Device and method for measuring plastic deformation of press

Abstract

The invention provides a device and a method for measuring plastic deformation of a press, and relates to the technical field of press deformation measurement. Comprising a displacement sensor, a measuring support, a reference plate, a cushion block and a laser gradienter. The displacement sensors are mounted on the measuring bracket, and a plurality of displacement sensors are arranged; the reference plate is installed on the table top of a press to be detected through a cushion block, and the laser level meter is installed on the table top of the press to be detected. A reference plate and a laser level meter are arranged, and when the plastic deformation of a table top of a press to be detected of the press is detected, the displacement of the reference plate measured by a displacement sensor is taken as a reference; the displacement of the to-be-detected press table top is assisted by the displacement sensor, so that the plastic deformation of the to-be-detected press table top is accurately obtained.

Description

Technical Field

[0001] The present invention relates to the technical field related to the deformation measurement of presses, and relates to a device and method for measuring the plastic deformation of a press, specifically to a device and method for measuring the plastic deformation amount of a press table after multiple stampings. Background Art

[0002] In industrial production, a press is one of the indispensable devices. Its application is extensive and can meet the production needs of different industries. During the production process of a press, factors such as large working loads on the table, uneven forces on the table, and deviations and damages of the mold will cause plastic deformation of the press table and permanent deformation. The plastic deformation of the press table will affect the deformation amount of the mold cavity during mold operation, and further lead to deviations between the dimensions of the stamped parts and the designed dimensions. This part of the deformation amount should also be compensated in the mold cavity, provided that the plastic deformation amount of the mold cavity is known. At present, there is no set of good methods for testing the plastic deformation of the press table.

[0003] The current methods for measuring the plastic deformation of the press table mainly rely on visual observation by the human eye and measurement with measuring tools. These methods will cause large measurement errors, resulting in large deviations in the final compensation of the table, and continuous adjustment of the table dimensions is required, consuming a large amount of time and manpower. Summary of the Invention

[0004] This application aims to solve the problems existing in the prior art. For this purpose, this application proposes a device and method for measuring the plastic deformation of a press table, which can improve the accuracy of measuring the plastic deformation of the press table and reduce the time for table compensation.

[0005] The present invention provides a device for measuring the plastic deformation of a press, including a displacement sensor, a measurement bracket, a reference plate, a spacer block, and a laser level;

[0006] The displacement sensor is installed on the measurement bracket, and multiple displacement sensors are provided for separately detecting different positions of the press table to be detected;

[0007] The reference plate is installed on the press table to be detected through the spacer block, and the laser level is installed on the press table to be detected for detecting the levelness of the upper end surface of the reference plate; when any edge of the upper end surface of the reference plate is in the same horizontal state as the horizontal laser of the laser level, it is determined that the upper end surface of the reference plate is in a horizontal state, and the upper end surface of the reference plate is used as the reference plane for measuring the plastic deformation of the press table to be detected; when a certain edge of the upper end surface of the reference plate is not in the same horizontal state as the horizontal laser of the laser level, the spacer block with different height dimensions is replaced according to actual needs until any edge of the upper end surface of the reference plate is in the same horizontal state as the horizontal laser of the laser level.

[0008] Further, the measuring bracket includes a first bracket, a second bracket and legs. There are two pieces of the first bracket arranged at intervals along the X direction. On the lower end surface of a single-piece first bracket, there are two pieces of legs arranged at intervals. The single-piece legs are arranged close to the side end surface perpendicular to the length direction of the single-piece first bracket; there are at least two pieces of the second bracket arranged at intervals along the Y direction;

[0009] There are at least two groups of displacement sensors arranged in one-to-one correspondence with the second bracket. In a single group of displacement sensors, there are multiple pieces arranged at intervals along the X direction.

[0010] Further, both the first bracket and the second bracket are arranged as aluminum profile structural parts, and the legs are arranged as rubber structural parts.

[0011] Further, the displacement sensor is arranged as a pen-type LDVT voltage displacement sensor.

[0012] Further, the interval between two adjacent displacement sensors is set to 200 - 400 mm.

[0013] Further, the reference plate is arranged as a smooth glass plate.

