Research and application development of compound energy field processing—laser microjet
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2020-01-07 |
| Journal | Zhongguo kexue. Wulixue Lixue Tianwenxue |
| Authors | Xizhao Lu, Kaiyong Jiang |
| Institutions | Huaqiao University, Xiamen University |
| Citations | 3 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Laser Microjet Processing of Hard Materials
Section titled āTechnical Documentation & Analysis: Laser Microjet Processing of Hard MaterialsāReference Paper: å¢åøé, ę±å¼å. å¤č½åŗå¾®å°ęµę°“åƼęæå å å·„ē ē©¶åå±ę¦åµ. äøå½ē§å¦: ē©ēå¦ åå¦ å¤©ęå¦, 2020, 50: 034203.
Executive Summary
Section titled āExecutive SummaryāThis review analyzes the Laser Microjet (LMJ) technique, a compound energy field processing method highly relevant for micro-machining hard and brittle materials, including diamond.
- Core Technology: LMJ couples a high-energy laser (typically 1064 nm or 532 nm) with a stable, low-pressure deionized water microjet, which acts as an optical fiber via Total Internal Reflection (TIR).
- Thermal Control: The water jet provides simultaneous cooling and debris removal, significantly reducing the Heat Affected Zone (HAZ), micro-cracks, and recast layers, which are major limitations in conventional laser processing.
- Geometric Advantage: The technique enables flexible focus extension, achieving exceptionally high aspect ratios (typically 10-100) for deep holes, slots, and seams in thick materials (5-25 mm).
- Target Materials: LMJ is proven effective for high-value materials critical to the semiconductor and aerospace industries, including Polycrystalline Diamond (PCD), Single Crystal Silicon Carbide (SiC), Gallium Arsenide (GaAs), and hard alloys.
- Processing Quality: LMJ improves the verticality of cut surfaces, reduces taper angle, and enhances the overall surface quality (e.g., achieving finer, nanometer-scale features compared to microsecond LMJ).
- 6CCVD Relevance: The successful processing of Polycrystalline Diamond (PCD) and SiC directly validates the need for 6CCVDās high-quality MPCVD diamond materials for advanced micro-machining applications.
Technical Specifications
Section titled āTechnical SpecificationsāThe following hard data points were extracted from the comparison of LMJ and femtosecond laser parameters, and general process conditions:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| LMJ Wavelengths | 1064, 532, 1552 | nm | Common laser sources used |
| LMJ Pulse Duration | 20 | Āµs | Microsecond regime (LMJ example) |
| Femtosecond Pulse Duration | 800 | fs | Comparison for ācold processingā |
| LMJ Pulse Energy | 9 | mJ | Typical energy per pulse |
| LMJ Fluence | 2.866 | J/cmĀ² | Energy density at workpiece |
| LMJ Peak Power | 450 | Wpeak | Calculated peak power (20 Āµs pulse) |
| LMJ Repetition Frequency | 2000 | Hz | Typical LMJ frequency |
| Water Jet Pressure | 50-800 | bar | Required for stable microjet fiber |
| Nozzle Diameter | 10-300 | Āµm | Range for microjet fiber diameter |
| Max Aspect Ratio | 10-100 | Ratio | For deep holes, slots, and seams |
| Max Thickness Processed | 5-25 | mm | Deep cutting capability |
| Alignment Precision | 2 | Āµm | Required axial/radial coupling accuracy |
Key Methodologies
Section titled āKey MethodologiesāThe effectiveness of Laser Microjet (LMJ) processing relies on precise control over the coupling mechanism and fluid dynamics.
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Laser Coupling and Beam Shaping:
- The laser beam is precisely focused and coupled into the stable, low-pressure deionized water jet.
- Optical systems (e.g., axicon non-diffracting lens or inverted telescope) are used to reshape the Gaussian beam into a flat-top profile, ensuring uniform energy distribution across the processing area.
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Total Internal Reflection (TIR) Guidance:
- The water jet acts as an optical waveguide, guiding the laser energy via TIR to the workpiece surface.
- Critical control parameters include the laser incidence angle, beam quality, and the stability/laminar flow of the water jet.
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Thermal and Debris Management:
- The continuous flow of the water jet provides efficient cooling, minimizing thermal accumulation and reducing the Heat Affected Zone (HAZ).
