Need Help!- Laser suitable to engrave stainless steel?

[el_tony33]

Hello everyone, and thanks to pass by

I'm some kind of new in these world of laser engraving

I have bought a little cnc machine designed for routing and engraving and I want to test it with a laser to make some engraving, I think I can start doing it in scissors made of stainless steel

I found an example on the internet of what I intend to do, are the next images (attached?):





And, the point is if I can use these laser from a ebay seller, that have atracted my attention: (link)

laser from ebay

in fact I think is a good price, but, I have some questions:

- It is suitable to engrave stainless steel?
- Is it dangerous if the beam gets reflected from the steel?
- If is dangerous, is any way to filter the reflected beams?
- Any way to control the diameter of the marking point?
- Is any way to control the power output of the laser? Due to prevent getting trough (cut?) the borders of the material?
- What about the focus of the laser? :O?
- Is any way to control it from Mach3 like a plasma torch? :O?
- In the case that it is siutable, what ranges of speeds work for engraving?

The cnc that I have has a precision better than 0.04 mm, uses ballscrews and 1,500 RPM (nominal) nema 23 steper motors, I have no tested yet the real limit speed of the feed in all axis

but the seller says: No load Speed: 0-5000mm/min

so please, I'm very interested in this type of engraving in my machine, it will be very helpful to "personalize" the items that I'm intendig to sell, jeje

any info will be very very very very! apreciated

thanks a lot!

Tony

[zax15uk]

Tony,

First I will answer you questions...

- It is suitable to engrave stainless steel?
NO
- Is it dangerous if the beam gets reflected from the steel?
YES
- If is dangerous, is any way to filter the reflected beams?
YES (glasses or laser shield for 808nm)
- Any way to control the diameter of the marking point?
YES (focus lens and distance, but reduced power at larger spot size)
- Is any way to control the power output of the laser? Due to prevent getting trough (cut?) the borders of the material?
YES (input current and/or TTL pulse width will control output power, but since it won't do anything to the stainless steel you won't need to worry about cutting through)
- What about the focus of the laser? :O?
Lens / Z-height
- Is any way to control it from Mach3 like a plasma torch? :O?
Yes, the same as a torch control (plug in for laser is available)
- In the case that it is siutable, what ranges of speeds work for engraving?
Not suitable except for engraving on paper/wood or cutting thin wood or some plastics

Now, what you probably want to know... how to achieve the results shown in your pictures. They are most likely done using an additive process and CO2 laser, research Cermark http://www.ferro.com/Our+Products/Co...rkets/CerMark/ LMM6000 or similar (it's sold under several brand names).

It isn't cheap, but the results are very good.

Zax.

[el_tony33]

Thanks a lot zax15uk for the answer !

ok then,I have investigated about that kind of engraving spray and is very interesting how it works

I think I buy some from ebay,

Some other questions get into my mind now, in this moment wen you aclared my path

- Are there any wattage requirements from the laser to engrave stainless steel using this spray? (is some info that I haven't found in the sellers page, jeje)

- and other thing, these kind of ceramic layer is jointed via an oxide in the surface of the metal, with an atom of silicium, (Si), so, is any way that it gets off of the piece? for example in surgical scissors aplications, that are washed with some solvents ad maybe with ultrasonic devices

the thing is that it will "hold" in the piece until you.... (X) ?? ??

now I'm watching this two machine on ebay:

http://cgi.ebay.com/New-40W-Desktop-...item1e59dabebe

and this one:

http://cgi.ebay.com/CO2-LASER-ENGRAV...item2557ce79ce

The problem is if this power output from thelaser is enough to make the markings and activate the spray coating

jajaja, thanks a lot for the help and any idea of something that helps to improve this "road to success" are really apreciated!!

thanks again zax15uk !!

Tony

[Litografa]

Minimum power you need for products like Cermark is 17Wt. But note that this 17 Wt is for Synrad tube and laser from e-bay use glass tube. For glass tube 40Wt is minimum and 60-80 Wt will be better solution as power can decrease during work due many different reasons (stability of water cooling is main). Also keep in mind that stability of power bring you CONSISTENT BLACK engraving. If power will fluctuate during engraving you can have yellow/light brown lines during engraving (banding)

[zax15uk]

Tony,

Yes, both of those 40W systems would be suitable for the laser marking spray.

