Dual angle paper tube cutting blade

Abstract

The utility model provides a double angle paper tube cutting blade, blade mouth part is divided into blade mouth front end and blade mouth rear end, blade mouth front end and blade mouth rear end adopt different angle design, make the cutting edge break through the paper tube surface fast simultaneously still can restrain paper tube fibre to both sides extension, to offset the transverse tear force, thereby reduce the burr production in the paper tube cutting process, secondly, set up the micro tooth at the blade mouth front end, make the blade mouth front end present as fine sawtooth shape on the whole, the design of micro tooth blade fixes the paper tube fibre through "multiple point occlusion" mode, avoids producing the slide tear, thereby further reduces the burr production in the paper tube cutting process.

Description

Technical Field

[0001] This utility model relates to the field of paper tube cutting, and in particular to a double-angle paper tube cutting blade. Background Technology

[0002] The core purpose of paper tube cutting blades is to precisely and efficiently cut paper tubes (including hollow paper tubes, solid paper columns, composite paper tubes, etc.) of various materials and specifications. Traditional single-angle circular blades leave a large number of burrs on the cut surface of the paper tube after cutting, which is extremely detrimental to subsequent processing. Summary of the Invention

[0003] To address the above problems, this utility model provides a dual-angle paper tube cutting blade.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: The dual-angle paper tube cutting blade is a ring-shaped blade with a cutting edge divided into a front end and a rear end. The front end is located in front of the rear end and the front and rear ends are an integrated structure. The angle range of the front end is 15°-20°, and the angle range of the rear end is 35°-45°.

[0005] Furthermore, several notches are evenly cut away along the outer circumference of the cutting edge, so that several protruding micro-teeth are evenly distributed at intervals at the cutting edge.

[0006] Furthermore, the notch (4) is V-shaped.

[0007] Compared with the prior art, the beneficial effects of this utility model are as follows: The dual-angle paper tube cutting blade of this utility model adopts different angle designs for the front end and the rear end of the cutting edge, so that the front end of the cutting edge can quickly break through the surface of the paper tube, and the rear end of the cutting edge can offset the lateral tearing force, so that the paper tube fibers are concentrated in force during the "cutting-cutting" process, reducing lateral displacement and thus reducing the generation of burrs during the paper tube cutting process. At the same time, micro-tooth is set at the front end of the cutting edge, so that the front end of the cutting edge presents a fine serrated shape. The design of the micro-tooth blade fixes the paper tube fibers through "multi-point biting" to avoid sliding tearing, thereby further reducing the generation of burrs during the paper tube cutting process. Attached Figure Description

[0008] Figure 1 This is a three-dimensional schematic diagram of the dual-angle paper tube cutting blade of this utility model; Figure 2 This is a cross-sectional schematic diagram of the dual-angle paper tube cutting blade of this utility model; Figure 3 This is a schematic diagram of the front end of the cutting edge of the dual-angle paper tube cutting blade of this utility model; Figure 4This is a schematic diagram of the main cutting angle 5 and the secondary support angle 6 of the dual-angle paper tube cutting blade of this utility model.

[0009] In the figure: 1. Cutting edge front end; 2. Cutting edge rear end; 3. Micro tooth; 4. Notch; 5. Main cutting angle; 6. Secondary support angle. Detailed Implementation

[0010] To provide a better understanding of the purpose, structure, features, and functions of this utility model, detailed descriptions are provided below with reference to specific embodiments.

[0011] Please refer to the reference. Figure 1 , Figure 2 , Figure 3 and Figure 4 The dual-angle paper tube cutting blade of this utility model is annular, and its cutting edge includes a cutting edge front end 1 and a cutting edge rear end 2. The cutting edge front end 1 is located in front of the cutting edge rear end 2, that is, the cutting edge front end 1 is on the outside and the cutting edge rear end 2 is on the inside. The cutting edge front end 1 and the cutting edge rear end 2 are an integral structure, which together constitute the cutting edge of the cutting blade.

