Score Line Grooving for Warping-Free Plastic Blanks
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Solution Overview
Problem
Existing methods for forming score lines on plastic blanks for hinged-lid packages cause warping, leading to distorted packages that cannot be used for packaging items like cigarettes, as the score-lined surfaces stretch and bulge, resulting in poor-quality packaging.
Innovation Solution
A method of forming score lines on a blank by creating grooves on one side through plastic deformation, using a cutting device with parallel blades, which prevents warping by not applying tensile stress, allowing the blank to be folded into a package with rounded edges without distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If score lines are formed by pressing blades against the blank, then rounded edges can be formed, but the score-lined surface stretches and warps
Solution Approach 1:
Instead of pressing blades from the outer surface side to form score lines (which causes stretching), the patent inverts the approach by pressing blades from the inner surface side. This reverse direction prevents the score-lined surface from stretching and eliminates warping, while still achieving the desired rounded edges when the blank is folded.
2Shape
If score lines are formed on the blank, then rounded edges are achieved, but the package becomes distorted
Solution Approach 1:
The patent applies the inversion principle by forming score lines from the inner surface side rather than the outer surface side. This prevents the score-lined areas from storing excessive return power that would cause distortion, while still achieving properly formed rounded edges on the package.
3Shape
If conventional score line forming is used, then rounded edges can be created, but the blank cannot be steadily supplied to packaging machines
Solution Approach 1:
By inverting the score line forming direction to press from the inner surface side, the patent prevents warping of the blank. This maintains the blank's sheet shape and flatness, enabling it to be steadily supplied to packaging machines without disruption to production flow.
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
The method enables the production of packages with rounded edges that fit comfortably in the hand, preventing warping and distortion, thus ensuring a high-quality packaging solution for items like cigarettes, while maintaining the sheet shape of the blank for steady supply to packaging machines.
Implementation Method 1
the score lines are formed in a manner causing grooves to be produced on a back side of each score line forming area, along the score lines, through plastic deformation
Data Source
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AI summary
The present invention has a blank forming step of forming a sheet-shaped resin blank (3) able to be formed into a box by folding and bending, and a score line forming step of forming score lines (7) in score line forming areas (8) of the blank (3) which are to be bent to form outer edges of the box, to extend in the direction in which the outer edges should extend. In the score line forming step, the score lines (7) are formed in a manner causing grooves (9) to be produced on the back side of each score line forming area (8), along the score lines, through plastic deformation. The blank (3) therefore does not undergo tensile stress pulling on the blank (3) to either side of each groove (9), and thus, does not undergo warping as a whole. The blank (3) thus retains its sheet shape and can be steadily supplied to a packaging machine.