lens longevity

[jud dinsmore]

thanks for the notes. we've only cleaned the lens one time (yesterday) and have never cleaned the mirrors. i'll give that a shot.

our 1/4" ply is imported. is there something else that would work better for template material (and considering costs, i'm sure there is a better medium)? we're using 1/4" ply, cut on the laser, as a template to make a 3/4" mdf template. we then take the 3/4" mdf template and use it to make cuts in the wood.

[Robert Bonenfant]

The best wood we have found so fair for cutting and affordability is Russian Baltic Birch. We go through about 15 skids a month of 1/8,1/4 and 1/2" and it always cuts well. It has a solid birch core so its strong and cuts great each sheet. We use it for our laser cut parts and we make tons of cabinet components - Since it has a solid core there no voids and we dont often see hard spots. Most plywood wholesalers have it in stock or can order it.

[Mike Null]

I clean my lens 3 or 4 times a day if I'm cutting wood or a lot of plastic. Mirrors less often. I also do a lot of Cermark which is a dirty material.

I never use water. Always lens cleaner or in a pinch acetone.

[Robert Bonenfant]

Mike why so often ???

With positive air flow the lens shouldn't be getting dirty that fast - We have two shifts on our lasers today (16 hours) and will only be cleaning them twice on a bad day.

Just curious , Im sure trotec lens are alot more expensive than my $30 lens so I might have answered my own question :-)

[Kev Williams]

Mike why so often ???

With positive air flow the lens shouldn't be getting dirty that fast

That's the trick, that positive airflow...

I don't cut wood, but I engrave and cut a lot of engraving acrylic.. that said--
My LS900 lens stays clean for weeks no matter what I engrave or cut. My mirrors hardly ever get dirty. GREAT airflow, NO smoke drifts upward.
My GCC lens and mirrors stay clean for a few minutes no matter what I engrave. It LOOKS like it has good air flow, but doesn't, and I'm working on that -- After engraving a square foot of anything on Romark, there's a haze buildup on the mirrors that highlight the red LED- a quick swipe with a dry Q-tip and the LED becomes almost invisible. And that's the mirrors, the lens gets worse, faster. I clean its lens and mirrors before any job, and especially Cermark, as a little haze can be the difference between being done or having to run a second pass.

[Joe Pelonio]

When I was running 8 hours a day I would clean twice a day, now only after a big cutting job. I have replaced all mirrors once, lenses twice, and that’s in 13 years. I still have and use the cleaner liquid provided by Epilog when I bought my machine, and Kodak lens cleaning tissues.

[Doug Fisher]

I use quality eyeglass cleaner which is good at cleaning light gunk off. Additionally, I have a dedicated micro fiber cloth for cleaning the lens because many lenses are coated with stuff that you don't want to get on other stuff. The cloths are cheap at the glasses counter at Walmart and they don't damage the surface/coating of the lens. A good wetting, application of mild dish soap and thorough rinsing under the tap will keep the cloth clean.

[Mike Null]

Robert
Compare my replacement frequency with yours. Granted, I don't cut much wood but I do cut a good bit of plastic and do a lot of raster engraving.

My mirrors rarely accumulate any grime but I do not use air assist on raster engraving as I find no apparent benefit. As Kev says in the next post, Cermark can make a mess of a lens in a hurry and as a matter of habit I clean the lens after a couple of hours of using Cermark.

[Robert Bonenfant]

Mike that makes sense and im sure trotec lens are alot higher quality than the junk ones we use. We could run them longer but for $30 a lens replacing them after a few months make sense if we see any type of imperfection. For the cost of the trotec lens I would probably clean them more often as well.

[Mike Null]

Robert
It's more typical for me to clean twice a day if I'm doing a lot of cutting or engraving. When I did an order for several thousand pieces of wood I cleaned every hour or so.

I can't speak to the quality of the lenses you're buying but this company is the supplier to Trotec. http://www.iiviinfrared.com/CO2-Lase...s/mirrors.html

[Brian Lamb]

So what do the lenses cost from iivi? And what type of lens is it that we use in a CO2 laser? They don't list lenses per application on their website, i.e. Trotec, ULS, etc. so it's rather confusing... I suppose a phone call would get the answers I need, just haven't done it yet. I'd like to get a back up 2" lens and a 3 or 4" focal length one for some rotary applications.

[Scott Shepherd]

So what do the lenses cost from iivi? And what type of lens is it that we use in a CO2 laser? They don't list lenses per application on their website, i.e. Trotec, ULS, etc. so it's rather confusing... I suppose a phone call would get the answers I need, just haven't done it yet. I'd like to get a back up 2" lens and a 3 or 4" focal length one for some rotary applications.

Probably close to $150. You need to measure the diameter and thickness of your existing lens. Call them and they'll be able to work with that and determine the right lens.

I'm with Mike. We have 4 or 5 lenses of different focal lengths and they look perfect. I know one of them is 7-8 years old and not a spec or pit on it. I think we ruined one lens once, by having air assist off and the nose cone on. Other than that, depending on what we are doing, we'll clean them a couple times a day to a couple times a month. Having said that, we check them every day. No dirt, no need to clean it, dirt, clean it. It's worked this long, so we'll keep doing that.

I guess our ULS is 10 years old now and it has the original lens and mirrors. Not a spot on the lens.

[Barb Macdonald]

Fascinating thread, thank you all.
Dumb person, aka me, forgot to clean lens (mirrors and encoder strips yes, lens, no) for a very long time. Finally noticed it, cleaned it, and I have two half-moon black rings (tiny) off centre of the lens. Vectoring improved as soon as I cleaned it, duh... Will I harm the beam if I don't replace the lens? Seems to be working fine. epilog legend ext, mature model from 2006. Airflow has been the bane of my existence, but it's the best we can do.
Apologies for the stupidity of the question...

[Jacob John]

Fascinating thread, thank you all.
Dumb person, aka me, forgot to clean lens (mirrors and encoder strips yes, lens, no) for a very long time. Finally noticed it, cleaned it, and I have two half-moon black rings (tiny) off centre of the lens. Vectoring improved as soon as I cleaned it, duh... Will I harm the beam if I don't replace the lens? Seems to be working fine. epilog legend ext, mature model from 2006. Airflow has been the bane of my existence, but it's the best we can do.
Apologies for the stupidity of the question...

Post a few pics if you can.

[Rodne Gold]

The cheap lenses do not engrave etc as well as the OEM expensive ones..ours in a VERY harsh environment last about 6 months , but at the price , they are considered consumables .. we have 9 lasers running almost continually , 8 of them use lenses .. so we keep quite a few in stock
OEM lenses last a lot longer.. 2 years sometimes , but despite training my operators re cleaning , its pretty rough and ready (spit and the corner of a shirt) , so we hae moved over to the cheapy lenses for general work