PLD-40 Fiber coupled laser diode, for CNC cutting/engraving

[paul1598419]

So you are actually just looking for a variable focus like you might get with a BE? That 16mm lens is very inexpensive, but how will you mount it?

 

[Alaskan]

That lens barrel has a long thread on it, lots of room to focus, what say Red?

 

[paul1598419]

How large can the lens be? This one is 16mm in diameter.

 

[RedCowboy]

Yes I think the module will be fine for my purpose, but if I wanted to use a bare lens I could make or buy a holder and make a mount.

I did order a 30 and 39mm FL as backups and for testing although they will take weeks to arrive.

I would probably use a 16mm ID tube with rings cut from a 16mm OD tube for seating the lens, ( after checking the exact lens dia. ) then mount my fiber in a 16mm OD length that could slide to focus inside the 16mm ID that holds the seated lens. There's plenty of aluminum tubing on ebay, I would polish it to a mirror finish so it wont seize up.

A slide to focus flashlight head could be adapted to work as well, I could get Rich to make a pocket for the lens in an insert, basically a heat sink that holds the lens so it's centered and square in the sliding head, then mount my fiber behind it and attach to my body for the module/driver and batteries, I am thinking about a using a 3 x 26650 housing and a blackbuck 8 driver, it will look a lot like that 5w 650nm that RT built, only no epoxy, same 3 x 26650 flashlight housing as it has a nice wide head and flat mounting area on a threaded screw in plate, I am debating using a TEC/fan or not, for 30 second duty cycles driven by a BB8 it may not need it but I sort of want to build it into a home made aluminum....imagine an aluminum sleeve of soda crackers made from aluminum plate.....I'm undecided, but 1st I will do some testing once I have all my parts, then decide on the finished build.

 

[Alaskan]

Seller confirmed the lens has a color in the listing photo due to AR coating, not just to represent NIR, I’m going to order one now too.

 

[RedCowboy]

I'm still waiting for my epoxy and module, but I was checking the fit of my fiber and noticed my termination/connector has no hole for the fiber, do I maybe need to polish the end to remove the shiny ceramic cap in order to expose the hole ? It's a shiny ceramic ferrule with no hole, when I put the fiber in from the other end it stops, I looked under a magnifying glass and saw no opening at all.

I will try polishing it when I get ready to see if removing some ceramic from the end exposes the opening and likely order the ST connector that Buontinh ordered as well.

----edit----
Ok after polishing the end with the coarse film I can see a tiny hair wide hole, it's super tiny and looks smaller than the stripped glass, it appears the 126um is the correct cladding size but the fiber I think is multi mode and the ferrule has an opening for very thin single mode, looks like we will need a different termination/connector.

Buontinh used this one : https://www.thorlabs.com/thorproduct.cfm?partnumber=30128C3

 

[Alaskan]

That's strange, I see a fiber in the middle, but I don't think it is a hole, or is the fiber supposed to push through? Shine a low power laser point up through the connector, I bought the same one you did from the same seller:

 

[RedCowboy]

The stripped glass doesn't seen to want to fit through it, yes we have to put the stripped glass through the hole in the ceramic ferrule then score and pull to break it clean along with dabbing it in epoxy and then 24 hours later polish the end flat and clear.

I think that hole is too small.

I don't have the epoxy yet but the stripped glass wont even fit through the tiny hole.


----Edit----
I may not have enough bare glass stripped, let me strip some more and see if the cladding is bottoming out, update in a few.

 

[Alaskan]

Can you see a hole using your USB micro magnifier? I can see it when holding a magnifying glass up to the end. I guess you are right, either the hole is too small, closed, or this connector has some kind of coupling inside to push the fiber against (although, you are probably right, not meant to be used that way), but I'm only familiar with those when they have index matching gel in them and seal closed when crimped.

 

[RedCowboy]

Ok this is my mistake, I did not have enough glass stripped and I can't see without my reading glasses, I stripped some more and it fits just fine.

IINM we will get the fiber stripped so the colored cover fits into the input and bottoms out after dipping the stripped fiber into epoxy, then insert as I just did......and score the fiber, pull the glass to break it away and dip the tip in epoxy and let it cure, then polish in the puck with the corse then fine sheets until the glass it flat and clear at the tip of the ceramic ferrule.

My termination doesn't appear to be a crimp type, I assume the epoxy will secure it.

I ordered this epoxy >>> https://www.ebay.com/itm/Fiber-Opti...PwAAOSwAL9UkEi~:sc:USPSFirstClass!30083!US!-1

 

[Alaskan]

Oh, good, I was thinking I had to order a different connector :beer:

 

[RedCowboy]

We still may want a thread type ST connector depending on what we want to connect to, I am planning to use that lensed module but if I buy a lensed coupling then I may want to put on a threaded type ST connector, at least we will have learned how to do this. :beer:

Just this last year I have really started to need low power reading glasses, just normal age related inability to focus up close, I used to be able to count the hairs on a fly's azz. :/

 

[Alaskan]

I have some optics which need a ST connector too, at least, I think that is what they take, I need to research this, I've been coasting on this project just following you

My eye sight for close in work started to get where I needed reading glasses about ten years ago, it sucks, but good thing we have glasses, without them for close in work, I'm Mr. Magoo.

This just came in the mail yesterday too, something to collimate the output of the fiber with, but too large to put in a pointer:

 

[RedCowboy]

Yea, that's one thing about the nifty 150.00 lensed coupler that Buontinh found, it's supposed to work with the terminated fiber, I may look into what else is available, if I terminate everything with a standard connector then I could share the nifty lensed coupler between lasers, just remember to put the dust cap on the connector and I should get one of those clicky type cleaners...This>>>> https://www.ebay.com/itm/One-Click-...itm=111647009483&_trksid=p2047675.c100623.m-1

Of course the diffraction limited lensed coupler is made for the wavelength so any other module of another wavelength would need it's own tuned lens anyway, I really want that 500w unit :eg: however I would like to get it at a better price.

I will see if that lensed module will work with the raw fiber output once it arrives and I have the termination polished, from what I have seen people using online I think it will.

p.s. That's a nice collimator you have there, does it adjust for alignment as well ? I see knobs on the top and side, so it looks like it will.

 

[Alaskan]

Yes, looks like made to hold a bare fiber, it moves in and out for focus and has X-Y adjustment. The 500 watt is cheap, but not cheap enough for me either. I saw that one click cleaner too.

 

[RedCowboy]

Well a quick update, I received my epoxy, it's a clear 2 part deal where you break the inner seal and mix it then apply it.

I stripped my fiber to length and slathered it in the epoxy then stuck it into the termination until it bottomed out with a little stripped glass sticking out the end, it says it will cure in 24 hours at room temp so this weekend I will see about scoring the bit sticking out of the tip and try to polish it.

I should have bought some extra connectors and epoxy packets but if I screw this up I will order more and try again, once we get some practice this should be no big deal, my lensed module is finally in the US according to tracking so hopefully I will get it soon, I don't mind buying a lensed connector like the one Buontinh referenced for 150.00 but I really want a big SOB pump of 100W + and I may as well save those funds for the bigger build unless what I buy will work with a 100-500w unit, I like the collimating unit you bought, it should work with a variety of fiber diameters, good choice. :gj: