technical reference
57
SYNRAD OEM v40 Operator’s Manual Version 4
Technical overview
Figure 4-2
“Flying optics” beam path
Focusing optics
When selecting a focusing optic, the primary consideration should be material thickness and any vertical
tolerances that occur during final part positioning rather than making a selection based only on minimum
spot size. The chosen focal length should create the smallest possible focused spot while providing the
depth of field required for the material to be processed.
Optics are fragile and must be handled carefully, preferably by the mounting ring only. Cleanliness is
another important issue affecting performance; a dirty or scratched lens will under perform and exhibit a
vastly shortened lifetime. When the application requires air (instead of nitrogen or argon) as an assist gas,
use only breathing quality air available in cylinders from a welding supply company. Compressed shop air
contains minute particles of oil and other contaminants that will damage optical surfaces. If compressed
shop air is the only choice available, it must be filtered and dried to the specifications shown in Table 3-1.
Table 4-1
Assist gas purity specifications
Purge Gas
Specification
Nitrogen
High Purity Grade 99.9500% purity or better
Air
Breathing Grade
99.9996% purity or better
Air
Compressed
99.9950% purity or better, water-free; oil filtered to 5 mg/m
3
or better; particulate filtered to < 1.0 micron; dried to lower
dew point below coolant temperature setpoint.
Caution
possible
equipment
damage
Small amounts of contaminants on the laser’s output window (or on
any optic in the beam path) can absorb enough energy to damage
the optic. Inspect all beam delivery optics periodically for signs of
contaminants and carefully clean as required. In dirty environments,
purge laser optics using filtered air or nitrogen to prevent vapor and
debris from accumulating on optical surfaces.
