Laser Advise

[Bruce Dorworth]

Ok guys and gals, this is my first post. I have been lurking and drooling over some of the post's on this forum.

I have been considering buying a Chinese Laser, and have a few questions. This will be used mostly for hobby, but like everybody I will not turn down the offer of money. The laser I was looking at has an 85 watt laser. I was considering upgrading to a 100 watt laser. QUESTION: What does this get me in terms of what I can cut? I am from the school of thought that bigger is better. I can get this laser in either 110 volts or 220 volts. QUESTION: Does this matter, or is this a case of bigger is better? 110 volts is of course easier for me, but I could have 220 volts run to where the laser is going to be.

This laser will have a rotary drive, Red dot alignment, and flame arrestor(or what ever it is called), Are there any other bells I should look at? My as well get them now as opposed to trying to add them later.

Thanks in advance,
Bruce D.

[Joe Pelonio]

The only other thing you'll need is a vector grid. If it's like most Chinese lasers it will be water cooled so make sure you have a water pump if it is not included. The power difference means you can cut
thicker material, and thinner material faster. Unless you have the need to cut 1" acrylic, for a hobbyist 80 watts should be plenty. In production the speed helps but that's when doing a lot of big jobs.

[Richard Rumancik]

Bruce, are you running this in a residential location? Are you in USA? Then I would assume you really have 240 volts available, not 220. I think you need 3-phase to get 220 which you would not have in a normal residential building. If it is 240V, make sure that the laser can accept 240 plus the line tolerance of your power company. China is 220VAC - you have to be certain that it can run okay up to say 250VAC. Some international equipment is rated to run up to 250V but you need to find out in advance.

Also note that you should have some power line surge suppression. It is easier and less expensive to get 120VAC equipment than 220/240 VAC equipment. So if you elect the higher voltage laser system make sure you have figured out how you will get the necessary voltage and how to protect the laser. Some UPS's have the necessary "buck and "boost" capability to ensure that you don't fry your equipment. You could set the voltage output to 230V and it would "buck" the 240 input down to 230. (The boost is for power sags.)

[Bruce Dorworth]

Hey guys thanks for the advice. Joe, you state that like most Chinese Lasers it probably is water cooled. Is that a bad or a good thing? Does that mean that all lasers don't use water cooled?

I was going to upload a brochure(pdf), but I didn't see a place to upload an attachment.

Thanks again,
Bruce

[Dan Hintz]

The Chinese systems use a water-cooled glass tube (the water flows in and around the entire tube, which is several feet long... the more power, the longer the tube, expect a good 3-4' for an 80W system). Long-term reliability is a crapshoot due to poor quality control.

The higher-priced systems use a self-contained all-metal construction, and except for the really high power systems (200W+) use air-cooling from a couple of small fans. Long-term reliability is significantly higher, but the cost to repair follows with it.

[Dean Fowell]

I have a Chinese system, and I brought a power converter on Ebay, for 85.00 usd and it still runs fine , the tube is longer and you would want to get two tubes and 3 lenses for setting up. you may not use them but you do not want to wait 30 days for a replacement ,


Good Luck

[Robert Walters]

Hi Bruce,

Welcome lurker number 1,324,345!

The difference between 85 and 100 watts may not be all that significant, it would really depend on what you plan on doing and what materials that you use.

110VAC is much easier to deal with. Mind you you may need multiple 110 circuits as I'm sure the laser itself is going to take near 15amps alone, plus you'll need to add a exhaust blower (dust collector) which can draw from 4-12A depending on what you get, lights, computer, air assist compressor, etc.

If you have an electric dryer hookup already, that may be the way to go. But as someone said be sure to check the requirements before purchasing as well as an estimate from an electrician on installing a 220V outlet.

I'm not sure what "flame arrestor" is, maybe that's air assist?
Air that's blown down on the workpiece to help with vector cutting.
If so, that's very good thing!

You'll want a vector cutting table, it allows the workpiece to be raised off the bed of the laser and smoke/fumes to exhaust better.

Auto focus is a nice feature to have.

Avoid any laser that requires a security "dongle" to be plugged into the computer.
It's just a PITA, and if you ever loose/break it you're screwed.


There are air cooled and water cooled lasers...

Most of the brand name laser engravers (ULS, Epilog, etc) are air cooled.
This is primarily a convince factor, no having to worry about leaking water lines, low water levels, refilling water, etc.

They say that water cooled (when designed properly) are better than air cooled for beam quality. Since a laser beam is NEVER "on" 100% of the time (it's just pulsed really fast) that the water gives better cooling and helps prevent the laser tube envelope(s) from thermal expanded/contracting as much as air cooled which maintains a more consistent beam quality.

