A measurement system and method for detecting press tonnage and pressure point gap

Abstract

The present invention discloses a measurement system and method for detecting the tonnage and pressure point gap of a press, which belongs to the field of mechanical engineering measurement technology. The method specifically comprises: installing a high-precision displacement sensor between the upper and lower molds of the press, and installing a force sensor on the work surface of the press, starting the displacement sensor and the force sensor, performing zero point calibration, recording the sensor readings in the initial state as a reference value, gradually increasing the load of the press, recording the readings of the displacement sensor and the force sensor each time the load is increased, calculating the actual tonnage of the press and detecting the pressure point gap using the readings of the displacement sensor and the force sensor under different loads, analyzing the detected data, drawing a pressure-displacement curve, checking the linearity and stability of the curve, outputting the tonnage and pressure point gap detection results of the press, and generating a detection report.

Description

Technical Field

[0001] The present invention belongs to the technical field of mechanical engineering measurement, and in particular relates to a measurement system and method for detecting the tonnage and pressure point gap of a press. Background Art

[0002] In modern manufacturing, presses are widely used to stamp sheet metal. However, due to prolonged, high-intensity operation, the press's tonnage and pressure gap may change during use, affecting processing accuracy and product quality. Existing techniques typically employ a combination of manual measurement and mechanical sensors for detection, but these methods suffer from low measurement accuracy and complex operation. Therefore, a new, simple, and highly accurate detection method is urgently needed.

[0003] For example, Chinese patent application publication number CN117606657A discloses a system for detecting the tonnage, pressure point gap, and deflection of large presses. The system includes a load cell, a hydraulic system, and a data acquisition and display system. The load cell consists of a piston body, a pressure plate, a load detection hydraulic cylinder, and a high-precision, fast-conversion pressure sensor. The hydraulic system has eight hydraulic branches, enabling tonnage and deflection detection for presses with a maximum tonnage of 4,000 tons. The data acquisition and display system utilizes a DT9844 signal acquisition board, capable of collecting and processing pressure values ​​from the high-precision, fast-conversion pressure sensors on the eight load cell bodies. This invention is used to detect the working load of a press and the deflection of a machine tool, as well as to measure the gaps at the pressure points of a two-point or four-point press, thereby ensuring the accuracy of the machine tool.

[0004] Defects of the above patent: Despite the above improvements to the machinery, gaps and other errors will still exist under long-term high-intensity work. Summary of the Invention

[0005] In response to the deficiencies in the prior art, the present invention proposes a measurement system and method for detecting the tonnage and pressure point gap of a press. A high-precision displacement sensor is installed between the upper and lower molds of the press, and a force sensor is installed on the work surface of the press. The displacement sensor and force sensor are started, zero-point calibration is performed, and the sensor readings in the initial state are recorded as a reference value. The load of the press is gradually increased. Each time the load is increased, the readings of the displacement sensor and force sensor are recorded. Under different loads, the readings of the displacement sensor and force sensor are used to calculate the actual tonnage of the press and detect the pressure point gap. The detected data is analyzed, a pressure-displacement curve is drawn, the linearity and stability of the curve are checked, the tonnage and pressure point gap detection results of the press are output, and a detection report is generated.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A measuring method for detecting the tonnage and pressure point gap of a press machine comprises the following specific steps:

[0008] Step S1: Install the displacement sensor between the upper and lower molds of the press, and install the force sensor on the working table of the press;

[0009] Step S2: Start the displacement sensor and force sensor, perform zero point calibration, and record the sensor readings in the initial state as the reference value;

[0010] Step S3: gradually increasing the load of the press, and recording the readings of the displacement sensor and the force sensor each time the load is increased;

[0011] Step S4: Under different loads, the actual tonnage of the press is calculated using the readings of the displacement sensor and the force sensor, and the pressure point gap is detected;

[0012] Step S5: Analyze the detected data, draw a pressure-displacement curve, check the linearity and stability of the curve, output the tonnage and pressure point gap detection results of the press, and generate a test report.

