Optics for welding clear polymers

Sill Optics provides asphere or 2-axis f-theta lens optics for use with 1.4µm to 2µm erbium or thulium fibre lasers, as used for welding clear polymers.

Lasers emitting from 1.4µm to 2µm have played a unique role in medical, airborne and manufacturing applications. They are used in applications such as micromachining of metals, ceramics and glass as well as in plastic welding. Only recently was the high level of absorption in various translucent and transparent polymers recognised to be suitable for welding using lasers. Some clear polymers show absorption rates of more than 50 per cent at 1.94µm. An additional benefit is the resulting welds are also optically clear. It is also possible to join thin layers of plastics using multiple weld passes. The key benefit is that no material modifications or infrared absorbing layers are needed.

Sill Optics provides a complete series of collimation aspheres, beam expanders and f-theta lenses for 1.55µm and 1.85µm-2µm. The focal lengths of the aspheres range from 20mm to 200mm with a variety of clear apertures. Fixed magnification beam expanders with expansion factors from 1.5 to 12 as well as zoom beam expanders with a variable magnification ratio from 1 to 3 are available. All optical elements used are made of fused silica and include anti-reflective coatings to ensure maximum transmission and minimum absorption. The optics are optimised for fibre lasers to ensure a consistent spot uniformity over the entire scan field. Standard and telecentric scan lens are available from field sizes from 20 x 20mm to 215 x 215 mm.