A detection system and method for the machining state of a cutting tool

Abstract

The present invention provides a detection system for the machining state of a tool, comprising: a raceway; a fixture for clamping a blank; a machine tool body; a tool; a spindle current detection device for detecting the spindle current during tool machining; a vibration frequency detection device disposed on the fixture for detecting the vibration frequency during blank machining; a temperature detection device for detecting the temperature of the tool; an alarm device for giving an alarm; and a data processing device connected to the alarm device, the data processing device monitoring the tool state and controlling the alarm device to give an alarm, the tool state including the spindle current, the vibration frequency and the temperature. The present invention also provides a detection method for the machining state of a tool.

Description

Technical Field

[0001] The present invention relates to the field of tool detection for numerical control machine tools, and particularly to a detection system and method for the machining state of tools. Background Art

[0002] Due to characteristics such as high machining efficiency and concentrated processes, numerical control machine tools have become the main machining equipment in the manufacturing industry. Among them, the tool is the direct executor of the machine tool, directly contacting the workpiece and chips during the machining process, being subjected to intense friction and impact, and being extremely prone to wear, which affects the performance of the machine tool and the machining quality.

[0003] The indirect detection method uses variable parameters related to tool wear in the cutting process to indirectly obtain the tool wear state. For example, the traditional method of monitoring the tool state by collecting the magnitude of the spindle current has the defect of low judgment accuracy. Chinese Patent CN110421408B discloses a method for monitoring the tool wear state, including: learning stage: collecting the driving motor current of the spindle during the machining of normal tools and worn tools to be replaced, respectively forming a reference current curve range and an ultimate current curve range, and respectively generating a reference torque characteristic curve range and an ultimate torque characteristic curve range after analysis and processing; collecting stage: collecting the driving motor current of the spindle during the machining of the tool to be monitored to form an analysis current curve; analysis and processing stage: obtaining an analysis torque characteristic curve by processing the analysis current curve; judgment and processing stage: comparing the analysis characteristic torque curve with the reference torque characteristic curve range and the ultimate torque characteristic curve range. When the tool to be monitored is in the replacement period, the tool reaches the wear limit and needs to be replaced.

[0004] Although the above method can monitor the tool state based on the upper and lower limits generated by the current, there are also some problems in the actual use process. First, if the upper and lower limit monitoring ranges of the current are set too small or too large, there will be false alarm situations. Second, the above method cannot pre-define the incoming materials. Especially when rough machining cast blanks, due to the large variation range of the allowance thickness of each blank, the detection results have large fluctuations, which is not conducive to accurate detection. Third, its machining process does not group the blanks and cutting parameters either, and cannot make full use of the tool based on the tool state detection system. Summary of the Invention

[0005] To solve the above problems, the purpose of the present application is to provide a detection system and method for the machining state of tools, which can monitor the tool state in real time and dynamically adjust the upper and lower limits of the spindle motor state monitoring according to the change of the tool state.

[0006] An embodiment of the present application provides a detection system for the machining state of tools, including:

[0007] Raceways, said raceways include a feeding raceway and a discharging raceway, the feeding raceway includes a standard blank feeding raceway and a classified and grouped blank feeding raceway, and the raceways are used to convey blanks;

[0008] Jigs, the jigs are arranged beside the raceways, and the jigs are used to clamp blanks;

[0009] Machine tool body, the machine tool body includes:

[0010] Moving axes;

[0011] Spindle box, the spindle box is connected to the moving axes;

[0012] Cutting tools, the cutting tools are connected to the spindle box, and the cutting tools include tool disks and cutting teeth;

[0013] Spindle current detection device, the spindle current detection device detects the spindle current during the machining of the cutting tools;

[0014] Vibration frequency detection device, the vibration frequency detection device is arranged on the jigs, and the vibration frequency detection device is used to detect the vibration frequency during the machining of the blanks;

[0015] Temperature detection device, the temperature detection device is used to detect the temperature of the cutting tools;

[0016] Alarm device, the alarm device is used to give an alarm;

[0017] Data processing device, the data processing device is connected to the alarm device, the data processing device monitors the tool state and controls the alarm device to give an alarm, and the tool state includes the spindle current, the vibration frequency and the temperature.

[0018] Furthermore, for the detection system of the cutting tool machining state, there are tool disk grooves arranged on the tool disks, and the temperature detection device includes:

[0019] Magnetic rods, the magnetic rods are arranged in the tool disk grooves;

[0020] Chip shields, the chip shields isolate the magnetic force of the magnetic rods, and the chip shields are slidably connected to the tool disk grooves;

[0021] Cylinders, the cylinders are connected to the chip shields, and the cylinders control the sliding of the chip shields so as to control the exposure / concealment of the magnetic rods.

[0022] Furthermore, the detection system of the cutting tool machining state further includes an air flow pressure detection device, the air flow pressure detection device is sleeved on the cutting tool, the air flow pressure detection device is used to detect the air flow rate of the cutting teeth, and the air flow pressure detection device includes:

[0023] A cutter tooth sleeve, the number of the cutter tooth sleeves matching the number of the cutter teeth, the cutter tooth sleeves being sleeved on the cutter teeth, and the cutter tooth sleeve comprising:

[0024] A housing, an air passage being arranged inside the housing;

[0025] An elastic member, the elastic member being arranged inside the housing;

[0026] A piston, the piston being movably connected to the housing, the piston being in contact with the cutter tooth through the elastic member, the piston and the cutter tooth forming a contact surface, and a narrow slit being arranged on the contact surface;

[0027] An air pipe, the air pipe being connected to the cutter tooth sleeve, and the air pipe blowing air into the air passage;

[0028] A pressure sensor, the pressure sensor being arranged on the piston, and the pressure sensor detecting the pressure change when the air pipe blows air.

