Carton forming and collapsing apparatus and method

Abstract

The paper box forming and pressing device and method belong to the technical field of paper box forming and processing, and comprise a main frame, a driving structure, a pressing assembly, a floating guide mechanism and a displacement detection assembly. A servo motor is arranged on the top of the main frame and drives the main sliding block to slide along the frame through an elastic coupling and a ball screw. The low-friction air cylinder of the pressing assembly is fixed to the bottom of the main sliding block, the piston rod extends downward, and the bottom surface of the pressing plate base is provided with a flexible contact plate. In the floating guide mechanism, the universal ball hinge connects the end of the piston rod and the center of the top surface of the base, and the guide light shaft sleeved with the spring connects the sliding block and the base. The reading head and the scale of the displacement detection assembly are respectively arranged on the front side of the main sliding block and the base, and cooperate to measure the extension and retraction displacement of the piston rod. The local thickness difference is compensated by mechanical floating, the pressing force is accurately controlled by direct driving, the uniformity of the pressing force and the pressing quality are ensured while the surface deformation of the paper box is adapted.

Description

Technical Field

[0001] This invention relates to the field of paper box forming and processing, specifically to a paper box forming and bubbling device and method. Background Technology

[0002] When a paper box forming blister press device presses the box blank, it needs to apply a stable downward pressure to ensure that the surfaces are tightly adhered. In the existing technology, due to the common differences in adhesive layer distribution, trapped air inside, and local thickness differences on the surface of the paper box, it is very easy to cause uneven force and pressing on one side first. At the same time, the mechanical fatigue and return clearance accumulated by the transmission components over a long period of operation can cause insufficient immediate downward pressure. In addition, abnormal blanks to be processed can easily cause mechanical interference and insufficient clamping force. To address the problems of existing bubble pressing devices, this invention introduces a floating guide mechanism and a displacement detection component to compensate for molding defects. Mechanical floating compensation incorporates a universal ball joint and a guide shaft in the pressing component, causing the pressure plate base to tilt under uneven stress to adapt to local thickness differences, and utilizing a flexible contact plate to buffer instantaneous contact stress. The drive mechanism employs a direct drive transmission without an intermediate deceleration device to reduce transmission clearance, and calculates instantaneous downward pressure by measuring relative displacement and combining it with the state of the sealed air cavity. This approach, combined with the transmission wear trend extraction model and the time-series anti-interference monitoring model in the control program, reduces the impact of mechanical wear and vibration on the synchronization of bubble pressing. Summary of the Invention

[0003] To address the problems in existing paper box forming and blistering technologies, such as uneven unilateral initial stress and compression caused by differences in the adhesive layer on the paper box surface and local thickness, insufficient instantaneous downward pressure due to mechanical fatigue and return clearance of the transmission mechanism after long-term operation, and equipment interference caused by abnormal blanks, this invention provides a paper box forming and blistering device and method, the technical solution of which includes: The system comprises a main frame, a drive structure, a pressing assembly, a floating guide mechanism, and a displacement detection assembly. The drive structure includes a servo motor, a plum blossom-shaped elastic coupling, a ball screw, and a main slider. The servo motor is fixedly connected to the top of the main frame. The output shaft of the servo motor is connected to the input end of the ball screw through the plum blossom-shaped elastic coupling. The screw nut of the ball screw is fixedly connected to the back of the main slider, and the two sides of the main slider are slidably connected to the main frame. The pressing assembly includes a low-friction cylinder, a pressure plate base, and a flexible contact plate. The cylinder barrel of the low-friction cylinder is fixedly connected to the bottom flange face of the main slider, the piston rod of the low-friction cylinder extends vertically downward, and the flexible contact plate is fixedly connected to the bottom surface of the pressure plate base. The floating guide mechanism includes a universal ball joint, a guide shaft, and a helical spring. The ball head of the universal ball joint is threaded to the end of the piston rod. The ball seat of the universal ball joint is fixedly connected to the center of the top surface of the pressure plate base. The guide shaft is connected between the bottom surface of the main slider and the top surface of the pressure plate base. The helical spring is sleeved on the outside of the guide shaft. The displacement detection assembly includes a reading head and a scale. The reading head is fixedly connected to the front side of the main slider, and the scale is fixedly connected to the front side of the pressure plate base via a bracket. The reading head and the scale are used to measure the extension and retraction displacement of the piston rod.

[0004] Furthermore, the flexible contact plate is made of polyurethane material; wherein, the thickness of the flexible contact plate is set to allow for elastic buffer deformation and the deformation is less than the upper limit of the effective compression displacement of the piston rod.

[0005] Furthermore, the upper and lower ends of the ball screw are supported on the main frame by angular contact ball bearings; The main slider is slidably connected to the main frame on both sides via linear guide rails; the output shaft of the servo motor is directly connected to the input end of the ball screw via the plum blossom-shaped elastic coupling; wherein, there is no speed reduction or speed increase structure in the drive structure.

[0006] Furthermore, each corner of the pressure plate base is connected to the guide optical shaft, and the upper end of the guide optical shaft slides through the main slider via a linear bearing; the two ends of the helical spring abut against the bottom surface of the main slider and the top surface of the pressure plate base, respectively.

[0007] Furthermore, the low-friction cylinder is equipped with an exhaust valve; wherein, the low-friction cylinder is filled with compressed air at a preset initial pressure and the air passage is closed to form a sealed air chamber.

