DIY RGB build on MDF with homemade turning/dichroic mounts. Pic heavy!

[LaserAdct]

Some time ago I made my first RGB build on a piece of MDF, see the "Cheap heatsink for ..." in my signature.

Now it was time to "upgrade" to a more compact version with the introduction of turning mirrors into the build + a dual LPC setup with a PBS (the PBS part is not done yet).

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First it was time to plan the build. I used a 10mm piece of MDF with the measures 17.5cm x 12.5cm. Below are a few pictures of the planning stage:

I can recommend using 12mm MDF instead of 10mm for added stability, unless you have a solid scanner baseplate to mount it on.

I am using the same brakets as heatsinks for the modules as I did in the previous RGB build. You can find links to a Austrian vendor of these in the "Cheap heatsink for..." link in my signature. The price was about 7.5 euros a piece when I bought them.

Next it was time to do some drilling. I am using the same procedure as earlier with a 4mm hole going through the MDF from one site and a 8mm hole going half way through the MDF from the backside to "sink" the head of the bolts used (picture from previous build):

Now that I had completed the first steps of the "baseplate" it was time to look at the dichroic/turning mirror mounts. I made these of "L" shaped aluminum profile cut into smaller pieces (3cm width). The aluminum profile is 1mm thick, and plenty sturdy for mounts like these. I have a few pictures below, but only of the turning mounts. I am using the mounts I previous made for the dichroics but the only difference is that the dichroic mounts have a hole in the center, and the mirror is placed on the other side of the adjustable plane.

Coated black:

I used a harddisk plate from a broken harddisk for the turning mirrors. These are really good for the purpose since they are made of nickel coated aluminum plates. The coating is the first surface the laser hits and no back reflection etc will ever occur. Compared to an ordinary mirror where the reflective part is the back surface. Of course if you get coated glass for the purpose you will have just as good a result:

Assembled mounts, without the turning mirror attached:

I also coated the heatsinks used for the laser modules (and the baseplate, but that is not shown in this picture):

Now I had all the parts prepped and was able to put it all together (without the PBS):

The next picture shows a comparison in size to my first build. Its a major improvement in the baseplates overall foodprint

I hooked it all up to 1 x flexmod p3 (have two more incomming in the mail) and two drivers that I made earlier (schematic made by C4R0). Notice that my green is from a crappy aligned chinese junk pointer so the beam is much narrower than it should be. It does not shoot straight out of the module which reults in most og the beam being "eaten" by the inside cavity of the module. Here are some beamshots:

That was about it. Hope someone finds inspiration from this. If there are any questions just post here or shoot me a PM.

Best regards

EDIT: I will update this post when I get my PBS included. I am currently waiting for a few flexmods as well before I can include the PBS. I have started a new project until then - 4x4x4 led cube controlled by an Arduino

 

[noesc]

Excellent creativity and.use of.materials

 

[Bionic-Badger]

Not the most sturdy or precise of beam tables, but definitely pretty cool what you did.

 

[LaserAdct]

Not the most sturdy or precise of beam tables, but definitely pretty cool what you did.

Thanks The precision is actually better than what the pictures indicate. The red and blue mix quite well and overlap almost perfectly. The green however is a different story. It is a very poorly aligned chinese junk pointer that results in a really narrow green beam because most of it is lost on the inside cavity. So the white mix is only occuring in the part of the beam where the green "fills" the blue/red mix :-( This has been a problem for me all along.

I am about to order a 100mw module from O-Like to use in this build instead, and I hope that gives a wider mixed beam ^^

 

[Bionic-Badger]

Actually, DPSS lasers generally have thinner beams anyway. It's just the nature of the laser technology. I have a CNI with a very thin beam, though at ~10m the spot is about the size of a dime (~1.2cm).

 

[LaserAdct]

Actually, DPSS lasers generally have thinner beams anyway. It's just the nature of the laser technology. I have a CNI with a very thin beam, though at ~10m the spot is about the size of a dime (~1.2cm).

I had noticed that the beam specs of greens was narrower, but with this particular pointer its the worst of the bunch that I have, unfortunately its also the strongest

If you have a look at the second last picture its quite obvious how thin the beam on this particular module is. It can be a bit hard to tell/compare, but from a pure visual observation how do you think the beam looks compared to a "normal" green module?

