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View Full Version : Experience: Cheap eBay focal lens from China



Henri Sallinen
10-02-2014, 3:35 AM
Just thought I'd share my experience about a cheap focal lens I ordered from China via eBay. I decided to try the eBay lens out because it cost about 85% less than from a local dealer and I was not in a hurry to get a new focal lens.

I placed the order for a "New HQ ZnSe Focal Lens for CO2 Laser Cutting Engraving Diam 18mm FL 50.8mm" on 4. september. I decided to go with the lens that said "Origin USA" and pay a bit of extra (bout 50$) compared to the one that didn't say the origin so precicely. The seller was called win-win-mechatronic. They sent a message the very next day that the item had been shipped. I received the lens yesterday, October 1. so the shipping took almost a month. Was getting a bit worried, but thankfully everything went ok with the delivery.

The lens was wrapped in a protective tissue and placed insice a cushioned plastic case. The case was then enclosed in a bubble wrap envelope.

The original lens on the Epilog machine is 1 mm larger in diameter than the one I ordered, and this was because they only sold 19.5mm (instead of 19mm) lenses and I was not sure if the tiny bit larger lens would fit in the case, so I ordered a smaller one instead. The 18mm fits in nicely, although you have to carefully align it to the center of the chase before tightening the screws. I'm thinking of placing something around the lens (or the lens chase) to keep it in the middle more easily.

Then to the cutting results:

I had noticed a bit of a power loss since my old settings weren't quite making it through the materials I had cut before with ease. This was probably because my focal lens had lost the surface coating and had a few scratches because of inappropriate cleaning techniques (my mistake I won't be doing again). When I placed the cheap focal lens on, my old settings started to cut through again. I've only done a few cut tests, but so far it seems that the cheap eBay lens gives as good of a cutting result, as the machine used to have with a non scratched original lens.

Hopefully this experience is of use for someone!

Mike Null
10-02-2014, 8:34 AM
Thank you Henri. Good information.

Dave Sheldrake
10-02-2014, 8:46 AM
Chinese 19.5mm is in fact 19.05mm Henri (ergo 3/4") probably a missprint as winwin's English isn't great.

cheers

Dave

Henri Sallinen
10-02-2014, 8:57 AM
Been testing out a lot of different engravings along the day including stamp rubber, metal + cermark, matboard and everything seems to work just fine if not better. So no problems with the new cheap lens so far.

Henri Sallinen
10-02-2014, 9:00 AM
Thanks for the tip Dave!

I had similar thoughts when ordering the lens but since I wanted to be sure that the first test lens would fit, I went with the smaller diameter.

I'll have to order another lens in the future with a longer focal lenght and try the 19.5mm (or 19.05mm) diameter.

Bill George
10-02-2014, 9:07 AM
You don't have to order from China, LightObject carries in stock and they are based in California. I have ordered from them in the past and find they ship fast and products are good.

Henri Sallinen
10-02-2014, 9:58 AM
Bill: That might be true if you live in the States

I've found out that when I try to order from US, the postage fees are almost as much as the products itself!

John Bion
10-02-2014, 10:18 AM
Bill: That might be true if you live in the States

I've found out that when I try to order from US, the postage fees are almost as much as the products itself!

Same problem from the UK

Julian Ashcroft
10-02-2014, 10:28 AM
I have the same lens, which I bought from Hong Kong. It arrived in around two weeks (I was expecting it to take longer). Haven't tried it yet as I just got it as a spare. Cost was £13.53 including delivery.

Jed Lawrie
10-02-2014, 4:48 PM
Thanks for the review! Some of their OEM stuff can be expensive! Glad to see there are alternatives out there.

