Synrad Novanta OEM ti Series, User Manual

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COOLING PAGE | 41
Cooling
Coolants
NOVANTA 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 NOVANTA lasers, the minimum 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) and total hardness
should be below 100 PPM. Install a filter on the chiller’s return line and inspect frequently.
Cooling & 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), condensation 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 water-cooled lasers are run in a high heat/high
humidity environment and the chiller’s coolant temperature is colder than the dew point temperature of
the surrounding air or when the system is shut down, but coolant 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.
•
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).
To use the following dew point table, look down the Air Temp column and locate an air temperature in
Fahrenheit or Celsius (°C values are shown in parentheses) that corresponds to the air temperature in
the area where your laser is operating. Follow this row across until you reach a column matching the
relative humidity in your location. The value at the intersection of the Air Temp and Relative Humidity
columns is the Dew Point temperature in °F (or °C). The chiller’s temperature setpoint must be set above
the dew point temperature.
For example, if the air temperature is 85 °F (29 °C) and the relative humidity is 60%, then the dew point
temperature is 70 °F (21 °C). Adjust the chiller’s temperature setpoint to 72 °F (22 °C) to prevent
condensation from forming inside the laser.
Refer to the dew point temperature table within the prior chapter 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 but should not exceed the environmental specifications located in
the Ti-Series General Specifications within the Technical References chapter of this manual.
•
Air-condition the room or the enclosure containing the laser.
•
Install a dehumidifier to reduce the humidity of the enclosure containing the laser.