A drawbench nip plate material length control system and method

Abstract

This invention relates to a control system and method for the biting length of sheet metal in a stretching machine, belonging to the field of aluminum alloy sheet processing technology. The invention aims to solve the problem that the biting length of existing stretching machines is fixed and cannot be adjusted according to the sheet metal thickness. In this invention, a distance sensor is installed inside the front crossbeam structure of both the moving and fixed ends of the stretching machine's jaws. The distance sensor is used to collect whether the sheet metal has entered the stretching machine's jaws. A human-machine interface unit receives the biting length and sheet metal thickness set by the user. The moving head control module receives the information that the sheet metal has entered the stretching machine's jaws, uses the current sheet metal position as the initial position for the advance, and calculates the advance compensation amount and the moving head advance amount based on the set biting length, sheet metal thickness, and stretching machine jaw information. The moving head advance amount information is then sent to the stretching machine's moving head drive unit, which drives the moving head of the stretching machine. This invention is applicable to the control of the biting length of sheet metal in a stretching machine's jaws.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy sheet processing technology. Background Technology

[0002] The 8000-ton stretching machine is one of the main processing equipment in sheet metal processing. The stretching process can effectively improve the unevenness of aluminum alloy sheets and improve the stress release and performance indicators within the sheet. The 8000-ton stretching machine was designed, manufactured, and installed by the Italian company DANIELI. Since its completion and commissioning in 2015, the jaw engagement length calculation model and device have consistently used a control logic connecting a cylinder and a probe rod. Each stretching operation results in a single-sided engagement length exceeding 350mm, and the combined engagement length of both jaws exceeding 700mm. This large jaw engagement length is detrimental to the precise control of sheet yield, regardless of whether the sheet is thick or thin.

[0003] The 8000-ton stretching press produces sheets with a thickness range of 6-250mm and a very large opening. A single jaw engagement length calculation model cannot fully and effectively meet the requirements of on-site production. When producing thick sheets, to ensure equipment safety and avoid the risk of breakage due to excessive jaw force, the jaw engagement length is defined as 350mm or more. This effectively reduces the risk of breakage when stretching thick sheets. However, this stretching press not only produces thick sheets but also sheets with a thickness of 6-50mm. Due to the smaller tensile force and jaw engagement force, and since these sheets are typically produced in batches, calculating the engagement length based on the original design of 350mm is unreasonable, wasting operation time and reducing the yield rate. Summary of the Invention

[0004] The present invention addresses the problem that the bite length of existing stretching machines is fixed and cannot be adjusted according to the thickness of the sheet material. A control system and method for the bite length of the sheet material in the jaws of a stretching machine are provided.

[0005] The present invention discloses a sheet material clamping length control system for a stretching machine jaws. A distance sensor is installed inside the front crossbeam structure of both the moving end and the fixed end jaws of the stretching machine. The distance sensor is used to collect whether the sheet material enters the jaws of the stretching machine. When the sheet material is detected to have entered the jaws of the stretching machine, the sensor sends the sheet material entry information to the moving head control module.

[0006] The human-machine interaction unit is used to receive the bite length and thickness of the board set by the user, and send the set bite length and thickness of the board to the moving head control module.

[0007] The moving head control module receives information about the sheet material entering the jaws of the stretching machine, takes the current position of the sheet material as the initial position for advancement, calculates the advancement compensation amount and the advancing amount of the moving head based on the set bite length, the thickness of the sheet material, and the jaw information of the stretching machine, and sends the advancing amount of the moving head to the moving head drive unit of the stretching machine. The moving head drive unit of the stretching machine is used to drive the moving head of the stretching machine according to the advancing amount information of the moving head.

[0008] Furthermore, in this invention, the distance sensor is model SICK DT50-P2113.

[0009] Furthermore, in this invention, the method for calculating the propulsion compensation amount is as follows:

[0010] Using the formula:

[0011]

[0012] Calculate the propulsion compensation amount x, where h is the thickness of the plate, L is the jaw depth, and M is the maximum distance between the upper and lower jaws.

