uv lamp working hours

[agus]

hello,
can you tell us the working hrs for uv lamp?
currently at our machine shown 1600 hrs? do we need to change?

 

[jonprintz]

There are a couple of different schools of thought on this subject. The UV system manufacturers normally say that you are still good for a few hundred (or more) hours. In the real world you may be due for a lamp replacement. The only way to truly tell is to measure the lamp energy. This is difficult with a sheetfed press as it is not possible to run a radiometer under the lamp. Some of the newer lamp systems have a probe radiometer that is designed to slide in from the end of the lamp that can measure the current output energy of the lamp.

The true test is whether your inks are curing. If you are having no curing issues on heavy density images you may be good for a while. Charting your results regularly and testing for good cure regularly will show you when you need to relamp.

 

[Data]

You can obtain a tape product which you stick on a sheet and pass it through the machine (on impression).

Depending what colour the tape is will determine if the lamp/s require change.

Although as the above post, if your lamps have no bulges and they are still curing you'll probably get another 400 hours from them.

 

[jonprintz]

The UV cure strips can help troubleshoot when there is a problem but are far from a precise cure test. They are subjective to operator reading and you will need to run them with brand new lamps and again periodically to compare the present strip to the master strip. The exposed master strips will change color slightly over time (even when in a lightproof area) leaving your comparisons largely speculative.

 

[MaMaDx]

For UV lamp life I'll give a quote with url's:
"When correctly used, Primarc UV Curing Lamps are guaranteed to produce a high level of curing efficiency for at least 1000 hours and, with proper handling, they will still be capable of delivering at least 80% of original output." Primarc
"Standard UV curing lamps emit enough UV to cure for 1000 hours: improved production techniques and higher grade materials have enabled Heraeus Amba to produce UV lamps with operating life in excess of 1500 hours, when operated in suitable machines under optimum conditions." Heraeus Amba
How to check:
1. Special UV strips (cheap but not precise) like this
2. UV intensity meter or radiometer (higher cost, but precise and continuous readings. Like this or this
3. Understanding that You got none of above mentioned - yeah just try with finger test. Though there is also testing equipment (like scratch-adhesion tester) for this purpose. But it would be like non-direct method of testing UVlamp.

I'm working with UV-lamps for 7 years. None of them reached 2000 hours to work in 100% Uv intensity. While time goes you need to slow down the conveyor speed in order to achieve uv irradiation power. AND!!! Check first of all sides of the sheets - cause UV lamp losses efficiency first of all on the lamp ends - that is so called "black ends"

 

[agus]

Thank you for all....

Currenly during press we have some problem especialy uv ink white color, uv ink white that we used cann't cured 100% & transfer to others units.
This happened only for white color.
We suspect on on UV lamp life.

 

[Data]

You could change the lamp although if white is transferring to other blankets its not always the lamp at fault.

See below

1. Run lamp between 80-100%
2. Run with as little water/ink as possible
3. Add some photo initiator
4. test another blanket - some pick worse than others
5. Sometimes to get going leave your latter blankets slightly wet 'damp' with solvent

Finally clean your reflectors and lamps with alcohol fortnightly

 

[Alpha-Cure]

looking at the lamp (when switched off, of course) and checking the texture of the quartz will tell you a good deal about its wear.
the quartz should be clear, with little or no opacity.
the texture of the quartz should feel smooth, just like glass. If not, you have external contamination which will restrict the amount of UV radiation emitted.

 

[Steve Arndt]

Agus,
Something else to keep in mind is that there is a significant difference between the different lamp manufacturers and lamp types with regards to life, curing ability and specialty applications. Most manufacturers will give an indication on the expected lamp life in their technical documentation. You may also be able to find this on their website.
If the "white" you are referring to above is opaque, there are lamps that are specifically doped to reduce curing issues associated with this process. It may be useful to have that discussion with your UV system manufacturer or lamp supplier.
I hope this helps.
Steve

 

[jmt]

what about i.r. lamps .some of them have reached the 5000 h mark. thou we are not having any drying issues as of yet.

 

[Steve Arndt]

jmt,

IR lamps have different characteristics and life expectancies. Therefore, I will assume you are using the standard Heidelberg bulbs in your dryer.

The 5000 hour limit that is recommended in the manual (and set on the Com Con for older systems), is the life expectancy number from the manufacturer. Once you have exceeded this number, you should monitor the operation more closely to ensure the lamps are still effective. To prevent any significant downtime, I would recommend purchasing a set of lamps to keep on hand if the performance deteriorates to the point where the lamps are no longer useful.

Realistically, I have seen lamps far exceed 5000 hours. There is no need to replace them if they are doing what they need to do… but be aware that they are nearing their “end of life” and be prepared accordingly.

Steve

 

[jmt]

thanks for the reply steve. we where also thinking of moving some of the bulbs since some of them only have 800 to 1500 hours on them. are local heidelberg tech said this should not be that there are supposed to cylce but not according to are times on the drier.