoretical spindle torque. Figure 3 Flowchart of the spindle cutting capability judgment method of the present invention. Detailed Implementation

[0016] The present invention will now be described in further detail with reference to the accompanying drawings.

[0017] The method for detecting the spindle cutting capability of the present invention includes the following steps: 1. Connect the machine tool via its network interface; See Figure 1 A monitoring system is formed by connecting the machine tool and the monitoring computer using a network cable. The specific operating steps are as follows: (1) Enter the machine tool's IP address on the computer and connect to the machine tool; (2) Select the machine tool spindle model. The available options are 105S, 130S, 150S, 180S, and 200S. (3) The user inputs a suitable acquisition frequency. The system supports a maximum acquisition frequency of 200ms.

[0018] 2. Input the actual process parameters according to the current processing technology; See Figure 2 Input the actual machining process parameters based on the current cutting process parameters, specifically including: cutting material, tool diameter d0, spindle speed n, feed rate F, number of cutting edges Z, and depth of cut a. p and cutting width a e .

[0019] 3. Click the "Start Monitoring" button to begin data acquisition, display, and real-time prompts for spindle cutting capability assessment; See Figure 3 After clicking the "Start Monitoring" button, the system calculates the spindle torque utilization rate based on the machine tool parameters entered by the user. If the spindle torque utilization rate continues to exceed the limit value, the system will alarm and prompt that the spindle cutting capability is insufficient under the current process parameters. Please adjust the process parameters and pay attention to the equipment status.

[0020] After clicking the "Start Monitoring" button, the system will simultaneously calculate the theoretically required spindle cutting torque based on the machining parameters input by the user. After matching the no-load torque, the theoretical cutting torque will be compared with the actual collected spindle cutting torque. If the deviation between the theoretical cutting torque and the actual cutting torque continues to exceed the limit range, an abnormal spindle cutting status will be indicated, prompting the user to pay attention to the equipment status.

Claims

1. A spindle cutting capacity detection method, characterized by: First step, obtain the spindle real-time torque through the machine tool networking interface and calculate the spindle torque utilization rate; Second step, calculate the actual spindle cutting torque, match the actual spindle cutting torque according to the current spindle speed corresponding to the no-load torque; Third step, calculate the theoretical spindle cutting torque, according to the current cutting process parameters, including cutting material, tool diameter d0, spindle speed n, feed speed F, tool edge number Z, cutting depth a p And cutting width a e , the full parameter section cutting torque calculation model is established, the empirical formula is fitted by using logarithmic multiple linear regression, and the theoretical spindle cutting torque is calculated by bringing each parameter into the fitted empirical formula; the theoretical spindle torque calculation formula is as follows: In the calculation formula, the meanings of each letter are as follows: d0 is the tool diameter in mm, a p is the depth of cut in mm, a e is the width of cut in mm, Z is the number of tool edges, n is the spindle speed in rpm, f z is the feed per tooth, m is a constant, and k1-k5 are different coefficients; Fourth step, judge the real-time spindle cutting capacity, judge the spindle cutting capacity under the current parameters in real time according to the current spindle torque utilization rate, and make a prompt when the spindle cutting capacity exceeds the set threshold, prompt the time of abnormal occurrence and the tool number, and prompt the user to adjust the process parameters; Fifth step, judge the real-time spindle cutting state, compare the current spindle actual cutting torque with the theoretical cutting torque, judge the spindle cutting state under the current process parameters, and make a prompt when the spindle cutting state is abnormal, prompt the user to adjust the process parameters; Sixth step, print the collected spindle real-time torque and spindle torque utilization rate to a fixed directory.

2. The method of claim 1, wherein the step of determining the cutting ability of the spindle comprises the steps of: The specific steps of the first step to calculate the spindle torque utilization rate are as follows: ​ (1) Obtain the current spindle real-time torque; (2) Calculate the current spindle torque utilization rate value according to the rated power and rated torque of the current spindle S6 mode.

3. The method of claim 1, wherein: In addition to supporting common materials 6 aluminum, 7 aluminum and 45 steel, the third step of calculating the theoretical spindle cutting torque also supports 4Cr13, Q235, and detailed calculation formulas are as follows: 6 series aluminum: 7-series aluminum: 45 steel: 4Cr13： Q235： In the calculation formulas of the above five materials, the meanings of each letter are consistent.

4. The method of claim 1, wherein: The fourth step of judging the spindle cutting capacity is to judge the spindle cutting capacity according to the spindle torque utilization rate; the spindle torque utilization rate changes with the current spindle model, machining tool, process parameters and cutting material; when any condition changes, the spindle torque utilization rate changes, and the spindle cutting capacity changes accordingly; The judgment basis of the spindle cutting capacity is: when the spindle torque utilization rate is less than the default set threshold of 60%, it is determined that the spindle cutting capacity is "good"; when the real-time torque utilization rate is between 60% and 80%, it is determined that the spindle cutting capacity is "general"; when the real-time torque utilization rate is between 80% and 100%, it is determined that the spindle cutting capacity is "to be optimized".

5. The method of claim 1, wherein: The fifth step of judging the spindle cutting state is to compare the deviation of the actual cutting torque from the theoretical cutting torque on the basis of the aforementioned formula to calculate the theoretical spindle cutting torque; if the deviation exceeds the set threshold, it is considered that the current spindle cutting state is abnormal and a real-time prompt is made; the judgment basis is: when the actual cutting torque deviates from the theoretical cutting torque by more than ± 50% for one minute, it is considered that the current cutting state is abnormal, the system makes a real-time prompt, and the user is prompted to adjust the process parameters.

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