Paul M. Harrison

Laser processing of polycrystalline diamond, tungsten carbide, and a related composite material

There are numerous industrial uses of superhard materials such as polycrystalline diamond, natural diamond, and tungsten carbide. These include tooling for mechanical processing as well as robust substrates for microelectronics in extreme environment applications. Processing these materials has presented a perennial problem for engineers. In this article cutting and milling of these materials is investigated using high average power nanosecond pulsed diode pumped solid-state lasers. The results are investigated with regard to developing models for nanosecond pulse laser milling. It is found that it is possible to process these materials at superior rates to conventional technologies, achieving comparable quality without the issues of tool wear and lubrication to contend with. It is also determined that this technology can both cut and mill these materials in concurrent processing—offering new flexibility for manufacturing design.There are numerous industrial uses of superhard materials such as polycrystalline diamond, natural diamond, and tungsten carbide. These include tooling for mechanical processing as well as robust substrates for microelectronics in extreme environment applications. Processing these materials has presented a perennial problem for engineers. In this article cutting and milling of these materials is investigated using high average power nanosecond pulsed diode pumped solid-state lasers. The results are investigated with regard to developing models for nanosecond pulse laser milling. It is found that it is possible to process these materials at superior rates to conventional technologies, achieving comparable quality without the issues of tool wear and lubrication to contend with. It is also determined that this technology can both cut and mill these materials in concurrent processing—offering new flexibility for manufacturing design.

Laser milling: a practical industrial solution for machining a wide variety of materials

Laser milling of diverse materials has been demonstrated with short pulse lasers ranging from microsecond to femtosecond pulse durations, and with wavelengths from the far infrared to vacuum ultra-violet. In all cases a balance between quality, throughput and cost of ownership must be struck in order to determine commercial relevance. Latest generation Q-switched Diode Pumped Solid State Lasers offer the potential to enable the industrial uptake of laser milling for a wide variety of materials including aerospace alloys, thermal barrier coatings, tool steels, diamond and diamond substitutes. This paper will investigate these practical applications of laser milling with reference to comparative laser and non-laser processes.

Deep engraving of metals for the automotive sector using high average power diode pumped solid state lasers

This paper investigates deep engraving of steel and aluminium by laser. By examination of laser and scanner parameters an optimal balance between feature quality and processing speed is achieved. Material removal rates of up to 20 mm3/min for steel and 40 mm3/min for aluminium are demonstrated up to a maximum engraved depth of 1mm. The effect of feature shape and feature size on the process is also investigated.Deep engraving of metals using latest generation Q-switched diode pumped solid-state lasers is a developing application across a range of market sectors. One key use is in creating indelible laser milled marks on high value components in the automotive industry for security reasons. These marks must be resistant to tampering, visible after subsequent painting, difficult to reproduce and not affecting the working properties of the component.This paper investigates deep engraving of steel and aluminium by laser. By examination of laser and scanner parameters an optimal balance between feature quality and processing speed is achieved. Material removal rates of up to 20 mm3/min for steel and 40 mm3/min for aluminium are demonstrated up to a maximum engraved depth of 1mm. The effect of feature shape and feature size on the process is also investigated.Deep engraving of metals using latest generation Q-switched diode pumped solid-state lasers is a developing application across a range of market sectors. One key use is in creating indelible laser milled marks on high value components in the automotive industry for security reasons. These marks must be resistant to tampering, visible after subsequent painting, difficult to reproduce and not affecting the working properties of the component.

Cutting flexible printed circuit board with a 532NM Q-switched diode pumped solid state laser

The authors investigate the high-speed laser cutting of flexible printed circuit boards (PCBs) using a low M2 532nm laser to create features 120mm/s are reported with a high quality kerf.The authors investigate the high-speed laser cutting of flexible printed circuit boards (PCBs) using a low M2 532nm laser to create features 120mm/s are reported with a high quality kerf.

Laser milling of metallic and nonmetallic substrates in the nanosecond regime with Q-switched diode pumped solid state lasers

Laser milling of a variety of substrates is investigated with the intention of achieving high quality material removal to create three-dimensional shapes in the material. A high power Q-switched Diode Pumped Solid State Nd:YAG Laser at 1064nm is used in all cases. Materials investigated include Nickel Superalloys, Thermal Barrier Coatings, Steels, Tungsten Carbide and Polycrystalline Diamond. Multi-layer substrates are also considered. The effects of laser intensity, plasma formation, pulse duration, material properties, and resulting removal rate, recast and surface finish are explored for this process. This paper defines the findings of this study within the context of commercial imperatives.