- The mechanical impulse of the water jet removes molten material, slag, and vaporized particles (typically 1 Āµm in size) from the cutting front, preventing re-deposition and improving surface cleanliness and verticality.
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Precision Alignment:
- High-precision alignment of the laser focus relative to the nozzle exit is paramount for efficient transmission. The paper notes required alignment accuracy of approximately 2 Āµm (radial and axial).
- The water layer thickness in the coupling chamber must be optimized (around 2 mm) to maximize transmission efficiency while preventing damage to upstream optical components.
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Material-Specific Parameter Selection:
- Laser parameters (wavelength, pulse duration, frequency) are selected based on the materialās absorption characteristics (e.g., 532 nm is preferred for materials with high photon energy requirements like diamond).
6CCVD Solutions & Capabilities
Section titled ā6CCVD Solutions & CapabilitiesāThe research confirms that Laser Microjet (LMJ) is a leading technology for the high-precision, deep micro-machining of ultra-hard materials. 6CCVD is uniquely positioned to supply the foundational MPCVD diamond materials required to replicate and advance this research.
| Research Requirement (LMJ Paper) | 6CCVD Solution & Value Proposition |
|---|---|
| Processing Polycrystalline Diamond (PCD) | Polycrystalline Diamond (PCD) Plates: We offer custom PCD wafers up to 125 mm in diameter, with thicknesses ranging from 0.1 Āµm to 500 Āµm. Our high-quality MPCVD PCD is essential for applications requiring deep, high-aspect-ratio cuts (10-100) as demonstrated by LMJ. |
| Processing Single Crystal Diamond (SCD) | Optical Grade SCD Substrates: For applications demanding the highest material purity and thermal performance (e.g., high-power laser optics or heat sinks), 6CCVD supplies SCD material up to 500 Āµm thick, and substrates up to 10 mm. |
| High Surface Quality Requirement | Advanced Polishing Services (Ra < 1 nm): LMJ efficiency is highly sensitive to surface scattering (Raman scattering). Our ultra-precision polishing achieves Ra < 1 nm for SCD and Ra < 5 nm for inch-size PCD, ensuring optimal laser coupling and minimal transmission loss. |
| Hybrid Processing (e.g., Electrochemical) | Boron-Doped Diamond (BDD): For researchers exploring hybrid LMJ techniques (such as combining LMJ with jet electrochemical machining), 6CCVD provides highly conductive BDD films and substrates. |
| Custom Dimensions and Thickness | Custom Dimensions and Substrates: We provide custom plates/wafers up to 125 mm, supporting the large-area and deep cutting applications (5-25 mm thickness) discussed in the review. |
| Device Integration & Contacting | In-House Metalization: We offer internal metalization capabilities (Au, Pt, Pd, Ti, W, Cu) for creating precise contacts or specialized coupling chamber interfaces on diamond wafers, streamlining device fabrication. |
| Global Supply Chain | Global Shipping (DDU/DDP): 6CCVD ensures reliable, global delivery of high-value diamond materials, simplifying logistics for international research teams. |
Engineering Support
Section titled āEngineering Supportā6CCVDās in-house PhD team specializes in MPCVD diamond growth and material science. We offer expert consultation on material selection, orientation, and surface preparation to optimize outcomes for advanced micro-machining projects, including Laser Microjet and ultra-short pulse laser applications.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Laser microjet is a kind of compound energy field processing, which combined laser with microjet processing as well. While processing laser couples with stabilize pressure microjet and transfers internal total reflection until it arrives at workpieces surface, and changes the Gauss energy distribution to flat-topped laser beam, as well as cools and brushes the processing cross section. The stable low flow pressure deionized water jet waveguides cutting laser flexible extension processing focus, to improve the laser energy distribution while removing chips and cooling and enhance the axial processing quality and accuracy, and improves the laser axial processing ability. Talking about the research development of LMJ and the key technologies of LMJ equipment which including the angle of laser total reflect inner microjet, laser quality, laser transverse model, focal points, coupling precision of laser with nozzle and the stable work distance of microjet etc. At the same time, this processing method is introduced which is suitable for controlling the heat of laser processing, enhancing the direction of laser processing, high quality deep holes, slot and seam with large aspect ratio (about 10-100) as well. The object of the processing method gradually includes high value-added occasions of insulating materials, low- k materials, semiconductor, cemented carbide, such as SiC, GaAs, polycrystalline diamond and other photoelectrical materials.