[0029] The embodiment of the present application further provides a method for detecting the machining state of a tool, using the detection system for the machining state of a tool as described above, including:

[0030] S1) Divide the full machining cycle of the tool into different tool stages according to the change of the cutter head temperature, and classify the blanks according to the material cutting performance of the blanks and the machining blank allowance of the blanks, so that different tool stages adopt blanks put in at different tool stages. The different tool stages include a first tool stage, a second tool stage, a third tool stage, and a fourth tool stage of the tool. The classified blanks include hard thick blanks, hard thin blanks, soft thick blanks, soft thin blanks, and standard blanks;

[0031] S2) Import the current correction amount B and the limit deviation range amount C of the blanks put in at different tool stages. The limit deviation range amount C includes an upper limit deviation range C1 and a lower limit deviation range C2;

[0032] S3) Obtain a calibrated spindle current curve A before the machining of different tool stages starts and ensure that the tool is not damaged;

[0033] S4) Determine the upper and lower limit current curves of different tool stages according to the calibrated spindle current curve A, the current correction amount B, and the limit deviation range amount C;

[0034] S5) Obtain the tool state during machining in real time and perform full-life cycle monitoring on the tool according to the upper and lower limit current curves of different tool stages. The tool state includes the cutter head temperature, vibration frequency, and spindle current change curve. The full-life cycle monitoring includes outputting an alarm signal when the tool is abnormal.

[0035] Further, for the method for detecting the machining state of the tool, the blank fed in different tool stages further includes:

[0036] When the tool is in the first tool stage, the soft and thick blank is used for machining. When the tool is in the second tool stage, the hard and thick blank is used for machining. When the tool is in the third tool stage, the hard and thin blank is used for machining. When the tool is in the fourth tool stage, the soft and thin blank is used for machining.

[0037] Further, for the method for detecting the machining state of the tool, step S3) further includes:

[0038] S31) Before the machining in different tool stages starts, one piece of the standard blank is fed for machining and the first main spindle current change curve of the standard blank is obtained;

[0039] S32) One piece of the blank fed in different tool stages is fed for machining and the calibrated main spindle current change curve A is obtained;

[0040] S33) One piece of the standard blank is fed for machining and the second main spindle current change curve of the standard blank is obtained;

[0041] S34) The second main spindle current change curve is compared with the first main spindle current change curve. If there is no change when the second main spindle current change curve is compared with the first main spindle current change curve, the machining continues. Otherwise, check whether the tool is damaged.

[0042] Further, for the method for detecting the machining state of the tool, the full life cycle monitoring further includes:

[0043] S51) Real-time obtain the main spindle current change curve during the machining of the blank;

[0044] S52) Perform the alarm judgment step on the obtained main spindle current change curve. The alarm judgment step includes comparing the obtained main spindle current change curve with the current upper and lower limit curves. If the sum of the horizontal distances of the abnormal intersection points between the main spindle current change curve and the current upper and lower limit curves and the cutting distance of the tool is greater than the contour error dimension of the blank along the feed axis direction, an alarm signal is output and the next step is executed. Otherwise, the machining continues;

[0045] S53) Continue to machine several pieces of the blanks fed in different tool stages and perform the alarm judgment step. If the alarm signal is continuously output, the next step is executed. Otherwise, the machining continues;

[0046] S54) Continuously process the several standard blanks and execute the alarm judgment step. If the alarm signal is continuously output, check whether the tool is damaged. Otherwise, update the spindle current change curve obtained in step S51) to the calibrated spindle current curve A and continue the processing.

[0047] Furthermore, for the detection method of the tool processing state, the cutter head temperature in the first stage of the tool is 25°C - 35°C, the cutter head temperature in the second stage of the tool is 35°C - 43°C, the cutter head temperature in the third stage of the tool is 43°C - 50°C, and the cutter head temperature in the fourth stage of the tool is 50°C - 70°C.

[0048] Furthermore, for the detection method of the tool processing state, the calculation expression of the current upper and lower limit curves is:

[0049] Y1 = A + B + C1;

[0050] Y2 = A + B - C2;

[0051] Where Y 1， Y2 is the current upper and lower limit curve;

[0052] A is the calibrated spindle current curve;

[0053] B is the current correction amount;

[0054] C1 is the upper limit deviation range;

[0055] C2 is the lower limit deviation range.

[0056] Furthermore, for the detection method of the tool processing state, the full life cycle monitoring further includes: when the vibration frequency differs from the vibration frequency during normal tool processing by more than 2 Hz, check whether the tool is damaged. The technical solutions provided by the embodiments of the present application have the following advantages:

[0057] 1. Due to the use of the vibration frequency detection device, the vibration frequency during blank processing can be detected in real time, and a quick judgment on tool abnormalities can be made;

[0058] 2. Due to the use of the air flow pressure detection device, the air flow rate of the air flowing through the cutter teeth can be detected, thus avoiding the need for manual judgment of the tool condition;

[0059] 3. Due to the use of the temperature detection device, the temperature of the tool during processing can be detected, and thus the current upper and lower limit curves of the monitoring spindle can be dynamically adjusted;

[0060] 4. Classify the blank according to the cutting performance of the blank material and the machining allowance of the blank, so as to make full use of the cutting tool and facilitate accurate detection;

[0061] 5. Obtain the calibrated spindle current curve A before the start of machining in different cutting tool stages and ensure that the cutting tool is not damaged, so as to make the monitoring of the cutting tool more accurate. Description of the Drawings

