NUBM44 blue- New Video

[VDX]

... what's wrong with your laser focus?

Mine looks much more symmetric - https://vimeo.com/87280864

Viktor

[kingjamez]

... what's wrong with your laser focus?

Mine looks much more symmetric - https://vimeo.com/87280864

Viktor

It's an artifact of the camera and the stray light from the lens being overexposed. It doesn't look like that at all though my safety goggles, much more like your video.

I've had little luck with the G2 or G9 lens working well with big blue diodes. They do meter higher on my LaserBee, but their cutting performance is inferior to some "450nm" coated Chinese lenses I bought on eBay.

I've tried many symmetrical lenses on many diodes and was hoping that someone would have a more exotic solution for me to explore. I wish I could find a cylindrical lens that would fit in the 12mm threads on the diode module.

-Jim

[kingjamez]

Oh my, a laser cutter that is not enclosed! Extraction? Protection?

And I thought the U.S. had the patent on Internet safety nazi's...

-Jim

[kingjamez]

The video helps a lot. The open nature of the head and work piece suggests you will be cutting thin organics and so the energy density and power does not need to be high.

As does the laser diode I'm asking about.

Furthermore, these items produce a lot of smoke and if you are not using pressurized air the keep debris away from the optics then you will want to use a long FL lens.

What short focal length lenses are available? I've found none suitable.

Also, with the low precision clamping (tape) the depth of focus needs to be pretty deep. You might just get away with a G9 collimator from DTR and adjust the focal distance to be close to the head to work distance.

Using tape to secure objects has zero effect on the z-height tolerance. I use a jig to set the z height off of the top of a secured object and get around 5 thou repeatability.

If I were searching for something to pounce upon, a better pick would have been the cardboard box used as a beam buffer.

Even with the relatively non-flat box top, material thickness is a much larger driver for long focal lengths. I can cut 1/4" balsa and even 1/4" ply in a pinch, and the long focal length reduces kerf as I go deeper in Z.

-Jim

[logsquared]

First off, I know jack about laser cutters.....

Have you tried the BDR-209 405nm diodes? They do like 900-1000mw with a SM or SM like beam. They should have much higher power density than any 445 diode.

[kingjamez]

First off, I know jack about laser cutters.....

Have you tried the BDR-209 405nm diodes? They do like 900-1000mw with a SM or SM like beam. They should have much higher power density than any 445 diode.

Yep! I've got one right now and run it when I need finer details than the 9mm 445. The 405 makes a much much smaller dot/cut.

I too thought the exact same thing, that a well focused 405 at 1 watt should do (much) better than my 445 at 2.5 watts. Reality was different though and I found the 445 to cut slightly deeper given the same material and speed settings. I don't understand why! Perhaps it's a material absorption thing, I don't know.

I like the 445's for their robustness as well. The 405's seem to die easily where the 445's are much more resilient to being over driven or otherwise not used in a blue ray player.

-Jim

[masterpj]

And I thought the U.S. had the patent on Internet safety nazi's...

-Jim

He has good intent though after all it's also with your vision and off others in mind but I'm sure you'll enclose it once you are done working on it. It's just the assumption that the unit wont be left unattended and you do not have unlimited supply of safety goggles. So why are you going for an 445nm diode and not a 808nm corrected diode or a high power CO2 tube with a protective cover?

[kingjamez]

He has good intent though after all it's also with your vision and off others in mind but I'm sure you'll enclose it once you are done working on it. It's just the assumption that the unit wont be left unattended and you do not have unlimited supply of safety goggles. So why are you going for an 445nm diode and not a 808nm corrected diode or a high power CO2 tube with a protective cover?

Co2 is too much trouble, it is hands down the best for $ to watt but is far more complex to setup.
808nm diodes (and IR diodes in general) do no cut nearly as well watt for watt as 445's. I think it's due to the absorption of materials.
Plus invisible death rays are more dangerous since you can't see where the reflections are going.

-Jim

[catalanjo]

I wish I could find a cylindrical lens that would fit in the 12mm threads on the diode module. -Jim

How would U manage the focus ?
If you adjusted it, the stripe would turn with respect to the diode .
Cheers

[kingjamez]

How would U manage the focus ?
If you adjusted it, the stripe would turn with respect to the diode .
Cheers

I would set the cylindrical lens so that it was fixed to shorten the long axis of the stripe. Where ever the focus ended up being, I'd just adjust the Z axis of my machine to properly focus the beam.

-Jim