Method for automatically pushing shear blades of double-side shears

Abstract

The invention discloses a method for automatically pushing shear blades of double-side shears, and belongs to the field of shear blade replacement of the double-side shears. The method comprises the steps of designing an automatic blade pushing device, designing automatic control of cutter pushing equipment and designing an automatic positioning function of a cutter changing trolley. The application of the invention not only improves the production efficiency, but also reduces the production cost. Due to the fact that the pushing and positioning process of the shear blade is automatic, manual intervention and errors are reduced, and the consistency and stability of production are improved. Meanwhile, due to the fact that the pushing process is more accurate and efficient, waste and loss in the production process are reduced, and the production cost is further reduced. And on the other hand, a series of safety problems caused by unsmooth communication of post operators in two places are eliminated due to the use of the automatic cutter pushing device, and the original cutter changing time is shortened.

Description

Technical Field

[0001] The invention relates to the replacement of the cutting blades of double-sided shears, and in particular to a method for automatically pushing the cutting blades of double-sided shears. Background Art

[0002] The 4.2M double edge shear in the thick plate plant is a key equipment in the production line. It is exquisitely designed and powerful. It is mainly composed of a three-axis three-eccentric rolling double edge shear carefully built by SMS. The main task of this machine is to perform precise edge trimming on the steel plate to meet the strict requirements on the width of the finished steel plate.

[0003] In the design of the double-sided shearing machine, the fixed side and the movable side shearing blades are each equipped with a shearing blade changing device, in order to ensure that the shearing quality of the steel plate always remains at the high standard of the industry. However, the replacement of the shearing blades on both sides of the double-sided shearing machine is still mainly dependent on manual operation. This shearing blade changing device has a complex structure, including a shearing blade changing trolley, guide rails, a transverse trolley, a transmission device, a lifting roller and a shearing blade transport roller. Among them, the lifting and transverse movement of the replacement trolley adopts advanced hydraulic cylinder technology, and the movement of the transverse trolley is achieved by a motor driving a sprocket.

[0004] At present, the replacement of the shear blades of double-sided shears is all done manually. All equipment actions need to be manually operated step by step before the next action can be executed. The entire shear blade replacement process is slow and time-consuming. With three operators, the time for replacing the shear blades on each side is about 60 minutes. The entire shear blade replacement device is still at the technical level of ten years ago, far behind the current level of automation technology. Manual replacement of shear blades poses a great safety hazard and needs to be improved urgently. In addition, the two sides of the double-sided shear blade replacement device are equipped with local operation boxes, which are mainly responsible for on-site equipment authority interaction and action execution. The shear blade lifting, transverse movement device, and shear blade replacement arm are close to the shear body, the internal environment is dim, and there is too much oil. The three are far away from the local operation box. Because the shear blade is changed manually, one operator must operate the shear blade at the near control console, and the other operator must command the shear blade to rise to ensure that it is in place and then lock it to prevent the shear blade from falling onto the waste belt. The two operators can only communicate through walkie-talkies, shouting, and passing on messages. The tool change efficiency is low, and the operation instructions are not easily communicated clearly, causing the equipment to malfunction and the shear blade to fall into the waste pit, which indirectly prolongs the tool change time (because the waste pit is small and dark, it takes 2 hours to pull the shear blade out of the waste pit). The operation instructions are not clearly communicated, and the safety of the commander himself cannot be guaranteed, which poses a great safety hazard. In addition, the double-sided shear blade transport roller mainly undertakes the shear blade conveying function. At present, the shear blade conveying roller is a mechanical roller operation without any drive device, and the shear blade must be manually pushed to the transverse trolley. The shear blade weighs about 1 ton. Each time the shear blade is replaced, it takes more than 5 minutes to push it to the transverse trolley. It takes longer for some operators with less strength to push it. If the personnel are not positioned correctly during the whole pushing process and the shear blade is not flat, it will cause personnel to fall, the shear blade will run off the roller and hit their feet, etc. There are great safety hazards in the whole process of pushing the shear blade. Moreover, the manual pushing of the shear blade to the lifting roller cannot guarantee the accuracy of the position. The shear blade often falls during the pushing, which prolongs the shear blade replacement time (it takes 30 minutes to deal with the shear blade falling), reducing the overall efficiency of the blade change. Summary of the invention

[0005] Purpose of the invention: The purpose of the present invention is to provide a method for automatically pushing the cutting blades of double-sided shears.

[0006] Technical solution: A method for automatically pushing the cutting blades of double-sided shears, comprising:

[0007] (1) Design of automatic blade pushing device

[0008] According to the various process steps of pushing the knife, a complete set of automatic pushing knife equipment is designed to automatically move the new and old shear blades on the auxiliary roller table;

[0009] (2) Design of automatic control of push blade equipment

[0010] According to the process steps of manual knife pushing and the structure of the newly added mechanical equipment, the automatic control of the knife pushing equipment is realized by adding photoelectric sensors, proximity switches, encoders, PLCs, frequency converters, and servo controller electrical equipment;

[0011] (3) Design the automatic positioning function of the tool changing trolley

[0012] After adding a position detection device for the tool changing trolley on the basis of the original equipment on site, the L1 program of the tool changing trolley needs to be modified. After interrupting the original trolley's walking process and adding two positions, the L1 program is modified to realize automatic positioning of the tool changing trolley at the two newly added positions.

[0013] Preferably, the automated blade pushing equipment mainly includes: a blade pushing trolley, a side positioning device, a lateral moving device and a conveying roller; the blade pushing trolley is used to push the old shear blade to the specified position and push the new shear blade to the lateral moving trolley, and the blade pushing trolley controls the driving gear and rack movement through the motor frequency conversion + encoder to obtain precise positioning, and the front and rear positions are set with limit position proximity switches and zero point proximity switches; the side positioning device is composed of two 80 cylinders, which are used for side positioning of the new shear blade; the lateral moving device is used for switching the pushing position of the blade pushing trolley at different positions, and the lateral moving device controls the driving gear and rack movement through the stepping motor to obtain precise positioning, and the front and rear positions are set with limit position proximity switches and zero point proximity switches; the conveying roller is mainly composed of a passive roller and a guide plate, the passive roller supports the shear blade, and the guide plate acts as a guide to enable the blade to slide smoothly during the pushing process.

[0014] Preferably, the automatic control process of the push knife device is as follows:

[0015] (1) The crane lifts the new shear blade to the feeding position of the conveyor roller, and the side positioning device pushes the shear blade to position it sideways, and the cylinder retracts after a delay of 5 seconds;

[0016] (2) The replaced old upper shear blade is transported to the designated position by the transverse trolley, and the shear blade pusher pushes the replaced old upper shear blade to the upper shear blade discharge roller position;

[0017] (3) The shear blade trolley returns to the designated position and pushes the replaced old lower shear blade to the upper shear blade discharge roller position;

[0018] (4) The shear blade trolley switches the shear blade position and pushes the new upper shear blade to the specified position of the transverse trolley;

[0019] (5) The side positioning cylinder pushes the remaining shear blade to position itself sideways again, and the cylinder retracts after a delay of 5 seconds;

[0020] (6) The shear blade trolley returns to the designated position and pushes the new lower shear blade to the fixed position of the outgoing transverse moving trolley;

[0021] (7) The shear blade trolley returns to the original position and the work is completed.

[0022] Beneficial effects: The application of the present invention not only improves production efficiency, but also reduces production costs. Since the pushing and positioning process of the shear blade is automated, manual intervention and errors are reduced, thereby improving the consistency and stability of production. At the same time, since the pushing process is more precise and efficient, waste and loss in the production process are also reduced, further reducing production costs. On the other hand, the use of the automatic blade pushing device eliminates a series of safety issues caused by poor communication between operators at the post and in two places, and shortens the original blade changing time. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the process flow of the automatic knife pushing device of the present invention;

[0024] Figure 2 Schematic diagram of closed-loop control of the knife pushing device. DETAILED DESCRIPTION

[0025] In order to make the technical solution of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] A method for automatically pushing the cutting blades of double-sided shears, comprising:

[0027] (1) Design of automatic blade pushing device

[0028] According to the various process steps of the push blade, a complete set of automatic push blade equipment is designed to automatically move the new and old shear blades on the auxiliary roller. It mainly includes: push blade trolley, side positioning device, lateral moving device, conveying roller, etc. The push blade trolley is responsible for pushing the old shear blade to the specified position and pushing the new shear blade to the lateral moving trolley. The push blade trolley controls the drive gear and rack movement through the motor frequency conversion + encoder to obtain precise positioning, and the limit position proximity switch and the zero point proximity switch are set at the front and rear positions. The side positioning device consists of two 80 cylinders and is responsible for the side positioning of the new shear blade. The lateral moving device is responsible for the push position switching of the push blade trolley at different positions. The lateral moving device controls the drive gear and rack movement through the stepping motor to obtain precise positioning, and the limit position proximity switch and the zero point proximity switch are set at the front and rear positions. The conveying roller is mainly composed of a passive roller and a guide plate. The roller supports the shear blade, and the guide plate plays a diversion role to enable the blade to slide smoothly during the pushing process.

[0029] The calculation of the click selection is as follows: Since the weight of the shear blade is 500Kg, the friction coefficient of the roller bed is about 0.1. According to the dynamic friction formula F = μF n , where μ = 0.1, F n=500Kg*9.8N / Kg=4900N, push F=490N, that is, the thrust that the transmission device needs to provide is about 490N.

[0030] Decompose the shearing action. At the beginning of the shearing, the thrust is greater than or equal to the static friction of the shear blade on the roller bed. Use the equilibrium condition method to solve the static friction. Since static friction is a passive force, it changes with the external force on the object. The value range of static friction is: 0≤F≤F max , has nothing to do with the normal pressure of the object, and the formula F=μF cannot be used n calculate.

[0031] The maximum static friction is equal to the external force along the contact surface when the object just slides, which means the maximum value of static friction is greater than sliding friction. The formula is F max =μ 静 *F n , μ of rolling bed 静 It is about 0.13, so the maximum static friction that the transmission device needs to overcome at the beginning of startup is about 637N.

[0032] The motor output torque of the system design is 115N / M, the gear rack mechanism reduction ratio of the reduction box is 22.6, the output speed is 62r / min, the gear pitch circle diameter is 100mm, and the trolley push speed is about 19.47m / min. Calculate the motor thrust F 推 =115N*22.6=2599N. That is, the maximum thrust of the system design is much greater than the static friction and dynamic friction of the shear blade. The system running speed of 19.47m / min also meets the production rhythm requirements.

[0033] Similarly, the static friction and sliding friction required for the cylinder to push the shear blade are calculated as follows:

[0034] F max =500Kg*9.8N / kg*2*0.34=3332N

[0035] F 推 =500Kg*9.8N / Kg*2*0.3=2940N

[0036] System design cylinder cylinder model 80-300, air pressure 5bar, cylinder thrust = 4*4*3.14*5*9.8 = 2461.7N.

[0037] Since there are 2 cylinders installed, the total thrust of the cylinders = 2461.7N*2 = 4923.5N>F max >F 推 . It fully meets the maximum thrust required for the shear blade's transverse action.

[0038] (2) Design of automatic control of push blade equipment

[0039] According to the process steps of manual knife pushing and the structure of the newly added mechanical equipment, the automatic control of the knife pushing equipment is realized by adding electrical equipment such as photoelectric sensors, proximity switches, encoders, PLCs, frequency converters, servo controllers, etc. (such as Figure 1 The automatic control process is as follows:

[0040] (1) The crane lifts the new shear blade to the feeding position of the conveyor roller, and the side positioning device pushes the shear blade to position it sideways, and the cylinder retracts after a delay of 5 seconds;

[0041] (2) The replaced old upper shear blade is transported to the designated position by the transverse trolley, and the shear blade pusher pushes the replaced old upper shear blade to the upper shear blade discharge roller position;

[0042] (3) The shear blade trolley returns to the designated position and pushes the replaced old lower shear blade to the upper shear blade discharge roller position;

[0043] (4) The shear blade trolley switches the shear blade position and pushes the new upper shear blade to the specified position of the transverse trolley;

[0044] (5) The side positioning cylinder pushes the remaining shear blade to position itself sideways again, and the cylinder retracts after a delay of 5 seconds;

[0045] (6) The shear blade trolley returns to the designated position and pushes the new lower shear blade to the fixed position of the outgoing transverse moving trolley;

[0046] (7) The shear blade trolley returns to the original position and the work is completed.

[0047] The shear blade pushing action during the operation of the equipment is achieved by using a variable frequency motor to drive the lead screw to move, a stepper motor is used to move the baffle of the shear blade horizontally, and a cylinder is used to move the shear blade horizontally on the roller bed.

[0048] The push-knife motor adopts speed closed-loop control with encoder (such as Figure 2 As shown in the figure, the automatic positioning of the pusher device is realized by combining the specific position value of the encoder. The encoder used for detection plays an important role in the control process. The overall control accuracy of the equipment is closely related to the detection accuracy and sampling period of the encoder. Therefore, it is also very important to obtain accurate feedback values.