[0062] Figure 1 Schematic diagram of the detection system for the cutting tool machining state preferred in the embodiment of the present invention;

[0063] Figures 2a - 2c Schematic diagram of the temperature detection device preferred in the embodiment of the present invention;

[0064] Figure 3a Side view of the air pressure detection device preferred in the embodiment of the present invention;

[0065] Figure 3b Preferred in the embodiment of the present invention Figure 3a Cross-sectional view of the air pressure detection device at A-A;

[0066] Figure 3c Preferred in the embodiment of the present invention Figure 3b Partial enlarged view of the gas pressure device at I;

[0067] Figure 4 Flowchart of the detection method for the cutting tool machining state preferred in the embodiment of the present invention;

[0068] Figure 5 Schematic diagram of the current curve of the specific application example of the detection method for the cutting tool machining state preferred in the embodiment of the present invention. Detailed Description of the Invention

[0069] To make the purpose, technical solution and advantages of the implementation of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the accompanying drawings in the embodiments of the present application. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions. The described embodiments are some, but not all, of the embodiments of the present application. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present application and should not be construed as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present application.

[0070] In addition, it should be noted that, unless otherwise clearly specified and defined, the similar terms such as "installed", "connected", and "linked" used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can also be the communication inside two components. Those skilled in the art can understand their specific meanings in this application according to the specific circumstances.

[0071] Figure 1 This is a schematic diagram of the detection system for the cutting tool processing state preferred in the embodiment of the present invention. As Figure 1 shown, the detection system for the cutting tool processing state includes: a raceway 10, which is used to convey the blank M, including a feeding raceway 11 and a discharging raceway 12. The feeding raceway 11 is used to feed the blank M to be processed, and the discharging raceway 12 is used to send out the processed blank M. The feeding raceway 11 includes a standard blank feeding raceway 111 and a classified grouping feeding raceway 112. Among them, the blank M to be processed is pre-grouped in advance, and the standard blank M1 and the classified grouping blank M2 are respectively fed into the standard blank feeding raceway 111 and the classified grouping feeding raceway 112 during processing. A fixture 20, which is arranged beside the raceway, and the fixture 20 can clamp the blank M conveyed on the raceway. A machine tool body 30, which includes: a moving axis 31; a spindle box 32, and the spindle box 32 is connected to the moving axis 31. A cutting tool 33, which is connected to the spindle box 32, and the cutting tool 33 includes a tool disc 331 and tool teeth 332. A spindle current detection device (not shown in the figure), which detects the spindle current when the cutting tool 33 is processing. A vibration frequency detection device 40, which is arranged on the fixture 20, and the vibration frequency detection device 40 is used to detect the vibration frequency during processing when the blank M is processed. The normal processing frequency is determined by the spindle speed of the equipment and the number of tool teeth. When the speed does not change, the processing frequency will decrease after a tool tooth breaks. If the vibration frequency during processing is abnormal, an alarm is issued. An air flow pressure detection device 50, which is used to detect the air flow corresponding to the tool teeth 332. The cutting tool 31 can be sleeved in the air flow detection device 50 through the movement of the moving axis 31. A temperature detection device 60, which is used to detect the temperature of the cutting tool 31. An alarm device (not shown in the figure), which is used to issue an alarm. A data processing device (not shown in the figure), which is connected to the alarm device, and the data processing device monitors the tool state of the cutting tool 33 and controls the alarm device to issue an alarm. The tool state includes obtaining the spindle current of the spindle current detection device, the vibration frequency of the vibration frequency detection device 40, and the temperature of the temperature detection device 60.

[0072] Figures 2a - 2cSchematic diagram of the temperature detection device preferred in the embodiment of the present invention. As Figures 2a - 2c shown, a cutter head groove 3311 is provided on the cutter head 331. The temperature detection device 60 includes: a magnetic rod 61, which has an N pole and an S pole. The magnetic rod 61 is arranged in the cutter head groove 3311. A chip guard sleeve 62, which is used to isolate the magnetic force of the magnetic rod 61 arranged in the cutter head groove 3311. The chip guard sleeve 62 is slidably connected to the cutter head groove 3311, and the chip guard sleeve 62 can slide in the cutter head groove. A cylinder 63, which is connected to the chip guard sleeve 62. The cylinder 63 controls the chip guard sleeve 62 to slide in the cutter head groove 3311 so as to control the exposure / concealment of the magnetic rod 61. Preferably in this embodiment, a spring 64 is further provided between the chip guard sleeve 62 and the cylinder 63, and the spring 64 expands and supports the chip guard sleeve 62 by abutting against the cutter head boss 3311 arranged on the cutter head groove 3311. During use, usually the chip guard sleeve 62 is in a concealed state. When the tool processing is finished, control the cylinder 63 to extend so as to overcome the spring supporting force. Cut a metal wire through the movement of the spindle box 32 to generate electromagnetic induction, thereby completing the acquisition of current, and further detecting the temperature change of the cutter head 331 according to different electrical signals.