[0013] Specifically, the zero point calibration in step S2 is as follows: before using the displacement sensor and the force sensor, by setting or adjusting, the displacement sensor and the force sensor output to zero under no external force or standard reference conditions.

[0014] Specifically, the specific steps of step S3 are:

[0015] Step S301: Start the press and check whether the press, displacement sensor and force sensor are operating normally;

[0016] Step S302: increasing the press load to a first incremental value ΔZ, stabilizing the press load, and waiting for the displacement sensor and force sensor readings to stabilize;

[0017] Step S303: The displacement sensor and force sensor read data and record the current load, displacement and pressure readings;

[0018] Step S304: Repeat steps S302 to S303, increasing the load increment ΔZ each time until the maximum load of the press is reached, and collect corresponding load, displacement and pressure data.

[0019] Specifically, the specific steps of step S4 are:

[0020] Step S401: Set the set of collected corresponding load, displacement and pressure data to S, where S = {(ΔZ, W1, P1), (2ΔZ, W2, P2), ... (nΔZ, Wn, Pn)}, where n represents the number of times the press increases the load, Wn represents the displacement data collected when the press increases the load for the nth time, and Pn represents the pressure data collected when the press increases the load for the nth time;

[0021] Step S402: Calculate the actual tonnage Tsi of the press when the i-th load is added based on the collected pressure data;

[0022] Step S403: Calculate the pressure point gap ΔGi when the press increases the load for the i-th time based on the collected displacement data.

[0023] Specifically, the specific formula for calculating the actual tonnage Tsi of the press in step S402 is:

[0024]

[0025] Among them, Pi represents the pressure data collected when the press increases the i-th load, Ai represents the effective area of ​​the press when the i-th load is increased, η represents the transmission efficiency of the press, taking into account factors such as mechanical transmission efficiency and friction loss, Ct represents the time correction coefficient, taking into account the performance changes of the press during long-term operation, α represents the thermal expansion coefficient of the pressed material, ΔT represents the temperature change of the press working surface, v represents the punch speed of the press, g represents the acceleration of gravity, and a represents the dynamic inertia coefficient of the press punch, taking into account the inertia effect of the punch during movement.

[0026] Specifically, the specific formula for calculating the pressure point gap ΔGi when the press increases the load for the i-th time in step S403 is:

[0027]

[0028] Among them, κ is the wear coefficient of the press, which reflects the wear of the machine, Em is the elastic modulus of the pressed material, l is the thickness of the pressed material, Cf is the press correction coefficient, which takes into account factors such as mechanical transmission efficiency and friction loss, SP is the pressure loss of the press punch, L is the length of the press force arm, K is the stiffness of the press, β is the thermal expansion coefficient of the press punch, and Gaz is the gap distance caused by the press installation.

[0029] Specifically, the specific steps of step S5 are:

[0030] Step S501: Analyze the detected data, plot the sensor pressure-displacement curve and the calculated pressure-displacement curve, use linear regression to check the linearity and stability of the curve, and calculate the determination coefficient R. The calculation formula is:

[0031]

[0032] Where kj represents the slope of the pressure-displacement curve of the sensor when the press increases the jth load, It represents the slope of the calculated pressure-displacement curve when the press increases the jth load. It represents the average value of the slope of the sensor pressure-displacement curve and the calculated pressure-displacement curve slope when the press increases the jth load;

[0033] Step S502: Output the press tonnage and pressure point clearance detection results and comparison results according to the determination coefficient R, and generate a detection report.

