Ultrasonic Cutter Blade Offset for Bevel Cutting Accuracy
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Solution Overview
Problem
Existing ultrasonic knives are limited in cutting edge bevels of plate-shaped workpieces, particularly with curved edges, as they induce transverse vibrations and material displacement, leading to defects in sensitive materials like honeycomb or fiber structures, and require separate knives for bevel cutting.
Innovation Solution
The ultrasonic knife design positions the axis of rotation offset from the blade, with the cutting edge aligned close to the axis of rotation and the open surface in the cutting plane, minimizing transverse vibrations and material displacement, allowing for precise cutting of bevels in thicker workpieces with curved edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the cutting edge is inclined relative to the rotation axis to enable bevel cutting, then bevel cutting capability is improved, but transverse vibrations increase and cutting accuracy deteriorates
Solution Approach 1:
The blade is designed with an asymmetric cross-section where the thickness varies across the width. Specifically, the distance from the rotation axis to the cutting edge is maximized at the center and decreases toward the edges, creating an asymmetric mass distribution that counteracts the transverse vibrations caused by the inclined cutting edge configuration
Solution Approach 2:
The blade thickness parameter is varied continuously across its width to optimize the mass distribution. By changing the thickness parameter asymmetrically, the design achieves both the required bevel cutting geometry and the vibration-dampening mass distribution
2Length of moving object
If the blade is made longer to cut thicker workpieces, then cutting capability is improved, but blade overload increases and stability deteriorates
Solution Approach 1:
The blade exhibits non-uniform local properties along its length and width. The thickness is greater near the root and decreases toward the tip, and also varies across the width, creating a gradient structure that maintains strength where needed while reducing mass and inertia where it contributes to vibration and overload
3Productivity
If the cutting wedge forms a displacement surface with the flank to remove material, then material removal is improved, but defects are created in sensitive materials
Solution Approach 1:
Instead of using the flank surface to displace material outward as in conventional designs, the invention inverts the approach by positioning the rotation axis and blade geometry such that the cutting action occurs primarily through the pressure surface, eliminating the harmful displacement surface effect on the workpiece
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 design enables precise, error-free cutting of bevels in plate-shaped workpieces with curved edges, maintaining cutting accuracy and reducing blade overload, even in materials with complex structures, by controlling the movement of the cutter head and maintaining a clearance angle to prevent material displacement.
Implementation Method 1
conventional ultrasonic knives, i.e. knives that are excited to vibrate using ultrasound
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A description is given of an ultrasonic cutter for the cutting of edge chamfers of sheet-like workpieces, with a cutter head (1), which forms an axis of rotation (6), and with a blade (2), which extends from the cutter head (1) and forms a cutting wedge, terminating in a straight cutting edge (5), between flank and contact faces (3, 4) determined by the wedge angle. In order to create advantageous structural conditions, it is proposed that the axis of rotation (6) running on the blade side of the flank face (3) is at a distance (e) from the flank face (3) that is equal to or greater than the distance (s) of the centre of gravity/mass (S) of the blade (2) from the flank face (3), and that the cutting edge ( 5), running in the direction of the axis of rotation (6) runs at a distance (a) from the axis of rotation (6) that corresponds at most to the blade thickness (d).