The ABS (acrylonitrile/butadiene/styrene) is a complex mixture consisting of styrene-acrylonitrile
copolymer, a graft polymer of styrene-acrylonitrile and polybutadiene and some unchanged
polybutadiene rubber. The presence of these rubber occlusions makes him inhomogeneous from the
optical point of view. Experimental investigations involved two types of ABS
(acrylonitrile/butadiene/styrene) plates. The first component is a natural ABS, semitransparent to the
laser wavelength as it is mentioned above, and the second one is a black pigmented ABS, opaque in
near-infrared spectrum. The general optical and thermal characteristics for the two materials are listed
in table 1. The values are given at ambient temperature (≈24◦C). For the 2mm thickness ABS natural
plates the transmission coefficient presented in table 1 indicates a strong scattering of the laser beam
with negligible absorption. This conclusion was drawn after infrared measurements of the temperature
raise during its laser irradiation.
The experiments were carried out using a diode laser LASERLINE with a maximum output
power of 100 W and a focal length of 0.150 m. The laser wavelength is 0.940 μm and the focal spot has
a rectangular shape (lx=1.7 mm, ly=1.3 mm).
To improve the contact between the two polymers a specially designed clamping device has been
used. The analyzed welding configuration was a T-type geometry for through-transmission laser
welding. The experimental setup is shown in figure 1.
The weld failure force was determined with a MTS machine presented in figure 2 with a special
fixture for the T-geometry. The traction speed was 5mm/min.
Basics of the process modelling