[0034] A measurement system for detecting the tonnage and pressure point gap of a press machine, comprising: a sensor installation module, a zero point calibration module, a load increase module, a tonnage and gap detection module, and a detection result analysis module;

[0035] The sensor installation module is used to install the displacement sensor between the upper and lower molds of the press, and to install the force sensor on the working table of the press;

[0036] The zero point calibration module is used to start the displacement sensor and the force sensor, perform zero point calibration, and record the sensor readings in the initial state as the reference value;

[0037] The load increasing module is used to gradually increase the load of the press and record the readings of the displacement sensor and the force sensor each time the load is increased;

[0038] The tonnage and gap detection module is used to calculate the actual tonnage of the press and detect the gap between the pressing points under different loads using the readings of the displacement sensor and the force sensor;

[0039] The test result analysis module is used to analyze the detected data, draw a pressure-displacement curve, check the linearity and stability of the curve, output the tonnage and pressure point gap test results of the press, and generate a test report.

[0040] Specifically, the tonnage and gap detection module includes: a tonnage detection unit and a gap detection unit;

[0041] The tonnage detection unit is used to detect the actual tonnage of the press under different loads;

[0042] The gap detection unit is used to detect the actual gap of the press under different loads.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1. The present invention proposes a measurement method for detecting the tonnage and pressure point gap of a press. When a predetermined load is applied, in addition to traditional displacement sensors and force sensors, a high-precision distance measuring instrument is added to record the distances between key points on the press. This improves measurement accuracy and can more accurately reflect the deformation of the press under different loads.

[0045] 2. The present invention proposes a measurement method for detecting the tonnage and pressure point gap of a press. A structural correction coefficient and a linear expansion coefficient of the material are introduced into the press tonnage calculation formula and the press gap calculation formula. The coefficient is determined based on the specific structural characteristics and material properties of the press to correct the measurement error caused by the structural differences of the press and the thermal expansion of the material, so that the measurement results are more accurate and reliable.

[0046] 3. The present invention proposes a measurement method for detecting the tonnage and pressure point gap of a press. A polynomial fitting algorithm is used to process the force-displacement data to obtain the deformation curve of the press, which can better reflect the actual working state of the press and improve the accuracy of the tonnage and pressure point gap calculation. By calculating the determination coefficient, the linearity and stability of the curve are checked to ensure the validity of the test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A flow chart of a measurement method for detecting press tonnage and pressure point gap provided by the present invention;

[0048] Figure 2 This is a diagram of the measurement system architecture for press tonnage and pressure point gap detection provided by the present invention. DETAILED DESCRIPTION

[0049] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, it should be noted that in the description of the present invention, the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "No. 1", "No. 2" and "No. 3" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. The present invention will be further explained below in conjunction with specific embodiments.

[0050] Example 1

[0051] See also Figure 1 The present invention provides an embodiment: a measurement method for detecting the tonnage and pressure point gap of a press machine, comprising the following specific steps:

[0052] Step S1: Install a high-precision displacement sensor between the upper and lower molds of the press, and install a force sensor on the working table of the press;

[0053] Step S2: Start the displacement sensor and force sensor, perform zero point calibration, and record the sensor readings in the initial state as the reference value;

[0054] Step S3: gradually increasing the load of the press, and recording the readings of the displacement sensor and the force sensor each time the load is increased;

[0055] The zero point calibration in step S2 is specifically as follows: before using the displacement sensor and the force sensor, by setting or adjusting, the displacement sensor and the force sensor output to zero under no external force or standard reference conditions.

[0056] The specific steps of step S3 are:

[0057] Step S301: Start the press and check whether the press, displacement sensor and force sensor are operating normally;

[0058] Step S302: increasing the press load to a first incremental value ΔZ, stabilizing the press load, and waiting for the displacement sensor and force sensor readings to stabilize;

[0059] Step S303: The displacement sensor and force sensor read data and record the current load, displacement and pressure readings;

[0060] Step S304: Repeat steps S302 to S303, increasing the load increment ΔZ each time until the maximum load of the press is reached, and collect corresponding load, displacement and pressure data.

