Ultrasonic welding device

Abstract

The present invention discloses an ultrasonic welding device, including an ultrasonic vibration component, a pattern roller, a fine-tuning mechanism and a driving mechanism, wherein the fine-tuning mechanism is connected to the ultrasonic vibration component and can make a micro-adjustment to the gap between the welding head and the pattern roller, the ultrasonic vibration component and the fine-tuning mechanism together constitute a moving component, and the driving mechanism is connected to the moving component and is used to control the stroke between the welding head on the moving component and the pattern roller. The present invention adopts a scheme of combining a driving part with a piezoelectric driver to achieve large displacement and micro displacement adjustment of the welding head relative to the pattern roller, wherein the piezoelectric driver has a sub-micron position adjustment accuracy and a millimeter response time, which can make the adjustment of the welding force have high precision and high responsiveness, and the driving part can achieve large displacement movement of the welding head by presetting the welding force safety threshold, thereby realizing continuous ultrasonic welding production.

Description

Technical Field

[0001] The invention relates to the field of disposable sanitary products manufacturing, in particular to a device for ultrasonically processing a sheet-like object, wherein the sheet-like object is one of single-layer and multi-layer finished products or semi-finished products of sanitary products or similar consumables. Background Art

[0002] In the past, as a disposable sanitary product, for example, there is known a disposable sanitary product having a front abdomen, a back and a crotch, and the front abdomen and the back are ultrasonically welded through a pair of side sealing parts (or welding parts). When forming the side sealing parts, a method is adopted in which a thermoplastic sheet used to form the front abdomen and the back is continuously supplied to an anvil roller that can rotate around a specified axis, and an ultrasonic horn that cooperates with the anvil and is arranged to face the outer peripheral surface of the anvil roller. Each thermoplastic sheet is supplied between the anvil and the ultrasonic horn in a state facing each other, and the thermoplastic sheet continuously supplied between the anvil and the ultrasonic horn is ultrasonically welded intermittently in a period when the anvil approaches the ultrasonic horn. In this way, a welding part is formed in which the thermoplastic sheets facing each other are welded to each other.

[0003] Therefore, the ultrasonic horn and the anvil roller are required to be movable relative to each other. In addition, the gap between the ultrasonic horn and the anvil roller must be sufficient to allow the sheet to be introduced into the gap. In order to achieve the best welding effect, the ultrasonic horn is pressed onto the sheet with a predetermined welding force. For example, DE19753740 discloses a device having a pressure sensor for measuring the force applied by the sheet to the ultrasonic horn. Although the patent proposes the idea of ​​measuring the force by the pressure sensor and then adjusting the gap, the device has many problems such as complex installation of the pressure sensor, serious lag in force measurement, and inability to adjust the gap in real time according to the working conditions. Summary of the invention

[0004] In view of this, the present invention aims to provide an ultrasonic welding device to solve the problems of low welding force adjustment accuracy, insensitive response and inability to adapt to continuous welding production in existing devices.

[0005] The technical solution adopted by the present invention to solve the above technical problems is: an ultrasonic welding device, including an ultrasonic vibration component and a pattern roller arranged at intervals, and the sheet to be welded is transported between the welding head of the ultrasonic vibration component and the pattern roller to be welded to each other.

[0006] It also includes: a fine-tuning mechanism and a driving mechanism, wherein the fine-tuning mechanism is connected to the ultrasonic vibration component and can make a fine adjustment to the gap between the welding head and the pattern roller, the ultrasonic vibration component and the fine-tuning mechanism together constitute a moving component, and the driving mechanism is connected to the moving component to control the stroke between the welding head and the pattern roller on the moving component, and the stroke path is in the same direction or opposite to the path of the fine-tuning mechanism for fine-tuning the gap.

[0007] Furthermore, the driving mechanism comprises a base plate, a first slider connected to the moving assembly and capable of linear motion along the base plate, and a driving part, which can act on the first slider or directly on a component connected to the first slider. Preferably, the driving part is a cylinder or a motor.

[0008] Furthermore, the fine-tuning mechanism includes a support plate connected to the first slider, a second slider connected to the ultrasonic vibration component and capable of linear movement along the support plate, a piezoelectric driver arranged on one side of the support plate, and a pressure sensor coordinated with the piezoelectric driver; a spring is also arranged on the other side of the support plate.

