Trouble aligning laser diodes

Hey all,

I'm trying to get these laser diodes in a straight line. I 3d printed a holder for them to make this easier, but it didn't help all that much. I know that there will be some natural angling issues because the diodes are not 100% snug, but I think there may be some issues inside the diode as well, like the laser itself isn't aligned all that well. I've attached some pictures below. Any advice would be greatly appreciated! Should I buy other diodes, or is there a good way to go about adjusting the diodes I already have?



If you tap a hole in the side then you can insert a screw to press against the diode and get horizontal adjustment. If you tap a second hole at 90 degrees to the first then you can get vertical adjustment. That second hole isn't possible when you have the diodes in a row of course; you could either make two holders in the shape of a square each holding four diodes or one large holder in the shape of swastika.

Tap a hole for 6-32 set screw at center line of bore on each side to get the lateral adjustment.

try to burr a notch in the back at the top and bottom and insert a 6-32 x 1/2 screw in the top (to raise) or bottom (to lower) for verticle adjustment.

This method won't give you a great deal of adjustment, or any precision. But, it is better than nothin'.

Adjustment screws should be 1/4 circle apart but they don’t have to be vertical and horizontal wrt the stick they’re in. Set them at 45 deg angles and if you have to have V and H then tilt the stick 45.

|
V
| <— the stick
|
V <— adjustment screws
|
|
V
|

And you’d need something spongy/springy opposite the adjustment screws for push-back.

Every time the distance between the stick and wall changes, you will be busy with a screwdriver.

Goforsmoke,
From what I gather... I really like that idea, but I can't really understand what you're saying. Would you mind clarifying? Whats the stick?

The white plastic stick you made to hold the leds.

You could try to angle adjustment screws in from the sides so the screws are 90 degrees apart. The screws would adjust along one diagonal each instead of horizontal and vertical.

OTOH you could try using shim wedges in the holes that hold the lasers. That would be thin tapers going through the holes, how far any one is in or out would change the taper thickness between the side of the hole and the laser with a good bit of in and out making small change in aim.

Can you print individual led holders with a finger length stick out the back? Then that stick becomes a lever long-arm you can adjust easier than the little body of the laser. But how you mount and hold that I just dunno.

Better idea than mine. Good one, smoke.

Yeah but will it be enough?

You see what I mean about lever arm? It's like having a big dial vs a small dial to fine tune a radio. The diodes are small diameter so hard to adjust.

Another thought that might be better for staying aimed... put the diodes in ping-pong balls or the like and cut holes to hold them in stiff foam. Then turn the smooth ball to adjust aim and see if the foam holds it there. If the foam has some spring-back you might have to wiggle the ball as you aim or shave the hole a bit bigger. It's possible that square holes will do but I'd try round ones first.

That idea has the lever arm and a possible way to hold aim. Call it laser ball turrets.

Short of remaking the entire fixture, I would be tempted to pull the diodes out through the front (leaving the wires attached) clamp the holder in a vise close to a wall, and mark the intended "targets" for each diode on the wall. I would (working quickly) put a glop of hot glue in the diode holder hole, pull the diode back into the hole and attempt to align it to its intended target while the glue sets up. This is obviosly not a permanent / high temp solution, but for prototype work it will likely suffice. For a more workable and permannt soulution you could employ a 5 minute epoxy compatable with the poly resin you are using for the 3D printing, the downside of which is that those diodes are never coming out of there again.