During a recent test performed by the Gerber Products Company, the LM-9000 Continuous UV Lamp Monitor provided considerable information regarding the company’s curing equipment, and more importantly, about the company’s preventive maintenance programs.
During a 4-1/2 span, encompassing 188 hours of testing, Gerber used the LM-9000 to simultaneously monitor the performance of two Fusion NOVAX curing systems used on a flexographic printing press. On the first lamp, identified here at System 1, the unit was allowed to operate for approximately two weeks in order to establish the baseline performance of the lamp.
In the third week, the operators replaced the curing system’s lamp with a bulb that had accumulated 4700 hours of use. The LM-9000 clearly showed a dramatic drop-off in energy output across the full UV spectrum, but most noticeably in the 365 and 435 range, where the bulb delivered energy most useful to Gerber’s application. Upon reinstallation of the original lamp, energy output was restored to levels approaching that prior to the switching of the lamps. Yet, upon cleaning the curing system’s reflector and the bulb, the LM-9000 noted energy output returned to the level equal to when the lamp was initially installed.
During this same test period, a second lamp, identified as System 2, was monitored in the same manner. While the operators replaced the lamp when monitoring System 1, for System 2 they replaced the current reflector with an old reflector which had been previously replaced due to yellowing.
As was noted during the observation of System 1, the LM-9000 displayed a gradual fall-off in UV energy during the initial weeks of observation. After introducing the yellowed reflector in the third week, the graph for System 2 remained fairly constant. This consistency indicates the positioning of the LM-9000 sensor when looking directly at lamp output will not be affected by reflector characteristics. This is critical to when verifying that performance variances are due specifically the lamp, electrical current, air flow, or environmental conditions.
What both graphs do show is that clean lamps and reflectors are important and for that reason the company has changed its Preventive Maintenance program to every 350 hours for lamp and reflector cleaning.
An interesting point is both graphs show the 365/435 wavelengths increasing back close to the original baseline values at the end of the company’s evaluation, while other wavelengths remained steady or even decreased somewhat. While the customer did not track environmental influences, the customer does not know if this is due to power or weather variables, or whether this result was a function of drift.
The Test –
Type of units monitored: Fusion NOVAX UV Curing Systems
No. of units monitored: 2
Length of test: 4-1/2 weeks
No. of hours monitored: 188 hours
No. of charted readings: 8
Lamp 1/Sensor 1 – Lamp Replacement
1. Original baseline established for new lamp on 10/17
2. Reading was taken on 10/21 to detect lamp performance.
3. Reading was taken on 10/29 to detect lamp performance.
4. Daily reading was taken in early morning of 11/1 to detect lamp performance.
5. Bulb with 4700 hours was installed on 11/1 and reading was taken.
6. Original bulb was reinstalled on 11/1 and reading was taken.
7. Preventive maintenance was performed on UV system (lamp and reflector cleaned) on 11/1.
8. Normal operating reading was taken on 11/11.
Lamp 2/Sensor 2 – Reflector Replacement
1. Original baseline established for lamp on 10/17.
2. Normal operating reading was taken on 10/21 to detect lamp performance.
3. Normal operating reading was taken on 10/29 to detect lamp performance.
4. Normal operating reading was taken on 11/1 to detect lamp performance.
5. Operating reading taken on 11/1 with old reflector which had been removed due to discoloration.
6. Operating reading taken on 11/1 with original reflector which had been reinstalled.
7. Operating reading taken on 11/1 immediately following preventive maintenance (lamp and reflector cleaned).
8. Normal operating reading taken on 11/11.
Conclusions
1. The LM-9000 effectively monitored variations in the performance of two UV curing lamps operating within Fusion NOVAX curing systems. over a 4-1/2 week period.
2. The LM-9000 data shows that regular preventive maintenance, specifically cleaning the UV system’s lamps and reflectors, can improve operating efficiency by up to 15%.
3. Clean lamps and reflectors are the most critical elements to ensuring optimal lamp operation.
4. When the LM-9000 sensor is focused on the lamp, the LM-9000 will not be affected by reflector characteristics. This is critical to verifying performance variances are reflected specifically the lamp, electrical current, or environmental conditions which effect lamp operation.
Found
1. Fusion claims lamp will not operate until system (lamp or magnetron?) reaches 85% power. Discovered this was not true as lamp started with 50% output.