[0014] Further, it further includes a data acquisition instrument. The data acquisition instrument is connected to multiple displacement sensors through signal lines and is used to collect the voltage signal data collected by the multiple displacement sensors.

[0015] The present invention also provides a method for measuring the plastic deformation of a press, including the following steps:

[0016] Step 1: Assemble and debug the press plastic deformation measuring device as described above;

[0017] S1.1: Clean the tabletop of the press to be detected, then install a smooth glass plate and a laser level. Detect the levelness of the upper end surface of the smooth glass plate through the laser level and adjust it according to actual needs to ensure that the upper end surface of the smooth glass plate is in a horizontal state;

[0018] S1.2: Install the displacement sensors and the measuring bracket with each other;

[0019] S1.3: Fix the measuring bracket to the tabletop of the press to be detected;

[0020] S1.4: Adjust the relative positions between several displacement sensors and the tabletop of the press to be detected one by one, and ensure that the output signal of a single displacement sensor is between 1 / 2 and 1 / 3 of its range;

[0021] Step 2: Detect the vertical distance d between the tabletop of the press to be detected and the smooth glass plate;

[0022] Step 3: Taking the smooth glass plate as a reference, detect the displacement value of the measuring head of each displacement sensor on the smooth glass plate to obtain the displacement D1 of the measuring head of each displacement sensor on the smooth glass plate;

[0023] Step 4: Detect the displacement of the press table to be detected to obtain the displacement D2 of each displacement sensor on the press table to be detected;

[0024] Step 5: Based on the displacement D1 of each displacement sensor on the smooth glass plate and the displacement D2 of each displacement sensor on the press table to be detected, obtain the vertical deformation amount of the corresponding point on the press table to be detected.

[0025] Further, the specific process of obtaining the displacement D1 of a single displacement sensor on the smooth glass plate is as follows:

[0026] Take any time point before the voltage change of the current displacement sensor, and take this time point as the midpoint to calculate the average value of the voltage values of a total of one hundred time nodes before and after it;

[0027] For any time point after the voltage change of the current displacement sensor, take this time point as the midpoint to calculate the average value of the voltage values of a total of one hundred time nodes before and after it;

[0028] Subtract the average value after the change from the average value before the voltage change to obtain a voltage difference;

[0029] Based on the fact that 1V voltage corresponds to a displacement of 0.25mm, calculate the displacement of the current displacement sensor;

[0030] And mark its displacement as D1.

[0031] Further, the specific process of obtaining the displacement D2 of a single displacement sensor on the press table to be detected is as follows:

[0032] Take a time point before the voltage change of the current displacement sensor, and take this time point as the midpoint to calculate the average value of the voltage values of a total of one hundred time nodes before and after it;

[0033] Take a time point after the voltage change of the current displacement sensor, and take this time point as the midpoint to calculate the average value of the voltage values of a total of one hundred time nodes before and after it;

[0034] Subtract the average value after the change from the average value before the voltage change to obtain a voltage difference;

[0035] Based on the fact that 1V voltage corresponds to a displacement of 0.25mm, calculate the displacement of the measuring head of the current displacement sensor on the press table to be detected, and mark its displacement as D2.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) A press plastic deformation measurement device provided by the present invention includes a displacement sensor, a measurement bracket, a reference plate, a spacer block, and a laser level. By setting the reference plate and the laser level, when detecting the plastic deformation amount of the to-be-detected press bed surface, the displacement amount of the reference plate measured by the displacement sensor is used as a reference, and the displacement amount of the to-be-detected press bed surface measured by the displacement sensor is used as a supplement, so as to accurately obtain the plastic deformation amount of the to-be-detected press bed surface.

