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Thread: Q-Switched vs MOPA - A Common Sense Discussion

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  1. #1

    Q-Switched vs MOPA - A Common Sense Discussion

    I know, yet another fiber thread, but hear me out. I've been reading for weeks, gathering quotes, talking with vendors, etc., and I cannot find anyone that provides what I consider to be a clear, common sense explanation as to one vs the other.

    Here's what I've been told so far, by both Chinese and Western manufacturers and salespeople:
    • MOPA is only really better than Q-Switched if you're engraving on plastic.
    • MOPA is better at producing colors on various metals
    • Q-Switched is just as good as MOPA on colors/metals
    • You only need MOPA if you're interested in finer graphics, and Q-Switched produces good graphics, but MOPA allows for more intricate details


    If I can remember a few other things I'll post them, but as you can see, they are all over the place. Yes, some of it is simply trying to sell their equipment, but with an average of $3K-$4K difference in price between MOPA vs Q-Switched, I want to know bottom line, is MOPA worth it? This doesn't even begin to touch on the SPI, IPG, Raycus debate.

    As a side note, I saw someone as Triumph is a specific fiber they were selling is MOPA/Q-Switched, and this was the answer: "We use JPT laser which is mopa structure and pules width fixed as 200." What? Is it or is it not MOPA? Seems like there would be a clear answer.

    BTW, I've gathered around 15 quotes, and it's all over the place with pricing.

    Anyone else experience this while researching their purchase?
    Last edited by Jacob John; 07-29-2017 at 3:26 PM.
    Trotec Speedy 300 - 80 watt
    Synrad 30 Watt - CO2 Galvo
    LaserStar 3804 - 50 watt fiber - SPI Source
    Tykma Minilase - 20 watt fiber - SPI Source - (MOPA)
    CorelDraw X7

  2. #2
    Join Date
    Mar 2014
    Location
    Iowa USA
    Posts
    4,441
    FYI with my Ray Fine fiber (Raycus ) I can engrave text so small you will need a magnifying glass to read? So what are you trying to accomplish? Color with a fiber as I understand is very iffy and must be dialed in for each material. Time consuming and who pays for your experimenting for each job?
    Retired Guy- Central Iowa.HVAC/R , Cloudray Galvo Fiber , -Windows 10

  3. #3
    It's not what I initially want, but I would still like the option. But for $3K-$4K more, it might not be worth it right now. I'm really at this point trying to understand the precise differences between the two so that I can make an informed decision. And the companies are all over the place on why MOPA is either better or not.

    As far as experimenting, I would buy materials and slowly and methodically go through and record settings for my desired marks. This is well before I would offer my services to anyone. Thanks!
    Trotec Speedy 300 - 80 watt
    Synrad 30 Watt - CO2 Galvo
    LaserStar 3804 - 50 watt fiber - SPI Source
    Tykma Minilase - 20 watt fiber - SPI Source - (MOPA)
    CorelDraw X7

  4. #4
    Can anyone take a shot at explaining this statement from a well known manufacturer? "The laser source is JPT laser which is made by Mopa STRUCTURE which is ^more^ advanced than q-switched. Buy you can't mark color on stainless steel because the pulse width is fixed."

    So I know that JPT is obviously the source, but what else do they mean? That it's not a Q-Switched, not a MOPA, but built on the MOPA structure? Any fiber guys want to try and explain?
    Trotec Speedy 300 - 80 watt
    Synrad 30 Watt - CO2 Galvo
    LaserStar 3804 - 50 watt fiber - SPI Source
    Tykma Minilase - 20 watt fiber - SPI Source - (MOPA)
    CorelDraw X7

  5. #5
    Join Date
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    John, I dont know. This is the 20watt model I have and I can do black on stainless. No color. Titanium, yep, can get a pretty blue along with a few others. 200nm fixed pulse. I'm not concerned at this point, it is hard enough to get good setting for black, let alone colors. If you are in production and run same item repetitively, then it makes sense..otherwise go full Mopaand play with it or fergit color.
    Woodworking, Old Tools and Shooting
    Ray Fine RF-1390 Laser Ray Fine 20watt Fiber Laser
    SFX 50 Watt Fiber Laser
    PM2000, Delta BS, Delta sander, Powermatic 50 jointer,
    Powermatic 100-12 planer, Rockwell 15-126 radial drill press
    Rockwell 46-450 lathe, and 2 Walker Turner RA1100 radial saws
    Jet JWS18, bandsaw Carbide Create CNC, RIA 22TCM 1911s and others

