Laser Cutting Head

... in a German laser-forum there are some people repairing old gas-lasers - ask if you need some advice ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Thanks Viktor,
I have not decided what to use it for, it was offered and I just could not say no, would it be any good for cutting or sintering???.
3 watts sounds like a reasonable amount of power.

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Random Precision

... which wavelength?

3 Watts is only enough for cutting thin sheets of absorbing material or engraving organic materials like colour on PCB's or such.

With visible light it's normally used in show-laser-beamers with XY-scanning vector-graphis ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

All Laser Mech cutting heads come with the following features and benefits:

* Magnetic Crash Protection - Eliminates breakaway screws and reduces downtime after a crash to a few minutes
* Easy-Access Lens Drawers - Makes lens replacement, cleaning, and beam centering quick and easy
* Manual Focus Adjustment - Over ¾ of an inch of focus adjustment reduces setup time considerably
* Fixed Tip Assembly - Never have to center the tip again.
The addition of Laser Mechanisms' Height Sensing Unit (HSU) will allow you to remove the foot follower (as needed) and will enable your laser to cut sheet metal non-contact

I have been selling a 1.7W 455nm Diode Laser head that works in conjunction with the 3D extruder with no need to swap out for laser cutting. We have a Makerbot 3D printer that we use for laser cutting solder stencils and other things. We have sold upgrade kits to people with RepRaps and Felix printers as well.

Check out: www.laser-bot.com for more details.

Or check out www.jtechphotonics.com to buy the kit. 1.7W laser kit with adjustable 2.0 amp driver is only $224.99.

Jay

... in the 'old times', when no high power laserdiodes were available, the techs found other methodes to get the desired power -- attached ais an image of a medical laserdiodemodule with 20 Watts power combined of 60! diodes with 0.33 Watts each ... and attached glassfibers:




... all the fibers are combined to a bundle of roughly 0.8mm diameter and glued into a FSMA head:

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

... here I've made a video showing the difference between 20mm/s and 80mm/s engraving speed:

[vimeo.com]

With this machine 200mm/s should be doable, but then the table is shaking horribly ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Pretty Cool Viktor.

Hi Viktor,

I'm thinking of adding an 808nm Laser module to an existing CNC router. I hope to be able to cut 3mm black abs/acrylic and also mark/engrave black or clear anodized aluminium. My machine has a maximum speed of 33mm/sec so wouldn't be doing anything too fast.

What do you think of these kale units? Do you think a 10W unit would do the job?

[www.kalecnc.com]

Thanks for any advise.

Matt.

You probably should get CO2 at that price range.

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http://www.i3d.ro

Quote
MPower
You probably should get CO2 at that price range.

Right, but CO2 is going to be much harder to install on my existing machine, plus my machine is mobile! It is built in to a trailer, and as I understand it CO2 lasers do not like to be moved / or vibration?

Matt.

... cutting black plastic should work at slow speeds up to some centimeters with repeating passes and adjusting height ... maybe you should apply a thin/sharp jet of pressurized air into the cut to blow away smoke and fluid plastic ...

I'm marking black anodized aluminium with 2Watts@445nm, but fails with 9Watts@975nm -- here the 808nm should be better suited ...

*** EDIT: for cutting some centimeters deep you'll need focal distances of up to 120mm to get a clean cut ... but for engraving you need much lower distances ( 30mm to 10mm) to get really small focus sizes and enough energy density ...

Edited 1 time(s). Last edit at 11/06/2014 07:18AM by VDX.

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Hi Viktor,

Thanks for the advise!

So you can mark black anodized aluminium with 2W 445nm, Ok, well that's interesting. Do you have an examples of your work, what is the quality like?

As for the 808nm 10W, do you mean it will be better than 975nm 9W, but not as good as 445nm?

Have you tried clear anodized aluminium?

Edited 1 time(s). Last edit at 11/06/2014 09:05AM by winchymatt.

... attached is an example engraved with 1.7Watts ... but this can be much more white with even lower power on other types of anodizing.

For 'marking' clear anodized aliminium you'll need much higher energy densities - I've got white/grey markings with previously painting the clear aluminium with black paint and removing the paint with a fiber-laser and powers from 10Watts to 50Watts ... and here I've got nearly 10-fold the energy density if IR-diodes ...

Quote

"As for the 808nm 10W, do you mean it will be better than 975nm 9W, but not as good as 445nm?"

... yes ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

So in conclusion, for the purpose of marking anodised aluminium would you say I would be better buying a 3W 445nm laser than a 10W 808nm?

On a separate note, disregarding cutting speed, would a 3W 445nm or 10W 808nm cut 3mm ABS?

Thanks for sharing your expertise! Your example engraving looks very good!

Edited 1 time(s). Last edit at 11/06/2014 02:05PM by winchymatt.

I just got an email from Kale CNC who make the lasers, they also suggested one of their 1.55W 445nm for anodized aluminium.

This 2.8W kit looks pretty good! Although it does state that for prolonged periods of time the laser shouldn't be run at more than 2.2W.

... until now I was using 2W-diodes, but found the same types sold as 3.5Watt types too

Yes, you can overpower them for a while ... but then you reduce the 'expected lifetime' from some 10000 hours (if cooled properly) to some 10 hours!

But actually I've got quotations for 'real' 3.5W and 3.8W diodes with prices worth it testing ...

My experience shows, that most marking and cutting jobs are better done with the 445nm-diodes, especially for their finer focus diameter (0.04mm compared to 0.1mm with the fibercoupled 9W-IR-diodes) and so higher energy density.

The IR-diodes are better in respect of higher averaged power for use with black (better IR-absorbing) materials -- but especially black anodized aluminium is better engraved with the 2W@445nm-diodes ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

... some deco-stuff for Christmas, cut from gold+red cardboard and a test in yellow foam:

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

... because I had already posted this several times in other laser forums, here too - this is what other "high-power laser diodes" with outputs in the watts up to 100 watt range look like:

- red 680nm diode at 1, 2 and 7 Ampere:





- Infrared 808nm laser diode with maximum power of 20W - here at about 8A, so just at the start of laser ... mounted on a Peltier cooler:







- Infrared 808nm laser diode with maximum power of 25 Watt ... mounted on water cooler:





- Infrared 808nm laser diode with a maximum power of 500(?) watts (it says so, but I still have to measure it) - here above the 25W diode:







The fiber coupling is intended for fibers of 0.4mm (with the red diode for 0.6mm), so it is less suitable for engraving than the 975nm diodes with fixed 0.1mm fiber.

But I use them less for engraving than for "preheating" in a wire-weld test setup ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]