EDIT: The beam is also not shooting straight out of the module, but it is actually tilted in one direction.

 

[Benm]

Thats often a problem with green modules - beam coming out at a slight angle (a degree or two off). It's not that hard to correct if you give the mount a bit of adjustability (i.e. oval holes). The diameter/divergence part of it is more difficult, the only way to really fix that would be using a small beam expander in between... but on the other had the beams will be roughly the same diamter a few meters from the unit anyway.

One thing i'm curious about though: How stiff is that MDF? Do you need to re-align the mirrors/dichros after you move the whole unit around? I've had that using a plastic baseplate (6mm or so thick).

 

[LaserAdct]

I guess I have to live with it until I can get a better module.

The first build was on 12mm and this is on 10mm. That 20% extra thickness does a lot. When I lift the new build from the table the dot (15 feet away) misaligns a bit, but then realigns again once it sits back on a plane surface. I will recommend using 12mm if going for MDF in a hobby build like this. With 12mm there was no misalignment at all, will update the OP recommending 12mm for those that might attempt similar. For me it will be no issue since this setup will be placed on an alu baseplate in the scanner once I find something to put it all in

 

[Solonar]

I used 1/2" MDF on my first scanner build, and I constantly have to adjust my farfield alignment. I'm using 1/4" aluminum on my current build.

 

[LaserAdct]

How much is 1/2 inch in the metric system? :huh: :yh:

Did you use mdf as the actual scanner baseplate, or just the laser part like me? The larger the foodprint the bigger issues with alignment I would imagine

 

[Benm]

Half an inch is about 12mm.

And surely the misaligment gets worse the further lasers, dichros and mirrors are apart, so a compact design is less sensitive.

Using quarter inch aluminium is obviously nice, but it can be fairly expensive stuff if your local hardware store doesnt carry it and you need to have it shipped in.

 

[LtKernelPanic]

Very nice! Your first build is the reason I have a set of 30k galvos waiting for my eventual RGB PJ. FWIW 1 inch = 2.54 cm or 25.4mm

 

[LaserAdct]

Would have been lovely to use a thick aluminum baseplate, but then I would have to think about electrical isolation etc. That will come in the next scanner I make I have ALL bits ready now, but still havent found a suitable housing to put it all in. It has been a looooong process, but mostly due to missing parts like the spring(s) that I use in the mirror mounts. I found a local store just a few weeks ago with the exact perfect pressure spring that I could cut in smaller pieces.

What I really need now is to get some proper software. I have been playing around with HE-Laserscan and LFI player and none of them really does it for me. It has to be Soundcard DAC capable and not be too expensive. I have been looking at noodles, but I dont like that whole 1 license per pc deal where it is locked to a specific machine ID. What a hazzle when that machine dies in the middle of a show or something. Noodles is not the name of this software, but close ^^ for some reason the real name gets converted to ***, but most will probably know which I am talking about. Any suggestions would be nice

 

[Bionic-Badger]

What happens if you try and stiffen the MDF with struts, like some aluminum angle pieces? Those are pretty cheap, at least compared to a full piece of aluminum.

I'm also curious about those 80/20 extrusions (or their different/smaller cousins) and how those might work too. Then you can adjust them along the entire length of the extrusion rather than where the specific holes are.

 

[LaserAdct]

What happens if you try and stiffen the MDF with struts, like some aluminum angle pieces? Those are pretty cheap, at least compared to a full piece of aluminum..

I am almost certain that would do the trick stiffening the board to a point where no flexibility would be present. I will mount the laser assembly on a aluminum plate in my scanner once I find a usefull "host" So I should have no issues with alignment. If MDF is used as the actual scanner base I am sure stiffening with aluminum would make it sturdy enough. However I have a hard time imagining a scanner casing made entirely of MDF/wood Would be heavy as hell and look ancient somehow hehe.

I'm also curious about those 80/20 extrusions (or their different/smaller cousins) and how those might work too. Then you can adjust them along the entire length of the extrusion rather than where the specific holes are

:huh: I am not quite sure what you mean