Here is a design for a simple tool for aiding laser alignment.
It consist of ten layers of transparent 3mm acrylic 30mmx30mm in size, each with a laser etched 1mm graticule.
The layers are aligned and held together with three bolts.
The laser is height adjusted to have it’s focal point 15mm beneath the surface of the block.
The block is placed on the bed and the laser pulsed. The entry and exit coordinates of the beam can then be estimated by examining the top and bottom layers. Our laser seems to exhibit a drift of around 3mm in 30mm which is a ratio of 1/10, ArcTan 1/10 ≈ 5.7 degrees, suggesting our laser is probably between 4-7 degrees out of allignment.
Track of the laser path though the alignment block
Nice. Good sleuthing. If you now drip a few drops of the dichloromethane on the 4 sides of that stack, you can remove the bolts and any unsteadyness they may be imparting.
This is a really, really great idea, and fantastic testing already @stochastic_forest. Perhaps we could have a laser hacking session and get it properly aligned once and for all!
The only thing I can possibly criticise is that the block looks a little expensive to make in materials and time. I would say to accurately tune the laser, we’d need to repeat this a lot.
May I suggest something along the lines of http://www.instructables.com/id/Ballistic-Gel/ with some paper printed targets stuck and aligned onto it? I’m sure we could come up with a setting jig to align everything.
As far as I can see, the additional target layers are useful but not necessary?
No you are right the middle layers aren’t strictly necessary though I think they do help with alignment, but on the upside you can see the degree of focus as the beam progresses through the block and it’s like having your own mini cloud chamber
With regard to economy, the block can be used multiple times as each laser track is clearly identifiable.
For extra fun you could shine a laser through the track and get a larger baseline, but I’m not sure the length and registration of the cube layers would make it super accurate.
I do like the cloud chamber aspect! It’s why I had ballistic gelatine in mind, you’d get that effect too. I will come to the space with some if we decide to mix it up, and perhaps with a laser pointer too.