  6. #6
    Quote Originally Posted by John Lifer View Post
    John, I dont know. This is the 20watt model I have and I can do black on stainless. No color. Titanium, yep, can get a pretty blue along with a few others. 200nm fixed pulse. I'm not concerned at this point, it is hard enough to get good setting for black, let alone colors. If you are in production and run same item repetitively, then it makes sense..otherwise go full Mopaand play with it or fergit color.
    But what about the inconsistent remarks about MOPA vs Q-Switched? I'm more interested to understand if the $3K-$4K difference in price is really worth it. Reading another thread here, not many people get requests for color marked items. But beyond that, if that's all MOPA is really better at, I can't justify the increased cost.
    Trotec Speedy 300 - 80 watt
    Synrad 30 Watt - CO2 Galvo
    LaserStar 3804 - 50 watt fiber - SPI Source
    Tykma Minilase - 20 watt fiber - SPI Source - (MOPA)
    CorelDraw X7

  7. #7
    Posted in the wrong thread, but if I'm trying to get a consistent black mark on stainless steel, Q-Switch or MOPA?

    What about silver?

    Found a good thread talking about stainless and black marking with a MOPA. Still a head scratcher, but not as confusing. http://www.sawmillcreek.org/showthre...Laser-question
    Last edited by Jacob John; 07-31-2017 at 11:56 AM.
    Trotec Speedy 300 - 80 watt
    Synrad 30 Watt - CO2 Galvo
    LaserStar 3804 - 50 watt fiber - SPI Source
    Tykma Minilase - 20 watt fiber - SPI Source - (MOPA)
    CorelDraw X7

  8. #8
    In checking (one set of) my fiber's parameters,
    I found there's not much that's NOT grayed out on this page;
    only the min & max PWM settings are variable--
    fb1.jpg
    --and all THEY do is put a limit on the min and max
    numbers you can enter in the frequency settings
    in the main settings. I have yet to figure out what
    the ACTUAL minimum and maximum values really are!

    --but change 'fiber' to 'yag', and the board lights up--
    fb2.jpg
    -note 'Q-switching' can now be 'adjusted'...

    What this tells me is that my fiber doesn't have Q-switching capabilities. OR that they're they're not variable.

    I know what a MOPA can do. I have no idea what Q-switching can do, or what you call MY machine with apparently neither!
    ========================================
    ELEVEN - rotary cutter tool machines
    FOUR - CO2 lasers
    THREE- make that FOUR now - fiber lasers
    ONE - vinyl cutter
    CASmate, Corel, Gravostyle


  9. #9
    I still feel lost in this discussion.

    So would a 50 watt cut sterling silver easier than a 30 watt? Remember I asked ease of cut, not speed. I know someone that has a 50 watt and it cuts, but slowly.
    Trotec Speedy 300 - 80 watt
    Synrad 30 Watt - CO2 Galvo
    LaserStar 3804 - 50 watt fiber - SPI Source
    Tykma Minilase - 20 watt fiber - SPI Source - (MOPA)
    CorelDraw X7

  10. #10
    That's the problem isn't it? In order to get pre-sale support that answers questions that keep you from buying something that doesn't work, you need to buy it from a dealer that knows their stuff and knows the answers. Want to be able to talk to people who know, you have to spend the money to go with a name brand. Want to guess and what it might or might not do, and you end up with Chinese machines. I'm positive people like SPI and IPG can help. But you don't see many SPI sources in Chinese machines, so what they tell you probably won't apply to a source that's a knock off of their source.
    Lasers : Trotec Speedy 300 75W, Trotec Speedy 300 80W, Galvo Fiber Laser 20W
    Printers : Mimaki UJF-6042 UV Flatbed Printer , HP Designjet L26500 61" Wide Format Latex Printer, Summa S140-T 48" Vinyl Plotter
    Router : ShopBot 48" x 96" CNC Router Rotary Engravers : (2) Xenetech XOT 16 x 25 Rotary Engravers

    Real name Steve but that name was taken on the forum. Used Middle name. Call me Steve or Scott, doesn't matter.

  11. #11
    I feel like we're all guinea pigs when it comes to galvo fibers.
    Trotec Speedy 300 - 80 watt
    Synrad 30 Watt - CO2 Galvo
    LaserStar 3804 - 50 watt fiber - SPI Source
    Tykma Minilase - 20 watt fiber - SPI Source - (MOPA)
    CorelDraw X7

  12. #12
    Quote Originally Posted by Jacob John View Post
    I still feel lost in this discussion.