Mike Westbrook
10-05-2014, 5:09 PM
Thanks Henri,

I am in the the middle of a tune up on an Epilog Mini 24. I just ordered the 19.05mm lens from China. Hope it works as good for us but glad to know it's successful for you. I am replacing the lens, mirror, x drive belt, and ribbon cable that attaches to the encoder. Expecting to spend about $150 to replace these parts. Getting the drive belt, mirror, and ribbon cable from Epilog. If the Chinese lens performs well I will order a 4" version from there as well. Can't beat $29 plus free shipping for a 2" lens! Could replace it 6 or 7 times for the price of one from Epilog.

Chuck Stone
11-01-2014, 1:22 PM
I'm about to find out..
I ordered a 2" lens, a 1.5" lens and 3 mirrors.
Came to about $138 including shipping and
got here in about 10 days. (marked 'shipped' within
2 hours, but took 4 days to actually get to a post
office in China) got to the US 3 days later.

I just cut a new acrylic lens holder to test one out, but is
there something special about glue? Something I should
avoid? Anything I should use that I don't have? Don't
want to ruin anything before I even get started..

walter hofmann
11-02-2014, 5:21 AM
hi there
just my two cent on lens, I use GaAs lens for $34 including shipping from china and they are super excellent much more cutting power then the best ZnSe lenses and much more scratch resistance.
greetings
waltfl

abby ZHANG
11-05-2014, 3:20 AM
about focus lens

most of china focus lens Diameter is 20mm America focus lens Diameter is:19.05mm

Chuck Stone
11-05-2014, 9:08 AM
the ones I just got from winwin are both 19.05mm

Paul Phillips
11-05-2014, 10:55 AM
hi there
just my two cent on lens, I use GaAs lens for $34 including shipping from china and they are super excellent much more cutting power then the best ZnSe lenses and much more scratch resistance.
greetings
waltfl

Walt, just curious, if they are that much better with "much more cutting power" than ZnSe lenses then why don't they use them as the standard over ZnSe? Correct me if I'm wrong but I believe the majority of engraving industry lasers come standard with ZnSe lenses, at least my ULS machine did.

Martin Boekers
11-05-2014, 11:18 AM
The last 2" lens I ordered from Epilog in May 2013 was $108.00, got it in 3 days no worries as it came from Epilog.
I think the pervious lens that I bought many years ago was quite a bit more... I run 2 lasers 6hrs a day 5 days a week
so I don't mind paying a few extra $$ for service. The longer a laser is down the less profitability.

Always check pricing first from the manufacturer then make your decisions upon your situation. ;)

Bert Kemp
11-05-2014, 11:31 AM
Chuck,
Is that what you ordered ?or did you order 20mm and they sent 19.05

the ones I just got from winwin are both 19.05mm

Martin Boekers
11-05-2014, 11:50 AM
If you buy a lens other than OEM how do you adjust for focal distance?

John Noell
11-05-2014, 12:41 PM
I got the same focal length lens (from Mellor), popped it in the holder, double checked focal distance, spot on, done!
I also got a slightly longer fl lens (2.5"). Did the slanted piece of anodized to find best focal distance, cut a quick gauge to match, done. (I was cutting a lot of curved stuff and wanted just a bit more depth of field.)

Chuck Stone
11-05-2014, 1:22 PM
I ordered 19.05 and that's what I got. $29.
Made a holder and popped it in. Focus is right on.

Martin Boekers
11-05-2014, 1:22 PM
I got the same focal length lens (from Mellor), popped it in the holder, double checked focal distance, spot on, done!
I also got a slightly longer fl lens (2.5"). Did the slanted piece of anodized to find best focal distance, cut a quick gauge to match, done. (I was cutting a lot of curved stuff and wanted just a bit more depth of field.)


Thanks John! I forgot about that test!