[0073] Figure 3a Side view of the air pressure detection device preferred in the embodiment of the present invention. Figure 3b Preferred in the embodiment of the present invention Figure 3a Cross-sectional view of the air pressure detection device at A-A. Figure 3c Preferred in the embodiment of the present invention Figure 3b Partial enlarged view of the gas pressure device at I. As Figures 3a - 3b shown, the air pressure detection device 50 includes: a cutter tooth sleeve 51, the number of which matches the number of cutter teeth 332. When detecting whether there is a missing cutter tooth, the cutter tooth sleeve 51 is sleeved on the cutter tooth. The cutter tooth sleeve 51 includes: a housing 511, and an air passage 5111 is arranged inside the housing 511. An elastic member 52, which is arranged inside the housing. A piston 53, which is arranged inside the housing, one end of which extends out of the housing 52 and is movably connected to the housing 52. The other end is in contact with the cutter tooth 332, and the piston 53 and the cutter tooth 332 form a contact surface, and a narrow slit (not shown in the figure) is formed on the contact surface for air to flow through. An air pipe 54, which is connected to the cutter tooth sleeve 51. Further, the air pipe 54 is connected to the housing 511, and compressed air can be blown into the housing 511 through the air pipe 54. A pressure sensor 55, which is arranged on the piston 53, and the pressure sensor detects the pressure change when the air pipe 54 blows air.

[0074] During use, the number of cutter tooth sleeves 51 matches the number of cutter teeth 332. The cutter teeth 332 extend into the cutter tooth sleeves 51 under the movement of the headstock 32. The piston 53 presses against the cutter teeth 332 through the elastic member 52, and compressed air is blown into the housing 511 through the air pipe 54. The air flow forms a narrow slit through the contact surface formed by the piston 53 and the cutter teeth 332, and the pressure sensor 55 detects the pressure of the air flow passing through the narrow slit. When a cutter tooth 332 is missing, due to Bernoulli's law, the air flow rate at the corresponding position increases, and the pressure sensor 55 detects a decrease in pressure, thereby detecting the missing cutter tooth.

[0075] Preferably, the detection system for the tool processing state may further include a photosensitive device, and the system is arranged in a closed space. When the tool bursts, the fragments of the cemented carbide cutter teeth are embedded in the workpiece. Subsequently, the cemented carbide cutter teeth impact the cemented carbide fragments embedded in the workpiece, generating sparks and light. When the photosensitive device detects the sparks and light, it issues an alarm to check whether the tool is damaged.

[0076] Figure 4 It is a flowchart of the detection method for the tool processing state preferably in the embodiment of the present invention. As Figure 4 shown, the detection method for the tool processing state, using the detection system for the tool processing state as described above, includes:

[0077] S1) Divide the full processing cycle of the tool into different tool stages according to the change of the cutter head temperature, and classify the blanks according to the cutting performance of the blank material and the machining blank allowance of the blank, so that different tool stages use blanks put in at different tool stages. The different tool stages include the first tool stage, the second tool stage, the third tool stage, and the fourth tool stage of the tool. The classified blanks include hard thick blanks, hard thin blanks, soft thick blanks, soft thin blanks, and standard blanks;

[0078] S2) Import the current correction amount B and the limit deviation range amount C of the blanks put in at different tool stages. The limit deviation range amount C includes the upper limit deviation range C1 and the lower limit deviation range C2;

[0079] S3) Obtain the calibrated spindle current curve A before the start of processing in different tool stages and ensure that the tool is not damaged;

[0080] S4) Determine the upper and lower limit current curves of different tool stages according to the calibrated spindle current curve A, the current correction amount B, and the limit deviation range amount C;

[0081] S5) Real-time obtain the tool state during processing and perform full-life cycle monitoring on the tool according to the upper and lower limit current curves of different tool stages. The tool state includes the cutter head temperature, vibration frequency, and the change curve of the spindle current. The full-life cycle monitoring includes outputting an alarm signal when the tool is abnormal.

[0082] The following specifically describes Figure 4 the method for detecting the machining state of the cutting tool.

[0083] Step S1): Divide the entire machining cycle of the cutting tool into different tool stages according to the change in the cutter head temperature, and classify the blanks according to the material cutting performance of the blank and the machining allowance of the machined blank, so that different tool stages use blanks put in different tool stages. The different tool stages include the first tool stage, the second tool stage, the third tool stage, and the fourth tool stage of the tool. The classified blanks include hard thick blanks, hard thin blanks, soft thick blanks, soft thin blanks, and standard blanks.

[0084] Specifically, for the standard blank, the machining allowance, hardness, tensile strength, and other material cutting performance parameters are controlled more precisely and standardly. For example, for the cast blank, the machining allowance is controlled between 3.00 - 3.05 mm, and the hardness is between 235 - 240 HB. The blanks to be machined are pre-grouped according to the machining allowance and material cutting performance. The material cutting performance can be divided by hardness, tensile strength, elastic modulus, etc. In this example, it is divided by hardness. The normal machining allowance of the cast blank is within 2.0 - 5.0 mm, and the hardness is within 210 - 260 HB, which varies randomly with the change of the casting mold batch. The blanks with a machining allowance of 2.0 - 3.5 mm are defined as thin blanks, the blanks with a machining allowance of 3.5 - 5.0 mm are defined as thick blanks, the blanks with a hardness of 210 - 235 HB are soft blanks, and the blanks with a hardness of 235 - 260 HB are hard blanks. Thus, they are divided into four groups: "hard thin", "soft thin", "hard thick", and "soft thick" as shown in Table 1:

[0085] Table 1:

[0086] Pre - group Cutting performance of materials Machining stock allowance Hard and thin 235 - 260HB 2.0 - 3.5 mm Soft and thin 210 - 235HB 2.0 - 3.5 mm Hard and thick 235 - 260HB 3.5 - 5.0 mm Soft and thick 210 - 235HB 3.5 - 5.0 mm Normal blank Hardness is 210 - 260HB 2.0 - 5.0 mm

[0087] Furthermore, according to the slope of the increase in the cutter head temperature change, the machining is divided into four stages, namely the first tool stage of 25°C - 35°C, the second tool stage of 35°C - 43°C, the third tool stage of 43°C - 50°C, and the fourth tool stage of 50°C - 70°C.

