Laser-Augmented Diamond Drilling for Brittle Materials
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Solution Overview
Problem
Drilling brittle and hard materials like ceramics and semiconductors poses challenges due to low fracture toughness, leading to severe fracture and surface damage, as conventional methods struggle to produce high-quality holes without fractures and micro-cracks.
Innovation Solution
A laser augmented diamond drilling method where a laser is focused through a diamond cutting tool to thermally soften materials, inducing high pressure phase transformation and reducing the pressure needed for drilling, allowing for ductile mode machining and increased material removal rates without requiring high force, thus minimizing brittleness and fracture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional mechanical drilling is used on brittle and hard materials, then the drilling process can be performed with simple equipment, but severe fracture and surface damage occur due to low fracture toughness of the materials
Solution Approach 1:
The patent applies parameter changes by heating the workpiece material to elevate temperatures (e.g., 50-200°C above ambient) before and/or during drilling. This temperature parameter change transforms the material properties, reducing brittleness and enabling ductile mode machining, thereby eliminating fracture and surface damage while maintaining hole quality.
Solution Approach 2:
The patent implements preliminary action by pre-heating the workpiece material before the drilling operation begins. This preliminary thermal treatment prepares the material in advance to be less brittle and more ductile, preventing fracture and surface damage during the subsequent mechanical drilling process.
2Productivity
If higher force is applied during drilling to increase material removal rate, then productivity improves, but fracture and brittleness increase in hard and brittle materials
Solution Approach 1:
The patent changes the temperature parameter of the workpiece material during drilling, heating it to reduce brittleness and enable ductile deformation. This allows higher material removal rates to be achieved without increasing force that would cause fracture, as the heated material becomes more tolerant of mechanical stress.
Solution Approach 2:
The patent introduces dynamics by continuously heating the material during the drilling process rather than using static room temperature conditions. This dynamic thermal field adapts the material properties in real-time to match the mechanical loading conditions, enabling higher productivity without compromising strength.
3Temperature
If laser heating is applied before or after drilling, then some softening effect is achieved, but the laser energy is not optimally utilized during the critical cutting process
Solution Approach 1:
The patent applies preliminary action by heating the material before cutting occurs, but improves upon prior art by maintaining this elevated temperature throughout the drilling process. The laser continues to heat the workpiece during drilling, ensuring the material remains in a ductile state throughout the critical cutting phase, optimizing energy utilization.
Solution Approach 2:
The patent implements continuity of useful action by maintaining continuous laser heating throughout the entire drilling process rather than applying heat only before or after. This continuous thermal field ensures the material consistently remains ductile during material removal, maximizing the effectiveness of laser energy application.
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 method achieves smooth hole sidewalls, reduced tool wear, and improved ductility, resulting in higher quality holes with minimal damage and increased efficiency, capable of drilling various materials including composites and ceramics with reduced pressure and laser power.
Implementation Method 1
a laser is focused through a hard light-transmitting material (e.g. diamond) to a tip (cutting edge) of a tool to thermally soften hard and brittle materials during a drilling process
Implementation Method 2
the laser beam has a non-circular cross sectional shape corresponding to the cutting edge (or edges) of the diamond cutting tool... the laser heats and softens the HPPT material in situ
Implementation Method 3
the diamond contact and resultant pressure on the material being machined (e.g. drilled) may create a high pressure phase transformation (HPPT) (at room pressure and temperature), which lowers the hardness by converting the material from a covalent bond to a metallic bond
Data Source
AI summary
A laser beam is transmitted through a drill bit comprising diamond or other suitable light-transmitting material having sufficient hardness. The laser beam exits a tip of the drill bit, thereby heating and softening the material being drilled at and/or near the interface of the drill with the material being drilled. The process may be utilized to drill hard and brittle materials such as ceramics and semiconductors, composites and ceramic matrix composites. The process may cause high pressure phase transformation, resulting in a more ductile and plastic material near the drill point/tip. The process provides more rapid drilling, improved surface quality in drilled holes, and less tool wear.