[0012] like Figure 2 and Figure 4As shown, the angle presented by the cutting edge 1 is the main cutting angle 5, which ranges from 15° to 20°. This angle ensures the sharpness of the cutting edge 1, allowing the blade to quickly cut into the surface of the paper tube. The core function of the main cutting angle 5 is to pierce the surface of the paper tube with minimal resistance and initiate precise shearing, rather than squeezing or tearing the fibers. According to the pressure formula (pressure = force / area), the smaller the angle, the sharper the blade tip and the smaller the contact area with the paper tube. Under the same shear pressure, an acute angle of 15°-20° can generate much greater pressure than an obtuse angle, easily breaking through the "puncture resistance threshold" of the surface fiber and achieving "instant surface breaking". When the acute-angled blade cuts in, the "shear direction" of the fiber is closer to the fiber direction (rather than perpendicular compression), which can reduce the probability of the fiber being "crushed" or "dragged", directly severing the fiber connection point and avoiding subsequent burrs caused by the deformation of the surface fiber due to compression. The angle range of 15°-20° is the optimal range that balances "sharpness" and "blade durability". The core contradiction in choosing the main cutting angle is that "the smaller the angle, the sharper it is, but the easier it is to chip; the larger the angle, the stronger it is, but the lower the surface breaking efficiency". If the angle is less than 15°, the blade tip is too thin and the strength is greatly reduced. If the paper tube contains tiny impurities (such as pulp clumps or coated particles), the blade is easily "bumped" and tiny notches appear. At the same time, an overly sharp blade will cause "too deep and too fast cutting", which will cause deep fiber tearing due to concentrated shearing force. If the angle is greater than 20°, the blade tip becomes blunt, the contact area increases, and the pressure per unit area decreases. At this time, greater shearing pressure is required to pierce the surface layer, which will not only prolong the surface breaking time and reduce cutting efficiency, but also cause the surface fibers to extend and deform to both sides due to "compression", forming "surface burrs".

[0013] Furthermore, through "blade bending stress calculation" and "fiber deformation calculation," it is demonstrated that a main cutting angle of 5° (15°-20°) can simultaneously meet the core requirements of "no blade chipping" and "no fiber deformation (no burrs)," and is a feasible optimal range that aligns with industrial equipment parameters and material properties. Calculations are performed using high-speed steel blades and kraft paper tubes as examples. Blade parameters include: blade tip cross-sectional width (a) of 3mm, blade radius (ρ) of 0.02mm, and effective force-bearing length (L) of 1mm. Equipment and load parameters include: rated pressure of shearing equipment (Ftotal) of 80N, and maximum reaction force of impurities in the paper tube (Fimpurities) of 12N. Paper tube parameters include: fiber puncture resistance (σpuncture) of 20MPa, and allowable fiber deformation (Δallowable) of 0.05mm. Material performance parameters include: high-speed steel compressive strength (σsteel) of 500MPa. First, the main cutting angle 5° (… The corresponding blade strength is calculated, and the key formulas include: the section modulus (Z) of the blade tip. Where t is the thickness of the cutting edge tip, and is related to the main cutting angle 5 ( The relationship is ,in The thickness contributed to the fillet radius of the cutting edge, avoiding absolute sharpness, bending stress formula. Qualification requirements < Secondly, the fiber deformation is calculated, and the key formulas include: fiber deformation ( ) ,in The fiber deformation at 15° is approximately 0.03 mm (measured experimentally, less than Δ allowable). ( ) represents the contact area at a certain main cutting angle of 5°. ( For contact length, and cos Inversely proportional, the larger the angle, The longer), that is ( =0.3mm is the contact length at 15°). Based on the above formula and combined with actual production experiments, it is found that the optimal range for the main cutting angle 5 is 15°-20°, which can simultaneously meet the requirements of "no chipping" and "no burrs".