[0061] Step S4: Under different loads, the actual tonnage of the press is calculated using the readings of the displacement sensor and the force sensor, and the pressure point gap is detected;

[0062] The specific steps of step S4 are:

[0063] Step S401: Set the set of collected corresponding load, displacement and pressure data to S, where S = {(ΔZ, W1, P1), (2ΔZ, W2, P2), ... (nΔZ, Wn, Pn)}, where n represents the number of times the press increases the load, Wn represents the displacement data collected when the press increases the load for the nth time, and Pn represents the pressure data collected when the press increases the load for the nth time;

[0064] Step S402: Calculate the actual tonnage Tsi of the press when the i-th load is added based on the collected pressure data;

[0065] Step S403: Calculate the pressure point gap ΔGi when the press increases the load for the i-th time based on the collected displacement data.

[0066] The specific formula for calculating the actual tonnage Tsi of the press in step S402 is:

[0067]

[0068] Among them, Pi represents the pressure data collected when the press increases the i-th load, Ai represents the effective area of ​​the press when the i-th load is increased, η represents the transmission efficiency of the press, taking into account factors such as mechanical transmission efficiency and friction loss, Ct represents the time correction coefficient, taking into account the performance changes of the press during long-term operation, α represents the thermal expansion coefficient of the pressed material, ΔT represents the temperature change of the press working surface, v represents the punch speed of the press, g represents the acceleration of gravity, and a represents the dynamic inertia coefficient of the press punch, taking into account the inertia effect of the punch during movement.

[0069] The effective area Ai of the press when the i-th load is added is the area of ​​the pressure acting on the pressed material object, which can usually be obtained through area formulas or numerical simulations. The transmission efficiency η of the press is obtained through a large number of experimental calibrations by personnel in this field. The time correction coefficient Ct is obtained from the data of long-term use of the press. The dynamic inertia coefficient a of the press punch can be obtained through dynamic analysis.

[0070] The specific formula for calculating the pressure point gap ΔGi when the press increases the load for the i-th time in step S403 is:

[0071]

[0072] Among them, κ is the wear coefficient of the press, which reflects the wear of the machine, Em is the elastic modulus of the pressed material, l is the thickness of the pressed material, Cf is the press correction coefficient, which takes into account factors such as mechanical transmission efficiency and friction loss, SP is the pressure loss of the press punch, L is the length of the press force arm, K is the stiffness of the press, which reflects the deformation characteristics of the press system under stress, β is the thermal expansion coefficient of the press punch, and Gaz is the gap distance caused by the press installation.

[0073] Step S5: Analyze the detected data, draw a pressure-displacement curve, check the linearity and stability of the curve, output the tonnage and pressure point gap detection results of the press, and generate a test report.

[0074] The specific steps of step S5 are:

[0075] Step S501: Analyze the detected data, plot the sensor pressure-displacement curve and the calculated pressure-displacement curve, use linear regression to check the linearity and stability of the curve, and calculate the determination coefficient R. The calculation formula is:

[0076]

[0077] Where kj represents the slope of the pressure-displacement curve of the sensor when the press increases the jth load, It represents the slope of the calculated pressure-displacement curve when the press increases the jth load. It represents the average value of the slope of the sensor pressure-displacement curve and the calculated pressure-displacement curve slope when the press increases the jth load;

[0078] The pressure-displacement data are processed using a polynomial fitting algorithm to obtain a sensor pressure-displacement curve and a calculated pressure-displacement curve. The calculated pressure-displacement curve is drawn by the displacement value measured by the measurement method of the present invention (the displacement value measured by the traditional method + ΔGi) and the pressure value Tsi;

[0079] Step S502: Output the press tonnage and pressure point clearance detection results and comparison results according to the determination coefficient R, and generate a detection report.