[0038] (2) In this application, a displacement sensor is used and fixed on the measurement bracket, and then the displacement sensor is fixed on the measurement bracket according to the pre-designed fixed position. A smooth glass plate is positioned on the to-be-tested table surface, and it is horizontally calibrated with a level. Then the test bracket is fixed and positioned on the to-be-detected press bed surface, and the positions of each displacement sensor relative to the to-be-detected press bed surface are recorded. At this time, the measurement heads of each displacement sensor generate displacements when falling on the glass plate. Adjust the displacement sensor so that when it falls on the smooth glass plate, the measured displacement is approximately half of its range, and each displacement sensor is perpendicular to the smooth glass plate. The data acquisition instrument collects the voltage signals of each sensor, calculates the displacement amounts of the measurement heads of each position sensor, removes the smooth glass plate, makes the measurement heads of the sensors fall on the to-be-detected press bed surface, collects the voltage signals of each displacement sensor again, and the displacement distances of the measurement heads of each displacement sensor can be obtained from the voltage differences measured before and after. Subtracting the vertical distance of the smooth glass plate relative to the to-be-tested press table surface from the displacement distances of the measurement heads of each displacement sensor, the vertical deformation distances of the points on the press table surface corresponding to each sensor are obtained.

[0039] In addition to the purposes, features, and advantages described above, the present invention has other purposes, features, and advantages. The following will refer to the drawings to further describe the present invention in detail. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0041] Figure 1 is a schematic structural diagram of a press plastic deformation measurement device in an embodiment of the present invention;

[0042] Figure 2 is Figure 1 the schematic structural diagram after the measurement bracket and the displacement sensor are connected to each other in

[0043] Figure 3It is a schematic flowchart of a method for measuring plastic deformation of a press in an embodiment of the present invention.

[0044] Wherein:

[0045] 1. Displacement sensor, 2. Measuring bracket, 2.1 First bracket, 2.2 Second bracket, 2.3 Leg, 3. Reference plate, 4. Spacer, 5. Laser level, 01. Press bed surface to be detected. Specific embodiments

[0046] To make the above objects, features, and advantages of the present invention more clearly understandable, the following will describe the specific embodiments of the present invention in detail with reference to the accompanying drawings. It should be noted that the drawings of the present invention are all in simplified forms and use non-precise scales, only for conveniently and clearly assisting in the description of the embodiments of the present invention; the several mentioned in the present invention are not limited to the specific quantities in the drawing examples; the orientation or positional relationships indicated by 'front','middle', 'back', 'left', 'right', 'up', 'down', 'top', 'bottom','middle', etc. in the present invention are all based on the orientation or positional relationships shown in the drawings of the present invention, and do not indicate or imply that the devices or components referred to must have a specific orientation, nor can it be understood as a limitation to the present invention.

[0047] Embodiment:

[0048] Refer to Figure 1 and Figure 2 As shown, a device for measuring plastic deformation of a press provided by the present invention includes a displacement sensor 1, a measuring bracket 2, a data acquisition instrument, a reference plate 3, a spacer 4, and a laser level 5;

[0049] The measuring bracket 2 includes a first bracket 2.1, a second bracket 2.2, and legs 2.3. There are two pieces of the first bracket 2.1 arranged at intervals along the X direction. On the lower end surface of a single-piece first bracket 2.1, there are two pieces of legs 2.3 arranged at intervals, and a single-piece leg 2.3 is close to the side end surface perpendicular to the length direction of the single-piece first bracket 2.1; there are at least two pieces of the second bracket 2.2 arranged at intervals along the Y direction;

[0050] At least two groups of the displacement sensors 1 are arranged in one-to-one correspondence with the second bracket 2.2. In a single group of displacement sensors 1, there are multiple pieces arranged at intervals along the X direction, and the interval between two adjacent displacement sensors 1 is set to 200 - 400 mm;

[0051] The data acquisition instrument is signal-connected to multiple displacement sensors 1 and is used to store the voltage signal data collected by the multiple displacement sensors 1;

[0052] The reference plate 3 is installed on the tabletop 01 of the press to be detected through the cushion block 4. By adjusting the cushion block 4, the upper surface of the reference plate 3 can simulate an ideal press tabletop.

[0053] The laser level 5 is arranged on the tabletop 01 of the press to be detected and is used to detect the levelness of the reference plate 3. When the horizontal laser of the laser level 5 is parallel and coincident with the edge of the reference plate 3, it can be determined that the current edge of the reference plate 3 is in a parallel state. After measuring one side of the reference plate 3, then measure the levelness of its opposite side, and then measure the levelness of the other two pairs of sides until all four sides of the reference plate 3 coincide with the horizontal laser of the laser level 5, it can be determined that the reference plate 3 is in a parallel state. If the edge of the reference plate 3 does not coincide with the horizontal laser, adjust the height of one corner of the reference plate 3 with the cushion block 4 to make this side coincide with the horizontal laser.

