Question on Cleaning Lenses

[Dave Rawn]

How often does everybody clean their lenses and Mirrors. I have been told that you should clean them once a day which I do and some have said to clean them as little as possiable. The cleaning solution I use is everclear grain alcohol and no I don't mix it with tomato juice:rolleyes: . I have a legend 75 watt with a 32 inch bed so every thing is very easy to reach and clean. Let me know what you think

[Chuck Burke]

Dave,
I clean my laser every morning. Lens, mirrors, tracks, and a good vacuuming.
On those times I get busy and don't take the time, I wish that I had because I will find a degradation in performance, and it takes twice as long the next day.
I use lense cleaning solution available at any good camera shop.

Chuck

[Michael McDuffie]

When I'm doing Cermark or aluminum, I rarely clean, altho I probably should. When cutting leather, it's every hour or so even with air blast and my 1500 CFM exhaust.
I use the solution that came with the Legend for quicky cleanings of the moving lens and mirror assembly and wash the whole thing in mild soap when it gets really gunky. The fixed mirror just get the Lens Clens.
Mine came with Lens Clens industrial optical cleaner #1 for coated optics.
www.lensclens.com

Michael

[Mike Mackenzie]

To Everyone,

The cleaning of Optics should only be done if NEEDED!! If you continue to clean an already clean Optic you will slowly remove the coating. Thus making the replacement sooner than later. Rule of thumb " DON'T CLEAN A CLEAN MIRROR" But always keep a eye on it in other words check them often if they need cleaning do it if they don't then don't.

Also it is important to use the proper cleaning solution. These industrial optics do not like WATER. You should use the Lens Clens or use 100% pure Alcohol. If you are using something bought from a camera store check the ingredients my guess is that is has at least 80% water. Water will degrade the spacial coatings on industrial laser optics.

[Chuck Burke]

Mike thanks for the info. It make sense. I'll check my cleaner.


Chuck

[Tim Warris]

The cleaning of Optics should only be done if NEEDED!!

Hi Mike,

This is good advice, but what is one to do if the optics seem to need cleaning often? I HAVE to clean mine 4-5 times a day when cutting, if I don't the cutting will become so degraded it will not work.

I have noticed the coating on the lense has changed color over the last year or so, and this is likely due to cleaning so often, but the alternative is not being able to cut at all...

Tim

[Mike Mackenzie]

Tim,

Two questions

1) How is your exhaust? A weak or poor airflow exhaust system allows the smoke to linger in the can thats what makes the optics dirty. You can check the exhaust plenum to be sure that there is no restrictions. You can easily remove these and really clean them.

2) are you using air assist? If not you may want to add it onto your system. If you are make sure you do not have any leaks. If any of the hoses are leaking it acts like a vacuum pulling the dust and smoke into the Len's area.

Tim if you have to clean your Len's that often this could be the reason for the inconsistent cutting problem you are experiencing.

[Tim Warris]

Hi Mike,

I am using a 750 CFM blower exhausted outside, it draws very well. I have covered the opening on the plenum so all the air is drawn through the down draft table, this keeps the sheets of plywood flat onto the table, and draws the majority of the smoke down through the cut.

Prior to covering the plenum, it was very difficult to keep the material flat, and the smoke rose up into the lens before being sucked back and out of the machine.

The material I am using is very smoky when it cuts, and leaves a very visible white film on the lens. Other materials I have leave a dark resin coating.

Unfortunately, due to the type of items I am cutting, I can not use the air assist. The parts have several thousand small rectangle cut outs that when the air hits them they tip up and get stuck in the grate of the table, the air nozzle then hits these throwing the entire machine off.

I have tried several work around to this problem, but come to the conclusion the lesser of the two evils was to omit the air assist.

The running of the air compressor was driving everyone nuts anyway....

[Shari Loveless]

Mike,
Could Tim use the air assist without the little nozzle attachment? Or is this a no no. Just thought maybe a little air pushing the smoke down without the nozzle hitting the tipped up pieces might help a keep stuff away from the lens.
Shari

[Rodne Gold]

We use a Kodak lens cleaning kit , which was included with our machines. Lens and mirror cleaning are essential. ESPECIALLY lens cleaning , dirty lenses WILL ruin the lens as the dirt can make the optic heat up or the deposits can actually destroy the ZnSE coating . Apart from that , the obvious like beam scatter and a weak beam is the result. We clean a lot and most of our lenses are exhibiting some loss of outer coating with almost no ill effects. We tried a brand new lens in our machine with the worst "damaged" lens and there was little if no improvement.
A good strategy to keep your lenses clean is to positively pressurise them or the chamber around them but diverting some air assist to them. Failing that , its pretty easy to rig up a nozzle type air assist that can be pointed to blow smoke and debris away from the lens but not to blow on the material if you find parts flying around. Not using air assist is bad news generally , it has multiple functions other than to keep flaming down and cn considerbaly improve and speed up cutting if used correctly. Consider using some sort of suction at the cutting point as well , when we cut styrene for stencils we find a huge amount of dust all over the machine , a simple low powered suction system almost totally cures that. You can use the same tube for suction as for pressure , use a T-piece somewhere with 2 take offs and valves - fish tank tubing is where we found ours.

[Dave Rawn]

I guess that I have been cleaning my lenses and mirrors to often I do it out of routine cleaning the machine every morning before I start cutting. I cut thousands of parts a week from 1/8 inch baltic birch and have cleaned them on a routine basis for the last 3 years. I think I will change that to only when the get dirty. Thanks for all of your input.

[Mike Mackenzie]

Tim,

One suggestion would be to use the 1.5 inch air cone rather than the 2.0 inch. this will give you an extra 1/2 inch clearance. Also set your air pressure down to 7-10 psi a small amount of air pressure will help keep the optics clean but not blow the parts around. And the last thing is you can run the air assist without the cone on. It will have air blowing over the optic to help keep it clean but it won't force the air through the cone.
I know that the compressors are noisy but they can really help if set-up properly.