What do i need for a laser?

So I have a working homebuilt cnc milling machine. I want to add a fairly powerful (as in capable of cutting acrylic and 6mm plywood)laser. What exactly do I need to buy?

I see 40w laser tubes on ebay for not too much money but I really don't know what else is needed beyond that. Is the tube just a focusing system? Does a diode go on the tube? Are external mirrors needed? I really know nothing about the operation of the laser outside of the fact that idbneed an external controller to modulate the laser and control power.

Can anyone explain this to me? Everything I have tried to read about this starts off assuming I already know about lasers.

Thanks

I had and in parts still have the same problem. There are really not a lot of good material about it. Some blogs/posts but the vast majority are discontinued or dosen't provide enough information.

What I have done, and what I think you should also consider doing, is start out with something less powerful. A 40W laser as a first build is a lot if you do not buy it as a finished and working laser cutter. Everything from the power supply (very high voltage) to reflections from the invisible laser beam can be very dangerous and getting pretty much everything setup seems hard.

Instead, get one of the blue 1.6W or 3.5W lasers. They can supposedly cut thin ply-wood and non-transparent acrylic.

If you buy the parts separately (not a working package) and try to combine the parts your self with focusing optics, electronics and diode and cooling then that should give a real challenge and I think give a better learning curve.


- That is what I am doing and still I am struggling.

... the CO2-laser is a 'gas-laser', where the gas mixture is energetized by high voltage and moving electrons, ionising some of the gas molecules, which starts the 'LASER'-effect between the two end-mirrors, where one of them is semi-transparent, so a part of the generated light can escape as beam.

In the diode a really small semiconductor crystal with special doping generates light from moving electrons in the crystal, what's resulting in a similar light emission.

The generated wavelengths are different (10640nm from the CO2, 405nm to 975nm from the typical diodes), so this two types of lasers behave very different with different materials.

There is much more about lasers, but this is an essential part of the 'learning curve' ...

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Viktor
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Quote
VDX
... the CO2-laser is a 'gas-laser', where the gas mixture is energetized by high voltage and moving electrons, ionising some of the gas molecules, which starts the 'LASER'-effect between the two end-mirrors, where one of them is semi-transparent, so a part of the generated light can escape as beam.

In the diode a really small semiconductor crystal with special doping generates light from moving electrons in the crystal, what's resulting in a similar light emission.

The generated wavelengths are different (10640nm from the CO2, 405nm to 975nm from the typical diodes), so this two types of lasers behave very different with different materials.

There is much more about lasers, but this is an essential part of the 'learning curve' ...

Viktor,

I've read quite a few posts in this forum concerning laser engravers/cutters and you seem to be very well versed on the subject. I have a Prusa I3 3d printer and am thinking of modifying it to do some laser engraving or cutting. The cutting would primarily be paper/card stock and balsa wood no thicker than 1/8 inch. I value your input as to whether these items would be a good fit:

Laser diode holder:

[www.ebay.com]

Laser diode:

[www.ebay.com]

Power driver board:

[www.ebay.com]

I'm looking at hooking it up to my Ramps 1.4 board as well. As for safety, what type of laser safety glasses would I need? I'm familiar with rotating red laser levels which have a much lower power level, where I use red laser glasses, but I don't think they would be sufficient enough for this type and power of laser.

Many thanks for whatever advice you could give.

Pete

I checked the laser glasses and they're only used to "enhance" the red beam when used in bright light. NOT for protection!

Edited 2 time(s). Last edit at 01/22/2016 01:40PM by psneddon.

See
JTech Photonics

[jtechphotonics.com]

everything you need to know about diode lasers and applications

Cozmicray

I've checked that site out before. Thanks. I looked the site over again and was checking out the laser shielding. The price looked very reasonable, so I put one in the shopping cart and went to their checkout page and was shocked to see the shipping costs for USPS for a piece of 12" x 12" shielding!

$50 to ship via US Mail is OUTRAGEOUS!!

I'm using color filter foil ( dark amber for blue LD/ blue for red LD ) which is normally used for stage spotlights. You have to use a double layer to filter enough light, but it is cheap and easy to ship.

0_lampe,

Do you have a link or source for the color filter foil? Is it SAFE?

I am thinking about using a "1W 1000mW Laser Diode Blue 445nm" so the dark amber would be the one to use.

I want to start off engraving wood and maybe some paper/card stock cutting and I'm trying to gather as much information as possible before I buy anything. My main concern right now is safety.

From all the postings I've read from yourself, VDX and others, eye safety and ventilation are the primary safety concerns.

One other question I have concerns ventilation of the fumes. I understand that many materials can produce toxic/carcinogenic fumes, but what about paper and soft woods like balsa wood? Do these materials also produce such toxic/carcinogenic fumes? If so, how is it safe to be around burning paper or campfires?

Thanks again for your input. You've provided very helpful input on my previous 3d printer questions as well. I welcome all advice and useful information.

Edited 1 time(s). Last edit at 01/23/2016 01:26PM by psneddon.

... burning wood or paper is less toxic/carcinogenic than plastic, but not this much -- especially, when burning/evaporating them with much higher temperatures than in a camp-fire, as done in the laser-spot.