[0088] The use of blanks put in different tool stages in different tool stages further includes:

[0089] When the tool is in the first tool stage, use the soft thick blank for machining; when the tool is in the second tool stage, use the hard thick blank for machining; when the tool is in the third tool stage, use the hard thin blank for machining; when the tool is in the fourth tool stage, use the soft thin blank for machining.

[0090] Specifically, the rough blanks are classified and grouped, and the grouped rough blanks are put into processing in a specific order to make full use of the cutting tools and facilitate accurate detection. In the first stage of the cutting tool, the rough blanks of the "soft and thick" group are put in. At this time, the cutting teeth are relatively sharp, and the advantages of the wear-resistant but not impact-resistant cutting tooth coating can be exerted. In the second stage, the rough blanks of the "hard and thick" group are put in. At this time, after a period of running-in of the cutting teeth, the cutting edge of the cutting teeth is chamfered and strengthened, and the cutting performance is the most stable at this time. It is suitable for cutting the rough blanks of the "hard and thick" group. In the third stage, the rough blanks of the "hard and thin" group are put in. At this time, after a period of cutting of the cutting edge of the cutting teeth, the cutting edge coating begins to fall off, the cutting edge substrate begins to wear, and the cutting resistance begins to gradually increase. At this time, the rough blanks of the "hard and thin" group are put in. The cutting spindle power can be kept unchanged as much as possible. Secondly, the main wear point of the cutting edge is located at the position where it contacts the oxide skin of the cast rough blank. When the rough blanks of the "hard and thick" group are switched to the rough blanks of the "hard and thin" group. The position where the cutting edge contacts the oxide skin of the cast rough blank. Moves a distance towards the workpiece, which is beneficial to avoiding the position where the cutting edge contacts the oxide skin of the cast rough blank in the second stage. In the fourth stage, the rough blanks of the "soft and thin" group are put in. At this time, the cutting edge and coating of the cutting teeth enter a rapid wear stage after severe wear. The cutting performance is unstable, and chipping will occur when encountering a large cutting load. At this time, the cutting resistance of the rough blanks of the "soft and thin" group is less likely to cause tool breakage and false alarm compared with the rough blanks of other groups. Make full use of the remaining cutting ability of the cutting teeth as much as possible.

[0091] S2) Import the current correction amount B and the limit deviation range amount C of the rough blanks put in at different cutting tool stages.

[0092] Specifically, in this embodiment, it is preferred that the steps of obtaining the current correction amount B and the limit deviation range C are as follows:

[0093] First, use the pre-classified standard rough blanks to process the tool life cycle of all the cutting teeth of the cutting tool, and collect the corresponding cutter head temperature at the same time. Collect the change curve of the spindle power of the machine tool when each part is processed. Take the average value of each workpiece current curve and associate it with the corresponding cutter head temperature one by one to obtain the current correction amount B.

[0094] The limit deviation range C is a parameter that determines the detection accuracy of the system. When the value of C is set larger, it is easy to miss alarms, and when the limit deviation range C is set smaller, it is easy to generate false alarms. In actual production, the limit deviation range C can be measured by the calibration method. In this embodiment, it is preferred to select the rough blanks of "thick and hard" and the standard rough blanks, and process and compare them to obtain the upper limit deviation range C1 value. Select the rough blanks of "thin and soft" and the standard rough blanks, and process and compare them to obtain the lower limit deviation range C2 value. Import the current correction amount B and the limit deviation range C of different cutting tool stages into the system.

[0095] Step S3) Obtain the calibrated spindle current curve A before the start of processing at different cutting tool stages and ensure that the cutting tool is not damaged.

[0096] Specifically, step S3) further includes:

[0097] S31) Before the start of machining in the different tool stages, put one piece of the standard blank for machining and obtain the first spindle current change curve of the standard blank;

[0098] S32) Put one piece of the blank placed in the different tool stages for machining and obtain the calibrated spindle current change curve A;

[0099] S33) Put one piece of the standard blank for machining and obtain the second spindle current change curve of the standard blank;

[0100] S34) Compare the second spindle current change curve with the first spindle current change curve. If there is no change in the second spindle current change curve compared with the first spindle current change curve, continue machining; otherwise, check whether the tool is damaged.

[0101] It should be noted that a mathematical correlation calculation is performed on the first spindle current change curve and the second spindle current curve. If the correlation between the two is greater than the correlation threshold, it is considered that there is no change in the second spindle current change curve compared with the first spindle current change curve. The preferred range of the correlation threshold in this embodiment is 1% - 5%.

[0102] Furthermore, before the start of machining in each tool stage, it is first necessary to determine whether the tool is damaged, and at the same time obtain the calibrated spindle current change curve A when the tool processes the corresponding blank in this stage.

[0103] To check whether the tool is damaged, the machine can be stopped manually for inspection, or the air pressure detection device 50 of the above-mentioned tool machining state detection system can be used for inspection.

[0104] Step S4) Determine the upper and lower limit current curves of the different tool stages according to the calibrated spindle current curve A, the current correction amount B, and the limit deviation range amount C.

