Rotary Die Cutter Snippet Removal via Guide Elements
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Solution Overview
Problem
In existing rotary punches, larger snippets often cover the smaller suction air opening, resulting in reduced suction power and holding force, making it difficult to safely transport and remove snippets.
Innovation Solution
A rotary punch design featuring a punch cylinder connected to a suction air source and a counter pressure cylinder with a cylinder elevator, incorporating a first guide element within the closed shape of the punch knife and a second guide element in the cylinder elevator, both designed as bridges or grooves to enhance air flow and snippet detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a small suction opening is used in the punching die, then the structure is compact and simple, but larger snippets completely cover the opening, reducing suction power and holding force
Solution Approach 1:
The patent introduces guide elements with channels that create a three-dimensional air path structure. Instead of a simple planar suction opening, the air flow is directed through vertically extending channels (first and second guide elements) that wrap around and contact the snippet from multiple directions, effectively increasing the functional suction area without increasing the planar footprint of the die.
Solution Approach 2:
The suction function is segmented into multiple independent air flow paths through the first guide element and second guide element. Each guide element contains its own channel that independently directs air to different portions of the snippet, allowing the total suction force to be the sum of multiple smaller air flows acting on different surfaces of the snippet.
2Area of stationary object
If suction air acts on a small portion of the chip surface, then the suction opening remains accessible, but the holding force is lower than necessary for secure retention
Solution Approach 1:
The guide elements extend vertically from the suction opening, creating a three-dimensional air delivery system. The channels in these guide elements direct air to contact the snippet at multiple elevation levels and from multiple angles, effectively increasing the surface area of the snippet that is exposed to suction force without blocking the suction opening itself.
3Reliability
If snippets are to be safely transported and removed, then sufficient holding force is needed, but the suction opening gets covered by larger snippets
Solution Approach 1:
The guide elements act as intermediary structures between the suction opening and the snippet. Instead of air flowing directly from the opening to the snippet surface, the guide elements with their internal channels serve as mediators that transport air around and along the snippet, ensuring comprehensive air contact even when the snippet completely covers the original suction opening location.
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 improved air flow and snippet detachment capabilities allow for effective removal of snippets from both the punch cylinder and the cylinder elevator, enhancing the holding force and ensuring safe transportation and processing of snippets.
Implementation Method 1
the punching cylinder is connected to a suction air source and preferably alternately to a blowing air source
Implementation Method 2
This can increase the suction force, as well as the holding force
Implementation Method 3
This can also improve the separation of the snippet from the printing material if blast air is used alternately instead of suction air
Data Source
Figure 1
Figure 2~3
Figure 4a~4c
AI summary
The invention relates to a rotary die cutter for cutting out a piece of material or a snippet from a substrate, e.g., paper, comprising: a die-cutting cylinder (3) and an associated counter-pressure cylinder (4), wherein the die-cutting cylinder is connected to a suction air source (7); a die-cutting form (9) arranged on the die-cutting cylinder with at least one die-cutting knife (10) which has a closed form (11) and a suction opening (12) within the closed form; a cylinder lift (13) arranged on the counter-pressure cylinder; at least one raised or recessed first guide element (14) for guiding suction air, which is arranged within the closed form and/or at least one recessed or raised second guide element (15) for guiding air, which is arranged in the cylinder lift.The invention enables the trouble-free removal of the snippet from the printing material, conveying of the snippet with the die-cutting cylinder and ejection of the snippet from the die-cutting form or the die-cutting knife.