[0008] A paper box forming and blistering method includes the following steps: S1: Injecting compressed air with a preset initial air pressure into the low friction cylinder, and then sealing the air passage to make the low friction cylinder a sealed air chamber; S2: The servo motor drives the main slider to move downward at a preset speed, and the low-friction cylinder maintains its maximum extension state under the action of internal air pressure. The extension displacement measured by the reading head and the scale remains at the initial zero value. S3: When the flexible contact plate contacts the surface of the paper box to be pressed, the reaction force of the paper box to be pressed forces the piston rod to retract upward relative to the main slider, resulting in a sudden change in telescopic displacement. The control program set by the system controls the servo motor to stop moving downward at a preset speed according to the sudden change in telescopic displacement, and enters the displacement feedback control stage. S4: In the displacement feedback control stage, the control program calculates the instantaneous downward pressure based on the real-time measured expansion and contraction displacement; if the instantaneous downward pressure is less than the preset bubble pressure target, the servo motor is controlled to drive the main slider to continue pressing down; if the instantaneous downward pressure is greater than or equal to the preset bubble pressure target, the servo motor is controlled to stop pressing down and enter the pressure holding stage. S5: During the pressure holding phase, the servo motor is controlled to maintain its current position, and the pressure is maintained by the compressed air expanding inside the low-friction cylinder.

[0009] Furthermore, during continuous production, the control program records the position coordinates of the servo motor each time the preset bubble-pressing target pressure is reached; if the position coordinates show a gradual downward trend as the number of bubble-pressing work cycles increases, the control program extracts the downward position and automatically increases the initial target stroke of the servo motor in the next bubble-pressing cycle; if the position coordinates do not show a gradual downward trend, the control program keeps the initial target stroke unchanged.

[0010] Furthermore, the control program monitors the measured contact time in real time; if the contact time is earlier than a preset time window, the control program triggers the servo motor to reverse and lift the main slider, and opens the exhaust valve of the low-friction cylinder to release the internal air pressure; if the contact time is at or later than the preset time window, the control program continues to execute subsequent bubble control steps.

[0011] This invention provides a paper box forming and bubble pressing device and method, which has the following improvements and advantages compared with the prior art: 1. This invention uses a low-friction cylinder, a displacement detection component and a servo motor to calculate and control the downward pressure in real time by measuring the displacement; combined with a universal ball joint and a flexible contact plate, the pressure plate base can be tilted in space to adapt to the deformation of the paper box surface, and the internal compressed air is used to naturally expand and compensate for local gaps, ensuring that the pressure on the bubble is uniform.

[0012] 2. This invention automatically increases the target stroke by recording the downward trend of the servo motor position coordinates, effectively compensating for the stroke error caused by transmission backlash during continuous production; at the same time, it monitors the contact time in real time, triggering the motor to reverse and opening the exhaust valve to release pressure when abnormal premature contact occurs, thereby realizing rapid equipment reset and improving the safety and stability of operation. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall external structure of the device; Figure 2 This is a schematic diagram of the driving structure; Figure 3 This is a schematic diagram of the main slider and its connecting structure; Figure 4 This is a schematic diagram of the process flow of the method of the present invention.

[0014] In the diagram: 1. Main frame; 2. Drive structure; 201. Servo motor; 202. Plum blossom-shaped flexible coupling; 203. Ball screw; 204. Screw nut; 205. Main slider; 206. Angular contact ball bearing; 207. Linear guide rail; 3. Pressing assembly; 301. Low-friction cylinder; 302. Cylinder barrel; 303. Piston rod; 304. Pressure plate base; 305. Flexible contact plate; 306. Exhaust valve; 4. Floating guide mechanism; 401. Universal ball joint; 402. Ball head; 403. Ball seat; 404. Guide shaft; 405. Helical spring; 406. Linear bearing; 5. Displacement detection assembly; 501. Reading head; 502. Scale; 503. Bracket. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0016] Please see Figure 1-3 A paper box forming bubble pressing device is used to perform controlled pressing on the surface bonding area of ​​a box blank; the paper box forming bubble pressing device includes a main frame 1, a drive structure 2, a pressing component 3, a floating guide mechanism 4, and a displacement detection component 5; The drive structure 2 includes a servo motor 201, a plum blossom-shaped flexible coupling 202, a ball screw 203, and a main slider 205. The servo motor 201 is fixedly connected to the top of the main frame 1. The output shaft of the servo motor 201 is connected to the input end of the ball screw 203 through the plum blossom-shaped flexible coupling 202. The screw nut 204 of the ball screw 203 is fixedly connected to the back of the main slider 205. The two sides of the main slider 205 are slidably connected to the main frame 1. The pressing assembly 3 includes a low-friction cylinder 301, a pressure plate base 304, and a flexible contact plate 305. The cylinder barrel 302 of the low-friction cylinder 301 is fixedly connected to the bottom flange surface of the main slider 205, the piston rod 303 of the low-friction cylinder 301 extends vertically downward, and the flexible contact plate 305 is fixedly connected to the bottom surface of the pressure plate base 304. The floating guide mechanism 4 includes a universal ball joint 401, a guide shaft 404, and a helical spring 405. The ball head 402 of the universal ball joint 401 is threaded to the end of the piston rod 303. The ball seat 403 of the universal ball joint 401 is fixedly connected to the center of the top surface of the pressure plate base 304. The guide shaft 404 is connected between the bottom surface of the main slider 205 and the top surface of the pressure plate base 304. The helical spring 405 is sleeved on the outside of the guide shaft 404. The displacement detection component 5 includes a reading head 501 and a scale 502. The reading head 501 is fixedly connected to the front side of the main slider 205, and the scale 502 is fixedly connected to the front side of the pressure plate base 304 through a bracket 503. The reading head 501 and the scale 502 are used to measure the extension and retraction displacement of the piston rod 303.

