14
Synrad
Firestar OEM v30
reference guide
Cooling connections
(cont.)
Chiller preparation guidelines
■
You must provide fittings to adapt the laser’s 1/2-inch O.D. polyethylene cooling tubing to your chiller’s Inlet and Out-
let ports. These fittings can be “quick disconnect” or compression type fittings.
■
Because Firestar’s cooling tubing is specified in inch sizes, do not use metric tubing fittings unless you have installed the
appropriate inch-to-metric tubing adaptors. The use of metric fittings on inch size tubing will lead to coolant leaks or
may allow the pressurized tubing to blow-off the fitting.
Coolants
SYNRAD recommends that the laser’s cooling fluid contain at least 90% distilled water by volume. In closed-loop systems,
use a corrosion inhibitor/algaecide such as Optishield
®
Plus or equivalent as required. Avoid glycol-based additives because
they reduce the coolant’s heat capacity and high concentrations may affect power stability. For SYNRAD lasers, the mini-
mum coolant setpoint is 18 °C (64 °F) so glycol is not necessary unless the chiller is subjected to freezing temperatures. If tap
water is used, chloride levels should not exceed a concentration of 25 parts per million (PPM). Install a filter on the chiller’s
return line and inspect frequently. Firestar OEM v30 lasers incorporate the following wetted materials in the coolant path—
nickel-plated brass, copper, acetal, PBT, polyethylene, stainless steel, and Viton
®
.
Note:
DO NOT use de-ionized (DI) water as a coolant. DI water is unusually corrosive and is not recommended for mixed
material cooling systems.
Setting coolant temperature
Choosing the correct coolant temperature is important to the proper operation and longevity of your laser. When coolant
temperature is lower than the dew point (the temperature at which moisture condenses out of the surrounding air), conden-
sation forms inside the laser housing leading to failure of laser electronics as well as damage to optical surfaces.
The greatest risk of condensation damage occurs when the laser is in a high heat/high humidity environment and the
chiller’s coolant temperature is colder than the dew point of the surrounding air or when the system is shut down, but cool-
ant continues to flow through the laser for extended periods of time.
The chiller’s temperature setpoint must always be set above the dew point temperature. In cases where this is not possible
within the specified coolant temperature range of 18 °C to 22 °C (64 °F to 72 °F), then the following steps MUST be taken
to reduce the risk of condensation damage.
■
Air-condition the room or the enclosure containing the laser.
■
Install a dehumidifier to reduce the humidity of the enclosure containing the laser.
■
Stop coolant flow when the laser is shut down.
■
Increase coolant flow by an additional 3.8 lpm (1.0 GPM). Do not exceed a coolant pressure of 414 kPa (60 PSI).
Table 4 on the following page provides dew point temperatures for a range of air temperature and relative humidity values.
Remember that the laser’s coolant temperature must be set above the dew point temperatures shown in the chart; however,
for best results and performance, do not exceed a coolant temperature of 22 °C (72 °F).