[0054] Preferably, both the first support 2.1 and the second support 2.2 are preferably set as aluminum profile structural members, and the leg 2.3 is preferably set as a rubber structural member.

[0055] Preferably, the displacement sensor 1 is preferably set as a pen-type LDVT voltage displacement sensor. Specifically, the pen-type LDVT voltage displacement sensor includes an iron core, an armature, a primary coil, and a secondary coil. The primary coil and the secondary coil are distributed on the coil skeleton, and there is a rod-shaped armature that can move freely inside the coil. When the armature is in the middle position, the induced electromotive forces generated by the two secondary coils are equal, so the output voltage is 0; when the armature moves inside the coil and deviates from the center position, the induced electromotive forces generated by the two coils are not equal, and there is a voltage output, and the magnitude of the voltage depends on the displacement magnitude.

[0056] Preferably, the interval between two adjacent displacement sensors 1 is set to 300 mm.

[0057] Preferably, the cushion block 4 is set to include several standard blocks with different heights. By setting at least one cushion block 4 between the reference plate 3 and the tabletop of the press to be detected, the levelness of the upper surface of the reference plate 3 is ensured, so that the upper surface of the reference plate 3 serves as an ideal press tabletop (its detection reference surface).

[0058] Preferably, the reference plate 3 is preferably set as a smooth glass plate.

[0059] As a further embodiment of the present invention, see Figure 3 As shown, the specific process of detecting the plastic deformation of the press by using the above-mentioned press plastic deformation measuring device is as follows:

[0060] Step 1: Assemble and debug the press plastic deformation measuring device as described above;

[0061] S1.1. Clean the tabletop of the press to be tested to prevent foreign objects on the tabletop of the press to be tested from affecting the measurement accuracy. Then install a smooth glass plate and a laser level, and use the laser level to detect the levelness of the upper end face of the smooth glass plate and adjust it according to actual needs to ensure that the upper end face of the smooth glass plate is in a horizontal state.

[0062] S1.2. Install the displacement sensor and the measurement bracket with each other.

[0063] S1.3. Fix the measurement bracket to the tabletop of the press to be tested. The specific method is as follows: Fix and position the measurement bracket on the tabletop of the press to be tested with bolts and rubber feet. Put the rubber feet into the T-shaped groove of the press tabletop, and then connect the measurement bracket and the rubber feet with bolts to fix the measurement bracket. Finally, adjust the position of the measurement bracket so that the center of the measurement bracket coincides with the center of the press tabletop. In this way, the relative position of the displacement sensor on the measurement bracket can correspond to the position to be measured on the press tabletop.

[0064] S1.4. Adjust the relative positions between several displacement sensors and the tabletop of the press to be tested one by one, and ensure that the output signal of a single displacement sensor is between 1 / 2 and 1 / 3 of its range. Specifically, the specific method for adjusting several displacement sensors is as follows: Before measurement, it is necessary to adjust the telescopic amount of the displacement sensor measuring head when it touches the surface to be measured to ensure that the output signal of each displacement sensor is within the range where the displacement sensor measures most accurately, that is, about half of the range. And it is necessary to make each displacement sensor perpendicular to the glass plate. If the displacement sensor is tilted, the displacement of its measuring head cannot be equivalent to the deformation amount in the vertical direction of the measurement tabletop. Here, a triangular straightedge is used for calibration.

[0065] Step 2. Use a vernier caliper to measure the vertical distance d between the smooth glass plate and the tabletop of the press to be tested.

[0066] Step 3. Take the smooth glass plate as a reference and detect the displacement value of the measuring head of each displacement sensor on the smooth glass plate.

[0067] The specific method is as follows: Use the smooth glass plate to simulate an ideal press tabletop that has not undergone plastic deformation. After the displacement sensor is adjusted, the circuit starts to be powered on. The data acquisition instrument records the voltage signals of each displacement sensor and processes the collected voltage signals of each displacement sensor to obtain the displacement amount D1 of each displacement sensor on the smooth glass plate.

