Foil Application and Laser Cutting for Security Sheets
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Solution Overview
Problem
Existing methods for applying foil material onto successive sheets, such as those used in security document production, face challenges in precision, complexity, and suitability for various sizes, particularly in cutting and evacuating waste portions, especially when using laser cutting.
Innovation Solution
A method and installation that involves applying a continuous band of foil material onto sheets, cutting it using a laser beam to separate individual sheets, and using a waste handling unit with aspiration to seize and hold waste portions before cutting, ensuring precise application and efficient evacuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser cutting is used to cut the continuous band of foil material, then cutting precision and efficiency are improved, but waste portions of foil material are generated and require effective evacuation
Solution Approach 1:
The patent extracts and removes waste portions of foil material from the continuous band during the laser cutting process. A waste handling unit with aspiration system is integrated into the installation to suction and evacuate the cut waste foil material, separating it from the continuous production stream and preventing it from interfering with downstream processes.
Solution Approach 2:
The patent introduces an intermediary waste handling unit between the laser cutting unit and the downstream processing areas. This intermediary system includes aspiration nozzles and collection containers that intercept and manage waste foil material, acting as a buffer to prevent waste from affecting the precision of subsequent operations.
2Ease of operation
If the foil material application process is simplified, then ease of operation is improved, but precision of application may be compromised
Solution Approach 1:
The patent merges multiple functions into a single integrated installation: the foil material application unit, the laser cutting unit, and the waste handling unit operate as one coordinated system. This integration allows the process to remain simple and automated while maintaining precision through synchronized operation of all components.
Solution Approach 2:
The patent replaces complex mechanical cutting and waste removal systems with a laser-based system. The laser cutting unit provides precise cutting without mechanical contact, and the aspiration system replaces mechanical waste removal mechanisms, simplifying the overall process while enhancing precision through non-contact, programmable control.
3Manufacturing precision
If a specifically-designed aspiration system is used to transport foil strips, then precision of positioning is improved, but device complexity increases
Solution Approach 1:
The patent designs the aspiration system to serve multiple functions: it handles waste foil material evacuation, assists in positioning the continuous band during cutting, and manages the cutting zone environment. This multi-functionality reduces the need for separate specialized systems, thereby limiting the increase in device complexity while maintaining positioning 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 enables precise and efficient application of foil material without disrupting downstream processes, allows for various sizes of foil material application, and effectively manages waste evacuation, improving upon previous methods by simplifying the process and enhancing precision and adaptability.
Implementation Method 1
the said at least one continuous band of foil material is cut by means of a laser beam such that the continuous flow of sheets is again separated into individual sheets
Implementation Method 2
waste portions of said at least one continuous band of foil material that are not to remain on the sheets are evacuated by seizing the waste portions prior to cutting by the laser beam and are held throughout the cutting process
Data Source
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AI summary
There is described a method for applying foil material (200) onto successive sheets (S), especially sheets for the production of securities, such as banknotes. In a first step, individual sheets (S) are transported in succession along a sheet transport path. In a second step, at least one continuous band of foil material (200) is applied onto the individual sheets (S) along a direction substantially parallel to a direction of displacement (A) of the individual sheets, thereby forming a continuous flow of sheets linked to one another by the said at least one continuous band of foil material (200). In a third step, the said at least one continuous band of foil material (200) is cut by means of a laser beam (L) such that the continuous flow of sheets is again separated into individual sheets (S) with portions of foil material (200*) remaining on the sheet. The cutting is performed at positions located on the sheets (S) such that said portions of foil material (200*) remaining on the sheets do not extend beyond leading and trailing edges of the sheets (S). Waste portions (205) of said at least one continuous band of foil material (200) that are not to remain on the sheets (S) are seized prior to cutting by the laser beam (L) and are held throughout the cutting process. There is also described an installation for carrying out the above method.