[0105] Specifically, the calibrated spindle current curve A of the blanks classified in the different tool stages, the current correction amount B introduced in the different tool stages, and the limit deviation range amount C introduced are converted into the upper and lower limit current curves of the different tool stages. The upper and lower limit current curves of the different tool stages are used to provide an alarm reference for the tool during different machining stages. Among them, the calculation expression of the upper and lower limit current curves is:

[0106] Y1 = A + B + C1;

[0107] Y2 = A + B - C2;

[0108] Among them, Y 1，Y2 is the upper and lower limit curve of the current, Y1 is the upper limit curve of the current, and Y2 is the lower limit curve of the current;

[0109] A is the calibrated spindle current curve;

[0110] B is the current correction amount;

[0111] C1 is the upper limit deviation range;

[0112] C2 is the lower limit deviation range.

[0113] Step S5) Obtain the tool state during machining in real time and perform full-life cycle monitoring on the tool according to the upper and lower limit curves of the current in different tool stages. The tool state includes the cutter head temperature, vibration frequency, and the spindle current change curve. The full-life cycle monitoring includes outputting an alarm signal when the tool is abnormal.

[0114] Specifically, the full-life cycle monitoring further includes:

[0115] S51) Obtain the spindle current change curve during the machining of the blank in real time;

[0116] Specifically, monitor and obtain the spindle current change curve during the machining of classified blanks.

[0117] S52) Perform an alarm judgment step on the obtained spindle current change curve. The alarm judgment step includes comparing the obtained spindle current change curve with the upper and lower limit curves of the current. If the sum of the horizontal distances of the abnormal intersection points between the spindle current change curve and the upper and lower limit curves of the current and the ratio of the cutting distance of the tool is greater than the contour error size of the blank along the feed axis direction, then output an alarm signal and perform the next step; otherwise, continue machining.

[0118] Specifically, when the obtained spindle current change curve exceeds the lower limit curve of the current in different tool machining stages set, intersections will be generated. For example, the horizontal distance between the first and the second intersection points is D1. The abnormal intersection points are D2, D3, and D4. When the sum of the horizontal distances between the intersection points in the entire machining area is D. When the ratio E of D to the total machining cutting distance L is greater than the set value F, an alarm signal is output. Among them, the F value is set according to the contour error size of the blank along the feed axis direction and experience.

[0119] S53) Continue machining several blanks put in different tool stages and perform the alarm judgment step. If the alarm signal is continuously output, then perform the next step; otherwise, continue machining.

[0120] S54) Continuously process the several standard blanks and execute the alarm judgment step. If the alarm signal is continuously output, check whether the tool is damaged. Otherwise, update the spindle current change curve obtained in step S51) to the calibrated spindle current curve A and continue the processing.

[0121] Preferably, the full life cycle monitoring further includes: when the vibration frequency differs from the vibration frequency during normal tool processing by more than 2 Hz, check whether the tool is damaged.

[0122] Preferably, the real-time acquisition of the tool state during processing can also include the electrical signal of the firelight. The full life cycle monitoring further includes: when the electrical signal of the firelight is acquired, check whether the tool is damaged.

[0123] Figure 5 It is a schematic diagram of the current curve of a specific application example of the detection method for the tool processing state preferred in the embodiment of the present invention. As Figure 5 shown, curve Z1 is the calibrated current curve of the tool at a certain stage. Curve Z2 is the spindle current change curve of the tool when processing the blank at a certain stage. Curve Z3 is the current upper limit curve of the tool at a certain stage. Curve Z4 is the current lower limit curve of the tool at a certain stage.

[0124] When curve Z1 is between the upper limit curve Z3 and curve Z4, the equipment continues to process normally.

[0125] When curve Z1 exceeds and intersects with the upper limit curve Z3. For example, the horizontal distance between the first and the second intersection points is D1. The abnormal intersection points are D2, D3, and D4. When the sum of the horizontal distances between the intersection points in the entire processing area is D. When the ratio E of D to the total processing cutting distance L is greater than the set value F, output the first-level suspected alarm signal. The value of F is set according to the profile error size of the blank along the feed axis direction and experience.

[0126] The following is a complete embodiment of the full life cycle monitoring:

[0127] First, group the blanks in the above manner, and then start the system and the monitoring method.

[0128] When the tool is in the first stage, the tool state is relatively unstable. When a first-level suspected alarm signal is output for one blank, continue to detect the subsequent two blanks. If the first-level suspected alarm signal is sent for three consecutive blanks, output the second-level suspected alarm signal to the PLC.

[0129] When the tool is in the second and third stages, the tool state is relatively stable. When a first-level suspected alarm signal is output for one blank, directly output the second-level suspected alarm signal to the PLC.

[0130] When the tool is in the fourth stage, the tool state is relatively unstable. When a suspected alarm signal is output from one blank output stage, continue to detect the subsequent blank. If the first-stage suspected alarm signals are sent out by two consecutive blanks, a second-stage suspected alarm signal is output to the PLC.

[0131] After the PLC receives the second-stage suspected alarm signal, call the feeding system to continuously feed three standard blanks to calibrate the tool. If three consecutive standard blanks are within the monitoring limit range, it is considered that the tool is in good condition. If the current curve rises due to a sudden increase in the batch allowance of the blank or a sudden hardening of the blank material, cancel the alarm output signal and continue normal processing. The system automatically updates the processing current data of the blank with the first-stage suspected alarm signal to the calibrated spindle current curve A. Then call the system to feed one standard blank, collect the spindle current during processing, and compare it with the current data of the three standard blanks before updating the A data. Verify again that the tool is good to ensure that the tool state is good when collecting data A. Determine that the previous suspected alarm was caused by blank factors.