[0017] The main frame 1 serves as the mounting reference for the entire machine, supporting the drive structure 2, pressing assembly 3, floating guide mechanism 4, and displacement detection assembly 5, and maintaining the stable spatial relative relationship between the components. The servo motor 201 in the drive structure 2 outputs rotational motion, which is transmitted to the input end of the ball screw 203 via the plum blossom-shaped elastic coupling 202. The ball screw 203 converts the rotational motion into linear motion of the main slider 205 along a set direction. The plum blossom-shaped flexible coupling 202 is used to transmit torque and absorb the coaxiality deviation formed during the assembly process, reduce the additional load in the drive chain, and enable the main slider 205 to maintain the displacement response within the preset fluctuation range during the reciprocating pressure cycle. The low-friction cylinder 301 in the pressing assembly 3 is fixedly mounted on the bottom flange surface of the main slider 205 and moves as a whole with the main slider 205; the piston rod 303 of the low-friction cylinder 301 extends downward and is connected to the pressure plate base 304 through the universal ball joint 401; the bottom surface of the pressure plate base 304 is fixed with a flexible contact plate 305, which is in direct contact with the surface of the carton; the low-friction cylinder 301, as a compliant pressure-bearing unit, has its piston rod 303's extension and retraction displacement relative to the main slider 205 as a characteristic quantity characterizing the change in the force on the pressure plate base 304 in contact with the carton; The universal ball joint 401 in the floating guide mechanism 4 provides multi-degree-of-freedom swing capability. The guide optical shaft 404 and the helical spring 405 together apply a restoring constraint to the pressure plate base 304, so that the pressure plate base 304 can tilt to a limited extent when the force is uneven, and return to the reference posture after the external load is lost. The reading head 501 in the displacement detection component 5 is fixed to the main slider 205, and the scale 502 is fixed to the pressure plate base 304. After the two are set relative to each other, the displacement change of the pressure plate base 304 relative to the main slider 205 can be directly output, thereby providing a data source for subsequent contact determination and pressure calculation. The pressing process is achieved by providing feed through drive structure 2, elastic compression through low-friction cylinder 301, attitude adaptation through universal ball joint 401 and guide optical axis 404, and displacement measurement through reading head 501 and scale 502. This structural combination is used to reduce the impact of transmission wear, local thickness difference and bonding resistance fluctuation on the uniformity of bubble pressing, and to obtain parameter data for controlling the bubble pressing action.

[0018] The flexible contact plate 305 is made of polyurethane material; the thickness of the flexible contact plate 305 is set to allow for elastic buffer deformation and the deformation is less than the upper limit of the effective compression displacement of the piston rod 303.

[0019] The flexible contact plate 305 is disposed on the bottom surface of the pressure plate base 304, serving as a functional layer that directly contacts the pressing component 3 with the surface of the paper box; the polyurethane material is a polymeric elastic material with recoverable elastic deformation capability and stable surface friction characteristics, used to disperse the concentrated load transmitted by the pressure plate base 304 to the effective contact area of ​​the paper box surface. The thickness of the flexible contact plate 305 is set to a preset thickness threshold. The preset thickness threshold is determined comprehensively based on the allowable indentation amount on the paper box surface, the target bubble pressure range, and the allowable compression displacement range of the low-friction cylinder 301. This ensures that the flexible contact plate 305 can conform to the local dimensional fluctuations of the paper box surface during the bubble pressing stage, and will not absorb deformation exceeding the predetermined displacement range due to the thickness exceeding the preset upper limit, thus affecting the correspondence between the cylinder compression amount and the instantaneous downward pressure. The preset thickness threshold is a parameter used to limit the upper limit of the thickness of the flexible contact plate 305 participating in deformation. This thickness parameter is used to make the flexible contact plate 305 produce surface-adhesive buffer deformation and limit the interference of the deformation of the flexible contact plate 305 on the relative compression displacement detection results. The process of determining the preset thickness threshold includes: firstly, determining the allowable surface deformation range of the flexible contact plate 305 under the target pressure based on the allowable indentation amount on the surface of the cardboard box. Based on the preset target pressure for foaming and the allowable compression displacement range of the low-friction cylinder 301, the displacement absorbed by the flexible contact plate 305 during the foaming stage is limited to less than the predetermined proportion of the effective compression displacement of the piston rod 303. In combination with the compression and rebound characteristics of polyurethane material, a thickness value that meets the above two conditions is selected through pressing test or calibration test, and the thickness value is stored as a preset thickness threshold. When the control program or process settings change the paper box material, adhesive layer thickness or target pressure level, the preset thickness threshold can be reselected to ensure that the main change output by the displacement detection component 5 still corresponds to the compression displacement of the piston rod 303 of the low friction cylinder 301. When the main slider 205 drives the low-friction cylinder 301 to move downward, the flexible contact plate 305 first establishes surface contact with the surface of the cardboard box; if there are local undulations in the adhesive layer or raised areas formed by residual air on the surface of the cardboard box, the polyurethane material will buffer the local area through its own elastic deformation, reducing the instantaneous contact stress peak. The preset thickness threshold of the flexible contact plate 305 is also matched with the resolution requirements of the displacement detection component 5, so that the displacement change measured by the reading head 501 and the scale 502 represents the compression displacement of the piston rod 303 of the low friction cylinder 301, and eliminates the interference of nonlinear surface collapse displacement caused by the contact layer thickness exceeding the upper limit threshold; thus, the flexible contact plate 305 is used for surface protection and stabilization of the force transmission path, providing a corresponding basis for subsequent real-time downforce calculation.

[0020] The upper and lower ends of the ball screw 203 are supported on the main frame 1 by angular contact ball bearings 206; the two sides of the main slider 205 are slidably connected to the main frame 1 by linear guide rails 207; the output shaft of the servo motor 201 is directly connected to the input end of the ball screw 203 by a plum blossom-shaped elastic coupling 202; there is no speed reduction or speed increase structure in the drive structure 2.

