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Thread: I learned a lesson from EBay... 100w fiber

  1. #1

    I learned a lesson from EBay... 100w fiber

    Well Hi yíall,

    This is my first post on here so go easy on me!

    Recently I got the laser engraver itch and decided to purchase a 100w fiber laser off eBay.
    I read all the horror stories, did hours of research and finally narrowed down the unit I wanted from a few different sellers with good reviews.

    Well, I ordered the laser, was in constant communication with the vender and had no issues getting my unit shipped from China to my little part of Texas.

    Well, everything seemed great until I started checking out what it can do. It seemed to not engrave/mark stainless as well as Iíve experienced in the past with a 50w laser my work uses for marking surgical instruments. (Similar galvo head fiber laser)

    I thought maybe it was something in the settings or maybe a loose connection somewhere.
    So I went down the list of troubleshooting and made sure the focus was good and the settings were ok. Everything software wise looks fine.

    So I decided to look at my laser source.... low and behold, it has one label that states 10-50w series but the service tag that has the model and serial number has been scraped off completely. There are some nice gouges where they must of used a scraper on it.

    So to me this indicates that I more than likely have a lower wattage laser than they advertised. Iíve contacted the seller and they insist it is a 100w unit (why would they admit to scamming me anyways) and say that the unit is a genuine 100w Raycus source.
    The laser looks like an authentic Raycus but without the service tag, I have no clue what the power is.

    My question to you all is, is there a way to find out what power the laser source is?


    Iím trying to get them cornered into sending me a 100w laser source for me to install into the unit, but so far they have been giving me the runaround like
    ďCheck marking area sizeĒ
    ďCheck focusĒ
    ďSend video of unitĒ

    Iím about to put in a complaint with PayPal and eBay but Iíd like to have concrete proof that this unit is a lesser wattage than what I paid for. (As if a scraped of service tag isnít evidence enough)

    Any help on how to find the units actual power would be much appreciated.

    Lastly, I will acknowledge that everyone and their mother warned against buying a laser off eBay. I almost went with a US company but after a long talk with the wife, it was determined to be an acceptable risk since eBay and PayPal have a decent return policy.


    Thank you all for your help in advance!

  2. #2
    Depending on how janky you want to go, you could get a block of known material that definitely absorbs the beam, then defocus it and blast the laser at it for 30 seconds and measure the temperature rise. The formula is Q * t = m * dT * Cp, where Q is the power in watts, s is the time in seconds, m is the mass in g, dT is the temperature change in degrees C, and Cp is the specific heat of the material. For example, 6061 aluminum's Cp is 0.896 J/g-C.

    For example, a 100 W laser shining on a 100 g piece of aluminum for 10 seconds should increase by 11 degrees. Note this is *average* power, so adding crosshatching or rastering or something will dramatically reduce the actual "beam on" time of the laser. This is definitely much easier to do with a DC tube.

    Another way to do this if you have access to a 50 W laser is to run the same profile on both and see how they perform, or check the temperature rise on each.

    By the way, it's important to defocus the beam for thermal tests, as if it's focused you may start ablating the material which carries away a lot of heat.

    PS: Someone please check my math

  3. #3
    Join Date
    Aug 2006
    Location
    Suwanee, GA
    Posts
    3,683
    I would file a claim with PayPal and eBay asap, the sooner the better. Send them the correspondence you have so far. This should get the seller to act quicker and hopefully in your favor.

    I did a quick google search for power meters for fiber lasers and there are a lot of various options and I'm not sure which would be appropriate for your machine, or wattage, but you might want to contact some of the sellers to see what might work.

    I would also contact Raycus to see if they can give you any guidance - it might take opening the source to check components, or maybe as simple as checking the power supply - surely there is a big difference between a PSU for a 10-50 watt source and a 100 watt source!

    edit: A quick search on Aliexpress for Raycus sources give me this:

    Output Power (W)
    10
    20
    30
    50
    Power Consumption (W)
    120
    170
    240
    340

    Quote Originally Posted by Ryan Bond Sr. View Post
    Well Hi y’all,

    This is my first post on here so go easy on me!

    Recently I got the laser engraver itch and decided to purchase a 100w fiber laser off eBay.
    I read all the horror stories, did hours of research and finally narrowed down the unit I wanted from a few different sellers with good reviews.

    Well, I ordered the laser, was in constant communication with the vender and had no issues getting my unit shipped from China to my little part of Texas.

    Well, everything seemed great until I started checking out what it can do. It seemed to not engrave/mark stainless as well as I’ve experienced in the past with a 50w laser my work uses for marking surgical instruments. (Similar galvo head fiber laser)

    I thought maybe it was something in the settings or maybe a loose connection somewhere.
    So I went down the list of troubleshooting and made sure the focus was good and the settings were ok. Everything software wise looks fine.