The other thing about Chinese lasers is the availability of parts in the US (or your location). I'd say support too, but that is pretty much non existent compared to Domestic mfgs. I'd find a seller located in the US that can ship from the US as well.

Call them up, ask questions. *ALL* first time laser buyers have questions, and rightly so.
They should be willing to answer your questions without you feeling like you're clueless (even if you are). They should be able to give you all the details about their product and if they don't know the answer, should be able to contact the mfg and get the information you need.

Many of the people that import, are just "flipping" them for quick sale. After years of searching, I did find one that was ore than willing to let me come to his shop, run some tests, ask questions, and was knowledgeable and friendly.

Be sure to find out how long have they 1) been in business, and 2) how long have they been selling this particular brand/model laser, 3) availability of parts in the US (not imported or shipped from China).




Ok guys and gals, this is my first post. I have been lurking and drooling over some of the post's on this forum.

I have been considering buying a Chinese Laser, and have a few questions. This will be used mostly for hobby, but like everybody I will not turn down the offer of money. The laser I was looking at has an 85 watt laser. I was considering upgrading to a 100 watt laser. QUESTION: What does this get me in terms of what I can cut? I am from the school of thought that bigger is better. I can get this laser in either 110 volts or 220 volts. QUESTION: Does this matter, or is this a case of bigger is better? 110 volts is of course easier for me, but I could have 220 volts run to where the laser is going to be.

This laser will have a rotary drive, Red dot alignment, and flame arrestor(or what ever it is called), Are there any other bells I should look at? My as well get them now as opposed to trying to add them later.

Thanks in advance,
Bruce D.

[Dan Hintz]

They say that water cooled (when designed properly) are better than air cooled for beam quality. Since a laser beam is NEVER "on" 100% of the time (it's just pulsed really fast) that the water gives better cooling and helps prevent the laser tube envelope(s) from thermal expanded/contracting as much as air cooled which maintains a more consistent beam quality.
I agree with everything else you posted, but this particular statement is dubious, at best. Beam quality is based upon consistency of the lasing elements, and a water-cooled glass tube simply does not have that consistency. This inconsistency increases with the length (and therefore the wattage) of the tube. The water is free to flow (or not) however it wants through the tube, leading to local vortices (i.e., hot spots). The quality control of Chinese glass tubes also leads to optics that are not perfectly aligned (unless you're extremely lucky), so you lose potential power. Higher power systems (kW) are typically flowing gas, and therefore water cooled, but you're out of the realm of Chinese quality control there... and beam quality in those cases is a different animal altogether because of the beam mode being used (no longer TEM00).

[Robert Walters]

I agree with everything else you posted, but this particular statement is dubious, at best. Beam quality is based upon consistency of the lasing elements, and a water-cooled glass tube simply does not have that consistency. This inconsistency increases with the length (and therefore the wattage) of the tube. The water is free to flow (or not) however it wants through the tube, leading to local vortices (i.e., hot spots). The quality control of Chinese glass tubes also leads to optics that are not perfectly aligned (unless you're extremely lucky), so you lose potential power. Higher power systems (kW) are typically flowing gas, and therefore water cooled, but you're out of the realm of Chinese quality control there... and beam quality in those cases is a different animal altogether because of the beam mode being used (no longer TEM00).

That's kinda why I stated "(when designed properly)",
and I'm speaking in the under 200W range.

As it was explained to me many moons ago:
With water is a better thermal conductor than air...
Cooling the tube with water you have a more consistent envelope temperature, which reduce the overall thermal expansion differential; which cause less flux with the tubes internal optics.

It's it's most basic form, it does sound reasonable (at least in theory).

[Dan Hintz]

A 5'-long tube simply does not have the same rigidity as a 2'-long chunk of aluminum. That aside, there's a reason all major manufacturers use an aluminum billet for their cartridges compared to a glass tube... beam quality. Even with the best glass blowers, you simply cannot get the same beam quality (M) and repeatability from a glass tube. Glass tubes are used in the Chinese machines because they're dirt cheap to manufacture. The high-voltage DC drives glass tubes use are also easier to construct (and cheaper to manufacture) than an equivalent RF drive for a metal cartridge, but by their very nature are not consistent in drive capabilities, again leading to a less-than-desirable beam quality.

Water is a better thermal conductor than air, but that misses the point. The heat created during the lasing process is transferred to the tube walls via the Helium in the mixture, and this will be your limiting factor, a transfer of heat through a gas. Some cartridges (I think Synrad's Firestar series is one) even offer water cooling on metal cartridges (their 200W+ units, if memory serves).