technical reference
56
SYNRAD OEM v40 Operator’s Manual Version 4
Technical overview
Figure 4-1 v40 beam characteristics
RF power supply
A compact, self-contained RF power supply mounted internally in the laser chassis converts 30 VDC input
power into a radio frequency (RF) signal using a crystal-controlled oscillator. The 81.36 MHz RF output
from the oscillator is then amplied to obtain approximately 400 watts of RF power. From the amplier, RF
power is routed to the electrode structure in the laser tube where it excites carbon dioxide (CO
2
) gas in the
tube to produce lasing.
Control circuit
Control circuitry built into the laser interrupts operation if any critical parameter is violated. Switches and
sensors on the control board monitor various conditions and parameters that, if exceeded, pose a risk of
potential damage to the laser. Additionally, laser operation is interrupted in response to the following con-
ditions: (1) the manual Shutter Switch is closed; (2) the Shutter Open Request input signal is missing; (3)
an over temperature condition occurs; (4) the coolant ow rate is too low; (5) the Remote Reset/Start
Request signal is enabled; or (6) the Remote Interlock signal is missing.
Optical setup
After selecting a laser for a CO
2
laser processing system, the two most important elements to consider are:
(1) delivery optics to transmit the beam to the work area; and (2) focusing optics to focus the beam onto
the part or material to be processed. Each element is crucial in the development of a reliable laser-based
material processing system and each element should be approached with the same careful attention to
detail.
Delivery optics
Divergence, or expansion, of the laser beam is important for materials processing since a larger beam
entering the focusing optic produces a smaller focused spot. Because the laser beam diverges slowly,
increasing by four diameters over one meter, this means that for optimum performance the laser should
be mounted a distance of 40–60 inches (1.0–1.5 meters) away from the work area and no closer than 30
inches (0.75 meters). Right angle turning mirrors are often used in conjunction with the laser mount-
ing position to obtain this distance. Following gure shows how right angle turning mirrors in a “ying
optics” setup create this longer beam path.
Expander/collimators are optical devices that reduce beam divergence while at the same time increasing
beam diameter by a selectable magnication factor. Adding an expander/collimator to the “ying optics”
setup shown above would substantially reduce beam divergence and any variance in beam diameter caused
by the changing optical path length. In xed-length delivery systems where the laser is positioned only one
meter away from the focusing optic and a small spot size is required, an expander/collimator is again the
best solution to provide the required beam expansion before reaching the focusing optic.
Beam Waist Diameter 2.5 mm
Full Angle Div
Ø
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