Variable Speed Anvil Roll for Absorbent Sheet Cutting
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Solution Overview
Problem
The existing manufacturing processes for absorbent articles like disposable diapers face instability during cutting due to excessive tensile force caused by the difference between the conveying speed of the first continuous sheet and the rotation speeds of the receiving and cutter blades, leading to potential ripping of the sheet.
Innovation Solution
A method and apparatus where the first continuous sheet is cut and bonded to a second continuous sheet with a speed pattern that matches the conveying speed of the second sheet, ensuring the receiving and cutter blades' speeds are synchronized to reduce the tensile force applied during cutting, using separate motors for the holding and cutter rolls to maintain stability and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the rotation speeds of the receiving and cutter blades are increased to match the conveying speed of the second continuous sheet, then the transfer efficiency is improved, but the tensile force during cutting increases causing sheet ripping
Solution Approach 1:
The patent applies dynamics by making the rotation speeds of the receiving and cutter blades variable rather than constant. The speeds are dynamically adjusted based on the position in the rotation cycle: lower during the cutting phase (when blades pass the first predetermined position) to reduce tensile force on the first continuous sheet, and higher during the transfer phase (when blades pass the second predetermined position) to match the conveying speed of the second continuous sheet. This dynamic speed adjustment resolves the contradiction between transfer efficiency and cutting stability.
2Productivity
If the rotation speed of the anvil roll is increased to improve sheet conveying speed, then the production rate increases, but the speed difference with the cutter blade increases causing excessive tensile force
Solution Approach 1:
The anvil roll rotation speed is dynamically controlled to have a defined speed pattern that varies during the rotation cycle. The speed is lower when the receiving and cutter blades are at the cutting position (first predetermined position) to minimize speed difference and tensile force on the first continuous sheet. The speed increases when the blades are at the transfer position (second predetermined position) to enable efficient transfer to the second continuous sheet. This dynamic speed control resolves the contradiction between production rate and tensile force.
3Device complexity
If constant rotation speeds are used for simplicity of control, then the device complexity is reduced, but the cutting precision and transfer quality deteriorate due to speed mismatch
Solution Approach 1:
The patent implements dynamic speed control with a defined speed pattern for the anvil roll and synchronized variable speeds for the receiving and cutter blades. This allows the system to optimize both cutting quality (by reducing speed difference during cutting) and transfer quality (by matching speeds during transfer), while maintaining relatively simple control logic based on the rotation positions of the blades. The dynamic approach resolves the contradiction between device complexity and manufacturing precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances cutting stability by reducing the difference in speeds between the conveying sheet and the cutting blades, preventing sheet ripping and ensuring reliable cutting even with materials of poor ease-of-cutting, while maintaining smooth transfer and reducing adhesive attachment on the cutter blades.
Implementation Method 1
multiple suction holes (not shown) that suction and hold the first continuous sheet 3a are provided in an outer circumferential surface 21a' of the anvil roll 21'
Implementation Method 2
the first continuous sheet 3a becomes clamped between the receiving blade 23' and the cutter blade 33' of the cutter roll 31' , thus cutting the first continuous sheet 3a
Implementation Method 3
the cutform sheet 3 is bonded and transferred to the second continuous sheet 5a
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A composite body (1a) is manufactured by a process in which a first continuous sheet (3a) conveyed at a first speed value, which is lower than a second speed value, is held on an outer circumferential surface (21a) of a rotating holding roll (21) so as to slide upstream thereon, then when a receiving blade (23) of the roll (21) passes a first position (S31) in the rotation direction of the roll (21), the first continuous sheet (3a) is cut with the receiving blade (23) in conjunction with a cutter blade (33) of a cutter roll (31) that rotates in the same position (S31), thus producing a cutform sheet (3), and then when the sheet (3) held in a non-sliding manner on the surface (21a) passes a second position (S43), the sheet (3) is bonded and transferred to a second continuous sheet (5a) being conveyed at the second speed value. The number of receiving blades and the number of cutter blades are the same, and the arrangement pitches thereof in the rotation direction are also the same. The speed value of the receiving blade (23) when passing the second position (S43) is the same as the second speed value, and the speed value of the receiving blade (31) when passing the first position (S31) is lower than the speed value of the receiving blade (23) when passing the second position (S43).