[0014] The angle presented by the rear end 2 of the cutting edge is the secondary support angle 6, with an angle range of 35°-45°. This angle provides shearing support force when the front end 1 of the cutting edge cuts the paper tube, while simultaneously constraining the paper tube fibers to extend to both sides. The secondary support angle 6 is an "auxiliary cutting edge angle" behind the main cutting angle 5. It does not participate in direct cutting but prevents the fibers from tearing to both sides through "force constraint," which is equivalent to adding a "stabilizer" to the shearing process. When the main cutting angle 5 cuts into the paper tube, it will generate forces in two directions on the fibers. One is the longitudinal force that pushes the cutting edge deeper into the paper tube to complete the cut, and the other is the component force that "pushes" the fibers to both sides due to the inclination of the cutting edge, i.e., the lateral tearing force. After the cutting edge of the secondary support angle 6 contacts the side of the paper tube, it will form an inclined support surface. According to the force decomposition, this support surface generates a component force perpendicular to the transverse tearing force, preventing the fibers from extending to both sides. At the same time, the contact between the support surface and the paper tube can fix the fibers in the cut area, so that the subsequent longitudinal shearing only acts on the fibers to be cut, rather than pulling the already positioned fibers, reducing tearing from the source. The angle of the secondary support angle 6 directly determines the effective component force of the support force and the frictional resistance between the cutting surface and the paper tube. If the angle is less than 35°, the inclination of the cutting surface of the secondary support angle 6 is too large (close to the main cutting angle 5), and the contact area between the support surface and the paper tube is too small. At this time, the generated "reverse support component force" is insufficient and cannot completely offset the transverse tearing force. The fibers will still extend slightly to both sides, resulting in "side burr residue". If the angle is greater than 45°, the cutting surface of the secondary support angle 6 is too gentle, and the contact area with the paper tube increases significantly. Although the support is sufficient, the "frictional resistance" will increase accordingly. During the shearing process, the support surface will slide against the paper tube surface, causing the surface fibers of the paper tube to be "dragged" and forming "friction burrs". At the same time, excessive friction will reduce the shearing speed and affect the processing efficiency.

[0015] Furthermore, the determination of the range of the secondary support angle 6 is based on two main mechanical conditions: "lateral support force balance" and "frictional resistance constraint." This range is then adjusted using actual industrial parameters and verified experimentally. The core logic is to ensure sufficient reverse force to counteract the lateral tearing force while avoiding excessive frictional resistance that could lead to fiber dragging or efficiency reduction. Calculations were performed using a high-speed steel blade and kraft paper tube as examples. The basic mechanical parameters included: lateral tearing force at the main cutting angle (Flateral) of 15N, and the friction coefficient between the blade and the paper tube (μ) of 0.3. Blade structural parameters included: effective contact length of the secondary support surface (lsupport) of 1.2mm, and blade width (a) of 3mm. Equipment and performance parameters included: maximum allowable frictional resistance (Ffriction) of 8N, and a support force safety factor (k) of 1.2. First, the lateral support component is calculated to determine the lower limit of the secondary support angle 6. The core function of the secondary support angle 6 is to generate a lateral reverse support component (F_lateral support) to counteract the lateral tearing force (F_lateral) brought by the main cutting angle 5, thus preventing the fibers from extending to both sides. This must meet the following requirements. Secondary support angle 6 ( The supporting force originates from the "normal pressure between the supporting surface and the paper tube (F method)", and the lateral supporting force (F lateral support) is calculated based on trigonometric function decomposition. And longitudinal component (F longitudinal support) The normal pressure (F-method) is related to the longitudinal pressure during the shearing process; in the simplified model, we take... ,Right now =40N, substituting the data into the formula yields... Calculated using the arcsine function The theoretical lower limit was found to be approximately 26.7°. However, in practice, slight deformation occurs on the support surface, and the paper tube wall thickness is uneven, requiring a further increase in angle to ensure support stability. Based on industrial experience and experimental verification, the theoretical lower limit of 26.7° was revised to 35°. The supporting force redundancy is sufficient to completely offset the lateral tearing force; then, the frictional resistance constraint is calculated to determine the upper limit of the angle. The larger the secondary support angle θ, the smoother the support surface, the larger the contact area with the paper tube, and the greater the frictional resistance (F_friction). If F_friction exceeds the allowable value, it will drag the surface fibers, producing burrs and reducing cutting efficiency. It must meet the following requirements. Actual measurement When the inclination of the support surface is 45°, the actual frictional resistance is moderate. No fiber drag; when At 50°, the support surface is too gentle; actual measurement... This results in short, frayed edges. Therefore, an upper limit of 45° is preferable.