[0021] The drive structure 2 adopts a direct drive transmission chain consisting of a servo motor 201, a plum blossom-shaped flexible coupling 202, a ball screw 203, an angular contact ball bearing 206, a linear guide rail 207, and a main slider 205. The upper and lower ends of the ball screw 203 are supported on the main frame 1 by the angular contact ball bearing 206. The angular contact ball bearing 206 is used to simultaneously bear the radial load and axial load during the operation of the ball screw 203, and to limit the axial movement of the screw, so that the linear feed of the main slider 205 and the output angle of the servo motor 201 maintain a stable mapping relationship. The main slider 205 is slidably connected to the main frame 1 on both sides by linear guide rails 207. The linear guide rails 207 are used to constrain the motion freedom of the main slider 205, so that the main slider 205 can move smoothly along the set axis and reduce the interference of lateral swing on the compression state of the low friction cylinder 301. The output shaft of the servo motor 201 is directly connected to the input end of the ball screw 203 through the plum blossom-shaped flexible coupling 202. No reducer or speed increaser is set in the drive structure 2. After eliminating the intermediate speed change mechanism, the sources of tooth backlash in the transmission chain are reduced, the number of torsional elastic links is reduced, and the position command of the servo motor 201 can be transmitted to the ball screw 203 more directly. For the contact judgment and the pressing control of the corresponding preset feed step in the blister pressing process, the displacement of the main slider 205 needs to correspond to the position coordinates of the servo motor 201. If there is an additional speed change mechanism in the drive structure 2, the gear meshing clearance and additional return error will amplify the displacement uncertainty in the contact stage; by adopting the direct drive structure of this embodiment, the main slider 205 can maintain the repeatability of the set accuracy in the bubble pressing cycle, and the subsequent control logic for extracting the transmission wear trend based on the position coordinates has a feasible mechanical basis.

[0022] Each corner of the pressure plate base 304 is connected to a guide optical shaft 404. The upper end of the guide optical shaft 404 slides through the main slider 205 via a linear bearing 406. The two ends of the helical spring 405 abut against the bottom surface of the main slider 205 and the top surface of the pressure plate base 304, respectively.

[0023] Each corner of the pressure plate base 304 is connected to a corresponding guide optical axis 404, which is arranged along the relative movement direction between the main slider 205 and the pressure plate base 304. The upper end of each guide optical axis 404 slides through the main slider 205 via a linear bearing 406. The linear bearing 406 is used to reduce the frictional resistance between the guide optical axis 404 and the main slider 205, so that the pressure plate base 304 can generate displacement relative to the main slider 205 along the direction of the guide optical axis 404 under pressure. A helical spring 405 is sleeved on the outside of the guide optical axis 404, and the two ends of the helical spring 405 abut against the bottom surface of the main slider 205 and the top surface of the pressure plate base 304, respectively, thereby applying a restoring force along the axial direction of the guide optical axis 404 to the pressure plate base 304. The floating guide structure is used to provide multi-degree-of-freedom swing compensation and axial motion constraint for the pressure plate base 304; the guide optical shaft 404 is distributed at different positions around the pressure plate base 304, which can provide multi-point guide constraint for the pressure plate base 304; when the universal ball joint 401 allows the pressure plate base 304 to generate angle compensation around the connection center, the guide optical shaft 404 slides relatively in the linear bearing 406, and the helical spring 405 generates corresponding compression differences at different positions, thereby forming an elastic limit on the tilting posture; When the local height or resistance distribution on the surface of the cardboard box is inconsistent, the pressure plate base 304 can form a limited adaptive posture under the combined action of the guide optical shaft 404 and the helical spring 405, reducing the uneven pressing caused by the unilateral first force; after the external load is released, the helical spring 405 releases the stored energy and pushes the pressure plate base 304 back to the set reference posture, ensuring that the initial conditions of the next bubble pressing cycle are consistent.

[0024] The low-friction cylinder 301 is equipped with an exhaust valve 306; wherein, the low-friction cylinder 301 is filled with compressed air at a preset initial pressure and the air passage is closed to form a sealed air chamber.

[0025] The low-friction cylinder 301 is equipped with an exhaust valve 306, which is connected to the internal air chamber of the low-friction cylinder 301. During the preparation stage, the low-friction cylinder 301 is filled with compressed air at a preset initial pressure, and after reaching the set inflation state, the air passage is closed to form a sealed air chamber inside. The preset initial pressure is determined based on the piston force area, the target pressure range of the pressure bubble, and the allowable compression displacement range, so that the piston rod 303 remains in an extended state when there is no external load, and can produce a measurable retraction displacement under the action of the paper box reaction force. The low-friction cylinder 301 is configured as an actuator and a gas compression force measuring unit. Since the gas path is in a closed state, the pressure change in the gas chamber has a calculable relationship with the compression displacement of the piston rod 303, that is, the current pressure can be obtained by displacement inversion. The exhaust valve 306 is used to actively relieve pressure under abnormal working conditions. If the blister pressing action is stopped, or if an abnormality is detected in the incoming material position and the pressing load needs to be released, the control program can control the exhaust valve 306 to open, so that the air pressure inside the sealed air chamber decreases, the reverse thrust force borne by the piston rod 303 is reduced, and the contact load of the pressure plate base 304 on the carton is released. This structure keeps the pressing assembly 3 in a sealed and pressure-bearing state during operation and performs pressure relief action under abnormal unloading conditions.

