Full Version: Too Much Laser Power
From: MR C (MOSHE) [#1]
12 Jun 2006
To: ALL
Is there any reason not to get a 80 watt laser as opposed to a 60 watt laser for lasering plaques?
is it possible that the 80 watt is not as precise as the 60 watt
EDITED: 13 Jun 2006 by DGL
From: Mike (MIKEN) [#2]
12 Jun 2006
To: MR C (MOSHE) [#1] 12 Jun 2006
I had occasion to use 2 100w Epilogs for about a year and a half. Never did have occasion to use full power and felt that my employer could have saved a lot of money by going to something like a 50 watt machine.
Just found out that he replaced one of his 100's with a 45w and will likely replace the other with the same machine. His work is wood , metal and acrylic awards. No cutting.
Mike
EDITED: 12 Jun 2006 by MIKEN
From: bobkat [#3]
12 Jun 2006
To: Mike (MIKEN) [#2] 12 Jun 2006
You may never have used full power, but you were able to engrave at a higher speed than you can with lower power.
In answer to the original poster, wattage has no bearing on the accuracy of the laser; it is all in the size and shape of the beam brought to bear on the substrate. Quality optics and a good quality output from the tube are a must.
From: Mike (MIKEN) [#4]
12 Jun 2006
To: bobkat [#3] 13 Jun 2006
Bobcat:
I concur with your point in some applications but not all. There are many instances when you can engrave with a 100w machine at 25%power but 100% speed. In fact, in most of the instances I described.
My point was that most of the work we did could have been done just as well, just as fast with a lower powered machine.
One of the machines was a dual head machine which did take better advantage of the 100w of power.
I believe the proof of my original remark is that the owner of the business is down-sizing his machines to 45w models.
Mike
EDITED: 12 Jun 2006 by MIKEN
From: Boz (CHEDDARHEAD) [#5]
13 Jun 2006
To: ALL
You can laso run into an occassional problem trying to run a higher powered laser at lower power settings. Getting down to very low power might change how a laser fires. Some "tubes" won't run under a certain threshold.
That being said, we are talking about having something like a 100 watt laser might have trouble firing at 5 or 6 watts of power on a consistent basis. Kinda like a Ferrari liking to run at 25 mph. 1st gear ith a foot on the brake and the ride is "rough".
From: MR C (MOSHE) [#6]
13 Jun 2006
To: Boz (CHEDDARHEAD) [#5] 4 Oct 2006
From: Harvey only (HARVEY-ONLY) [#7]
13 Jun 2006
To: MR C (MOSHE) [#6] 13 Jun 2006
Possibly the 80 watt tube does not put out as tight a tight beam.
Just fishing for a possibility. Assumption that everything else is the same, it might not be.
From: laserman (MIKEMAC) [#8]
13 Jun 2006
To: MR C (MOSHE) [#6] 13 Jun 2006
Moshe,
Thats says it all it has to do with the GLASS type tubes!
Actually with higher power tubes there are more problems with cooling than lower power tubes when a 60 watt or higher tube heats up it can actually change the mode of the laser and how it fires.
In the past you would not have even seen a 50 watt laser that was not water cooled. Now that the technology has switched to air cooled laser tubes you are seeing more issues strictly due to the heat that is created from the higher powers. This has nothing to do with running it at 10% power or 100%power just turning the system on heats up the laser tube. We have seen 100 watt tubes after being on for 15 minutes actually twist and change the spot from a round to a slight oval when this happens the quality will suffer.
No one would ever see the difference if all they did was wood products because wood is very forgiving. If you do this test you can probably see the difference.
Run a 12 point line of text on a piece of wood at say 100 power 100 speed first thing once the system has been turned on then run the same line of text directly below the first line one hour later without turning off the system you will probably notice a difference between the two lines of engraving.
Typically we will see this on single higher power laser tubes rather than on lower power tubes.
Some rules that we have learned is to be sure there is adequate air flow around the system. Most systems take the room air and blow it over the laser tube what happens is if the system is against the wall/walls the air that is exhausting gets pulled back into the cooling fans thus blowing warm air over the tube instead of the cooler room air and causing the tubes to heat up faster.
Some system use the exhaust fans to cool the tubes. This is not a great idea because the debris gathers in the cooling fins and causes the tube to heat up. The bottom line is if you keep the laser tube cool the mode stays consistent and your quality will do the same.
From: Ken D. (KDEVORY) [#9]
14 Jun 2006
To: ALL
Another interpretation, "accuracy" referred to "resolution". (How accurately you can fine tune the power setting.)
If power is set in 1% increments:
1% of 100W is 1W (4%=4W, 5%=5W - a 25% increase in power)
1% of 40W is 0.4W (10%= 4W, 11%=4.4W - a 10% increase in power)
From: Dave Jones (DAVERJ) [#10]
15 Jun 2006
To: Ken D. (KDEVORY) [#9] 15 Jun 2006
The increase from a 4% setting to a 5% setting is 25% increase, no matter the power of the laser. The same for a 10% to 11% setting change always being a 10% increase in power, no matter what the wattage of the laser.
But your point is a good one. Not looking at it as percentage of increase, but in the size of the steps in absolute power you do get smaller steps with the lower power laser. Where a 100 watt laser gives 1 watt steps and a 50 watt laser gives 1/2 watt steps, or a 25 watt gives 1/4 watt steps.
On the other hand, the higher wattage laser can often do the job faster, or cut thicker materials in a single pass.
Of course table size is also something to think long and hard about. I went with a 24" wide table because I knew that some things I wanted to do would be more than the 18" of the smaller models. But I just came across a project that requires a 36" table. If I had a bit more confidence in the project panning out long term I might consider buying my second laser after only 2 months. :O
From: Stunt Engraver (DGL) [#11]
15 Jun 2006
To: Dave Jones (DAVERJ) [#10] 15 Jun 2006
In an unofficial survey a friend of mine took, while visiting shops in the San Diego, CA area, he found that it was extremely common to find multiple laser machines, in those businesses, who used lasers.