Magnus 400 platesetter question

[appstro]

We have a magnus 400 cassette load platesetter. We use Kodak Sword ultra grain positive plates. Lately we have had issues with several hot spots on our plates about the size of a pea. It was very dry and cold outside. I started to wonder if it had anything to do with the lack of moisture in the air in our plating room. We also did a laser intensity adjustment during that time, so that was questioned as well.... Now that the moisture has come back up a bit, the hot spots seem to have gone away almost entirely. Do you think that this is coincidence? Anyone else out there have these issues?

If anyone has any tips or advice concerning the Magnus 400 or Lotem please let me know, i would appreciate it.

 

[Rob Robinson]

Re: Magnus 400 platesetter question

Hi there - you might benefit from checking out the GUA forums here:

http://www.mygua.org/forums/index.php

It's solely for users of Kodak products, there is a wealth of information there and if you can't find what you are looking for, post your question and hopefully you'll get a response!

 

[noregret0808]

Re: Magnus 400 platesetter question

Hi Appstro,
From your descript,I consider the most possibility is the plate problem and not related to the moisture.You would replace the plates with another batch.If the result is same,you will have to check the equipments step by step.As to the laser intensity or focus ,I think they are not important.But I want to learn how you adjust the laser parameters.Can you help me.my e-mail address: [email protected]
See you again!

 

[nemo]

Re: Magnus 400 platesetter question

Hot spots on Magnus 400 (non quantum) can be caused by machine. Your laser has a static focus system so it doesn't compensate for a plate with poor attachment to the drum. This may be caused by loading issues, low vacuum or dust on the drum.
All you can do is to wipe the drum and clean the holes. If you use mostly one plate size you can tape some of the holes that are not covered by the plate to increase the vacuum level.
Under the drum there is a set of small rollers that are supposed to press the plate against the drum at loading. During a flyoff some of them may come off causing poor plate attachment.
If the issue went away by itself I also think it may have been a bad batch of plates.

Oh, I just noticed you said pea size hot spots - this sounds like dust or other particles between drum and plate, not a plate attachment issue. When humidity is low, static is higher and more likely to have particles adhere to the back of plate or on drum. One other thing that may cause this is water or oil in your air lines getting on plate - there is an airjet (called "fufu" on this machine) supposed to blow away the ablation from laser path and it can be turned of for testing.

Edited by: nemo on Jan 22, 2008 11:09 PM