    So would a 50 watt cut sterling silver easier than a 30 watt? Remember I asked ease of cut, not speed. I know someone that has a 50 watt and it cuts, but slowly.
    Tim's been having fun with his 50w, it seems to be so efficient that it needs to be tempered down by either lowering power, changing frequency or a combination of both. He's going to have a great time with it once he gets everything dialed in!

    I tried to cut thru a .010" thick stainless sawblade awhile back, it was 3" diameter, my customer wanted it 2-1/2" diameter. No problem, I'll just draw a 2-1/2 circle and let 'er rip!

    Yeah, right - the problem, was that as the kerf got deeper, the metal began to melt back into the kerf behind the beam, much like plex does when trying to cut too deep with not enough power. So my 'ease of cut' was dependent on the depth of cut and how much room there was for the beam. Had I started cutting the sawblade with say, 5 circles spaced .015mm apart for a few passes, then reduced to 4 circles, then 3, etc,-- by the time the laser was finally thru the cut would've been much cleaner and just better overall because the first cuts would make room for the beam to fit down to the bottom of the cut. The slight bevel probably wouldn't have mattered. The way I did it, the metal WAS cut thru but the melted slag held it all together. And oh, was it warped!

    It took nearly a year for me to learn the most important lesson in getting good results with my fiber... Have Patience... One of my repeat jobs is an aluminum lid with several words and symbols, requires .004" depth by laser. I've tried a zillion different arrangements of settings to get me to .004" deep in the shortest amount of time. No matter if I go slower and less passes, much faster and more passes, and every combination in between, my time to an acceptable depth is between 4:40 and 5:00. Any less time spent than 4:40 and it's not deep enough. And working settings between the 4:40 and 5:00 marks I can get an increase in the quality of the engraving without a depth increase. I've given up trying to find a faster way -The routine I run now goes 5:17, insurance that I'll never get any parts NCR'd because they're shallow. I just work on another job during those 5 minutes...
    Last edited by Kev Williams; 09-11-2017 at 7:31 PM.
    ========================================
    ELEVEN - rotary cutter tool machines
    FOUR - CO2 lasers
    THREE- make that FOUR now - fiber lasers
    ONE - vinyl cutter
    CASmate, Corel, Gravostyle


  13. #13
    Join Date
    Dec 2010
    Location
    NW Arkansas
    Posts
    1,951
    Blog Entries
    1
    Yep, you should have seen the look my wife gave me when I mentioned I should get another fiber to not waste time when I was running a 4 min cycle..... I'm not nearly thinking about it now.
    Woodworking, Old Tools and Shooting
    Ray Fine RF-1390 Laser Ray Fine 20watt Fiber Laser
    SFX 50 Watt Fiber Laser
    PM2000, Delta BS, Delta sander, Powermatic 50 jointer,
    Powermatic 100-12 planer, Rockwell 15-126 radial drill press
    Rockwell 46-450 lathe, and 2 Walker Turner RA1100 radial saws
    Jet JWS18, bandsaw Carbide Create CNC, RIA 22TCM 1911s and others

  14. #14
    As for cutting, there is no real advantage to using a MOPA laser source. There are a couple of standard JPT laser sources that are considered MOPA lasers. The M1+ version is a MOPA but with a fixed 200ns pulse width while the M6+ (more expensive) allows you to control the pulse width. Advantages of any MOPA system is that they are more stable and tend to have better specs...beam quality, quicker response times, greater Frequency ranges, better quality at a cost. If you want to do colors on Steel you don't have to move the focus to achieve it. You can get a better dark engraving in aluminum, you can get some lighter engravings in some black plastics and the quality of the engravings are cleaner and sharper if you really, really, really look hard! Good luck trying to see the difference.
    We always use a JPT 60W set-up (M1+) for cutting, cheaper and no performance difference vs the M6+.IMG_20180720_101011.jpg
    Depending on the thickness, material, and curve distance the cutting times can vary quite a lot. This photo shows 2 1mm thick Silver name tages. The top one took about 6 minutes, the bottom one took 10 minutes.
    Floyd
    You can watch the link
    https://www.linkedin.com/feed/update...86205239545856

  15. #15
    Quote Originally Posted by John Lifer View Post
    Nice, Actually If a person were really good with electronics, steppers and controls, I'd bet this would really be something pretty easy to cobble up.
    But not me for sure. Think of turning the rotary into a flat, just long x step rather than turning rotary. This is all that is happening, at least in the video. Now add Y movement driven by controller, that's a different thing. (but that video didn't show that happening)
    Software would be a challenge. Good for a conveyor-belt application.

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