Slotter Knife Speed Control for Carton Notch Groove Integrity
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Solution Overview
Problem
Existing slotter devices in box making machines generate cracks in the end portion of notch grooves due to speed differences between slotter knives and sheet transfer, complicating the structure with additional mechanisms for prevention.
Innovation Solution
A slotter device with a control system that synchronizes the circumferential speed of the slotter knife with the sheet transfer speed to prevent interference by the protrusion portion when it exits the sheet, using a drive device and control device to manage the relative speeds and phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the circumferential speeds of the slotter knives and the transfer speed of the sheet are matched, then the notch grooves are formed at appropriate positions, but the protrusion portions generate cracks in the end portions of the notch grooves due to speed difference
Solution Approach 1:
The patent applies dynamics by making the slotter knife's rotation speed variable rather than constant. The control device dynamically adjusts the rotation speed of the slotter knife during operation, specifically reducing it when the protrusion portion is about to exit the sheet and increasing it afterward. This dynamic speed adjustment prevents the protrusion portion from catching on the notch groove end while maintaining precise positioning capability.
Solution Approach 2:
The patent changes the operational parameters of the slotter knife by adjusting its rotation speed based on the position of the protrusion portion relative to the sheet. The control device monitors the phase relationship and modifies the circumferential speed parameter in real-time, reducing speed when the protrusion portion approaches exit from the sheet to prevent crack formation, then restoring normal speed for continued operation.
2Reliability
If a cutter is added in the creaser device to prevent cracks, then the notch groove integrity is improved, but the device structure becomes complicated
Solution Approach 1:
The patent applies self-service by making the slotter knife itself perform the dual function of cutting the notch groove and preventing cracks through its controlled motion. Instead of adding a separate cutter component, the control device enables the existing slotter knife to automatically adjust its speed based on the processing stage, allowing the protrusion portion to smoothly exit the sheet without causing damage, thus eliminating the need for additional preventive mechanisms.
Solution Approach 2:
The patent makes the slotter knife multi-functional by enabling it to perform both the primary cutting function and the secondary crack-prevention function through dynamic speed control. The same slotter knife that cuts the notch groove also prevents cracks by having its rotation speed adjusted during the protrusion portion's exit phase, eliminating the need for a separate dedicated cutter component.
Data Source
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AI summary
A slotter apparatus (30), comprising: a slotter knife (36) provided so as to rotate in the same direction as a conveyance direction (TD) of a sheet (10) that is conveyed on a conveyance path, the slotter knife (36) being such that a cutting edge for forming a notch groove (12) in the sheet (10) is provided to the outer periphery of the slotter knife (36); a protruding part (38) provided so as to protrude outward from the cutting edge at one end of the slotter knife (36), the protruding part cutting an end part (14) of the notch groove (12) by piercing the sheet (10); a drive device (60) that drives the slotter knife (36) so as to rotate; and a control device (70) that, at least when the protruding part (38) passes through from the upper surface of the sheet (10), controls the relative relationship between the circumferential velocity of the slotter knife (36) and the conveyance velocity (Vs) of the sheet so that the protruding part (38) does not interfere with the end part (14) of the notch groove (12).