[0132] If three consecutive standard blanks are outside the monitoring limit range, a third-stage suspected alarm signal is output to the PLC. The turret stops rotating and accurately stops at the corresponding angle corresponding to the tool sleeve. The spindle box moves to the disc sleeve to detect whether there are missing tool teeth. If missing tool teeth are detected, the final alarm is output, the equipment stops, and the equipment lights up a red light. If no missing tool teeth are detected, a warning alarm is output. The equipment is allowed to continue processing ten workpieces without stopping, the current alarm signal in this stage is blocked, and the equipment lights up a yellow light. It is judged that the tool is severely worn at this time, but there is no chipping yet, and the tool can still cut ten workpieces. Call the operator to prepare a spare tool and change the tool as soon as possible. If the operator has not changed the tool after continuing to process ten workpieces, the equipment stops and the equipment lights up a red light.

[0133] When the electrical signal of the detected firelight or the electrical signal of the decrease in the tool tooth processing frequency is detected, the system directly outputs a third-stage suspected alarm signal to the PLC. Thus, the false alarm caused by the instability during the initial stage of tool running-in is reduced.

[0134] This application provides a detection system and method for the machining state of a tool, which can monitor the state of the tool in real time and dynamically adjust the upper and lower limits of the spindle motor state monitoring according to the change of the tool state.

[0135] The technical solution provided by the embodiment of this application has the following advantages:

[0136] 1. Due to the use of the vibration frequency detection device, the vibration frequency during blank machining can be detected in real time, and a quick judgment on tool abnormalities can be made; 2. Due to the use of the air flow pressure detection device, the air flow rate of the air flowing through the tool teeth can be detected, thus avoiding the need for manual judgment of the tool condition.

[0137] 3. Since a temperature detection device is used, the temperature of the cutting tool during machining can be detected, so that the upper and lower limit curves of the current for monitoring the main shaft can be dynamically adjusted;

[0138] 4. Since the blanks are classified according to the cutting performance of the blank material and the machining allowance of the machined blank, the cutting tool can be fully utilized and accurate detection is facilitated;

[0139] 5. Since the calibrated main shaft current curve A is obtained before the start of machining in different tool stages and ensuring that the tool is not damaged, the monitoring of the tool is made more accurate.

[0140] Those skilled in the art will appreciate that information, signals, and data can be represented using any of a variety of different technologies and techniques. For example, the data, instructions, commands, information, signals, bits, symbols, and chips described throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0141] Those skilled in the art will further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or a combination of the two. To clearly illustrate this interchangeability of hardware and software, the various illustrative components, blocks, modules, circuits, and steps are described above in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

[0142] The various illustrative logical modules and circuits described in connection with the embodiments disclosed herein can be implemented or executed using a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0143] The steps of the methods or algorithms described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read from, and write to, the storage medium. In an alternative, the storage medium may be integrated into the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In an alternative, the processor and the storage medium may reside as discrete components in a user terminal.

[0144] In one or more exemplary embodiments, the described functionality may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software as a computer program product, the functions may be stored on or transmitted via a computer-readable medium as one or more instructions or code. The computer-readable medium includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage medium may be any available medium that can be accessed by a computer. By way of example, and not limitation, such computer-readable medium can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a web site, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable medium.

[0145] The above embodiments are provided to those skilled in the art to implement or use the present application. Those skilled in the art can make various modifications or variations to the above embodiments without departing from the application idea of the present application. Therefore, the protection scope of the present application is not limited by the above embodiments, but should be the maximum scope that conforms to the innovative features mentioned in the claims.

Claims

1. A detection system for the machining state of a cutting tool, comprising: Raceways, said raceways including a feeding raceway and a discharging raceway, the feeding raceway including a standard blank feeding raceway and a classified and grouped blank feeding raceway, and the raceways being used for conveying blanks; A fixture, said fixture being arranged beside the raceways and being used for clamping blanks; A machine tool body, said machine tool body including: Moving axes; A spindle box, said spindle box being connected to the moving axes; A cutting tool, said cutting tool being connected to the spindle box, and the cutting tool including a cutter head and cutting teeth; A spindle current detection device, said spindle current detection device detecting the spindle current during the machining of the cutting tool; A vibration frequency detection device, said vibration frequency detection device being arranged on the fixture and being used for detecting the vibration frequency during the machining of the blanks; A temperature detection device, said temperature detection device being used for detecting the temperature of the cutting tool; An alarm device, said alarm device being used for giving an alarm; A data processing device, said data processing device being connected to the alarm device, the data processing device monitoring the state of the cutting tool and controlling the alarm device to give an alarm, and the state of the cutting tool including the spindle current, the vibration frequency and the temperature; A cutter head groove is arranged on the cutter head, and the temperature detection device includes: A magnetic rod, said magnetic rod being arranged in the cutter head groove, and the magnetic rod having an N pole and an S pole; A chip guard sleeve, said chip guard sleeve isolating the magnetic force of the magnetic rod, and the chip guard sleeve being slidably connected to the cutter head groove; A cylinder, said cylinder being connected to the chip guard sleeve, and the cylinder controlling the sliding of the chip guard sleeve so as to control the exposure or shielding of the magnetic rod; Wherein, the magnetic rod drives the cutting of a metal wire through the movement of the spindle box to generate electromagnetic induction, thereby completing the acquisition of current, and further detecting the temperature change of the cutter head according to different electrical signals.

