Mirror alignment

Discussions on optics for laser cutter/engravers

Mirror alignment

Postby artwood_decor » Wed Oct 10, 2012 3:43 am

I have used this method of alignment and since it worked great I thought it is worth be shared here.

I have used some temporary MDF guides which centered in the laser tube brackets, helping me determine the nylon screw position using the smaller diameter.

The disks in the center I cut on the PCB cnc machine at work. The hole is 0.5mm so it will force the beam to stay sharp and centered.

These guides worked so well that I used them to align all the mirrors and when I put the tube in place and fired for the first time it burned a nice round shape 4-5 mm diam in the wood on the table (the lens is not installed yet).

The red dot is not very visible on the mirrors, so I temporarily used small pieces of masking tape.


IMG_0039.jpg
First guide holds a small red pointer laser


IMG_0040.jpg
The pcb material (fiberglass + copper) has a hole 0.5mm


IMG_0042.jpg
Second guide. The beam passes through the second disc and can be seen on the cardboard box behind (where the first mirror sits).


IMG_0041.jpg
Both guides seen here
artwood_decor
 
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Re: Mirror alignment

Postby Techgraphix » Wed Oct 10, 2012 8:35 am

I did the same, thought it was THE solution...
Unfortunately, when i placed the actual tube it really was so wrong.. despite all the effort..
Just center the beam on the first mirror using a paper sticker with low power (just color the sticker.. it's wise to cover the actual mirror first or place it afterwards)
Move the second mirror close to the first, do the same. Move it as far as possible, fire again, align the dots etc etc..
There are many tricks and how-to's on the internet..
I think you can align all the mirrors in about 5-10 minutes..

Kees
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Re: Mirror alignment

Postby dren.dk » Wed Oct 10, 2012 8:52 am

I got myself some heat-sensitive labels for a label printer, that I stick onto the mirrors to align the beam.

To avoid messing up the mirrors, I add a strip of tin foil to the back of the label where it would come into contact with the mirror.

Even with 4 mirrors to align the entire process takes about 15 minutes and there's no danger of the visible laser disagreeing with the actual tube.
dren.dk
 
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