Nanoscale analysis of laser ablated thin films used in industrial manufacturing of flat panel displays

Flat panel display manufacturing has recently been revolutionized by the industrial uptake of laser direct write techniques to replace lithography for patterning active thin films on glass. The use of diode pumped, high average power, nanosecond pulsed, kilohertz repetition rate infrared lasers to directly pattern electrically active thin films on glass substrates has eliminated as many as five production stages in the manufacture of flat panel displays. Such lasers are now available in average powers nearing one kilowatt, which allows sufficient productivity to take this process from the lab into industry.One key issue of concern is quantifying the removal of the thin films and how that relates to beam homogeneity and energy density on the workpiece. In this paper the authors attempt to quantify the removal of the thin films from glass by comparing advanced analytical techniques such as Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) with optical microscopy for a range of laser parameters. This analysis is put into context of the wider laser direct write technique of thin films on glass; particularly that of Indium Tin Oxide (ITO) for the manufacture of Plasma Display Panels (PDPs).Flat panel display manufacturing has recently been revolutionized by the industrial uptake of laser direct write techniques to replace lithography for patterning active thin films on glass. The use of diode pumped, high average power, nanosecond pulsed, kilohertz repetition rate infrared lasers to directly pattern electrically active thin films on glass substrates has eliminated as many as five production stages in the manufacture of flat panel displays. Such lasers are now available in average powers nearing one kilowatt, which allows sufficient productivity to take this process from the lab into industry.One key issue of concern is quantifying the removal of the thin films and how that relates to beam homogeneity and energy density on the workpiece. In this paper the authors attempt to quantify the removal of the thin films from glass by comparing advanced analytical techniques such as Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) with optical microscopy for a range of laser param...

Enhanced cutting of polycrystalline diamond with a q-switched diode pumped solid state laser

In this paper a progressive empirical study is conducted refining the laser cutting of Polycrystalline Diamond (PCD) as ongoing work.PCD is one of the hardest substances known and is used extensively in cutting tools for non-ferrous materials. It is extremely difficult to cut by conventional means and the current incumbent technology, Electro-Discharge Machining (EDM), is relatively slow and has some serious drawbacks in terms of tool wear, unidirectional cutting and post processing. The PCD is extremely hard but brittle and so is typically mounted on Tungsten Carbide (WC) in the form of a laminar disk. Cutting this laminar structure creates additional challenges because the materials have dissimilar properties.In previous work the authors have successfully demonstrated and modelled rapid laser cutting and drilling of PCD using high average power Q-switched diode pumped solid-state lasers. In this paper the cutting process is refined empirically to improve cut edge quality, reduce surface dross and create complex shapes whilst still achieving a comparatively high cutting velocity.In this paper a progressive empirical study is conducted refining the laser cutting of Polycrystalline Diamond (PCD) as ongoing work.PCD is one of the hardest substances known and is used extensively in cutting tools for non-ferrous materials. It is extremely difficult to cut by conventional means and the current incumbent technology, Electro-Discharge Machining (EDM), is relatively slow and has some serious drawbacks in terms of tool wear, unidirectional cutting and post processing. The PCD is extremely hard but brittle and so is typically mounted on Tungsten Carbide (WC) in the form of a laminar disk. Cutting this laminar structure creates additional challenges because the materials have dissimilar properties.In previous work the authors have successfully demonstrated and modelled rapid laser cutting and drilling of PCD using high average power Q-switched diode pumped solid-state lasers. In this paper the cutting process is refined empirically to improve cut edge quality, reduce surface dross and create...

Laser engraving reflective metals to create scanner readable barcodes

Laser marking of metals and plastics is one of the most widespread of all laser materials processing techniques used throughout the industrial sectors. One remaining challenge is the creation of scanner readable marks on highly reflective materials such as aluminium without the aid of a surface coating. In previous work the authors have presented a novel technique employing a high average power diode pumped solid-state Q-switched laser to locally change the surface roughness, creating high contrast regions between highly scattering laser roughened marks and the unmarked reflective substrate. In this paper the effect of surface modification is quantified and analysed for aluminium, and the techniques are transferred and adapted to other widespread industrial materials such as stainless and galvanized steel. In this way the authors demonstrate the applicability of this laser technique for a range of reflective metals. Applications such as traceability and security are discussed for high volume industrial sectors such as automotive manufacture.Laser marking of metals and plastics is one of the most widespread of all laser materials processing techniques used throughout the industrial sectors. One remaining challenge is the creation of scanner readable marks on highly reflective materials such as aluminium without the aid of a surface coating. In previous work the authors have presented a novel technique employing a high average power diode pumped solid-state Q-switched laser to locally change the surface roughness, creating high contrast regions between highly scattering laser roughened marks and the unmarked reflective substrate. In this paper the effect of surface modification is quantified and analysed for aluminium, and the techniques are transferred and adapted to other widespread industrial materials such as stainless and galvanized steel. In this way the authors demonstrate the applicability of this laser technique for a range of reflective metals. Applications such as traceability and security are discussed for high volume industrial se...

Innovative Applications in FPD Manufacture using High Power Q-Switch DPSS Lasers

An overview is presented of state of the art FPD manufacturing techniques using high power nanosecond pulsed IR lasers to directly pattern thin films on glass. This includes an innovative method for patterning Black Matrix on glass for LCD manufacture, as well as patterning ITO on glass for PDP manufacture.