Dave Sheldrake
11-05-2014, 4:27 PM
GaAs lens's tend to be less subject to scratching or heat damage, their actual pass through rate is lower so the top power they can produce is below that of a ZnSe however they do tend to be Plano-convex rather than meniscus giving a slightly different cutting structure.

cheers

Dave

Tim Earling
02-24-2015, 3:56 PM
I need to replace my mirror and lens on an Epilog Mini 24x12 45 watt 2004 machine.
I wanted to try the cheaper China manufactured lens and mirror that the company lightobject. com sells. However, I noticed they have a few different diameters and wanted to make sure I order the correct one.
I measure my lens and mirror and both are 19mm. I was told that the mirror is normally slightly larger than the lens and just wanted to confirm it's the same size with others who may have ordered both from a 3rd party supplier.
Also, any recent feedback on how the lens are preforming?
Thanks

Chuck Stone
02-24-2015, 6:15 PM
no issues on my end.. they were exactly as described.
Cutting and engraving just fine.

Chris Corwin
02-24-2015, 6:56 PM
I have noticed a difference at LO between the standard quality lenses and high quality ones. You can see clearly through the high quality lens and show a definite improvement in cutting power. The standard quality lenses are cloudy and I can confirm the laser needs more power to do the same cut. I run two 80w lasers in school and the cheaper lenses tend to burn out sooner. I'm sure my air assist was not as clean and dry as I would like it but there is a true difference.

Tim Earling
03-12-2015, 1:24 PM
I ended up buying a lens ($50) and mirror ($25) from lightobject.com out of Sacramento. They were very helpful and the lens and mirror fit perfectly in my machine. I have noticed a difference in sharpness and power, both are much better. I have only had the lens in for a few weeks, but it's working great.

Chris Corwin
03-13-2015, 11:09 PM
I ended up buying a lens ($50) and mirror ($25) from lightobject.com out of Sacramento. They were very helpful and the lens and mirror fit perfectly in my machine. I have noticed a difference in sharpness and power, both are much better. I have only had the lens in for a few weeks, but it's working great.

Good choice! Just make sure you clean it regularly and it should last a long time.

Ray Scott
03-15-2015, 3:46 PM
I think the point of all the measurement stuff.. Make sure you order whatever your laser machine needs. Most Chinese laser machine are 20mm Diameter lenses and 25mm Diameter mirrors. Most American laser machines use 3/4 inch .. (0.75 inches is 19.05mm)

About the glue .. Many of the USA laser systems glue the lens into a holder. Make sure to use the special "Low-Odor" glue with minimal fumes. You otherwise need to mitigate all the fumes while the holder is drying.

Ivica Vasic
02-20-2016, 9:13 PM
Thanks for the tip Dave!

I had similar thoughts when ordering the lens but since I wanted to be sure that the first test lens would fit, I went with the smaller diameter.

I'll have to order another lens in the future with a longer focal lenght and try the 19.5mm (or 19.05mm) diameter.

Hello..
Have u tried to order 19.05 mm lense?

I have Epilog Helix 40 watt laser with 2'' 19.05 mm lens and I m just about to order new lense because old has lost its clearness and the protective layer is all peald off!
I have dillema where to buy...from Epilog or some chinese seller!
Thank you in advance!

Ivica
Serbia

Kev Williams
02-21-2016, 1:23 PM
I've bought two 4", three 3", three 2" and one 1.5" cheap ebay lenses. Around $21 each IIRC...

I've broken two (my fault), had two crack (partly my fault, something on the lens superheated I guess), and they tend to scratch easily.

But-- Even cracked, and one with an overheat stain, I've seen no engraving difference with them.

And- I've used a couple of them on my LS900, and found no noticeable engraving differences between the cheap and my original Gravo lens.

So yes, they seem to have durability issues, but, since I can't detect any appreciable engraving differences between them and my 'good' lens, I see no reason to pay $100 for ONE when I can get 4 or 5 of the cheap version for the same price, and get a variety to boot...

As for CUTTING, I don't have enough experience to know... :)

Ivica Vasic
02-21-2016, 8:08 PM
In first thread u said that u bought smaller 18mm lens because u didnt know if bigger will fit in original case....Did you bought again smaller or this time u bought bigger ... 19.05mm