[0026] Please see Figure 1-4 A paper box forming and blistering method includes the following steps: S1: Injecting compressed air with a preset initial air pressure into a low friction cylinder 301, and then sealing the air passage to make the low friction cylinder 301 a sealed air chamber. S2: Servo motor 201 drives main slider 205 to move downward at a preset speed. Low friction cylinder 301 maintains maximum extension under internal air pressure. The extension displacement measured by reading head 501 and scale 502 remains at the initial zero value. S3: When the flexible contact plate 305 contacts the surface of the paper box to be pressed, the reaction force of the paper box to be pressed forces the piston rod 303 to retract upward relative to the main slider 205, resulting in a sudden change in the telescopic displacement. The control program set by the system controls the servo motor 201 to stop moving downward at a preset speed according to the sudden change in the telescopic displacement, and enters the displacement feedback control stage. S4: In the displacement feedback control stage, the control program calculates the instantaneous downward pressure based on the real-time measured expansion and contraction displacement; if the instantaneous downward pressure is less than the preset bubble pressure target, the servo motor 201 is controlled to drive the main slider 205 to continue pressing down; if the instantaneous downward pressure is greater than or equal to the preset bubble pressure target, the servo motor 201 is controlled to stop pressing down and enter the pressure holding stage. S5: During the pressure holding stage, the servo motor 201 is controlled to maintain its current position, and the pressure is maintained by the compressed air that expands inside the low-friction cylinder 301. The paper box forming bubble pressing method is applied to the aforementioned paper box forming bubble pressing device; in step S1, compressed air with a preset initial pressure is introduced into the low friction cylinder 301 and the air passage is closed, so that the low friction cylinder 301 forms a sealed air chamber; at this time, the piston rod 303 is in the initial extended state under the action of the air chamber pressure, and the relative displacement of the reading head 501 and the scale 502 is set to the initial zero value. In step S2, the servo motor 201 drives the ball screw 203 to move the main slider 205 toward the paper box. Since the pressure plate base 304 has not yet contacted the paper box, the low-friction cylinder 301 is not subjected to external compression resistance, and its piston rod 303 remains in an extended state supported by internal air pressure. Therefore, the output value of the displacement detection component 5 remains at the initial zero value. The preset speed adopts a setting method in which the speed of the approach stage is greater than the speed of the pressing stage, so as to achieve a smooth transition to the contact pressing state. In step S3, after the flexible contact plate 305 establishes contact with the surface of the cardboard box, the reaction force of the cardboard box is transmitted to the piston rod 303 through the pressure plate base 304 and the universal ball joint 401, causing the piston rod 303 to retract relative to the main slider 205. Since the output of the displacement detection component 5 changes from a stable zero value to a continuously increasing value before and after contact, the control program can identify this change as a sudden change in relative compression displacement and use it as the basis for contact determination. The control program uses the sudden change in relative compression displacement as the basis for contact determination to reduce the interference of transmission chain friction noise on the determination. In step S4, the control program reads the real-time compression displacement, calculates the current air chamber pressure by combining the initial volume and initial absolute air pressure of the low-friction cylinder 301, and then converts the pressure into the instantaneous downward pressure of the flexible contact plate 305 on the cardboard box; if the instantaneous downward pressure is lower than the preset bubble compression target pressure, the control program continuously outputs a downward displacement command to the servo motor 201, so that the main slider 205 continues to advance and increases the compression amount of the piston rod 303; if the instantaneous downward pressure reaches or exceeds the target pressure, the control program stops continuing to press down and keeps the main slider 205 in the corresponding position; In step S5, after entering the pressure holding stage, if the surface of the cardboard box experiences local height changes due to adhesive flow or material rebound, the universal ball joint 401 allows the pressure plate base 304 to tilt to a limited extent, and the compressed air inside the low-friction cylinder 301 adjusts its volume accordingly, thereby compensating for local gap changes. This method establishes contact recognition, pressure establishment, and posture adaptation on the same mechanical measurement link to achieve repeated execution in continuous bubble pressing cycles.

[0027] The specific process of the control program to calculate the instantaneous downpressure is as follows: Based on the preset isothermal compression model, the current volume is calculated according to the initial volume of the low-friction cylinder 301, the piston force area and the real-time compression displacement. Then, the current absolute pressure is calculated by combining the initial absolute pressure and the back pressure effect of the ambient standard atmospheric pressure is deducted to calculate the instantaneous downpressure. Among them, the initial volume of the low-friction cylinder 301 is used as a preset constant parameter in the calculation.

[0028] When the control program calculates the instantaneous downward pressure, it uses the initial volume of the low-friction cylinder 301, the initial absolute air pressure, the piston force-bearing area, and the compression displacement output by the displacement detection component 5 as input parameters. The initial volume of the low-friction cylinder 301 refers to the effective volume of the sealed air chamber when the piston rod 303 is in the initial extended state and the air passage is closed. This parameter is calibrated during the equipment debugging stage and stored in the control program as a preset constant parameter. The current compressed volume is obtained by subtracting the product of the piston force-bearing area and the real-time compression displacement from the initial volume; the control program divides the initial volume and the current volume and multiplies it by the initial absolute air pressure to obtain the current instantaneous pressure inside the air chamber; the control program then multiplies the current pressure by the piston force-bearing area to obtain the instantaneous downward pressure applied by the pressure plate base 304 to the surface of the cardboard box through the flexible contact plate 305. The calculation process derives the instantaneous downforce from the compression displacement data. Since the initial volume and piston force-bearing area are known structural quantities, the only real-time change is the compression displacement. The control program performs consistency judgment on the continuously sampled compression displacement data and updates the pressure calculation value only when the direction of displacement change matches the contact state within adjacent system cycles. With this implementation method, the instantaneous downforce is determined by both mechanical displacement and the state of the sealed air chamber, and the force results corresponding to the structural state can be continuously output during the bubble compression stage. The control program internally constructs an ideal gas isothermal compression model, which estimates the internal pressure change of the sealed gas cavity after it is compressed. The model receives the initial volume, initial absolute pressure and real-time compression displacement as input, and outputs the current pressure by calculating the reduction ratio of the volume. In this model, the absolute pressure of the sealed gas under the condition that the compression rate is lower than the preset rate threshold and the heat exchange rate is higher than the preset exchange rate threshold is inversely proportional to the volume. Based on the thermal conductivity of the cylinder barrel 302 of the low-friction cylinder 301 and the preset compression amount, the heat generated by the gas is dissipated, and the system adopts an isothermal compression model. At the same time, since the mechanical friction resistance of the low-friction cylinder 301 itself is lower than the preset resistance threshold, the product of the piston force area and the current pressure can be converted into an instantaneous downward pressure on the paper box, thereby establishing the correlation between mechanical displacement, gas state and compressive force. The data flow and interaction steps of the isothermal compression model include: the control program receives the digital signal fed back by the displacement detection component 5 in real time through the I / O interface, and parses it into real-time compression displacement. The control program's calculation module calls the initial volume stored in the internal registers. Initial absolute pressure and the piston's force-bearing area ; Current volume The calculation formula is: ; Current absolute pressure The calculation formula is: ; Immediate downforce The calculation formula is: ; in: This represents the current internal volume of the air chamber, in units of: ; The initial volume of the sealed air chamber of the low-friction cylinder, in units of: ; The piston force-bearing area of ​​a low-friction cylinder, unit: ; For real-time compression displacement, the unit is: ; The instantaneous absolute pressure inside the air chamber, in units of: ; The initial absolute pressure of the sealed air chamber of the low-friction cylinder, in units of: ; Standard atmosphere, unit: ; The instantaneous downward force output by the piston rod, in units of: Once the calculation is complete, the control program will immediately apply downward pressure. The data is written to shared memory in floating-point form for use in the displacement feedback control stage.