[0013] Furthermore, in this invention, the method for calculating the propulsion amount y of the moving head is as follows:

[0014] y = set length + x.

[0015] A method for controlling the length of sheet metal gripped by the jaws of a stretching machine includes:

[0016] Step 1: A distance sensor is installed inside the front crossbeam structure of both the moving head and the fixed head jaws of the stretching machine. The biting length and thickness of the sheet to be stretched are set through the human-machine interaction unit.

[0017] The advance compensation amount of the moving head is calculated using the engagement length and thickness of the sheet to be stretched, and the advance amount of the moving head is calculated using the compensation amount.

[0018] Step 2: Control the moving head jaws of the stretching machine to close, so that the jaws push the sheet to be stretched towards the fixed head. When the distance sensor inside the fixed head detects that the sheet to be stretched has entered the jaws of the fixed head, the current position of the moving head is taken as the first initial position of the moving head.

[0019] Step 3: Control the moving head to continue advancing the specified amount from the first initial position and then stop; control the jaws of the stretching machine's fixed head to engage; complete the engagement of the sheet metal by the jaws of the stretching machine's fixed head.

[0020] Step 5: Open the moving jaws and control the moving head to continue advancing towards the fixed end (at this time, the material remains stationary while the moving jaws move towards the fixed end) until the distance sensor inside the moving head jaws collects information that the material has entered the moving head jaws. Take the current position of the moving head as the second initial position of the moving head. Using the advance amount, control the moving head to continue advancing from the second initial position until the advance amount is reached. Then, control the moving head to stop and the moving head jaws to engage.

[0021] The system described in this invention can automatically calculate the corresponding bite length based on the different thicknesses of the sheet being stretched. A laser rangefinder sensor installed between the C-shaped plate beams of the stretching machine jaws detects whether the sheet to be stretched has reached the sensor's installation position. The starting point is when the sheet head just reaches the sensor's detection position. The length of the sheet fed into the jaws is recorded to calculate the feed amount of the moving head. The model program calculates the required bite length based on different sheet thicknesses. When the length of the sheet fed into the jaws reaches the automatically calculated required bite length, the equipment stops feeding and begins automatically executing the jaw biting function. This effectively adjusts the stretching length according to different sheet thicknesses, improving the yield rate of the sheet. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0023] Specific Implementation Method 1: The stretching machine jaw biting plate length control system described in this embodiment has a distance sensor installed inside the front crossbeam structure of both the moving end and the fixed end jaws of the stretching machine. The distance sensor is used to collect whether the plate has entered the jaws of the stretching machine. When the plate is detected to have entered the jaws of the stretching machine, the information of the plate entering the jaws of the stretching machine is sent to the moving head control module.

[0024] The human-machine interaction unit is used to receive the bite length and thickness of the board set by the user, and send the set bite length and thickness of the board to the moving head control module.

[0025] The moving head control module receives information about the sheet material entering the jaws of the stretching machine, takes the current position of the sheet material as the initial position for advancement, calculates the advancement compensation amount and the advancing amount of the moving head based on the set bite length, the thickness of the sheet material, and the jaw information of the stretching machine, and sends the advancing amount of the moving head to the moving head drive unit of the stretching machine. The moving head drive unit of the stretching machine is used to drive the moving head of the stretching machine according to the advancing amount information of the moving head.

[0026] Furthermore, in this embodiment, the distance sensor is model SICK DT50-P2113.

[0027] Furthermore, in this embodiment, the method for calculating the propulsion compensation amount is as follows:

[0028] Using the formula:

[0029]

[0030] Calculate the propulsion compensation amount x, where h is the thickness of the plate, L is the jaw depth, and M is the maximum distance between the upper and lower jaws.

[0031] Furthermore, in this embodiment, the method for calculating the propulsion amount y of the moving head is as follows:

[0032] y = set length + x.