[0068] Further, the specific process of obtaining the displacement amount D1 of a single displacement sensor on the smooth glass plate is as follows:

[0069] Take any time point before the voltage change of the current displacement sensor, and take this time point as the midpoint to calculate the average value of the voltage values of a total of one hundred time nodes before and after it;

[0070] Take any time point after the voltage change of the current displacement sensor, and take this time point as the midpoint to calculate the average value of the voltage values of a total of one hundred time nodes before and after it;

[0071] Subtract the average value after the change from the average value before the voltage change to obtain a voltage difference;

[0072] Based on the fact that 1V voltage corresponds to a displacement of 0.25mm, calculate the displacement of the current displacement sensor;

[0073] And mark its displacement as D1.

[0074] Step 4: Detect the displacement of the tabletop of the press to be detected, and obtain the displacement D2 of each displacement sensor on the tabletop of the press to be detected.

[0075] The specific process is as follows:

[0076] S4.1: Remove the smooth glass plate and the cushion block;

[0077] Remove the smooth glass plate and the cushion block from the tabletop of the press to be detected, so that the measuring heads of each displacement sensor fall on the tabletop of the press to be detected.

[0078] S4.2: After the measuring head of the displacement sensor falls on the tabletop of the press to be detected and is in a stable state, the data acquisition instrument collects the voltage signals of each displacement sensor and processes them to obtain the displacement D2 of each displacement sensor on the tabletop of the press to be detected.

[0079] Preferably, the specific process of obtaining the displacement D2 of a single displacement sensor on the tabletop of the press to be detected is as follows:

[0080] Take a time point before the voltage change of the current displacement sensor, and take this time point as the midpoint to calculate the average value of the voltage values of a total of one hundred time nodes before and after it;

[0081] Take a time point after the voltage change of the current displacement sensor, and take this time point as the midpoint to calculate the average value of the voltage values of a total of one hundred time nodes before and after it;

[0082] Subtract the average value after the change from the average value before the voltage change to obtain a voltage difference;

[0083] Based on the fact that 1V voltage corresponds to a displacement of 0.25mm, calculate the displacement of the measuring head of the current displacement sensor on the tabletop of the press to be detected, and mark its displacement as D2.

[0084] Step Five: Based on the displacement D1 of each displacement sensor on the smooth glass plate and the displacement D2 of each displacement sensor on the press table to be detected, obtain the vertical deformation amount of the corresponding point on the press table to be detected.

[0085] The specific calculation formula is as follows:

[0086] D1 - D2 - d.

[0087] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A press plastic deformation measuring device, characterized in that: It comprises a displacement sensor (1), a measuring bracket (2), a reference plate (3), a cushion block (4) and a laser level (5); The displacement sensor (1) is mounted on a measuring bracket (2), and the displacement sensor (1) is provided with a plurality of pieces, and is used to respectively detect different positions of the press table (01) to be detected; The reference plate (3) is installed on the press table (01) to be tested via a cushion block (4); the laser level (5) is installed on the press table (01) to be tested and is used to detect the horizontality of the upper end surface of the reference plate (3); when the horizontal laser of the laser level (5) and any edge of the upper end surface of the reference plate (3) are in the same horizontal state, it is judged that the upper end surface of the reference plate (3) is in a horizontal state, so that the upper end surface of the reference plate (3) is used as the reference plane for measuring the plastic deformation of the press table (01) to be tested; when the horizontal laser of the laser level (5) and any edge of the upper end surface of the reference plate (3) are not in the same horizontal state, the cushion blocks (4) of different height sizes are replaced according to actual needs until the horizontal laser of the laser level (5) and any edge of the upper end surface of the reference plate (3) are in the same horizontal state.