[0009] When performing welding operation, the spring can press the ultrasonic vibration component against the end face of the piezoelectric driver through the pressure sensor, and the driving unit pushes the moving component to the preset position. Then, under the action of the piezoelectric driver, the ultrasonic vibration component approaches the pattern roller in the form of micro-displacement; in the process of the welding head approaching the pattern roller, the piezoelectric sensor detects the reaction welding force of the pattern roller on the ultrasonic vibration component and compares it with the preset welding force. According to the comparison result, the piezoelectric driver controls the ultrasonic vibration component to approach or move away from the pattern roller. The scheme of combining the driving unit with the piezoelectric driver is adopted to realize the large displacement and micro-displacement adjustment of the welding head relative to the pattern roller, wherein the piezoelectric driver has a sub-micron position adjustment accuracy and a millimeter response time, which can make the adjustment of the welding force have high precision and high responsiveness. The driving unit preferably uses a cylinder, and by presetting the welding force safety threshold, it can realize the large displacement movement of the welding head, thereby realizing the continuous welding production of ultrasonic waves.

[0010] In order to prevent the welding head from colliding with the pattern roller and thus protect the welding head, a limit block is provided on the substrate on the stroke of the moving component close to the pattern roller. When the first slider abuts against the limit block, the distance between the end face of the welding head and the surface of the pattern roller is 0.06-0.15mm.

[0011] Furthermore, the stroke range of the piezoelectric driver is 0.08-0.2 mm, and the maximum thrust range that can be output is 4000-8000 N. During the welding process, the piezoelectric driver generates displacement under the action of voltage. When encountering material joint welding interference, the driving voltage of the piezoelectric driver can be set to 0 volts, and the micro displacement generated at this time is zero.

[0012] Furthermore, the driving part is a cylinder, the stroke of the cylinder is 10-30 mm, and the output pressure of the cylinder during the welding process is 100-1500N.

[0013] Beneficial effects of the present invention:

[0014] 1. The piezoelectric driver is used to directly drive the ultrasonic vibration component without an intermediate transmission link, which can obtain higher micro-displacement response characteristics; at the same time, the sub-micron displacement control accuracy of the piezoelectric driver can make the control of the welding force more accurate.

[0015] 2. Large displacement and small displacement are controlled separately to facilitate operational adjustments during the welding preparation process.

[0016] 3. The driving part preferably uses a cylinder, and the maximum welding force is controlled by setting a pressure limit on the cylinder, which has the function of protecting the ultrasonic vibration system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0018] The present invention will be described below with reference to the accompanying drawings showing embodiments of the present invention.

[0019] Example

[0020] like Figure 1 As shown, an ultrasonic welding device is used to transport a sheet to be welded between a welding head of an ultrasonic vibration component and a pattern roller to weld them together, and includes: an ultrasonic vibration component 101, a pattern roller 102, a fine-tuning mechanism 103 and a driving mechanism 104.

[0021] The fine-tuning mechanism 103 is connected to the ultrasonic vibration component 101 and can make a slight adjustment to the gap between the welding head 1 and the pattern roller 102 . The ultrasonic vibration component 101 and the fine-tuning mechanism 103 together constitute a moving component.

[0022] The driving mechanism 104 is connected to the moving assembly and is used to control the large displacement stroke between the welding head 1 on the moving assembly and the pattern roller 102 .

[0023] A first matching portion 2 and a second matching portion 3 are fixed on both sides of the second sliding block 32 on the ultrasonic vibration assembly 101 .

[0024] The structures of the driving mechanism 104 and the fine-tuning mechanism 103 are further described below.

[0025] The driving mechanism 104 comprises a base plate 41 , a first sliding block 42 connected to the moving assembly and capable of linearly moving along the base plate, a cylinder 43 , and a stop block 44 .

[0026] The stroke of the cylinder 44 is 10-30 mm, and the output pressure of the cylinder during welding is 100-1500 N. The main shaft of the cylinder 44 acts on the support plate 31 connected to the first slider.

[0027] The limit block 44 is arranged on the base plate 41 and is located on the travel of the moving component close to the pattern roller. When the first slider abuts against the limit block, the distance between the end face of the welding head and the surface of the pattern roller is 0.06-0.15 mm.

[0028] The fine adjustment mechanism 103 comprises: a support plate 31 connected to the first slider, a second slider 32 connected to the ultrasonic vibration assembly and capable of linear motion along the support plate, a piezoelectric driver 33 disposed on one side of the support plate, and a pressure sensor 34 matched with the piezoelectric driver. A spring 35 is also disposed on the other side of the support plate. The stroke range of the piezoelectric driver 33 is 0.08-0.2 mm, and the maximum thrust range that can be output is 4000-8000 N.

