Wire Bonding Capillary Machining With Tangential Laser Ablation
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Solution Overview
Problem
Existing methods for machining wire bonding capillaries from sintered ceramic materials are inefficient and result in relatively rough surfaces due to the absorption of entire laser pulses by individual grains, leading to slow processing times and poor surface finish.
Innovation Solution
A method involving tangential laser machining of sintered ceramic blanks, combined with continuous rotation and controlled laser beam orientation, allows for rapid and precise creation of small-scale structures on the capillary surfaces, including smooth transitions between different sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the laser beam is oriented at a right angle to the surface being machined, then the entire energy of a laser pulse is absorbed by individual grains, but this results in a relatively rough overall structure of the material surface
Solution Approach 1:
The patent changes the orientation parameter of the laser beam from perpendicular (90 degrees to surface) to tangential (parallel to surface). This parameter change transforms the energy absorption pattern from complete grain evaporation to partial grain evaporation, thereby reducing surface roughness while maintaining effective material removal.
Solution Approach 2:
Instead of directing the laser beam perpendicular to the surface as conventionally done, the patent inverts the approach by directing it tangentially along the surface. This inversion changes the interaction mechanism from volumetric heating and complete grain removal to surface-level ablation with finer control, producing smoother surfaces.
2Manufacturing precision
If the laser beam is oriented tangentially to the surface, then only a part of the energy of a pulse is absorbed by each grain, but this requires a more complex laser beam orientation mechanism
Solution Approach 1:
The patent introduces rotational motion of the capillary blank as an additional dimension to achieve tangential beam orientation. Instead of complexly adjusting the laser beam angle directly, the system rotates the workpiece so that the surface moves tangentially under a relatively fixed beam, achieving the desired orientation through workpiece motion rather than beam manipulation.
Solution Approach 2:
The rotating capillary blank itself serves to create the tangential orientation condition. The rotation of the workpiece generates the relative tangential motion between the laser beam and surface, eliminating the need for complex beam steering mechanisms. The workpiece's own motion is utilized to achieve the optimal beam-surface interaction geometry.
3Manufacturing precision
If traditional grinding and polishing methods are used to form the basic shape of capillaries, then the process is time-consuming, but this results in slower production rates
Solution Approach 1:
The patent replaces mechanical grinding and polishing systems with a laser-based ablation system. The laser beam directly removes material through vaporization and sublimation processes, eliminating the need for mechanical contact between grinding tools and the capillary surface. This substitution dramatically reduces machining time while maintaining or improving surface quality and dimensional accuracy.
Solution Approach 2:
The laser machining process utilizes phase transitions (vaporization and sublimation) of the ceramic material to remove material. Instead of mechanically grinding away material through friction and wear, the laser energy directly transforms solid material into vapor or sublimated gas, enabling much faster material removal rates while producing cleaner surfaces without mechanical contact marks.
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 faster and more precise machining of wire bonding capillaries with finer surface finishes, reducing processing time and improving structural integrity by minimizing grain evaporation or sublimation, thus enhancing the overall quality of the capillary.
Implementation Method 1
the grain will only evaporate or sublimate in part
Implementation Method 2
the grain will only evaporate or sublimate in part
Implementation Method 3
laser machining the blank with a laser beam oriented to impinge tangentially on the surface of the blank
Data Source
Figure 1~4
Figure 5~11
AI summary
A method for machining a blank comprises the steps of • providing a blank made of a sintered ceramic material; • laser machining the blank with a laser beam (22) oriented to impinge tangentially on the surface of the blank, • while continuously rotating the blank (1) around an axis of rotation, corresponding to a longitudinal axis of the blank (1), • thereby machining at least two surface sections of the blank, o the at least two surface sections being rotationally symmetric with regard to the longitudinal axis (19), and o the at least two surface sections being separated by a boundary curve, where a curve on the surface crossing the boundary curve has a stepwise change in curvature, and a smooth change in the direction of a surface normal, o in particular wherein the boundary curve lies in a plane that is normal to the longitudinal axis (19).