2. The detection system for the cutting tool processing state according to claim 1, characterized in that, It further includes an air flow pressure detection device, said air flow pressure detection device being sleeved on the cutting tool and being used for detecting the air flow of the cutting teeth, and the air flow pressure detection device includes: Cutting tooth sleeves, the number of said cutting tooth sleeves matching the number of the cutting teeth, the cutting tooth sleeves being sleeved on the cutting teeth, and the cutting tooth sleeves including: A housing, an air passage being arranged inside the housing; An elastic member, said elastic member being arranged inside the housing; A piston, said piston being movably connected to the housing, the piston contacting the cutting teeth through the elastic member, the piston and the cutting teeth forming a contact surface, and a narrow slit being arranged on the contact surface; An air pipe, said air pipe being connected to the cutting tooth sleeve, and the air pipe blowing air into the air passage; A pressure sensor, said pressure sensor being arranged on the piston, and the pressure sensor detecting the pressure change when the air pipe blows air.

3. A method for detecting the machining state of a cutting tool, using the detection system for the machining state of a cutting tool according to any one of claims 1 or 2, characterized in that, Including: S1) Divide the full machining cycle of the cutting tool into different tool stages according to the change of the cutter head temperature, and classify the blank according to the material cutting performance of the blank and the machining blank allowance, so that different blanks are used for different tool stages. The different tool stages include the first tool stage, the second tool stage, the third tool stage and the fourth tool stage. The classified blanks include hard thick blanks, hard thin blanks, soft thick blanks, soft thin blanks and standard blanks; S2) Import the current correction amount B and the limit deviation range amount C of the blanks put in different tool stages. The limit deviation range amount C includes the upper limit deviation range C1 and the lower limit deviation range C2; S3) Obtain the calibrated spindle current curve A before the machining in different tool stages starts and ensure that the cutting tool is not damaged; S4) Determine the upper and lower limit current curves of different tool stages according to the calibrated spindle current curve A, the current correction amount B and the limit deviation range amount C; S5) Obtain the tool state during machining in real time and perform full-life cycle monitoring on the cutting tool according to the upper and lower limit current curves of different tool stages. The tool state includes the cutter head temperature, vibration frequency and spindle current change curve. The full-life cycle monitoring includes outputting an alarm signal when the cutting tool is abnormal; Among them, whether the cutting tool is damaged is checked by manually stopping the machine or using the air flow pressure detection device of the detection system of the cutting tool machining state; The material cutting performance of the hard thin blank is 235 - 260HB, and the machining blank allowance is 2.0 - 3.5 mm; The material cutting performance of the soft thin blank is 210 - 225HB, and the machining blank allowance is 2.0 - 3.5 mm; The material cutting performance of the hard thick blank is 235 - 260HB, and the machining blank allowance is 3.5 - 5.0 mm; The material cutting performance of the soft thick blank is 210 - 235HB, and the machining blank allowance is 3.5 - 5.0 mm; The material cutting performance of the standard blank is 235 - 240HB, and the machining blank allowance is 3.00 - 3.05 mm.

4. The detection method for the cutting tool machining state according to claim 3, wherein That the different tool stages use blanks put in different tool stages further includes: When the cutting tool is in the first tool stage, use the soft thick blank for machining. When the cutting tool is in the second tool stage, use the hard thick blank for machining. When the cutting tool is in the third tool stage, use the hard thin blank for machining. When the cutting tool is in the fourth tool stage, use the soft thin blank for machining.

5. The detection method of the tool processing state according to claim 3, characterized in that, The step S3) further includes: S31) Put in a standard blank for machining before the machining in different tool stages starts and obtain the first spindle current change curve of the standard blank; S32) Put in a blank put in different tool stages for machining and obtain the calibrated spindle current change curve A; S33) Put in a standard blank for machining and obtain the second spindle current change curve of the standard blank; S34) Compare the second main spindle current change curve with the first main spindle current change curve. If there is no change in the second main spindle current change curve compared with the first main spindle current change curve, continue the machining. Otherwise, check whether the tool is damaged.

6. The detection method for the tool processing state according to claim 3, wherein The full life cycle monitoring further includes: S51) Obtain the main spindle current change curve during the machining of the blank in real time; S52) Perform an alarm judgment step on the obtained main spindle current change curve. The alarm judgment step includes comparing the obtained main spindle current change curve with the upper and lower current limit curves. If the sum of the horizontal distances of the abnormal intersection points of the main spindle current change curve and the upper and lower current limit curves divided by the cutting distance of the tool is greater than the contour error dimension of the blank along the feed axis direction, output an alarm signal and perform the next step. Otherwise, continue the machining; S53) Continue machining several blanks placed in different tool stages and perform the alarm judgment step. If the alarm signal is continuously output, perform the next step. Otherwise, continue the machining; S54) Continuously machine the several standard blanks and perform the alarm judgment step. If the alarm signal is continuously output, check whether the tool is damaged. Otherwise, update the main spindle current change curve obtained in step S51) to the calibrated main spindle current curve A and continue the machining.

7. The detection method for the tool processing state according to claim 3, characterized in that The tool disc temperature in the first stage of the tool is 25°C - 35°C, the tool disc temperature in the second stage of the tool is 35°C - 43°C, the tool disc temperature in the third stage of the tool is 43°C - 50°C, and the tool disc temperature in the fourth stage of the tool is 50°C - 70°C.

8. The detection method of the cutting tool processing state according to claim 3, characterized in that, The calculation expression of the upper and lower current limit curves is: Y1 = A + B + C1; Y2 = A + B - C2; Among them, Y 1， Y2 is the upper and lower limit curves of the current; A is the calibrated main spindle current curve; B is the current correction amount; C1 is the upper limit deviation range; C2 is the lower limit deviation range.

9. The detection method of the cutting tool machining state according to claim 3, characterized in that, The full life cycle monitoring further includes: when the vibration frequency differs from the vibration frequency during normal tool machining by more than 2 Hz, check whether the tool is damaged.

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