A multi-prism wobble curve punching device and method

Abstract

The application belongs to the technical field of laser drilling equipment, and particularly relates to a multi-prism deflection curve drilling device, which comprises a rack, a mobile pushing mechanism arranged on the rack, a drilling medium connected to the mobile pushing mechanism, a lens arranged above the drilling medium and close to the center, a multi-prism arranged above the lens, a laser arranged on the right side of the multi-prism, and the lens and the laser are fixedly connected with the rack, horizontal shafts are respectively connected to the front and back end surfaces of the multi-prism, the horizontal shafts are rotationally connected with the rack, a rotary driving mechanism is connected to the horizontal shafts, and the included angle between the side surface of the multi-prism and the axial direction of the horizontal shaft is 0°≤θ<90°. The device realizes the deflection of the focused light beam in the direction perpendicular to the movement direction of the drilling medium by controlling the included angle between each reflection surface of the multi-prism and the axial direction thereof, and the combination of the movement of the drilling medium and the regular deflection of the light beam can form the marks or hole distribution in a certain curve (fold line) distribution on the drilling medium.

Description

Technical Field

[0001] This invention belongs to the field of laser drilling equipment technology, specifically relating to a multi-prism deflection curve drilling device and method. Background Technology

[0002] In many cases, continuous marking or perforation is required on long media. For example, when making easy-tear strips at the opening of plastic packaging bags, a row of shallow engraved marks needs to be made at the opening. The strength of plastic with shallow engraving is much lower than that of normal plastic, making it easier to tear the plastic bag. Another example is on cigarette tipping paper, where long straight tear lines are often printed. In particular, perforations on cigarette tipping paper allow air to enter the filter rod through the perforated tipping paper. The mixing of fresh air and smoke can promote the synthesis of harmless carbon dioxide from carbon monoxide, while also lowering the temperature of harmful substances such as tar, making it easier for them to deposit on the filter rod, thereby reducing the harmfulness of cigarettes.

[0003] Marking and perforation on long, straight, continuous media can often be done using lasers. For example, shallow engraving at the opening of plastic packaging bags typically uses a pulsed laser beam to quickly vaporize the surface of the plastic without penetrating the bag. This ensures both the bag's seal and the easy-tear string. Perforation of cigarette tipping paper has gone through the development stages of mechanical perforation, electrical discharge machining (EDM) perforation, and laser perforation. Currently, it is generally believed that only laser perforation can meet the requirements for air permeability range and stability. Laser perforation of cigarette tipping paper has become a widely adopted basic technical solution internationally.

[0004] The aforementioned long, straight media are all basic consumer goods with very large production volumes, so the production efficiency requirements are very high. When performing laser processing, it is often necessary to adopt a mode in which the medium moves continuously while the beam is fixed. Since the distribution of the marks or holes is basically linear, the actual laser processing mode is basically the same: the pulsed laser is focused onto the surface of the long, straight medium, the long, straight medium moves continuously, and the laser pulse leaves linear marks or punches linear holes on the surface of the medium.

[0005] Since machining multiple straight lines on a long, straight surface often requires the simultaneous processing of multiple laser pulses, the most common method to avoid using multiple lasers simultaneously is to decompose a continuous laser beam into multiple pulsed laser beams using a rotating prism. A rotating prism is typically a multi-faceted cylindrical shape with multi-faceted plane mirrors on its surface. When a continuous laser beam strikes the rotating prism, the plane mirrors reflect the incident laser. Because the rotating reflected light from the prism scans repeatedly within a certain spatial angle, if multiple focusing mirrors are placed within the scanning area, a laser pulse will be generated when the scanning beam hits a particular focusing mirror. Since the prism's reflection scanning is repetitive, repeated pulses will be formed on this focusing mirror. The repetition frequency of the pulses depends on the scanning speed of the prism. Because scanning can target multiple focusing mirrors, a continuous laser beam can be decomposed into multiple pulsed laser beams by rotating a prism.

[0006] A perforation machine employing the principle of rotating prism scanning and beam splitting has been successfully developed (e.g., Chinese patent "Laser Perforation Machine for Tipping Paper" ZL200820147995.4). In this type of cigarette tipping paper laser perforation machine, the rotating prism scans the continuous laser beam repeatedly into N closely arranged focusing lenses, decomposing the continuous laser beam into N (4, 8, 16, 32) pulsed lasers. Each pulsed laser is focused onto the surface of the continuously moving cigarette tipping paper, creating a row of small ventilation holes on the moving tipping paper. The size and spacing of the ventilation holes are controlled by controlling the focusing and the scanning speed of the prism.

