Typical MTBF of blowers is 27,000 hours. Most blower failures in an oven are likely the result of prolonged exposure to heat. This is largely dependent on the operating conditions. Elevated ambient room temperatures and operating the machine at extreme temperatures (max. or near max. setpoints) will significantly shorten the lifespan. Also, if the machine is not equipped with additional cooling fans (equipped on machines built late 2015-current) or if the fans are not functioning properly this will have an adverse effect on blower lifespan.
Adequate exhaust is also very important to the blower life span. The machine requires properly balanced exhaust for safe and efficient machine operation. The connection is made via 6 in. duct fittings. Please refer to the Engineering Data Sheet or Sales Drawing for proper requirements. Not only does proper exhaust help reduce excess heat retention, it also helps with the removal of flux resides that could collect on blowers and lead to premature failures.
Open-chamber heat rush:
When the heating chamber is opened before the temperature inside cools to an acceptable level much of this heat gets trapped underneath the machine hood and surrounds the blowers. An isolated incident of this will likely not cause extensive damage, however repetitively opening a hot chamber to retrieve boards or expedite cool-down will have a detrimental impact on blower life.
Cool-down process not followed:
The machine software is written such that when a machine is placed in “Stop” mode the blowers will remain running until the temperature inside the process chamber is below 80°C. This is done because the blowers need to be running to cool themselves from the heat in and around the process chamber. If the oven is shut down via emergency stop or if power is removed from the oven, the blowers will stop spinning and excessive heat will build up in and around the blowers. This could potentially cause premature blower failures.
Recommendations for maximizing blower life:
- Utilize the software-controlled machine cool-down process so the blowers can run until they reach the safe cool-down temperature (i.e. do not use emergency stop or power disconnect to shut down the machine).
- Keep the chambers closed during the machine cool-down process so there is no heat rush on the top blowers (i.e. do not open the chamber to quickly cool it down for the end of a shift or to reduce recipe changeover times).
- Consider using other machine parameters (i.e. blower speed, conveyor speed) to fine tune profiles using the lowest temperature settings possible. This will not only reduce energy consumption, but also extend the life of the blowers, heaters, and other machine components.
- Consider retrofitting the additional cooling fans that were added to machines at the end of 2015, if not already equipped. Upgrades are available and you can contact Technical Support for a quote.