Laser Machining Cylindrical Workpieces with Anti-Adhesive Spray
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Solution Overview
Problem
Existing methods for laser engraving cylindrical workpieces, such as printing or embossing cylinders, face challenges with debris adhesion due to centrifugal forces and high energy densities, leading to uneven ink retention and color deviations, as liquid anti-adhesive agents applied before processing are ineffective on rapidly rotating surfaces.
Innovation Solution
Applying a liquid anti-adhesive agent in a short time interval along the path of the laser beam on the rotating workpiece's peripheral surface, using a spray nozzle to ensure coverage just before processing, minimizing dwell time and preventing debris adhesion, with a preferred duration of less than 0.1 seconds and a spray pattern that precedes the laser beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a liquid anti-adhesive agent is applied to the entire surface of the workpiece before laser machining, then debris adhesion is prevented, but the liquid layer becomes thinner and thinner due to centrifugal forces on rapidly rotating cylindrical workpieces, making the method ineffective
Solution Approach 1:
The liquid anti-adhesive agent is applied to the workpiece surface in advance, shortly before the laser beam processing begins. This preliminary application ensures the surface is coated with the anti-adhesive agent before debris generation starts, allowing the liquid layer to be present when needed without being completely removed by centrifugal forces during prolonged rotation
Solution Approach 2:
The invention applies the liquid anti-adhesive agent specifically to areas where debris adhesion is most problematic, such as along the laser processing path and in cell regions, rather than uniformly coating the entire workpiece surface. This localized application optimizes the anti-adhesive effect where it is most needed while reducing overall liquid consumption and centrifugal removal
2Productivity
If high energy density laser beams are used for direct engraving of metal printing cylinders, then efficient material removal is achieved, but the liquid evaporates in a wide area around the laser path, leaving no liquid on adjacent processing tracks
Solution Approach 1:
The liquid anti-adhesive agent serves as an intermediary substance between the laser beam and the workpiece surface. It is applied in advance to create a protective layer that prevents debris adhesion, while its controlled distribution and rapid reapplication ensure coverage is maintained even as the laser beam evaporates surrounding liquid. The intermediary liquid layer is replenished faster than it is consumed by evaporation
Solution Approach 2:
The liquid anti-adhesive agent is applied periodically at intervals synchronized with the laser processing cycles and workpiece rotation. This periodic reapplication ensures that even though the high energy density laser evaporates liquid in the surrounding area, fresh liquid is continuously supplied to maintain coverage on adjacent processing tracks throughout the engraving process
3Productivity
If the workpiece rotates at high speed during laser engraving, then processing efficiency is improved, but centrifugal forces throw off the liquid anti-adhesive agent, preventing effective debris prevention
Solution Approach 1:
The liquid anti-adhesive agent is applied to the workpiece surface in advance, shortly before the laser beam processing begins. This preliminary application ensures the surface is coated with the anti-adhesive agent before debris generation starts, allowing the liquid layer to be present when needed without being completely removed by centrifugal forces during prolonged rotation
Solution Approach 2:
The application system is designed to dynamically adapt to the high-speed rotation of the workpiece. The liquid anti-adhesive agent is applied in a manner that accounts for the rotational speed and centrifugal forces, ensuring proper coverage is maintained despite the dynamic conditions. This may involve adjusting application timing, rate, or location to compensate for the rotating surface
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
Effectively prevents debris adhesion on the workpiece surface, allowing for precise engraving with reduced debris accumulation, especially at edges and in deeper areas, ensuring smooth ink removal and maintaining desired cell volume and surface quality.
Implementation Method 1
a liquid layer applied to the peripheral surface of the cylinder before processing is caused by the centrifugal forces acting on the liquid completely or partially thrown off the peripheral surface
Implementation Method 2
the liquid is not only heated and evaporated directly along the path of the laser beam
Implementation Method 3
the laser beam generated by a laser radiation source is fed into a laser processing tool of the engraving machine
Implementation Method 4
the thermal energy of the laser beam melts and vaporizes material on the surface, digging indentations in the surface
Implementation Method 5
the thermal energy of the laser beam melts and vaporizes material on the surface
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a method and a device (10) for machining a cylindrical workpiece (12) with at least one laser beam (16), wherein the workpiece (12) is set in rotation and the laser beam (169 is directed onto a circumferential surface (20) of the rotating workpiece (12) in order to produce recesses in the workpiece (12) along a movement path (50) of the laser beam (16) over the circumferential surface (20) by melting and evaporating a material of the workpiece (12). In order to be able to prevent or minimize the adhesion of ejected melted material during the machining of rapidly rotating cylindrical workpieces (12), it is proposed according to the invention that, prior to the machining with the laser beam (16), the circumferential surface (20) of the rotating workpiece (12) is wetted with a liquid adhesion prevention agent, thereby minimizing the adhesion of ejected melted material on the circumferential surface (20), and that the liquid adhesion prevention agent is applied on the circumferential surface (20) of the rotating workpiece (12) shortly before the production of the recesses along the movement path (50) of the laser beam (16).