Full Version: 40 watts, how to tell?
From: sroehlk (ELECTECH1) [#1]
25 Feb 2007
To: ALL
I have one of the chinese lasers that is advertised at 40 watts.
How can I tell it is really 40 watts? I am looking at the electronics to try and determine if it can put out 40 watts.
But, is there something that a 40 watt laser will do that a less powerful laser can not do? Can a 40 watt cut something that a 30 or 25 watt laser could not?
Steve
From: Stunt Engraver (DGL) [#2]
25 Feb 2007
To: sroehlk (ELECTECH1) [#1] 25 Feb 2007
There is a device which reads how much power a tube is putting out. Semi-expensive to buy, but some companies rent them out.
I think LaserBits is one.
From: Engravin' Dave (DATAKES) [#3]
25 Feb 2007
To: sroehlk (ELECTECH1) [#1] 25 Feb 2007
Steve,
You may be able to more effectively mark some of the softer metals with a 40-watt laser and Cermark versus a lower-powered model.
You can vector cut materials more quickly the higher your wattage is.
You can raster engrave materials more quickly the higher your wattage is.
From: PenTrophy (PENINSULATROPHY) [#4]
25 Feb 2007
To: Stunt Engraver (DGL) [#2] 25 Feb 2007
This is the Power Wizard
http://www.synrad.com/pw/index.htm
From: sroehlk (ELECTECH1) [#5]
25 Feb 2007
To: ALL
Thanks all for the info. I was really hoping for some one to say, if you can cut 1/16" oak then you have 40 watts. (just an example)
But I guess it is not that easy! I am not sure I am going to spend any money to find out. I do know at least one person who thinks this model will actually put out more power than 40 watts. But I think he is comparing it to another laser.
I should be able to figure it out electrically, I think. I will keep working on it.
I am going to get some cermark and see out it works, that will at least tell me if I have enough power. :)
Here is a chewbarka tag I engraved, I am working on speed, power and focus still.
EDITED: 25 Feb 2007 by ELECTECH1
From: Dave Jones (DAVERJ) [#6]
25 Feb 2007
To: sroehlk (ELECTECH1) [#5] 25 Feb 2007
I doubt that you can figure it out electrically. It would be 40 Watts of light energy out, not 40 watts of electrical power going into the tube.
With my 45 watt Epilog I am able to vector cut 1/2" birch 9-ply plywood at 100% power, 2% speed 500 frequency (ppi). I do black anodized aluminum at 30% power, 50% speed, 600dpi. It also works well at 18% power, 25% speed, 600 dpi. But my speed and yours may be unrelated, so I'm not sure there's any way to compare settings like that. We would probably have to compare the amount of time it takes to vector cut a specific length cut in thick material at your maximum power and a slow speed.
From: sroehlk (ELECTECH1) [#7]
25 Feb 2007
To: Dave Jones (DAVERJ) [#6] 26 Feb 2007
Interesting. I would think that the power in to the laser has to be related to the power out of the laser.
The power and speed settings are going to be very different, at least in the way I set mine. But this does give me something to try!
I have a potentiometer to set power and I have to select a number between 1-8 for speed. But the numbers go from 1 to 99. Should not be hard to figure each one but still not direct comparison.
The birch you laser, do you buy that for the laser or from a local source? I have a speciality wood shop just down the road is why I am asking. Is wood you cut with a laser "special"?
EDITED: 25 Feb 2007 by ELECTECH1
From: Dave Jones (DAVERJ) [#8]
26 Feb 2007
To: sroehlk (ELECTECH1) [#7] 26 Feb 2007
I've been buying my birch plywood from sloans:
http://www.sloanswoodshop.com/plywoods.htm
As for watts, a watt is a term of measuring energy and comes in many different forms.
In electrical terms a watt is 1 volt potential across a resistive load drawing one amp.
For other uses it is calculated as one joule per second.
You can boil water and the steam generated can be measured in thermal watts. The energy required to lift a weight off the floor can be measured in watts.
A typical glass laser tube might require 200 watts of high voltage to get out 40 watts of optical power. And that 200 watts of electrical power might come from a power supply with 75% efficiency and require 265 watts of AC power from the wall.
That's just an example. I have no idea of the efficiency of your power supply or the power required by your laser tube to generate it's output. The point is that you will not be able to judge optical output power based on measuring input electrical power.
EDITED: 26 Feb 2007 by DAVERJ
From: Mark (MAXMACHINE) [#9]
26 Feb 2007
To: Dave Jones (DAVERJ) [#8] 26 Feb 2007
One of the meters actually has a stone in it that is heated up. The temperature difference then is calculated to read in watts.
Mark
From: sroehlk (ELECTECH1) [#10]
26 Feb 2007
To: Dave Jones (DAVERJ) [#8] 26 Feb 2007
Thanks for the link! I am going to order some to see how my laser does cutting the stuff.
I
From: Harvey only (HARVEY-ONLY) [#11]
27 Feb 2007
To: sroehlk (ELECTECH1) [#10] 27 Feb 2007
You can judge your maximum speed if you can set up an output in percentage, approximately. With a knob it is difficult.
You can get the lower settings by vectoring a line across the table at very low power and using a stopwatch. The higher speeds mess you up with acceleration/deceleration time and too short of a time to actually use a stopwatch. You can at least calibrate the lower speeds using this method.
Power in/power out has no bearing on a laser. At least in the beginning, probably now also, the tube manufacturing is not quite an exact science. A run of tubes were made and what the actually put out was the power rating. Same input but the outputs of the same style tube ran from 10 Watts to 50 Watts.
From: Rodney Gold (RODNEY_GOLD) [#12]
27 Feb 2007
To: ALL
the Glass tubes are not stable , they will lose power over about 800 hrs of operation to 1/2.
And its actually not wattage that counts , it's power density that does. IE the power over area figure.
For example if your laser had a larger spot size with more power , it might underperfom a lower power laser with a much more concentrated spot.
If your laser has a water jacket , investing in a small chiller will pay dividends in tube stability and life. The tubes are realtively cheap , but increases in stability and extended life means you dont have to constantly change settings.
I was quoted a price of $1000 for the machine you have and I thought it very little money to take a chance on , even if it did 1/2 of what it claimed , it would still make you money. Your samples look good.
Try cut 3mm perspex , you should go thru at max power at a rate of at least 2" per second , you can time a square. thet will tell you that you are at least at rated or near rated power.
From: PenTrophy (PENINSULATROPHY) [#13]
27 Feb 2007
To: Rodney Gold (RODNEY_GOLD) [#12] Unread
From: sroehlk (ELECTECH1) [#14]
27 Feb 2007
To: ALL
I think I will do what Rodney is suggesting.
By the way there is a PW-250 power wizard on ebay with 3 days to go at 349.00.
And there are several other items that for about $150 you can put together a power measuring device. That is using your own multimeter.
From: sroehlk (ELECTECH1) [#15]
27 Feb 2007
To: Rodney Gold (RODNEY_GOLD) [#12] Unread
I will cut the 3mm acrylic and see what I get. Thats what I was looking for, something easy just to get a general idea of where I am at right now. With a new tube. Later I can compare and judge the power loss.
I think I can get replacement tubes for $175 plus shipping, that is just a quote and I have not actually tried to get the tubes at that price.
I can get a tube from the laser manufacturer for $250 plus shipping. That is really less than a new set of sublimation inks, I can just consider the tube an expendible item.