[0080] This example provides an experiment with the following experimental conditions:

[0081] Press: 100-ton punch press;

[0082] Measuring load range: 0 tons - 100 tons;

[0083] Measuring point: one load point is added for every 10%, and one load point is 10 tons;

[0084] Measurement methods: the measurement method proposed by the present invention and the traditional measurement method;

[0085] Detailed experimental data are shown in Table 1 Experimental Data Table:

[0086] Table 1 Experimental data table

[0087]

[0088]

[0089] The determination coefficient R of the measurement method of the present invention is 0.99;

[0090] Results analysis: 1) Within the same load range, the displacement and force values ​​measured by the measurement method proposed in the present invention have higher measurement accuracy than those measured by traditional methods;

[0091] 2) The press tonnage and pressure point clearance calculated by the measurement method proposed in the invention are more accurate and can better reflect the working status of the press under different loads;

[0092] 3) By comparing the experimental data, it can be clearly seen that the measurement method proposed in the present invention shows higher accuracy and reliability in tonnage and pressure point gap detection;

[0093] 4) If R is greater than 0.98, it indicates that the linearity of the curve is good and the test result is valid. Otherwise, recalibration and measurement are performed. The value of the determination coefficient R of the measurement method of the present invention is 0.99, and the test effect is valid.

[0094] Example 2

[0095] See also Figure 2 , another embodiment provided by the present invention: a measurement system for detecting tonnage and pressure point gap of a press machine, comprising: a sensor installation module, a zero point calibration module, a load increase module, a tonnage and gap detection module and a detection result analysis module;

[0096] The sensor installation module is used to install the high-precision displacement sensor between the upper and lower molds of the press, and to install the force sensor on the working table of the press;

[0097] The zero point calibration module is used to start the displacement sensor and the force sensor, perform zero point calibration, and record the sensor readings in the initial state as the reference value;

[0098] The load increasing module is used to gradually increase the load of the press and record the readings of the displacement sensor and the force sensor each time the load is increased;

[0099] The tonnage and gap detection module is used to calculate the actual tonnage of the press and detect the gap between the pressing points under different loads using the readings of the displacement sensor and the force sensor;

[0100] The test result analysis module is used to analyze the detected data, draw a pressure-displacement curve, check the linearity and stability of the curve, output the tonnage and pressure point gap test results of the press, and generate a test report.

[0101] The tonnage and gap detection module includes: a tonnage detection unit and a gap detection unit;

[0102] The tonnage detection unit is used to detect the actual tonnage of the press under different loads;

[0103] The gap detection unit is used to detect the actual gap of the press under different loads.

[0104] In addition, the parts of the above technical solutions provided in the embodiments of the present application that are consistent with the implementation principles of the corresponding technical solutions in the prior art are not described in detail to avoid excessive redundancy.

[0105] The above-described specific embodiments further illustrate the objectives, technical solutions, and beneficial effects of the present invention. It should be understood that the above description is merely a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A measurement method for detecting press tonnage and pressure point gap, characterized in that: The specific steps include: Step S1: Install the displacement sensor between the upper and lower molds of the press, and install the force sensor on the working table of the press; Step S2: Start the displacement sensor and force sensor, perform zero point calibration, and record the sensor readings in the initial state as the reference value; Step S3: gradually increasing the load of the press, and recording the readings of the displacement sensor and the force sensor each time the load is increased; Step S4: Under different loads, the actual tonnage of the press is calculated using the readings of the displacement sensor and the force sensor, and the pressure point gap is detected; Step S5: Analyze the detected data, draw a pressure-displacement curve, check the linearity and stability of the curve, output the press tonnage and pressure point gap test results, and generate a test report; The specific steps of step S4 are: Step S401: Set the corresponding collected load, displacement and pressure data set to , , where n represents the number of times the press increases the load, It represents the displacement data collected when the press increases the load for the nth time. It represents the pressure data collected when the press increases the load for the nth time. Indicates the incremental value of the press load; Step S402: Calculate the actual tonnage of the press when the i-th load is added based on the collected pressure data ; Step S403: Calculate the pressure point gap when the press increases the i-th load based on the collected displacement data ; The actual tonnage of the press is calculated in step S402 The specific formula is: ， in, represents the pressure data collected when the press increases the load for the i-th time, It represents the effective area of ​​the press when the load is increased for the i-th time, Indicates the transmission efficiency of the press, represents the time correction factor, Indicates the thermal expansion coefficient of the pressed material, Indicates the temperature change of the press working surface, Indicates the punch speed of the press, represents the acceleration due to gravity, Indicates the dynamic inertia coefficient of the press punch; In step S403, the pressure point gap is calculated when the press increases the load for the i-th time. The specific formula is: ， in, Indicates the wear coefficient of the press, represents the elastic modulus of the compressed material, Indicates the thickness of the pressed material, Indicates the press correction factor, Indicates the pressure loss of the press punch, Indicates the length of the press force arm, represents the stiffness of the press, Indicates the thermal expansion coefficient of the press punch, Indicates the gap distance caused by press installation.

