DT-40 block mounting

[blowfly]

Hi guys,

What's the best way to mount a scanner block? I was thinking of drill and tapping all the way through the base plate, and bolting the block in from the other side.

Here's a pic of my scanner block:


The DT 40 also came with an extra mounting plate which I haven't found a home for yet. As since in the final pic, it doesn't seem to fit with the block. Do you guys know where it is intended to go?



Suggestions appreciated. Thanks!
Mike

[buffo]

I was thinking of drill and tapping all the way through the base plate, and bolting the block in from the other side.

That's the way I did it on my projector.

Another option is to use the second plate you have, assuming it's larger than the scanner block (hard to tell from the pics). Drill holes through the second plate so they line up with the mounting holes on the scanner block. Now deeply countersink one end of those holes. Then bolt the plate to the scanner block. With luck, the heads of the allen screws will be below the surface of the plate. Now drill and tap holes in your optical plate and bolt the plate (with the scanner block attached) to your optical plate.

Adam

[blowfly]

That's the way I did it on my projector.

Another option is to use the second plate you have, assuming it's larger than the scanner block (hard to tell from the pics). Drill holes through the second plate so they line up with the mounting holes on the scanner block. Now deeply countersink one end of those holes. Then bolt the plate to the scanner block. With luck, the heads of the allen screws will be below the surface of the plate. Now drill and tap holes in your optical plate and bolt the plate (with the scanner block attached) to your optical plate.

Adam

Ah, this makes sense now. After careful inspection I noticed that the center hole in the plate is not perfectly centered. Two of it's countersunk holes fit perfectly with the scanner block. I could screw the block into the small plate, and then screw the small plate into the optical plate. I guess there are pros and cons for this. On one hand, the scanner is more centered in the aperture window of the case when using using the small plate. The small plate isn't anondized though so I'll need to spray paint it.

Should I put heat sink paste between the block, small plate, and optical plate? The DT-40 came with a blob of paste and this seems like the most logical place.

Do people ever use heat sink paste between the laser modules, drivers, and PSUs and the optical plate?

Thanks for your help Adam.

Mike

[buffo]

Should I put heat sink paste between the block, small plate, and optical plate? The DT-40 came with a blob of paste and this seems like the most logical place.

You can if you want to. I didn't. Scanners don't get *that* hot... If you've got a little air flow through the case you'll be fine.

Do people ever use heat sink paste between the laser modules, drivers, and PSUs and the optical plate?

My lasers all have thermal compound between them and the floating tables they're mounted on. Then again, my floating tables are quite small, so I figured it was a good idea. But the drivers and PSU's are just mounted straight to the baseplate with screws. No thermal paste at all.

Adam

[blowfly]

You can if you want to. I didn't. Scanners don't get *that* hot... If you've got a little air flow through the case you'll be fine.
My lasers all have thermal compound between them and the floating tables they're mounted on. Then again, my floating tables are quite small, so I figured it was a good idea. But the drivers and PSU's are just mounted straight to the baseplate with screws. No thermal paste at all.

Adam

Cool thanks Adam. I'm hoping to get away with using floating tables if I don't have to. The case would be more flexible to changes with floating tables. There isn't a ton of clearance in my case though and it seems like a good idea to leave some space for airflow.

Mike

[buffo]

Cool thanks Adam. I'm hoping to get away with using floating tables if I don't have to. The case would be more flexible to changes with floating tables. There isn't a ton of clearance in my case though and it seems like a good idea to leave some space for airflow.

I'm confused. Did you mean to write "without" instead of "with" in one of those sentences? Because as it stands now, I can't tell if you want to use floating tables or not.

Truthfully, the ideal layout is to add an extra bounce on the beams that hit the dichros. That way all lasers can be mounted directly to the baseplate, and the first bounce mirror is used to steer the beam to the precise intersection point on the dichro face for near-field beam alignment, while the dichro mount itself can be adjusted to correct the far-field alignment.

Such a dual-bounce layout is *very* easy to align (much easier than adjusting the height of a bunch of floating tables), but it does take up more real estate on the baseplate.

Here's a link to a diagram of one such layout, if you're curious.

However, the floating table layout also works well. You'll spend more time aligning it, but once you're done it's usually very stable. Also, with regard to airflow, remember that air can also circulate below the tables (between the lasers and the baseplate).

Adam

[stanwax]

I see you have worked out how to use the included plate - I winced when you talked about screwing in from below as I like to fix everything that I can (99.9% of stuff) from above with tapped holes. If you have to faff about with nuts and washers its a pia and working on kit is some much better when screwing into a tapped hole from above. Well worth the extra time to do...
Rob

[blowfly]

Interesting... I was wondering why people use an extra bounce mirror sometimes. It makes sense that the extra mirror allows for better beam positioning because you can distribute the deflection across multiple points.

Sorry yeah I meant "without" floating tables in my post above, but you guys have me rethinking this. If the components are bolted in directly from below, then removing them will end up being a big pain in the arse. This is especially true in my case where the optical plate has the laser modules on top and PSU and drivers on the bottom.

Thanks guys!!!!!

Mike

[buffo]

If you want to mount the lasers directly to the base plate, you can drill and tap holes and then run the bolts down from the top. No need to go all the way through either. This makes it easier to change things later, since everything is accessible from the top.

Through-bolting to the underside works too, but as Rob mentioned, it's harder to assemble and a real pain to take apart. (You really need to pull the whole plate out of the projector to work on it.)

Adam

[m0f]

As the beams tend not to all be at the same height, the standard way of correcting this if not using floating tables is to shim lasers to bring them all up to the same height, which I imagine could be a pain to get exact and maintain good heatsinking to the baseplate The extra bounce mirrors allow for easy near field alignment to line the lasers up on the dichro, then the dichro can be adjusted for far field alignment.