I've only used the paste and mixed it with thinner and sprayed with an air brush, it's MUCH cheaper than the can but more work I guess. The result was dark and impossible to remove short of scratching through the metal.

I didn't try an ultrasonic cleaner but doubt that would have any effect, and solvents certainly didn't.

Zax.

[benji2505]

the mark on the shear was electro-chem etched.

For marking of stainless you might want to consider a yag laser with a galvo head. faster and you need no additives. prices start at 30k.

[zax15uk]

Benji is correct and if you have a budget of $45k+ the Trotec Speedmarker, TRUMPF or Rofin units would be excellent solutions.

I didn't suggest them as your original link was for a sub $1k laser.

I use multiple (5) Rofin galvo heads for marking and they've been ultra reliable and are amazingly fast but cost ~$60k each.

Zax.

[Litografa]

We are buying lamp Yag lasers from China for $13 000. Work well first two years But price still far from e-bay proposals

[el_tony33]

Ok then, I think I'll try the laser from ebay jeje

I have no much money, you know, the typical recently titulated engineer :P jeje

And for try, I think it will be some kind of "adventure" experience

so then, this laser from ebay, do you think that will have problems about the heating of the laser tube? I think what Litografa mention is about the capacity of the water pump to cool it down, right?

So maybe I can design a little chiller, or maybe change the water pump, I think that something bigger like the ones used for acuariums or ponds will work (I'm a fish fan too :P) all this thing to avoid "banding" and maybe get a longer life of the laser tube?

And then something else, what about the software to control the machine? Does any one used it before?

Some recomendations about the software? or any software that works well?

I have searched about it but, all the lasers form diferents brands have his own software, I think they are not compatible between them for obvious reasons

Maybe an advice for the software will work for me

And for the last thing, do you know were can I find some protective laser googles? siutable for CO2 wavelengths?

Thanks to all for the fast answers, Zax, Benji, and Litografa, now I'm wiser man that several days ago thanks to you

Tony

[zax15uk]

Tony,

I think that is a good choice, you can always remove the components later and make a larger machine if needed. It's cheaper than buying all the parts

Cooling should not be a problem, just use a large tank of distilled water with a few drops of algaecide. The supplied pump isn't that good but will work unless you have to pump the water up several feet. I would add a digital aquarium temperature meter to monitor the water temp. You can use evaporative cooling (add a couple of PC fans) to keep the water temp constant if needed. The other item I recommend is a flow switch that can interrupt the laser ON signal in the event that flow isn't sufficient, that way if the pump fails or something becomes blocked it will not damage the laser (or it is less likely to).

The software to drive the laser should be Moshi or Newlydraw (Newlydraw 1.5 is the best). It is sufficient for basic designs (text) but you probably need Corel or something similar if you want to do logos, graphics etc.

No goggles required - CO2 is much safer and the Acrylic viewing window will prevent any reflected light from getting to your eyes. All the newer machines have safety interlocks on the laser and XY table enclosures. The top ebay link you provided was the better one, http://cgi.ebay.com/New-40W-Desktop-...item1e59dabebe and I would add the honeycomb table and you probably need the 220v transformer too (unless you have a 220v outlet for the laser).

Good luck with the adventure!

Zax.

[el_tony33]

Oh ok, a little doubt,

jeje,

what is a honeycomb?

is really needed? or what uses have? something special?

thanks!

Tony

[Machinaria]

Originally Posted by el_tony33 Oh ok, a little doubt, jeje, what is a honeycomb? is really needed? or what uses have? something special? thanks! Tony

A honeycomb is used to vector cut parts to reduce the back of the piece from burning, remember that the laser beam can be reflected of a metal panel. You can also use Plaster of Paris reduced 50/50 with alcohol by weight to engrave with a 35 watt on stainless steel, you have to either brush or spray the formula and wait till it is dry before engraving.

Best regards
www.machinaria.com