[0029] During continuous production, the control program records the position coordinates of the servo motor 201 each time the preset bubble-pressing target pressure is reached. If the position coordinates gradually move downwards with the increase of the number of bubble-pressing cycles, the control program extracts the downward movement and automatically increases the initial target stroke of the servo motor 201 in the next bubble-pressing cycle. If the position coordinates do not gradually move downwards, the control program keeps the initial target stroke unchanged.

[0030] In continuous production, the control program records the position coordinates of the servo motor 201 when the preset target pressure is reached in each foaming cycle; the position coordinates can be obtained from the coded feedback value of the servo motor 201 and stored in correspondence with the compression displacement and calculated pressure results for that cycle; the control program performs trend analysis on the recorded results of multiple consecutive foaming work cycles. If, under the condition that the paper box specifications, target pressure, and initial air pressure remain unchanged, the position coordinate of the servo motor 201 corresponding to the same target pressure continues to shift in the downward pressing direction, it indicates that the transmission clearance or wear in the drive structure 2 has accumulated. The main slider 205 needs to move its stroke after the compensation amount so that the low-friction cylinder 301 can obtain the same compression amount. The control program extracts the position downward shift amount accordingly and converts the position downward shift amount into the initial target stroke compensation amount in the next bubble compression cycle. In this embodiment, the position coordinates gradually shift downwards as the number of bubble pressing cycles increases. This means that within a preset continuous statistical batch, the position coordinates of the servo motor 201 at each time the preset bubble pressing target pressure is reached are offset downwards relative to the position coordinates of the reference batch, and this offset exceeds the allowable range of position sampling fluctuation. The position coordinates of the reference batch are selected as one or more average position coordinates when the equipment has been debugged and the transmission is in normal condition. The allowable range of position sampling fluctuations is used to filter out normal discreteness of paper box thickness, random fluctuations caused by encoder sampling errors and short-term vibrations; the trend judgment process of the control program includes: firstly, collecting the position coordinates corresponding to the time when the target pressure is reached in multiple consecutive bubble pressing cycles; then, eliminating abnormal points that deviate from the preset fluctuation range; and then comparing the difference between adjacent coordinates and their cumulative offset direction relative to the reference coordinates in the order of the number of bubble pressing cycles. When multiple consecutive valid batches show a downward offset and the cumulative offset exceeds the allowable range of position sampling fluctuation, the state is judged as a gradual downward trend; if the offset direction alternates between positive and negative, the cumulative offset does not exceed the allowable range of position sampling fluctuation, or only a few batches show downward shift, it is judged as not showing a gradual downward trend. The initial target stroke refers to the preset pressing feed reference of the servo motor 201 before the contact determination occurs; the control program increases this reference by the extracted position downward displacement in the subsequent bubble pressing cycle, so that the main slider 205 can restore the cylinder effective compression range in the initial setting state when it approaches the paper box and establishes compression. If the continuously recorded results do not show a stable downward trend, the control program does not change the initial target stroke to avoid redundant compensation for normal fluctuation data. This implementation method converts the gradual error caused by transmission wear into a recordable, identifiable, and compensable position parameter, reducing the insufficient pressure and decreased uniformity of pressing caused by the increase in return clearance after long-term operation. The control program is internally configured with a transmission wear trend extraction model. This model is used to identify unidirectional cumulative errors caused by mechanical wear in production data containing fluctuations. The model includes a data filtering module and a trend determination module. The data filtering module receives the position coordinates at each time the target pressure is reached, and outputs a smoothed effective coordinate sequence by removing outliers and filtering out random noise within the allowable range of position sampling fluctuations. The trend determination module receives the effective coordinate sequence, calculates the coordinate difference between adjacent batches and performs directional accumulation. When the cumulative offset reaches a set threshold, it outputs the determination result of a gradually downward trend and the corresponding downward position displacement. This model reflects the unidirectional expansion characteristics of tooth flank clearance and contact surface wear in the mechanical transmission system as the number of working cycles increases. Mechanical wear of the ball screw 203 and coupling under reciprocating force will cause the feed of the main slider 205 to lag behind the theoretical command value of the servo motor 201; the control program extracts the position downward displacement of the model output by the transmission wear trend and increases the initial target stroke to eliminate the influence of cumulative error on the instantaneous downward pressure; The data processing and flow steps of the transmission wear trend extraction model include: In the data filtering module, the control program first calculates the moving average and standard deviation of the position coordinates of N consecutive batches, and judges the coordinates that deviate from the moving average by more than 3 times the standard deviation as outliers and removes them; then, a first-order low-pass digital filtering algorithm is applied to process the remaining data to attenuate high-frequency random position sampling fluctuations and output a smoothed effective coordinate sequence; In the trend determination module, the control program sets a cumulative offset register with an initial value of zero. For adjacent batches in the valid coordinate sequence, the coordinate difference between the next batch and the previous batch is calculated. If the direction of the difference is downward, the absolute value of the difference is accumulated in the register. If the direction is opposite, the absolute value is subtracted from the register. When the value in the register exceeds the preset wear judgment threshold and the number of consecutive downward pressure difference values ​​reaches the set count limit, the system outputs a gradually downward trend signal and feeds back the current value of the register as the position downward displacement to the stroke control module of the servo motor 201 through the internal bus.