    So I decided to look at my laser source.... low and behold, it has one label that states 10-50w series but the service tag that has the model and serial number has been scraped off completely. There are some nice gouges where they must of used a scraper on it.

    So to me this indicates that I more than likely have a lower wattage laser than they advertised. I’ve contacted the seller and they insist it is a 100w unit (why would they admit to scamming me anyways) and say that the unit is a genuine 100w Raycus source.
    The laser looks like an authentic Raycus but without the service tag, I have no clue what the power is.

    My question to you all is, is there a way to find out what power the laser source is?


    I’m trying to get them cornered into sending me a 100w laser source for me to install into the unit, but so far they have been giving me the runaround like
    “Check marking area size”
    “Check focus”
    “Send video of unit”

    I’m about to put in a complaint with PayPal and eBay but I’d like to have concrete proof that this unit is a lesser wattage than what I paid for. (As if a scraped of service tag isn’t evidence enough)

    Any help on how to find the units actual power would be much appreciated.

    Lastly, I will acknowledge that everyone and their mother warned against buying a laser off eBay. I almost went with a US company but after a long talk with the wife, it was determined to be an acceptable risk since eBay and PayPal have a decent return policy.


    Thank you all for your help in advance!
    Last edited by Gary Hair; 01-28-2020 at 12:03 PM. Reason: added PSU info
    I have done so much with so little for so long, that I can do almost anything with practically nothing...

    Trotec Speedy 400 80 watt 8/2015
    G. Weike LF-30, 30 watt galvo fiber - 1/2016
    G. Weike LF-30, 30 watt galvo fiber - 3/2015
    Fargo HDP5000 Card printer


  4. #4
    Join Date
    Aug 2006
    Location
    Suwanee, GA
    Posts
    3,683
    Just curious - how much did this run and from what seller?
    I have done so much with so little for so long, that I can do almost anything with practically nothing...

    Trotec Speedy 400 80 watt 8/2015
    G. Weike LF-30, 30 watt galvo fiber - 1/2016
    G. Weike LF-30, 30 watt galvo fiber - 3/2015
    Fargo HDP5000 Card printer


  5. #5
    Well, that got me thinking and I went and grabbed my multimeter to check the amperage. The unit pulls .39amps static and .83 amp running a basic cross stitched hatch at 1000 speed, 100% power at 20khz.

    Running the calculation thatís about 199w of total power assuming a power factor of 1 (which I know it isnít).

    Thatís about a 20w system going by what Iíve deduced from the Raycus website.

    Sure does seem like I learned a valuable lesson!

    Well, Iíll tell the seller that they need to send a replacement source with an actual service tag or else Iíll just dispute the charges.

    Iíve already notified PayPal and they said as long as I do it within 180 days, Iím covered.
    Last edited by Ryan Bond Sr.; 01-28-2020 at 12:53 PM. Reason: Accidentally hit submit before finishing

  6. #6
    Goldcnc is the seller. I didnít see the 2 bad reviews until after my order.... when I did, I just crossed my fingers....

    All in all it was about 6k.

  7. #7
    Join Date
    Jul 2007
    Location
    Yorktown, VA
    Posts
    327
    One ebay seller advertised a 30w fiber. In fact they the outer enclosure had a label that said 30w, but the maxiphonic laser power supply label showed 20w. The manufacturer of the LPS said based on the serial number it was only a 20w. The seller indicate they had been dupped as well, yet they continued to sale the three remaining units on ebay as 30w, when there was a 99.9995 chance it was only a 20w.

    Send it back. I doubt they will want to take it back and will most likely just want to issue a partial refund.

    Honest sellers will take care of you and do what is right. They shady ones will drag it out and deny it until you provide you are right.

  8. #8
    Well seeing as the ID tag on this unit has been 100% scratched off, it looks like they didnít even care to try and hide the fact that they put a lesser powered unit in there.... Shame too because the case and everything else is actually very nice and clean!


    I will say they have been responding to emails, so at least I have that going for me.
    Itís Chinese New Years so they wonít be back to work until Friday at the earliest.

    Iím giving them one chance to make it right without excuses. Iíve spelled out how there is no way this is 100w laser according to all documentation and tests.

    Dang shame.

    Luckily itís not my first rodeo with a Chinese seller. Itís just very annoying to have to go through all the hoops with PayPal and eBay.

  9. #9
    Join Date
    Mar 2014
    Location
    Iowa USA
    Posts
    3,494
    The goal of the dishonest Chinese seller is to drag it out as long as they can, until the refund time is up. No labels no tags and 6K for a 100 watt fiber should be your clues. The next thing they will try is have you return it, in the mean time the clock is ticking.
    Retired Guy- Central Iowa. , LightObject 40w CO2 Laser and Chiller

  10. #10
    Yah, itís a shady and petty tactic. Luckily I saved the crate and have no issue with them sending me a prepaid label to return the whole unit.