[0033] A method for controlling the length of sheet metal gripped by the jaws of a stretching machine includes:

[0034] Step 1: A distance sensor is installed inside the front crossbeam structure of both the moving head and the fixed head jaws of the stretching machine. The biting length and thickness of the sheet to be stretched are set through the human-machine interaction unit.

[0035] The advance compensation amount of the moving head is calculated using the engagement length and thickness of the sheet to be stretched, and the advance amount of the moving head is calculated using the compensation amount.

[0036] Step 2: Control the moving head jaws of the stretching machine to close, so that the jaws push the sheet to be stretched towards the fixed head. When the distance sensor inside the fixed head detects that the sheet to be stretched has entered the jaws of the fixed head, the current position of the moving head is taken as the first initial position of the moving head.

[0037] Step 3: Control the moving head to continue advancing the specified amount from the first initial position and then stop; control the jaws of the stretching machine's fixed head to engage; complete the engagement of the sheet metal by the jaws of the stretching machine's fixed head.

[0038] Step 5: Open the moving jaws and control the moving head to continue advancing towards the fixed end (at this time, the material remains stationary while the moving jaws move towards the fixed end) until the distance sensor inside the moving head jaws collects information that the material has entered the moving head jaws. Take the current position of the moving head as the second initial position of the moving head. Using the advance amount, control the moving head to continue advancing from the second initial position until the advance amount is reached. Then, control the moving head to stop and the moving head jaws to engage. Specific implementation examples:

[0040] The central objective of this invention is to enable automatic jaw engagement according to the operator-set engagement length when a stretching machine produces sheets with thicknesses of 6-50mm or less, thereby reducing jaw engagement marks, lowering incoming material tolerances, and increasing the sheet yield. Specifically:

[0041] 1. Select a laser rangefinder sensor that is compatible with the PLC400 controller of the stretching machine.

[0042] Main technical parameters:

[0043] Two Siemens CPU 416-3DP modules, CPU model: 6ES7416-3XR05-0AB0; two ET200S AI analog input modules, model: 6ES7134-4MB02-0AB0, used to connect the distance sensor and the CPU; and two laser rangefinders, model: SICK DT50-P2113, operating voltage: DC 10V...30V.

[0044] Fabricate a mounting bracket to install the laser rangefinder sensor inside the jaws of the stretching machine. The existing CPU controller from the original Siemens PLC can be used. Add two new AI modules to the ET200S substation to receive signals from the laser rangefinder sensor and complete the on-site electrical wiring.

[0045] Specific implementation process:

[0046] (1) Fabricate a mounting bracket for the laser rangefinder sensor and install it in a suitable working position inside the jaws of the stretching machine. Through demonstration, a special bracket was welded inside the crossbeam structure on the front of the two jaws of the stretching machine for mounting the laser rangefinder sensor.

[0047] (2) Connect the laser rangefinder sensor installed in the jaws to the AI ​​channel of the nearest Siemens ET200S substation, and transmit the two laser signals to the CPU of the Siemens PLC400 via DP communication for data calculation.

[0048] (3) A distance sensor is used to detect the position of the plate head inside the jaws. When the detected position reaches the distance set by the operator, the moving head automatically stops feeding, and the jaws automatically engage. After completion, the automatic stretching operation is completed.

[0049] (4) In the computer screen of the stretching machine, develop and design the use and cancellation selection buttons for the automatic biting function of 6-50mm and below plates, and create a biting length input window for the operator to input the desired plate length.

[0050] This invention has a clear concept, well-defined objectives, a simple equipment system, convenient maintenance, and a long service life, making it suitable for production and process requirements.

[0051] This invention achieves automatic control of the plate engagement length by comparing the signal feedback from a laser rangefinder sensor with a set length. Simultaneously, to ensure stable equipment operation and reduce equipment malfunctions caused by misoperation, corresponding interlocks are added to the program to ensure that the minimum plate engagement length is 100mm.

