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Robert Bonenfant
09-20-2016, 7:37 PM
Hello Everyone

Ive been having a problem with a new laser cutter i bought. First Sheet of cuts are perfect, second sheet turns out good and then normally by the third full sheet it starts to go south. I have a 100 watt Camfive Laser (US Company Importing Chinese Machines) and it seems that the final mirror on the laser head is getting hot. Not really hot but hot enough to know somethings not right. I also have a 80 watt machine (same Model) and it works fine in the same space. I want to try all possible solutions before i call customer support, it will cut 1/8 wood perfect and really fast but as soon as i move to 1/4 Baltic birch it doesn't last long before bad parts. Water chiller keeps the water/antifreeze at around 17 c (When cutting 1/4 it rises a few degrees )
Power Settings
75 Power - Speed 10 mm/s (1/4")
65 power - Speed 40 mm/s (1/8)

Any ideals or suggest would be great
Also any one else have a 100 Watt machine - Should i be able to cut 1/4 Baltic Birch alot faster ?? My 80 watt Cuts at about the same speed for 1/4" (Slow on 1/8)

John Noell
09-20-2016, 7:55 PM
I am assuming that you have carefully aligned the beam. If the beam is even a little bit off and hitting the edge, it will make things hot. Otherwise, I could only guess a bad mirror. I just changed one out recently where the coating was falling off. Never seen such a thing before, mirror was nearly new, beam is aligned, etc. It apparently was just a bad coating.

Robert Bonenfant
09-20-2016, 8:03 PM
I realigned the machine today but i think in the morning im gonna make sure everything is perfect before I move to a new mirror.

Lee DeRaud
09-20-2016, 8:04 PM
I am assuming that you have carefully aligned the beam. If the beam is even a little bit off and hitting the edge, it will make things hot. Otherwise, I could only guess a bad mirror. I just changed one out recently where the coating was falling off. Never seen such a thing before, mirror was nearly new, beam is aligned, etc. It apparently was just a bad coating.^This.

If the mirror itself (as opposed to its metal mount) is getting hot, it's because it's absorbing energy from the beam instead of reflecting it. Under that condition, I would expect its remaining life to be measured in minutes.

Robert Bonenfant
09-26-2016, 9:03 PM
Thanks for The suggestions guys
So this issue is literary making me want to pull my hair out :D

Bought new lens and mirrors
Installed new concrete slab to ensure floor is perfectly level ( I might have went over board )
Checked to ensure Machine is leveled
I have found that all the past #3 mirrors have small dots on them - Not sure whats causing this but im sure its related (One mirror was only a few days old)

Any other ideals for what to check next ? If all else fails im gonna call a tec out and have them look at it (Trying to avoid this high cost $300 Ish)

Mirror #1 is perfect - Mirror #2 is perfect in front and back of machine
Mirror #3 is giving me trouble everywhere from each corners its off a little bit - Not sure if the X axis is out of alignment, Floor and machine are perfectly leveled.

Gonna give it a few more days until i call a tec. Taking a look on the forums now to find axis alignment guide

- Added - Wanted to add that the Laser will cut shapes and designs perfectly but as the head gets hot it affects power

Scott Marquez
09-26-2016, 9:53 PM
Thanks for The suggestions guys
So this issue is literary making me want to pull my hair out :D

Bought new lens and mirrors
Installed new concrete slab to ensure floor is perfectly level ( I might have went over board )
Checked to ensure Machine is leveled
I have found that all the past #3 mirrors have small dots on them - Not sure whats causing this but im sure its related (One mirror was only a few days old)

Any other ideals for what to check next ? If all else fails im gonna call a tec out and have them look at it (Trying to avoid this high cost $300 Ish)

Mirror #1 is perfect - Mirror #2 is perfect in front and back of machine
Mirror #3 is giving me trouble everywhere from each corners its off a little bit - Not sure if the X axis is out of alignment, Floor and machine are perfectly leveled.

Gonna give it a few more days until i call a tec. Taking a look on the forums now to find axis alignment guide

- Added - Wanted to add that the Laser will cut shapes and designs perfectly but as the head gets hot it affects power
What material are you cutting, and do you have good smoke/fume extraction?
Scott

Dave Sheldrake
09-27-2016, 2:41 AM
The beam is hitting the inside of the laser head heating the entire thing up OR the mirrors are the gold coated silicon type (wrong rating for the machine)

Klaus Madsen
09-27-2016, 4:11 AM
I think you have a problem with the air assist so your mirror gets dirty. You are writing that it can cut fine until you cut Baltic birch. A lot of plywood smokes a lot, not sure if it is the glue, but any way if you just forget for a few seconds to turn on the air assist then your lens will get dirty - really dirty. But of course you have checked the lens? and the air assist?

Henri Sallinen
09-27-2016, 4:26 AM
Our carriage/mirror was getting hot because the mirror had gone bad over the three year course it was used. Installed a new mirror and we got more power and no warming of carriage/mirrors. Since it's a new machine, I think Dave is on the right tracks of the possible problem.

Mike Lysov
01-18-2017, 12:06 AM
Hi Robert,

Have you found what causes it?

I have the same problem even though I am not sure that it wasn't like this from the beginning when I bought my laser brand new. Only in my case it is 280W two tube DC laser.

The laser head assembly is getting hot. Depending on what power I use and how long I run it with a job the metal parts of the top of the head(where the last mirro is siting can reach 70 degrees C or more. The bottom parts where lens is sitting and an air assist is connected is much cooler but this may be because of the air constantly cooling it down.