2. A method for measuring press tonnage and pressure point gap according to claim 1, characterized in that: The zero point calibration in step S2 is specifically as follows: before using the displacement sensor and the force sensor, by setting or adjusting, the displacement sensor and the force sensor output to zero under no external force or standard reference conditions.

3. A method for measuring press tonnage and pressure point gap according to claim 2, characterized in that: The specific steps of step S3 are: Step S301: Start the press and check whether the press, displacement sensor and force sensor are operating normally; Step S302: Increase the press load to the first incremental value , stabilize the press load and wait for the displacement sensor and force sensor readings to stabilize; Step S303: The displacement sensor and force sensor read data and record the current load, displacement and pressure readings; Step S304: Repeat steps S302 to S303, increasing the load increment each time , until the maximum load of the press is reached, and the corresponding load, displacement and pressure data are collected.

4. A method for measuring press tonnage and pressure point gap according to claim 3, characterized in that: The specific steps of step S5 are: Step S501: Analyze the detected data, draw the sensor pressure-displacement curve and the calculated pressure-displacement curve, use linear regression to check the linearity and stability of the curve, and calculate the determination coefficient. , the calculation formula is: ， in, It represents the slope of the pressure-displacement curve of the sensor when the press increases the jth load. It represents the slope of the calculated pressure-displacement curve when the press increases the jth load. It represents the average value of the slope of the sensor pressure-displacement curve and the calculated pressure-displacement curve slope when the press increases the jth load; Step S502: According to the coefficient of determination , output the press tonnage and pressure point gap detection results and comparison results, and generate a detection report.

5. A measurement system for detecting tonnage and pressure point gap of a press, used to implement a measurement method for detecting tonnage and pressure point gap of a press according to any one of claims 1 to 4, characterized in that: include: Sensor installation module, zero point calibration module, load increase module, tonnage and gap detection module and detection result analysis module; The sensor installation module is used to install the displacement sensor between the upper and lower molds of the press, and to install the force sensor on the working table of the press; The zero point calibration module is used to start the displacement sensor and the force sensor, perform zero point calibration, and record the sensor readings in the initial state as the reference value; The load increasing module is used to gradually increase the load of the press and record the readings of the displacement sensor and the force sensor each time the load is increased; The tonnage and gap detection module is used to calculate the actual tonnage of the press and detect the gap between the pressing points under different loads using the readings of the displacement sensor and the force sensor; The test result analysis module is used to analyze the detected data, draw a pressure-displacement curve, check the linearity and stability of the curve, output the tonnage and pressure point gap test results of the press, and generate a test report.

6. A measuring system for detecting press tonnage and pressure point gap according to claim 5, characterized in that: The tonnage and gap detection module includes: a tonnage detection unit and a gap detection unit; The tonnage detection unit is used to detect the actual tonnage of the press under different loads; The gap detection unit is used to detect the actual gap of the press under different loads.

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