how indeed does a beam combiner help?

[ivantandy]

as per href:

http://www.lightobject.com/20mm-laser-b ... -P765.aspx


"This is a beam combiner that allows a 10600um beam (CO2 laser) to pass through it like lens. However, it reflects other wavelength light beams, for example, the red laser pointer with 650nm, which is like a mirror. It's ideal to add a "red dot" to target a CO2 laser machine so it's without the hassle of adding a red laser pointer to the laser head."

Can I have a laser pointer help align or is this just an always on spot focus tool... ?

[Tech_Marco]

After the beam combiner set it up, you can use it for CO2 laser 'pointer'. Plus, you can use it to fine tuned the beam alignment which is the most difficult to do.

Marco

[lcornwell36]

Is there any documentation that explains how to setup a beam combiner?

[NickWL]

Will the LightObject beam combiner fit into a K40 - and are set-up instructions available for this configuration?

[lauckstreet]

I installed one on my 600x400 80w laser and I can tell you exactly how it works and how to set it up. Basically it is mounted between the end of the laser tube and the first mirror. It should be mounted very close to the laser tube but not touching as shown in this photo:

Inside the mount is the 5 volt red dot laser. You'll have to hook that up to a 5 volt DC source. I have mine activated by a switch to turn it on and off.

The mount must be at a height that the laser beam passes through the opening. The beam combiner is a special lens that sits at a 45 degree angle. Inside the tube of the mount is the red dot laser. When it hits the angled lens, it bounces off of it as though the lens were a mirror. But when the laser hits the lens, it passes through it.

On top of the mount are 3 adjustment screws. These are used to adjust the red dot so that it hits the same point that the laser is hitting.

The way I use mine is to align the mirrors. I drew a target in AutoCAD that is the exact same diameter as the mirror. It has a cross hear in it. I printed a bunch of these targets out.

First I cut out a target and used scotch tape to tape it over the piece of metal with the hole in it that is in front of the first mirror. I fired the laser at 20% power which leaves a small scorched ring on the target. I then adjusted the red dot laser/beam combiner to put the red dot on the target where the laser beam hit.

If the laser beam does not hit the center of the target on the first mirror, you can adjust the mirror mount left and right ONLY. The first mirror MUST be level with the second mirror and the second mirror must be level with the lens mount mirror. Do not adjust the first mirror mount up or down if the beam is hitting high or low. Instead, adjust the height of the laser itself. Make sure the laser is also level or just slightly higher in the front so that air bubbles in the waterline can easily escape.

Once you get the laser hitting the center of the target in the initial mirror and the red dot has been adjusted to also hit the center, remove that target and put a new one on the second mirror. The red dot can now be used to adjust the first mirror.

When firing the laser and making adjustments to the second mirror target, do not adjust the second mirror, adjust the first mirror until the laser beam is hitting the target in the center on the second mirror. If the red dot is slightly off from where the laser beam is hitting, adjust it. Remember, you adjust the red dot laser's position with the adjustment screws on the beam combiner.

You must test this at the forward most position of the y axis and the aft most position of the y axis. You may have to adjust the red dot laser some when you do these test until the red dot is also hitting the same point on the second target as the laser is hitting.

The next adjustment is on the second mirror. Put a target on the lens mount opening and fire the laser. Adjust the second mirror to get the laser to hit dead center on the lens mount target.

You must do this alignment at the far left and then the far right position of the x axis.

Check and recheck these alignments repeatedly until you're satisfied that the laser is hitting the center of each target at each extreme location of the axis. Also make any necessary adjustments to the red dot laser to be sure it is also hitting the center of each target at each extreme location

The final adjustment is on the the lens mount itself. To make this adjustment, you'll need a target that is the same diameter as the lens mount. Print several of these as well.

Remove the lens from the lens mount and the coned shaped end so that all you have is the hollow mount that the cone and lens fit into. Move the axis somewhere away from the sides, front and back. I used a small modelers square I bought from Micro Mark called a mini square, part number 82147 for this step.

I use a 3/4" piece of wood where I tape the target onto the board with scotch tape. Then using the mini-square, I align the edges of the target with the edges of the tube. Once I know it's aligned, I fire the laser to see where the beam is hitting the target. Then adjusting the screws on top of the lens holder, I adjust the red dot to hit dead center in the target. Then I fire the laser again and it should hit exactly where the red dot is hitting, dead center of the target.

When you've got the lens mirror adjusted you are good to go and should use the lock nuts on each mirror mount to lock your adjustment screws in place.

Without the red dot laser and beam combiner, I found it nearly impossible to get proper alignment of my laser so that it's full power came to bear on what I wanted to cut. The most critical adjustment is the final mirror in the lens mount. Using these procedures, you'll have the laser passing straight through the cone tube at the bottom to give you maximum beam concentration.

[NickWL]

Great description lauckstreet - many thanks.
(still need to know if it'll fit in my K40 - looks too tall, but I'm wondering whether the 'post' is a critical part or could I cut it down? Any thoughts?

[Tech_Marco]

Won't fit. Don't waste money on it. K40 got no room for it

Marco

[NickWL]

Thanks Marco!
BTW, I've just blown another ammeter - don't know what this is about, but my old teacher in the PC repair business (that's my main job) also said: "always look at the connections" - so I will. Meanwhile I'd better order a couple more...

[jeckardt]

While there certainly isn't room enough for this combiner mount in the optimal position between the laser tube and first mirror on the K40, couldn't it instead be mounted horizontally between first and second mirrors against the back wall of the cutting compartment?

[Tech_Marco]

Sure you can do it.

Marco

[jeckardt]

Marco,

Can you describe how the "standard" combiner mount is supposed to be used? Which side does the CO2 beam enter? I'm guessing the side with the "small" opening, which is presumably also where the combiner mounts? Meaning the reflecting surface is facing the adjusting knobs?

I'm trying to envision how I'd mount this thing in a K40 on the back wall of the cutting chamber. I'm thinking a simply "L" platform connected to the back wall below the beam path would do the trick.

Thanks,
Joe

[Tech_Marco]

The side with screws are facing the laser tube. The hole with threaded is the output and facing to the first mirror or second mirror if there is no room to place the mount in between the tube and the 1st mirror


Marco

[AndyKunz]

Like this. Tube is to the right of the blue beam combiner.

[parco]

I just ordered the combiner and lens but it does not have the black piece screwed into the back end. Where the threads are looks like it may have had a piece screwed in there.what would that be for? Also I have a gwieke l900 and it is too short to reach the alignment with the tube and mirror.any suggestion.oh and it will not fit between tube and first mirror, how can I align this?

[Tech_Marco]

I just ordered the combiner and lens but it does not have the black piece screwed into the back end. Where the threads are looks like it may have had a piece screwed in there.what would that be for? Also I have a gwieke l900 and it is too short to reach the alignment with the tube and mirror.any suggestion.oh and it will not fit between tube and first mirror, how can I align this?

The "Black" piece is a beam expander, it is not included.

Marco