[0049] For the closed-loop control system, two kinds of negative feedback control, speed and current, are actually designed in the system. The speed PID automatic regulator and the current PID automatic regulator are set in the system, and the two are connected in series. That is, the output of the speed regulator is used as the input of the current regulator, and the output of the current regulator is used to control the trigger device of the inverter bridge thyristor. In this way, the inner and outer loops are adjusted to achieve precise control of the motor. Conventional PID is the most widely used control algorithm in the industrial field. It has a simple structure, easy to adjust parameters, and does not rely on the precise mathematical model of the controlled system. For the motor speed control in this project, general PI control can achieve satisfactory results. Considering that the inverter control system is a sampling control system, the system adopts a PI control algorithm in the form of discretized recursive increments:

[0050] Ek=Ui-Uk

[0051] Pk=KcEk+Qk

[0052] Qk=Pk-KpEk

[0053] Where: Kp is the proportional coefficient; Kc = Kp (1 + Ki), Ki is the integral coefficient; Ui is the given value; Uk is the measured value of the Kth sampling, Qk is equivalent to the integral part of the correction amount, and the initial value can be Qk = 0. In the digital PI control system, when the system starts, stops or changes the given value significantly, the system output will have a large deviation. After the integral term is accumulated, integral saturation may occur, thereby increasing the system adjustment time and overshoot, affecting the control effect. Therefore, measures to prevent integral saturation should be added to the PI algorithm.

[0054] According to the system design of the present invention: when the sampling period T=50ms, Kp=0.85, Kc=1.02, the speed error of the motor should be less than 1.0%, and the position accuracy should be within ±5mm, which fully meets the requirements of the site for position control accuracy.

[0055] (3) Design the automatic positioning function of the tool changing trolley

[0056] The mechanical structure of the original tool-changing trolley and the positioning principle of the tool-changing trolley, the control system of the tool-changing trolley uses S7-400PLC, the internal program uses sequential step control, and each step is cycled in sequence. After adding the position detection device of the tool-changing trolley on the basis of the original equipment on site, it is necessary to modify the L1 program of the tool-changing trolley. After interrupting the original trolley's walking process and adding 2 positions, modify the L1 program to realize the automatic positioning of the tool-changing trolley at the two newly added positions (such as Figure 2 shown).

[0057] Example

[0058] The crane plays a key role in the loading process. It is responsible for accurately lifting the new blade to the designated loading position of the conveyor roller. Once the new blade reaches the predetermined position, the operator will activate the cylinder extension button to ensure that the new upper blade is accurately positioned. In order to ensure the accuracy of the positioning, the operator will manually check to confirm whether the new upper blade is fully in place. Once confirmed, the operator will press the cylinder retraction button to retract the cylinder.

[0059] The next step is to push out the old upper blade. In this step, the horizontal moving pusher will first stay at the origin position. The operator activates the push blade trolley forward button to move the push blade trolley to the start position of retracting. Then, the operator can manually control the pusher to move to the appropriate pusher working position through the left / right movement button. During the movement process, the operator needs to remain highly vigilant to ensure that the pusher does not collide with the equipment or other parts. When the pusher moves to the appropriate position, the operator will manually confirm that it is correct before activating the push blade trolley reverse button to push the replaced old upper blade to the discharge roller position.

[0060] After the old upper blade is pushed out, the next step is to push the new upper blade. The operator first activates the left shift button to return the lateral movement pusher to the initial position. Then, activate the back button of the blade pusher to move the blade pusher to the starting position of the blade pusher. Then, through the left shift button, the operator manually controls the lateral movement device to move to the appropriate position. Similarly, after manual confirmation, the forward button can be activated to push the new upper blade on the conveyor roller to the blade transporter.

[0061] After the push is completed, the lateral moving device will return to the origin position, and the push blade trolley will also return to the origin position. At this time, the operator will activate the cylinder extension button again to position the new lower blade. After the positioning is completed, the operator will manually check to confirm whether the new lower blade is fully in place, and then press the cylinder retraction button to retract the cylinder.

[0062] In the manual control process, waiting for tool installation and removal is an inevitable step. The operator needs to wait patiently to ensure that the tool installation and removal operations are performed at the right time. In the steps of pushing out the old lower blade and pushing in the new lower blade, the operation process is similar to pushing out the old upper blade and pushing in the new upper blade, but the operation objects are different.

[0063] The entire manual control process requires the operator to have rich experience and keen insight to ensure the accuracy and safety of each step. Through manual control, the operator can respond to various situations more flexibly and ensure the smooth progress of the production process.

