TWI Industrial Member Report Summary 960/2010
by J Blackburn and P A Hilton
Power beams have been used for many different types of surface modification. One of the more recent innovations is the generation of surface features using the Surfi-Sculpt® process, developed by TWI (Dance and Keller, 2002) using electron beams (EBs) to create arrays of customised features on the surface of a particular material. More recently, TWI has reported (Hilton et al, 2009) that arrays of surface features can also be produced on a wide range of metallic materials using a high brightness laser source. In this variant a focused laser beam is deflected, using mirrors, rapidly over the substrate surface to displace material in a controlled manner. This results in a textured surface consisting of an array of protrusions above the original surface and a corresponding array of intrusions or cavities in the substrate.
Diffraction limited solid-state laser sources are inherently brighter than the multi-mode lasers used by Hilton et al (2009) and hence can be focused to a much smaller spot size (<50µm is possible), whilst maintaining a working distance that can be used with easily available scanning systems made for laser marking. Lower power (<400W), diffraction limited, solid-state lasers are significantly less expensive than those used in earlier work and, if suitable for producing surface features using the Surfi-Sculpt process, a compact, table-top, laser Surfi-Sculpt machine, simpler and less expensive than an using EB system, could have significant potential in a range of industry sectors. This report details work performed with a 200W Yb-fibre laser and a high accuracy scan head, to produce arrays of surface features with significantly lower power and on a smaller scale than previously made with a laser beam.
- Produce laser surface features using a low power, diffraction limited Yb-fibre laser with a focal spot of less than 0.1mm in diameter.
- Produce an array of features tailored to a particular industrial application.