[0052] This invention also includes a modification to the stretching machine's operating screen program, adding a switch button for new functions and a bite length input function. A switch button for using the new functions and a bite length input window were developed within the Danieli operating screen program, allowing operators to choose whether to use the new functions. The WinCC program was edited, relevant PLC variables were added, and the communication function with the PLC was tested to meet the operator's functional requirements.

[0053] Using the system and method described in this invention, after program testing and production tracking, the automatic calculation model for the jaw engagement length of the stretching machine runs stably and effectively. When producing sheets of 6-50mm and below, in order to improve the production efficiency of the stretching machine, the operator selects and activates the custom function button in the HMI operation screen, inputs the desired engagement length, and then simply operates the feeding button normally on the control panel. The stretching machine will automatically feed the sheet into the jaws according to the new function, ensuring that the jaw engagement tolerance range is between 0-40mm, meeting production requirements, reducing the requirement of a normal engagement mark ≥350mm, and effectively improving the yield of the stretched sheet.

[0054] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A control system for the clamping length of sheet metal in a stretching machine, characterized in that, It includes a stretching machine moving head drive unit, a distance sensor (1), a moving head control module (2), and a human-machine interaction unit (3). A distance sensor (1) is installed inside the front crossbeam structure of both the moving end and the fixed end jaws of the stretching machine. The distance sensor (1) is used to collect whether the sheet material enters the jaws of the stretching machine. When the sheet material enters the jaws of the stretching machine, the sensor sends the information of the sheet material entering the jaws of the stretching machine to the moving head control module (2). The human-computer interaction unit (3) is used to receive the biting length and thickness of the board set by the user and send them to the moving head control module (2). The moving head control module (2) receives the information that the sheet enters the jaws of the stretching machine, takes the current position of the sheet as the initial position of the push, calculates the push compensation amount and the moving head push amount according to the set bite length, the thickness of the sheet and the jaw information of the stretching machine, and sends the moving head push amount to the moving head drive unit of the stretching machine. The moving head drive unit of the stretching machine is used to drive the moving head of the stretching machine according to the moving head push amount information. The calculation method for the amount of compensation is as follows: Using the formula: Calculate the propulsion compensation amount x, where h is the thickness of the plate, L is the jaw depth, and M is the maximum distance between the upper and lower jaws; The method for calculating the forward thrust y of the moving head is as follows: y = set length + x.

2. The sheet metal length control system for jaw engagement of a stretching machine according to claim 1, characterized in that, The distance sensor (1) is model SICK DT50-P2113.

3. A method for controlling the length of sheet metal gripped by the jaws of a stretching machine, characterized in that, include: Step 1: A distance sensor (1) is installed inside the front crossbeam structure of the moving head and fixed head jaws of the stretching machine. The biting length and thickness of the sheet to be stretched are set through the human-machine interaction unit (3). The advance compensation amount of the moving head is calculated using the engagement length and thickness of the sheet to be stretched, and the advance amount of the moving head is calculated using the advance compensation amount. Step 2: Control the moving head jaws of the stretching machine to close, so that the jaws push the sheet to be stretched towards the fixed head. When the distance sensor inside the fixed head detects that the sheet to be stretched has entered the jaws of the fixed head, the current position of the moving head is taken as the first initial position of the moving head. Step 3: Control the moving head to continue advancing the specified amount from the first initial position and then stop; control the jaws of the stretching machine's fixed head to engage; complete the engagement of the sheet metal by the jaws of the stretching machine's fixed head. Step 5: Open the moving end jaws and control the moving head to continue advancing towards the fixed end until the distance sensor inside the moving head jaws collects information that the board has entered the moving head jaws. Take the current position of the moving head as the second initial position of the moving head. Using the advance amount, control the moving head to continue advancing from the second initial position until the advance amount is reached. Then, control the moving head to stop and the moving head jaws will engage. The calculation method for the amount of compensation is as follows: Using the formula: Calculate the propulsion compensation amount x, where h is the thickness of the plate, L is the jaw depth, and M is the maximum distance between the upper and lower jaws; The method for calculating the forward thrust y of the moving head is as follows: y = set length + x.

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