    I tried going the ďhey you got caught, just make it rightĒ route first but PayPal itís pretty good to make sure those who do service through them donít get screwed. With all the documents and pictures and such, it should be cut and dry.

    Just a bummer and I guess I did it to myself.

    I figured with all the trade tariffs that sellers were dropping their prices to get US customers interested. Well, lesson learned.

    They are gonna be lucky if I donít mark a green laser pen with ďRaycusĒ and strap it to two bags of cement and send that to them.

    (Im not the type to do that, but it IS a funny thought)

    In the meantime itís back to the market I guess. Shame because I really like their case they put it in. Itís not like every other laser Iíve seen.

  11. #11
    You mention running it at 20kHz- Now, I don't pretend to know the 'why' but I've been told by several people, Gary would be one of them -and even read someone's math calculation that somewhat technically explained the 'why' (as in, there's a reason it's not possible-?) -- that-- as I understand it, a fiber laser cannot run at a kHz frequency below its wattage- Which is to say, my three 30w fibers don't or won't fire any lower than 30kHz. But then another question, does 'its wattage' refer to the sources max wattage, or to the actual output wattage while it's running-?

    No clue! But it may have some bearing here, since my machines, with their roughly 80kHz maximum, can't ablate much of anything even at full power... they do, but not like at 30kHz!

    So final question then, if my machines do actually have an 80kHz maximum, and a 100w machine's MINIMUM is actually100kHz by this rationale-- Will a 100w machine ablate similarly at 100kHz as a 30w machine at 30kHz? Or...?
    ========================================
    ELEVEN - rotary cutter tool machines
    FOUR - CO2 lasers
    THREE - fiber lasers
    ONE - vinyl cutter
    CASmate, Corel, Gravostyle


  12. #12
    Quote Originally Posted by Kev Williams View Post
    You mention running it at 20kHz- Now, I don't pretend to know the 'why' but I've been told by several people, Gary would be one of them -and even read someone's math calculation that somewhat technically explained the 'why' (as in, there's a reason it's not possible-?) -- that-- as I understand it, a fiber laser cannot run at a kHz frequency below its wattage- Which is to say, my three 30w fibers don't or won't fire any lower than 30kHz. But then another question, does 'its wattage' refer to the sources max wattage, or to the actual output wattage while it's running-?
    Kev, my understanding is that a 20W at 20kHz or a 30W at 30kHz is putting out about 1 mJ of energy per pulse. Higher than a mJ per pulse seems to be a rule of thumb that either the electronics or the optics, etc. don't like that much energy per pulse and you can damage things. Now, how this applies to a 100W laser, I'm not sure as that was out of my price range and I didn't do much research on them at the time. They may be more robust (to handle higher than a mJ per pulse) or maybe they have a whole different frequency range you have to operate in.
    Licensed Professional Engineer,
    Unlicensed Semi Professional Tinkerer

  13. #13
    Well, looks like the games have begun!

    I sure do love hearing excuses!

    The seller is coming up with every excuse in the book and now says they canít afford return shipping!

    Ahhh Chinese vendors...

    To top it off, I will lose my 5 year warranty for submitting a complaint.

    Shucks....

  14. #14
    I've been around engraving lasers for a while now. I've seen a couple 50W fiber galvo lasers out there but in all the posts I've seen around the internet, I've never seen anyone with a 100W Chinese fiber galvo. I'm confident they are out there, but it just struck me as odd that we've never seen a single mention of them that I can recall. To me, that's a point of interest that, like you, would make me look twice. I suspect a 100W would run into the $15,000-20,000 range. If it was in the $3-6,000 range, I'd say it's no way it's 100W.
    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.

  15. #15
    Join Date
    Aug 2006
    Location
    Suwanee, GA
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    3,683
    Quote Originally Posted by Ryan Bond Sr. View Post
    Well, looks like the games have begun!

    I sure do love hearing excuses!

    The seller is coming up with every excuse in the book and now says they can’t afford return shipping!
    That's pretty funny. My reply would be that they should have considered return shipping when they knowingly shipped you the wrong thing!



    To top it off, I will lose my 5 year warranty for submitting a complaint.
    Like you had a warranty anyway...
    I have done so much with so little for so long, that I can do almost anything with practically nothing...

    Trotec Speedy 400 80 watt 8/2015
    G. Weike LF-30, 30 watt galvo fiber - 1/2016
    G. Weike LF-30, 30 watt galvo fiber - 3/2015
    Fargo HDP5000 Card printer


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