[0031] The control program monitors the contact time in real time. If the contact time is earlier than the preset time window, the control program triggers the servo motor 201 to reverse and lift the main slider 205, and opens the exhaust valve 306 of the low-friction cylinder 301 to release the internal air pressure. If the contact time is at or later than the preset time window, the control program continues to execute the subsequent bubble control steps.

[0032] The control program monitors the contact determination result output by the displacement detection component 5 in each bubble pressing cycle and compares the system cycle position corresponding to the contact occurrence with the preset window. The preset window is set according to the feeding cycle of the carton conveying mechanism, the approach speed of the main slider 205 and the normal contact range, and is used to characterize the cycle range in which the flexible contact plate 305 should establish contact when the carton is in the predetermined position. If the contact determination result is earlier than the preset window, it is determined that the flexible contact plate 305 touches the edge or protrusion of the paper box in a non-predetermined state. If the pressure continues to be applied, it will cause damage to the paper box or interference with the mold. The control program outputs a reverse displacement command accordingly, so that the servo motor 201 drives the main slider 205 to lift away from the paper box, and at the same time controls the exhaust valve 306 to open, releasing the air pressure inside the low friction cylinder 301. Among them, the contact time is the system time point or corresponding control cycle number when the output value of the displacement detection component 5 changes from the initial zero value to a continuously changing state and meets the contact judgment condition; the preset time window is the timing judgment interval used to determine whether the incoming material is in place within the predetermined cycle time. Its starting boundary corresponds to the time point when the main slider 205 runs to the earliest normal allowable contact area according to the current approach speed, and its ending boundary corresponds to the time point when the main slider 205 runs to the latest normal allowable contact area. The process for determining the preset time window includes: first, under the conditions of fixed paper box specifications, conveying cycle time, and main slider 205 approach speed, recording the time points of contact judgment in multiple normal bubble pressing cycles; then, taking the earliest and latest contact times of multiple normal bubble pressing cycles as the statistical basis; then, adding the reserved safety time amount to form the start boundary and end boundary of the preset window respectively, and storing the window in the control program; the control program takes the system cycles output by the displacement detection component 5 for a continuous preset number of times exceeding the minimum change amount of contact recognition as the contact establishment condition, so as to filter out the misjudgment interference caused by single noise; The minimum change in contact identification is used to filter out random displacement fluctuations caused by mechanical vibration, micro-oscillation of scale 502 installation, and zero-point drift. If the contact time is earlier than the preset time window, the control program judges the state as an early material interference signal and immediately enters the lifting and depressurization joint protection step. If the contact time is within the preset time window, or although it is later than the starting boundary but still meets the subsequent bubble compression sequence allowed by the equipment, the control program continues to execute the subsequent bubble compression control steps. The servo motor 201 reverses and lifts, and the exhaust valve 306 releases the internal air pressure to form a dual unloading path; the main slider 205 lifts to release the overall feed amount applied by the drive structure 2, and the low-friction cylinder 301 releases pressure to release the elastic compression energy stored in the pressing assembly 3; after the two actions are performed simultaneously, the load on the paper box by the pressure plate base 304 is reduced, and the device returns to the preset initial waiting position. If the contact determination result is within or later than the preset window, the control program determines that the incoming material position meets the conditions for continuing to press the bubble, and maintains the subsequent displacement feedback control and pressure holding steps; this implementation method enables the incoming material abnormality to be identified in a timely manner by the set displacement detection component 5, and completes the executable protection process through the coordinated action of the drive structure 2 and the pneumatic structure. The control program is internally configured with a time-sequence anti-interference monitoring model. This model is used to determine in real time whether the position of the incoming paper box conforms to the preset position under the preset production cycle to avoid mechanical interference. The model divides the time axis into an early interference zone, a normal contact zone, and a missing / lagging zone, and receives the real-time compression displacement output by the displacement detection component 5 as a trigger signal. It extracts the system time point at the moment of trigger and compares it with the boundary of the preset window to establish the spatiotemporal coordination relationship between the paper box conveying cycle and the feed motion of the main slider 205. The cardboard box has a preset arrival time and the main slider 205 is pressed down at a preset speed. The preset contact time occurs within the preset time window. If the contact time output by the displacement detection component 5 is earlier than the preset time window, the control program determines that the material position is abnormal and outputs an interference alarm signal to trigger the servo motor 201 to reverse and lift and the exhaust valve 306 to release pressure. The data interaction steps within the control program include: when the system starts, the control program reads the paper box conveying cycle parameters and the pressing speed of the main slider 205 from the host computer, and calculates the theoretical time point for normal contact by combining the pre-calibrated reference contact distance; the control program extends the theoretical time point by a compensation constant before and after it, generates the start boundary timestamp and end boundary timestamp of the preset time window, and stores them in the timing monitoring register. During the compression process, the control program polls the relative compression displacement data of the displacement detection component 5 at a fixed sampling period. When the displacement increment is greater than the minimum change for contact recognition for three consecutive sampling periods, the internal clock of the current system control cycle is locked as the timestamp of the contact moment. The control program executes a comparison instruction: if the timestamp of the contact moment is less than the starting boundary timestamp, an external interrupt is triggered, and the servo inversion drive function and the exhaust valve 306I / O set instruction are immediately called; if it is within the window or greater than the termination boundary timestamp, the program pointer jumps to the normal displacement feedback control subroutine.