Like Dave suggested it may be because of the beam hitting the nozzle inside but after I found today that another mirror on a Y is also getting hot I can exclude the nozzle problem. The Y axis mirror is a bit cooler than the one in the head but it may be just 5-7 degree difference. The mirrors sitting near each tube are quite cool and do not have this problem. They may be completelly irrelevant as they get a single beam from each tube and never hit with combined power. The combing mirror is cool too but it works as pass through mirror from one side for one beam and reflect another from the other side.

All mirrors are in excellent condition and have been supplied by the laser manufacturer.

I probably should add that I am in Brisbane(AU) and it is normally very humid and temperature in my workshop is normally over +35 degrees in summer. It is mostly because of an outdoor temperature and the fact that my water chiller keeps water temperature at 18 degrees dropping all heat from cooling inside my workshop.

David Somers
01-18-2017, 3:07 PM
Robert, I also think Dave is on the right track. For what that is worth. (Dave's thoughts are worth a great deal...mine not so much. <grin>)

But...and this would be totally unrelated to your mirror heating issue. You mentioned you went to great lengths to have a level floor and to level the machine. What actually matters though is that your honeycomb table surface is parallel to the plane of your gantry XY plane. And I do mean parallel. On the money....at every corner and in the center. You probably already know that, but just going by what you said in your post.

Bill George
01-18-2017, 5:05 PM
If the floor needed to be level then the machine shops on ships could never work :rolleyes: All four or three feet need to be on the same plane. As your mirrors do also. I would trust Dave and his advice, wrong mirrors or wrong alignment.

Robert Bonenfant
01-18-2017, 9:55 PM
Hey guys,

I found the solution after spending countless hours and a good bit of money. I bought mirrors from another laser supplier (won't state there name) but they were junk and cause all of my issues. Bought new mirrors from cam five and it worked fine. The mirrors lasted about a hour and then got hot - premium doesn't always mean premium - even if they are in premium price range.

Mike Lysov
01-18-2017, 11:03 PM
Are saying that even premium mirrors lasted an hour before they started getting hot again?

I have expensive mirrors made by II IV infrared. Each cost over $200
They are designed for high power lasers and should not get hot. However they are still doing it.

John Blazy
01-19-2017, 2:20 PM
Here is an interesting hypothesis: The mirrors might be fine - its just beam spread that heats up the black mirror holding armature.

When I removed my 1st mirror and its access panel to send the laser beam into the middle of my shop to free hand cross cut 4 x 8 sheets of acrylic (worked great), the mirror armature got pretty hot when I was finished with a lot of cutting, even though I had dialed the beam to hit perfectly in the middle of the mirror.

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Therefore, I concluded that it was residual beam spread that was hitting the black finished frame holding the mirror. I also recall my hand getting warm whenever it was near the beam path, even as far away as 4 inches. Then I made a lexan guard (for safety reasons) to fit over the 3rd mirror frame, and it started to melt event though the beam was dialed into perfect center. Therefore its simple beam spread. High quality mirrors are great but there is no such thing as 100% of the laser beam being within its 1/4" DIA spot. I would say that 95% is within the central 1/4" and the rest spreads out.

As a matter of fact, when I first tested the beam spread from my laser in order to do this type of cutting, I burnt a 1-1/2" DIA spot in a pallet 14 feet away from the laser. Maybe US based lasers are more parallel beams with a better concentration of beam, but I was surprised at the spread of my chinese laser directly out of the tube.

Kev Williams
01-19-2017, 3:22 PM
What Blazy said :)

And to exaggerate beam spread, higher power tubes emit wider beams to begin with...

Mike Lysov
01-19-2017, 11:24 PM
I understand that the beam is wider but my mirrors are 2" in diameter so there is plenty of room for the centered beam not to touch a mirror frame.
Also I could understand the problem if it was just one mirror in the head getting too hot because it travels more and makes the beam path very long especially on 900x1200mm laser but the same happening with a mirror sitting along Y axis where beam path are no longer than 900mm and it is a puzzle.

yesterday I replaced the mirror in the head with just a MDF circle and run 3 second cut. I did not use 90% power as it would be a disaster on a 280W laser but with 15% it just burnt a spot exactly in the centre of that circle. The burn mark is not round but it is because it caught a fire and burnt rather an oval shape. But the burn mark even with a bit of burn added above because of fire is not close to the the edges of the circle.

I'd wish we would have devices to make laser beam visible. That would make a lot of stuff much easier.

Kev Williams
01-20-2017, 12:55 AM
some old-style fax paper or heat sensitive receipt paper may help- a 3" diameter piece attached to an aluminum disc or something for the laser to hit may give you an idea of the actual beam spread? The center would go toast quick obviously, but any appreciable amount of heat hitting the paper anywhere else will darken it...

John Blazy
01-20-2017, 2:35 PM
Kev - You are so the man!!! As I was reading Mikes response, I was thinking EXACTLY about placing a halo cutout of heat sensitive paper around the mirror to prove the heat from beam spread, and couldnt think right away of the material. Whenever I re-use boxes for shipping, I always take a torch to the old UPS label, which is so heat sensitive that you barely need a bic lighter to blacken it. That will certainly prove the spread.

Then now I am remembering the expensive high quality mirrors that I ordered with my laser, and after switching out and comparing the old chinese stock mirrors with the new, I could see uneven pits and variations in the old mirror. That uneven surface is CERTAIN to spread the beam, even though the beam spreads by itself quite well from my own test of the beam across 17 - 20 ft into my shop.

Bottom line is that I am certain of beam spreading beyond the radius of a 2" mirror. Not enough to be a problem, but if running a long cut program at 95% power will certainly heat up an armature.

David Somers
01-20-2017, 8:10 PM
John....95% power? Where does that put you in the milliamp rating of the tube? Or did you recalibrate your set up so 100% power is really set to be the top end of the recommended milliamp rating for the tube rather than a true 100% power?