2. The press plastic deformation measuring device according to claim 1, characterized in that: The measuring bracket (2) comprises a first bracket (2.1), a second bracket (2.2) and legs (2.3), the first bracket (2.1) being provided with two pieces spaced apart from each other along the X direction, the lower end surface of the single first bracket (2.1) being provided with two pieces spaced apart from each other, the single leg (2.3) being provided close to the side end surface of the single first bracket (2.1) which is perpendicular to the longitudinal direction; the second bracket (2.2) being provided with at least two pieces spaced apart from each other along the Y direction; The displacement sensor (1) is provided with at least two groups arranged in a one-to-one correspondence with the second bracket (2.2), and a single group of displacement sensors (1) is provided with a plurality of pieces arranged at intervals from each other along the X direction.

3. The press plastic deformation measuring device according to claim 2, characterized in that: The first bracket (2.1) and the second bracket (2.2) are both configured as aluminum profile structural parts, and the supporting legs (2.3) are configured as rubber structural parts.

4. The press plastic deformation measuring device according to any one of claims 1 to 3, characterized in that: The displacement sensor (1) is configured as a pen-type LDVT voltage displacement sensor.

5. The press plastic deformation measuring device according to claim 4, characterized in that: The interval between two adjacent displacement sensors (1) is set to 200-400 mm.

6. The press plastic deformation measuring device according to claim 5, characterized in that: The reference plate (3) is configured as a smooth glass plate.

7. The press plastic deformation measuring device according to claim 5 or 6, characterized in that: It also comprises a data acquisition device, which is connected to the plurality of displacement sensors (1) by a signal line and is used to acquire voltage signal data acquired by the plurality of displacement sensors (1).

8. A method for measuring plastic deformation of a press, characterized in that: The following steps are involved: Step 1, assembling and debugging the press plastic deformation measuring device as claimed in claim 7; S1.

1. Clean the press table to be tested, install the smooth glass plate and the laser level, and use the laser level to test the levelness of the upper end surface of the smooth glass plate and adjust it according to actual needs to ensure that the upper end surface of the smooth glass plate is in a horizontal state; S1.

2. Install the displacement sensor and the measuring bracket mutually; S1.3, connect the measuring bracket to the press table to be tested; S1.

4. Adjust the relative positions between several displacement sensors and the press table to be tested one by one, and ensure that the output signal of a single displacement sensor is between 1 / 2 and 1 / 3 of its range; Step 2: Detect the vertical distance d between the press table to be detected and the smooth glass plate; Step 3: Taking the smooth glass plate as a reference, the displacement value of the measuring head of each displacement sensor on the smooth glass plate is detected to obtain the displacement D1 of the measuring head of each displacement sensor on the smooth glass plate; Step 4: Detect the displacement of the press table to be detected, and obtain the displacement D2 of each displacement sensor on the press table to be detected; Step 5: Based on the displacement D1 of each displacement sensor on the smooth glass plate and the displacement D2 of each displacement sensor on the press table to be tested, the vertical deformation amount of the corresponding point on the press table to be tested is obtained.

9. The method for measuring plastic deformation of a press machine according to claim 8, characterized in that: The specific process of obtaining the displacement D1 of a single displacement sensor on a smooth glass plate is as follows: Take any time point before the voltage of the current displacement sensor changes, and take the time point as the midpoint to calculate the average voltage value of the 100 time nodes before and after it; For any time point after the voltage of the current displacement sensor changes, the voltage values ​​of the one hundred time nodes before and after the time point are averaged with the time point as the midpoint; Subtract the average value after the voltage change from the average value before the voltage change to get a voltage difference; Based on the fact that 1V voltage corresponds to 0.25mm displacement, the displacement of the current displacement sensor is calculated; The displacement is marked as D1.

10. The method for measuring plastic deformation of a press machine according to claim 8, characterized in that: The specific process of obtaining the displacement D2 of a single displacement sensor on the press table to be tested is as follows: Take a time point before the voltage of the current displacement sensor changes, and take the time point as the midpoint to calculate the average value of the voltage values ​​of a total of one hundred time nodes before and after it; Take a time point after the voltage of the current displacement sensor changes, and take the time point as the midpoint to calculate the average value of the voltage values ​​of a total of one hundred time nodes before and after it; Subtract the average value after the voltage change from the average value before the voltage change to get a voltage difference; Based on the fact that 1V voltage corresponds to a displacement of 0.25mm, the displacement of the measuring head of the current displacement sensor on the press table to be detected is calculated, and its displacement is marked as D2.

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