[0033] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A paper box forming and bubble pressing device, characterized in that, include: Main frame (1), drive structure (2), pressing assembly (3), floating guide mechanism (4) and displacement detection assembly (5); The drive structure (2) includes a servo motor (201), a plum blossom-shaped flexible coupling (202), a ball screw (203), and a main slider (205). The servo motor (201) is fixedly connected to the top of the main frame (1). The output shaft of the servo motor (201) is connected to the input end of the ball screw (203) through the plum blossom-shaped flexible coupling (202). The screw nut (204) of the ball screw (203) is fixedly connected to the back of the main slider (205). The two sides of the main slider (205) are slidably connected to the main frame (1). The pressing assembly (3) includes a low-friction cylinder (301), a pressure plate base (304), and a flexible contact plate (305). The cylinder barrel (302) of the low-friction cylinder (301) is fixedly connected to the bottom flange surface of the main slider (205). The piston rod (303) of the low-friction cylinder (301) extends vertically downward. The flexible contact plate (305) is fixedly connected to the bottom surface of the pressure plate base (304). The floating guide mechanism (4) includes a universal ball joint (401), a guide shaft (404), and a helical spring (405). The ball head (402) of the universal ball joint (401) is threaded to the end of the piston rod (303). The ball seat (403) of the universal ball joint (401) is fixedly connected to the center of the top surface of the pressure plate base (304). The guide shaft (404) is connected between the bottom surface of the main slider (205) and the top surface of the pressure plate base (304). The helical spring (405) is sleeved on the outside of the guide shaft (404). The displacement detection component (5) includes a reading head (501) and a scale (502). The reading head (501) is fixedly connected to the front side of the main slider (205), and the scale (502) is fixedly connected to the front side of the pressure plate base (304) through a bracket (503). The reading head (501) and the scale (502) are used to measure the extension and retraction displacement of the piston rod (303).

2. The paper box forming and blister pressing device according to claim 1, characterized in that, The flexible contact plate (305) is made of polyurethane material; The thickness of the flexible contact plate (305) is set to a value that allows for elastic buffer deformation and the deformation is less than the upper limit of the effective compression displacement of the piston rod (303).

3. The paper box forming and blister pressing device according to claim 1, characterized in that, The ball screw (203) is supported on the main frame (1) at both ends by angular contact ball bearings (206); The main slider (205) is slidably connected to the main frame (1) on both sides by linear guide rails (207); The output shaft of the servo motor (201) is directly connected to the input end of the ball screw (203) through the plum blossom-shaped flexible coupling (202); The drive structure (2) does not contain any deceleration or acceleration structure.

4. The paper box forming and blister pressing device according to claim 1, characterized in that, The pressure plate base (304) is connected to the guide optical shaft (404) at each corner, and the upper end of the guide optical shaft (404) slides through the main slider (205) via a linear bearing (406). The two ends of the helical spring (405) abut against the bottom surface of the main slider (205) and the top surface of the pressure plate base (304), respectively.

5. The paper box forming and blister pressing device according to claim 1, characterized in that, The low-friction cylinder (301) is equipped with an exhaust valve (306). The low-friction cylinder (301) is filled with compressed air at a preset initial pressure and the air passage is closed to form a sealed air chamber.

6. A method for bubbling and pressing paper boxes, applied to the paper box forming and bubbling apparatus as described in any one of claims 1-5, characterized in that, Includes the following steps: S1: Compressed air with a preset initial pressure is introduced into the low friction cylinder (301), and then the air passage is closed to make the low friction cylinder (301) a sealed air chamber. S2: The servo motor (201) drives the main slider (205) to move downward at a preset speed. The low-friction cylinder (301) maintains its maximum extension state under the action of internal air pressure. The extension displacement measured by the reading head (501) and the scale (502) remains at the initial zero value. S3: When the flexible contact plate (305) contacts the surface of the paper box to be pressed, the reaction force of the paper box to be pressed forces the piston rod (303) to retract upward relative to the main slider (205) to generate a sudden change in telescopic displacement. The control program set by the system controls the servo motor (201) to stop moving downward at a preset speed according to the sudden change in telescopic displacement, and enters the displacement feedback control stage. S4: In the displacement feedback control stage, the control program calculates the instantaneous downward pressure based on the real-time measured expansion and contraction displacement; if the instantaneous downward pressure is less than the preset target pressure of the pressure bubble, the servo motor (201) is controlled to drive the main slider (205) to continue pressing down; If the instantaneous downward pressure is greater than or equal to the preset target pressure of the bubble, then the servo motor (201) is controlled to stop pressing and enter the pressure holding stage; S5: During the pressure holding phase, the servo motor (201) is controlled to maintain its current position, and the pressure is maintained by the compressed air that expands inside the low-friction cylinder (301).

7. The paper box forming and blistering method according to claim 6, characterized in that, During continuous production, the control program records the position coordinates of the servo motor (201) each time the preset bubble-pressing target pressure is reached; if the position coordinates gradually shift downwards with the increase of the number of bubble-pressing work cycles, the control program extracts the downward shift and automatically increases the initial target stroke of the servo motor (201) in the next bubble-pressing cycle; if the position coordinates do not gradually shift downwards, the control program keeps the initial target stroke unchanged.

8. A method for forming and bubbling paper boxes according to claim 6, characterized in that, The control program monitors the contact time in real time. If the contact time is earlier than the preset time window, the control program triggers the servo motor (201) to reverse and lift the main slider (205), and opens the exhaust valve (306) of the low friction cylinder (301) to release the internal air pressure. If the contact time is at or later than the preset time window, the control program continues to execute the subsequent bubble control steps.

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