[0029] A first mounting block 36 and a second mounting block 37 are fixed on both sides of the support plate 31, wherein the spring 35 is arranged between the first mounting block 36 and the first matching portion 2, the pressure sensor 34 is mounted on the second matching portion 3, and the piezoelectric driver 33 is mounted on the second mounting block 37. When performing the welding operation, the spring 35 can press the ultrasonic vibration component against the end surface of the piezoelectric driver 33 through the pressure sensor 34.

[0030] During operation, the cylinder pushes the moving assembly to the preset position and contacts the limit block. At this time, the distance between the end face of the welding head and the surface of the pattern roller is 0.06-0.15mm; then the welding head of the ultrasonic vibration assembly approaches the pattern roller in the form of micro-displacement under the action of the piezoelectric driver. In the process of the welding head approaching the pattern roller, the piezoelectric sensor detects the reaction welding force of the pattern roller on the ultrasonic vibration assembly and compares it with the preset welding force. According to the comparison result, the piezoelectric driver controls the welding head of the ultrasonic vibration assembly to approach or move away from the pattern roller. The above-mentioned piezoelectric driver has sub-micron position adjustment accuracy and millimeter-level response time, which can make the adjustment of welding force have high precision and high responsiveness. The cylinder can achieve large displacement movement of the welding head by setting the preset welding force safety threshold. The above-mentioned cylinder combined with the piezoelectric driver can realize large displacement and micro displacement adjustment of the welding head relative to the pattern roller, thereby achieving the purpose of ultrasonic continuous welding production.

[0031] What is described above and shown in the drawings are only preferred embodiments of the present invention, but the protection scope of the present invention is not limited thereto. For any ordinary technician familiar with the technical field, within the technical scope disclosed by the present invention, equivalent replacements or changes made according to the technical solutions and inventive concepts of the present invention should be covered by the protection scope of the present invention.

Claims

1. An ultrasonic welding device, used for conveying a sheet to be welded between a welding head of an ultrasonic vibration assembly and a pattern roller to weld each other, comprising an ultrasonic vibration assembly and a pattern roller, characterized in that: It also includes a fine-tuning mechanism and a driving mechanism, wherein the fine-tuning mechanism is connected to the ultrasonic vibration component and can make a fine adjustment to the gap between the welding head and the pattern roller, the ultrasonic vibration component and the fine-tuning mechanism together constitute a moving component, and the driving mechanism is connected to the moving component and is used to control the stroke between the welding head and the pattern roller on the moving component, and the stroke path is in the same direction or in the opposite direction to the path of the fine-tuning mechanism for fine-adjusting the gap; The driving mechanism comprises a base plate, a first slider connected to the moving component and capable of linear movement along the base plate, and a driving part; The fine-tuning mechanism includes a support plate connected to the first slider, a second slider connected to the ultrasonic vibration component and capable of linear motion along the support plate, a piezoelectric driver arranged on one side of the support plate, and a pressure sensor matched with the piezoelectric driver; a spring is also arranged on the other side of the support plate, and the spring can press the ultrasonic vibration component against the end surface of the piezoelectric driver through the pressure sensor; The stroke range of the piezoelectric driver is 0.08-0.2 mm, and the maximum thrust range that can be output is 4000-8000 N; When the welding head approaches the pattern roller, the piezoelectric sensor detects the reaction welding force of the pattern roller on the ultrasonic vibration component and compares it with the preset welding force. According to the comparison result, the piezoelectric driver controls the welding head of the ultrasonic vibration component to approach or move away from the pattern roller. The piezoelectric driver has sub-micron position adjustment accuracy and millimeter response time.

2. The ultrasonic welding device according to claim 1, characterized in that: A limit block is also provided on the base plate on the stroke of the moving component close to the pattern roller. When the first sliding block abuts against the limit block, the distance between the end face of the welding head and the surface of the pattern roller is 0.06-0.15mm.

3. The ultrasonic welding device according to claim 1, characterized in that: The driving part is a cylinder or a motor.

4. The ultrasonic welding device according to claim 3, characterized in that: The driving part is a cylinder, the stroke of the cylinder is 10-30 mm, and the output pressure of the cylinder during welding is 100-1500N.

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