Another issue is the exposure time to the fumes and residues - as most DIY-lers use the laser-engravers in their work (or even living) rooms ...

Edited 1 time(s). Last edit at 01/23/2016 04:35PM by VDX.

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

Thanks for the info Viktor. I agree that most DIYers probably use their laser cutter/engravers in their living room. That's where I do all my 3d printing.

What do you think of the components I am looking at purchasing in my earlier post? I'm not looking at any serious cutting right now. i just want to get my feet wet and see if I can get one up and running like I did with my 3D printer.

... of course, you can start with the components from your links - when you have gained enough experience, then most likely you will know where to find better (and much more expensiver) parts

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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]

Thank you Viktor. I hope I will learn which pieces are better as I go along. I have already seen part of the expensive side of laser cutter/engravers - from $3,500 to $35,000+!!

I want to start at the roller skate level before I even think about the Grand Prix.

Thanks again!

P.S. This student built their own laser enclosure where they used an orange acrylic sheet to stop the beams reflection as seen here:

[www.instructables.com]

Will an ordinary sheet of colored acrylic or plexiglass suffice for the laser they're using? In that case, I would imagine the thicker the better? Would the same barrier work with a 1W blue 445nm laser?

Edited 1 time(s). Last edit at 01/24/2016 02:19PM by psneddon.

I've been reading up on laser safety, reflected laser light hazards and the dangers inherent with these lasers if not used properly and with the proper safety equipment. As such, I have decided against building a laser engraver attachment for my 3d printer. I believe I will pursue a different method of engraving/cutting. Maybe a CNC styled mini- router instead.

I thank everyone for the information.

I use $11.00

Red Acrylic Plexiglass Sheet #2423 1/8" 15.7/8"X 15.7/8

[www.ebay.com]

been using it for a year and don't need a white cane

Please don't rag on me for not having a $1000 optical transmission test performed

Quote
psneddon
Cozmicray

I've checked that site out before. Thanks. I looked the site over again and was checking out the laser shielding. The price looked very reasonable, so I put one in the shopping cart and went to their checkout page and was shocked to see the shipping costs for USPS for a piece of 12" x 12" shielding!

$50 to ship via US Mail is OUTRAGEOUS!!

... I'm mostly using orange coloured acrylic sheets as windows or inserting pieces in glasses.

Here is a common type - [www.plexiglas-shop.com]

You can test the material with a web-cam when pointing with the diode through the sheet on a piece of white paper and if it seems to block, then directly lighting through the sheet into the camera - if the camera don't overpower, then it's probably a good bet

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Viktor
--------
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The foil is different to acrylic sheet, because it can be doubled or even tripled easier :

Deep Amber foil

Yesterday I was watching my printer engraving balsa for hours and didn't get a headache or anything.
When I turn down PWM to "1", I can almost not see the spot through the foil.
-Olaf

My advice: Get yourself a "M140" LD. It comes with an inbuilt ESD-protection chip, which is really worth it. ( I killed a few red DVD LDs while handling them without ESD-protection )
Turn down the current to 1A and it will live forever.
It doesn't matter, if you use a 500mW or 9W LD, they both can make you blind instantaneously.

I was thinking of adding a laser to my printer as well but decided on a CO2 standalone model instead for these reasons:
1. without a really closed printer there is no chance to avoid scattered laser light and I hate running around with safety glasses for hours.
2. although a conversion seems pretty straight forward the standard Marlin firmware is not really a good start for laser stuff.
3. the limits of low power diodes are too annoying in terms of time and possibilites.
4. even proper laser modules from the professional department won't come close to the optical qualities of a gas laser.

Depending on the size some old printers and cheap steppers can be used for a x-y table for the head.
All that can be put into a nice enclosure and if you like with the bottom open to allow for bigger parts under the machine.
Apart from the mechanics (that some of us have around from old 3D printers anyway) and the laser itself the electronics including display and SD support are under 100 bucks (under 50 on Ebay)....

... when comparing CO2-lasers with 445nm-diodes -- CO2 lasers are superior for cutting organic materials, 2W@445nm-diodes are better (finer) for engraving.

So start with the CO2 and think about adding a diode to the head too

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

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

If you are doing the comparion like that I would say for everything organic, including glass CO2 is the way to go.
For serious metal engraving or even cutting on a hobby level nothing will beat a small ruby laser.
Even at considerable low power level a single pulse shoots right through a razor blade.
Lost my entire prototype to customs when I moved contry.
They stated it is portable enough to be considered a weapon and if I want it back I need to prove my personal use plus pay import taxes.
Of course they estimated the taxes about twice as high as my costs to build it
Was not too fuzzed about loosing it except for the 500W curled flash tube that was a perfect fit for the ruby rod

... where are you located now?

For metal (or dark/opaque ceramic materials) I'm using fiber lasers - have some with CW powers of 50 or 85 Watts or pulsing types with 16 Watts averaged or around 2kW pulse peak power -- and spot diameters of 20 microns ... with beam-expander even down to 10 microns.

Sometimes you can find old ones at ebay ...

Edited 1 time(s). Last edit at 01/25/2016 07:52PM by VDX.

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

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