[0007] Most of the currently used tipping paper perforation technologies are linear perforations. Huazhong University of Science and Technology proposed a method to achieve patterned perforation (e.g., Chinese patent "Laser Perforation Equipment for Cigarette Tipping Paper" ZL200920083451.0), which envisions arranging different focusing heads in relative positions to achieve a simple patterned perforation distribution through a combination of multiple rows of perforations. However, after long-term testing, we found that since each perforation focusing head is independent, it is practically impossible to guarantee the relative relationship between them, making it difficult to achieve stable patterned perforation distribution. Wuhan Kairui Company also proposed a patent for patterned perforation distribution (Chinese patent "Laser Perforation Device for Patterned Perforation of Cigarette Tipping Paper" 201320044668.7), in which multiple laser beams are output through a single perforation head, avoiding the randomness and irrelevance between multiple perforation heads, but the technology is complex. Summary of the Invention

[0008] The purpose of this invention is to address the shortcomings of existing technologies by providing a multi-prism deflection curve drilling device and method. By controlling the angle between each reflecting surface of the multi-prism and its axial direction, the focused beam is deflected in a direction perpendicular to the movement of the drilling medium. The combination of the movement of the drilling medium and the regular deflection of the beam can form a certain curved (broken line) distribution of marks or holes on the drilling medium.

[0009] The objective of this invention is achieved as follows: a multi-prism deflection curve drilling device includes a frame, a movable pushing mechanism mounted on the frame, a drilling medium connected to the movable pushing mechanism, a lens positioned near the center of the drilling medium, a multi-prism positioned above the lens, a laser positioned to the right of the multi-prism, the lens and the laser being fixedly connected to the frame, horizontal axes connected to the front and rear end faces of the multi-prism, the horizontal axes being rotatably connected to the frame, a rotation drive mechanism connected to the horizontal axes, and the angle between the side face of the multi-prism and the axial direction of the horizontal axis being 0°≤θ<90°.

[0010] Furthermore, the mobile pushing mechanism includes a roll A and a roll B, with both ends of the perforated medium wound around roll A and roll B respectively, and a drive motor connected to roll B.

[0011] Furthermore, the laser beam output by the laser reaches the lens after being reflected by the sides of the prism. The lens focuses the pulsed laser onto the surface of the perforated medium. The perforated medium moves at a constant speed, thereby causing the laser pulse to create small hole marks with a curved distribution on the surface of the perforated medium. The small hole marks are composed of curved units connected in sequence, and each curved unit consists of n small holes. The number of sides of the prism is an integer multiple of n.

[0012] A method for drilling holes in a prism's deflection curve, characterized by comprising the following steps:

[0013] 1) The punching medium is installed on the moving push mechanism, which then drives the punching medium forward at a constant speed.

[0014] 2) Select a suitable prism based on the shape of the curved unit and the number of holes on the punching medium, and install it on the transparent upper part of the frame;

[0015] 3) The moving push mechanism drives the punching medium forward at a constant speed, while the rotating drive mechanism drives the prism to rotate continuously. The laser beam output by the laser reaches the lens after being reflected by the side of the prism. The lens focuses the pulsed laser onto the surface of the punching medium, thereby punching small holes with a curved distribution on the surface of the punching medium.

[0016] The beneficial effects of this invention are:

[0017] This invention controls the tilt angle of each reflective surface of a prism relative to its axial direction to achieve the deflection of the focused beam in a direction perpendicular to the movement of the perforated medium. The combination of the movement of the perforated medium and the regular deflection of the beam causes the laser pulse to form a certain curved (broken line) distribution of marks or holes on the surface of the perforated medium. The device has a simple structure, is easy to operate, and can achieve stable patterned perforation through this method. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a prism deflection curve drilling device of the present invention.

[0020] Figure 2 This is a schematic diagram of the prism structure used in Example 1 of the prism deflection curve drilling device of the present invention.

[0021] Figure 3 This is a schematic diagram of the main structure of the prism used in Embodiment 1 of the prism deflection curve drilling device of the present invention.

[0022] Figure 4 This is a diagram showing the drilling effect of a multi-prism deflection curve drilling device of the present invention in Example 1.

[0023] Figure 5 This is a schematic diagram of the working process of the prism deflection curve drilling device of the present invention in Embodiment 1.