[0064] In the automatic control process, the system realizes automatic operation by monitoring the position of the tool carriage. First, the system monitors whether the tool carriage is in the retract position 1 or the retract position 2 through the proximity switch. If the system cannot detect the position signal, the system will not perform any action. Only when the system detects that the tool carriage is in the correct retract position will it start the retract operation.

[0065] During the retracting process, the push-blade trolley will move forward to the retracting start position, and then the lateral moving device will move to the retracting position 1. Subsequently, the push-blade trolley will start to retract, and the system will control the speed and position of the push-blade trolley according to the signal of the proximity switch. When the push-blade trolley retracts to the retracting deceleration position, the system will start to decelerate until it senses the retracting stop position proximity switch and stops. At this point, the retracting operation is completed, and the lateral moving device and the push-blade trolley will return to the origin position.

[0066] Next comes the blade-pushing operation. The system first starts the cylinder extension and lateral positioning process to ensure that the new blade is accurately positioned. Then, the blade-pushing trolley retreats to the blade-pushing starting position, and the lateral moving device moves to the blade-pushing position. Subsequently, the blade-pushing trolley starts to move forward, and the system controls its speed and position according to the signal of the proximity switch. When the blade-pushing trolley moves forward to the blade-pushing deceleration position, the system starts to decelerate until it senses the blade-pushing stop position proximity switch and stops. At this point, the blade-pushing operation is completed, and the lateral moving device and the blade-pushing trolley return to the origin position again.

[0067] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for automatically pushing the blades of double-sided shears, characterized in that: include: (1) Design of automatic blade pushing device According to the various process steps of pushing the knife, a complete set of automatic pushing knife equipment is designed to automatically move the new and old shear blades on the auxiliary roller table; (2) Design of automatic control of push blade equipment According to the process steps of manual knife pushing and the structure of the newly added mechanical equipment, the automatic control of the knife pushing equipment is realized by adding photoelectric sensors, proximity switches, encoders, PLCs, frequency converters, and servo controller electrical equipment; (3) Design the automatic positioning function of the tool changing trolley After adding a position detection device for the tool changing trolley on the basis of the original equipment on site, the L1 program of the tool changing trolley needs to be modified. After interrupting the original trolley's walking process and adding two positions, the L1 program is modified to realize automatic positioning of the tool changing trolley at the two newly added positions.

2. The method for automatically trimming the blades of double-sided shears according to claim 1, characterized in that: The automated blade-pushing equipment mainly includes: a blade-pushing trolley, a side positioning device, a lateral moving device and a conveying roller; the blade-pushing trolley is used to push the old shear blade to the designated position and push the new shear blade to the lateral moving trolley. The blade-pushing trolley controls the movement of the drive gear and rack through the motor frequency conversion + encoder to obtain precise positioning, and the front and rear positions are set with limit position proximity switches and zero point proximity switches; the side positioning device is composed of two 80 cylinders and is used for side positioning of the new shear blade; the lateral moving device is used to switch the pushing position of the blade-pushing trolley at different positions. The lateral moving device controls the movement of the drive gear and rack through the stepping motor to obtain precise positioning, and the front and rear positions are set with limit position proximity switches and zero point proximity switches; the conveying roller is mainly composed of a passive roller and a guide plate. The passive roller supports the shear blade, and the guide plate acts as a guide to enable the blade to slide smoothly during the pushing process.

3. The method for automatically trimming the blades of double-sided shears according to claim 1, characterized in that: The automatic control process of the push knife equipment is as follows: (1) The crane lifts the new shear blade to the feeding position of the conveyor roller, and the side positioning device pushes the shear blade to position it sideways, and the cylinder retracts after a delay of 5 seconds; (2) The replaced old upper shear blade is transported to the designated position by the transverse trolley, and the shear blade pusher pushes the replaced old upper shear blade to the upper shear blade discharge roller position; (3) The shear blade trolley returns to the designated position and pushes the replaced old lower shear blade to the upper shear blade discharge roller position; (4) The shear blade trolley switches the shear blade position and pushes the new upper shear blade to the specified position of the transverse trolley; (5) The side positioning cylinder pushes the remaining shear blade to position itself sideways again, and the cylinder retracts after a delay of 5 seconds; (6) The shear blade trolley returns to the designated position and pushes the new lower shear blade to the fixed position of the outgoing transverse moving trolley; (7) The shear blade trolley returns to the original position and the work is completed.

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