[0016] Traditional single-angle cutting blades are prone to "wedging" into the paper tube during the cutting process, causing the fibers to tear to both sides and resulting in burrs on the cutting surface. Increasing the blade angle will lead to insufficient shearing force due to excessive angle. The dual-angle design allows the main cutting angle 5 to quickly break through the paper tube surface, while the secondary support angle 6 counteracts the lateral tearing force. This concentrates the force on the paper tube fibers during the "cut-in-cut" process, reducing lateral displacement and thus reducing the generation of burrs during paper tube cutting.

[0017] like Figure 1 and Figure 3 As described above, several notches 4 are evenly spaced along the outer circumference of the cutting edge 1. The notches 3 are "V" shaped, creating several evenly spaced protruding micro-teeth 3 on the cutting edge 1, giving the cutting edge 1 a fine serrated appearance. Traditional cutting blades are mostly flat or arc-shaped blades, which have a "line contact" with the paper tube. This can easily lead to incomplete cutting in some areas due to uneven paper tube wall thickness, resulting in burrs on the cut surface of the paper tube. The micro-teeth design fixes the paper tube fibers through "multi-point interlocking," avoiding sliding tearing and thus reducing the generation of burrs during the paper tube cutting process.

[0018] As described above, the dual-angle paper tube cutting blade of this utility model adopts different angle designs for the front end 1 and the rear end 2 of the cutting edge, so that the front end 1 of the cutting edge can quickly break through the surface of the paper tube, and the rear end 2 of the cutting edge can offset the lateral tearing force, so that the paper tube fibers are concentrated in force during the "cutting-cutting" process, reducing lateral displacement and thus reducing the generation of burrs during the paper tube cutting process. At the same time, micro-tooth 3 is set on the front end 1 of the cutting edge, so that the front end 1 of the cutting edge presents a fine serrated shape. The design of the micro-tooth blade fixes the paper tube fibers through "multi-point interlocking" to avoid sliding tearing, thereby further reducing the generation of burrs during the paper tube cutting process.

[0019] This utility model has been described by the above-described embodiments; however, these embodiments are merely examples for implementing this utility model. It must be noted that the disclosed embodiments do not limit the scope of this utility model. Conversely, any modifications and refinements made without departing from the spirit and scope of this utility model are within the scope of patent protection of this utility model.

Claims

1. A double-angle paper tube cutting blade, which is a ring-shaped blade, characterized in that: The blade edge is divided into a front edge (1) and a rear edge (2). The front edge (1) is located in front of the rear edge (2). The front edge (1) and the rear edge (2) are an integrated structure. The angle range of the front edge (1) is 15°-20°, and the angle range of the rear edge (2) is 35°-45°.

2. The dual-angle paper tube cutting blade as described in claim 1, characterized in that: Several notches (4) are cut off evenly at intervals along the outer circumference of the cutting edge (1) so that several protruding micro-teeth (3) are evenly distributed at intervals at the cutting edge (1).

3. The dual-angle paper tube cutting blade as described in claim 2, characterized in that: The notch (4) is V-shaped.

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