[0024] Figure 6 This is a schematic diagram of the prism structure used in Embodiment 2 of the prism deflection curve drilling device of the present invention.

[0025] Figure 7 This is a schematic diagram of the main view of the quadrangular prism structure used in Embodiment 2 of the multi-prism deflection curve drilling device of the present invention.

[0026] Figure 8 This is a diagram showing the drilling effect of a multi-prism deflection curve drilling device of the present invention in Example 2.

[0027] Figure 9 This is a schematic diagram of the working process of the prism deflection curve drilling device of the present invention in Embodiment 2.

[0028] Explanation of reference numerals in the attached figures:

[0029] 1. Frame 2. Drilling medium 3. Prism 4. Lens 5. Laser 6. Horizontal axis 7. Roller A 8. Roller B 9. Surface A 10. Surface B 11. Surface C 12. Surface D 13. Small hole. Detailed Implementation

[0030] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0031] In the description of this invention, it should be understood that the terms "length", "width", "upper", "lower", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0033] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0035] like Figure 1As shown, a multi-prism deflection curve drilling device includes a frame 1, on which a moving pushing mechanism is provided. The moving pushing mechanism includes a roll A7 and a roll B8. The two ends of the drilling medium 2 are respectively wound around the roll A7 and the roll B8. A drive motor is connected to the roll B8. During operation, the drive motor drives the roll B8 to rotate continuously, thereby realizing the movement of the drilling medium 2 on the roll A7 from the roll A7 to the roll B8. A lens 4 is provided above the drilling medium 2 near the center position. Above the lens 4, multiple... A prism 3 has horizontal shafts 6 connected to its front and rear end faces, which are rotatably connected to the frame 1. A geared motor is connected to the horizontal shafts 6. A laser 5 is located on the right side of the prism 3. The lens 4 and the laser 5 are fixedly connected to the frame 1. A rotation drive mechanism is connected to the horizontal shafts 6, which are rotatably connected to the frame 1. The angle between the side of the prism 3 and the axial direction of the horizontal shaft is 0°≤θ<90°.

[0036] The laser beam output by laser 5 reaches lens 4 after being reflected by the side of prism 3. Lens 4 focuses the pulsed laser onto the surface of the perforated medium 2. The perforated medium 2 moves at a constant speed, so that the laser pulse punches small hole marks in a curved distribution on the surface of the perforated medium 2. The small hole marks are composed of curved units connected in sequence, and each curved unit is composed of n small holes 13. The number of sides of prism 3 is an integer multiple of n.

[0037] Because the perforating medium 2 moves continuously, the angles or tilt directions between different mirror surfaces of the prism 3 and its axial direction are different. Therefore, during the rotation of the prism 3, the reflected light on the prism 3 will be deflected in the direction perpendicular to the movement of the perforating medium 2, thereby achieving the purpose of zigzag (curved) perforation. Since one face of the prism 3 corresponds to one of the holes in a row, the position of each hole 13 can be controlled by controlling the angle of the reflecting surface of each prism 3. Thus, different prisms 3 can be designed as needed to meet the perforation requirements of different shaped hole distributions. This invention is compatible with current perforation technology and can achieve the purpose of curved (zigzag) distribution perforation without much modification.

[0038] The tilt angle of a prism depends on the drilling offset and the focal length of the focusing lens. If the required drilling offset is Δx and the focal length is f, then the tilt angle of the prism is Δθ = Δx / 2f. For example, if Δx = 0.5mm and the focal length is f = 50mm, then Δθ = 5mrad = 0.3°. Such a small tilt angle will not pose insurmountable difficulties for the processing of the prism.

[0039] Example 1

[0040] The prism uses, for example Figure 2 and Figure 3 The illustrated prism structure has surfaces A (9) and C (11) parallel to the prism's axis, and surfaces B (10) and D (12) parallel to each other with an angle greater than 0° and less than 90° between them and the prism's axis. Figure 5 (a), (b), (c), and (d) in the diagram represent the drilling diagrams at different positions of the prism when it is rotated to different prism faces. The laser output from the laser is reflected sequentially by faces A, B, C, and D of the prism before reaching the lens. The lens focuses the pulsed laser reflected from faces A (9), B (10), C (11), and D (12) onto the surface of the drilling medium 2. Because the drilling medium 2 moves at a constant speed, the laser pulse creates small hole marks on the surface of the drilling medium 2 in a curved (broken line) pattern. The small hole marks are composed of repeatedly connected curved (broken line) units, with each curved unit consisting of 4 small holes. The drilling effect is as follows: Figure 4 As shown.

[0041] Example 1

[0042] The prism uses, for example Figure 6 and Figure 7 The illustrated prism structure has faces A (9) and C (11) parallel to the prism's axis. Faces B (10) and D (12) have the same angle and tilt direction with respect to the prism's axis, with the angle between them greater than 0° and less than 90°. Faces C (11) and D (12) can be considered repetitions of faces A (9) and B (10). It is foreseeable that by maintaining different angles between adjacent faces of the prism, double-row drilling can be achieved. This angle can be adjusted and designed according to the required spacing between the two rows of holes. A tilt of approximately 0.6° is sufficient to achieve this. Figure 8 The pattern shown is to drill two rows of holes with a 1mm spacing between the two rows. There are many shapes of prisms that can achieve double-row drilling, but they all need to be arranged periodically with two adjacent different prism faces as the period, and the number of prism faces must be an integer multiple of 2.

[0043] Experiments show that for the production of easy-open tabs at the opening of plastic bags, two rows of shallowly engraved easy-open tabs that are closer together perform better than one row of shallowly engraved easy-open tabs.

[0044] Figure 9(a), (b), (c), and (d) in the diagram represent the drilling diagrams at different positions of the prism when it rotates to different prism faces. The laser output from laser 5 is reflected sequentially by prism face A 9, B 10, C 11, and D 12 before reaching the lens. The lens focuses the pulsed laser reflected from prism face A 9, B 10, C 11, and D 12 onto the surface of the drilling medium 2. Because the drilling medium 2 moves at a constant speed, the laser pulse creates small hole marks on the surface of the drilling medium 2 in a curved (broken line) distribution. The small hole marks are composed of repeatedly connected curved (broken line) units, and each curved unit consists of two small holes. Each rotation of the prism completes two cycles of double-row drilling. Figure 9 In the diagram, (a) and (b) represent one cycle, and (c) and (d) represent the next cycle. The punching effect is as follows: Figure 8 As shown.

[0045] The above are merely preferred embodiments of the present invention, and only specifically describe the technical principles of the present invention. These descriptions are only for explaining the principles of the present invention and should not be construed as limiting the scope of protection of the present invention in any way. Based on this explanation, any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention, as well as other specific embodiments of the present invention that can be conceived by those skilled in the art without creative effort, should be included within the scope of protection of the present invention.

Claims

1. A multi-prism deflection curve drilling device, comprising a frame, wherein a moving pushing mechanism is disposed on the frame, and a drilling medium is connected to the moving pushing mechanism, characterized in that: A lens is positioned near the center of the perforating medium. Above the lens is a prism, and to the right of the prism is a laser. The lens and laser are fixedly connected to the frame. Horizontal axes are connected to the front and rear end faces of the prism, and these axes are rotatably connected to the frame. A rotation drive mechanism is connected to the horizontal axes. The angle between the side face of the prism and the axial direction of the horizontal axis is 0°≤θ<90°. As the perforating medium moves continuously, the angles or tilt directions between different surfaces of the prism and its axial direction vary. The mobile pushing mechanism includes roll A and roll B. The two ends of the perforated medium are wound around roll A and roll B respectively. A drive motor is connected to roll B. The laser beam output by the laser reaches the lens after being reflected by the sides of the prism. The lens focuses the pulsed laser onto the surface of the perforated medium. The perforated medium moves at a constant speed, so that the laser pulse punches small hole marks in a curved distribution on the surface of the perforated medium. The small hole marks are composed of curved units connected in sequence, and each curved unit consists of n small holes. The number of sides of the prism is an integer multiple of n.

2. The drilling method of the multi-prism deflection curve drilling device as described in claim 1, characterized in that, Includes the following steps: 1) The punching medium is installed on the moving push mechanism, which then drives the punching medium forward at a constant speed. 2) Select a suitable prism based on the shape of the curved unit and the number of holes on the punching medium, and install it on the transparent upper part of the frame; 3) The moving push mechanism drives the punching medium forward at a constant speed, while the rotating drive mechanism drives the prism to rotate continuously. The laser beam output by the laser reaches the lens after being reflected by the side of the prism. The lens focuses the pulsed laser onto the surface of the punching medium, thereby punching small holes with a curved distribution on the surface of the punching medium.

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