Laser Etching

[tyzjames]

Hi,

I am in the midst of contracting a company to laser etch my powder-coated enclosures. If anyone has done it before, I would like to know some details:) Basically, I understand that the laser will 'burn' away the intended design areas thus leaving the aluminium base as the design. For fonts, say, the letter 'O', will the powder coat peel easily from the enclosure? Also, is there a very obvious layering on the pedal (since the etched area will be lower than the powder-coated area).

Secondly, does anyone laser etch their copper boards to make PCBs? Does it work?

Thanks!

[defaced]

The depth of the etch depends on the focus point of the laser.  You can literally etch through something (a cut) if the focus is past the backside part surface.  The large cutting lasers tend to have a deeper etch than the smaller labeling lasers in my limited experience with them (primarily on stainless steel).   It would be best to do a sample lot because you will be married to their laser process once you start up.  They should be able to help you much better than anyone here because they understand their laser's capabilities.  If they can't/won't, find someone else to work with - laser etching is not particularly exotic these days.    

Given the thickness of the copper (approx 0.001"), I don't think etch etching would be a good idea because I very much doubt the precision is there in most industrial laser tools (but it's worth a shot).  I imagine keeping it perfectly flat could become an issue.  Secondly, if you scorch the PCB material, it could become conductive which would cause you problems.  

[jimbeaux]

I recently went to a local MakerATX class for an Epilog 60w / CO2 laser. There was a list of materials that were OK to use & a number of materials that would produce toxic gasses (hydrogen chloride, hydrogen fluoride, and/or hydrogen cyanide) - fiberglass was one of the materials that could not be used.

The good news is that anodized metals are perfect for etching. There are a number of youtube videos on this. Painted metal can be etched. You could also etch regular metal, but you have to coat the surface with something like cermark spray or tapes.

http://www.youtube.com/watch?v=E49ARvhJ5og

[darron]

i laser engrave all of my pedals:

http://www.dazatronyx.com/

there's  video there. if you skip to about 2:00 in you'll see the enclosure being engraved.

if you skip to about 1:40 you'll see the pcb mask being prepared.



this is using a co2 laser however, NOT the kind defaced is describing.




to help answer your questions. you're right, it will burn away to reveal the metal underneath, so prepare the metal well. if it's dull-grey it will look dull-grey with less contrast. as always, you'd properly prepare enclosures before powder coating anyway.

the middle of the "O"s will be perfect! powder coating is VERY durable. i've never, ever had a problem with artwork falling off... i even do some sometimes as a negative where i engrave off ALL of the powder except where i want the text/artwork.

yes, i suppose there can be a little bit of obvious layering. i've never really thought too much about it or been bothered. powdering can be a little thicker than paint i suppose... so... if this is a problem for you, then like jimbeaux said you could anodize them and then laser that. that will make the text come up a frosty white sort of colour.




and PCBs, no. think about it. IF you did use a laser to go all the way through that heavy copper, what's to stop it quickly blasting right out the light fibreglass? getting the depth right has too many variables and isn't practical. also, just about all lasers wont cut/engrave copper. they use copper in all of the lenses of lasers for this reason. a co2 laser definitely won't (doesn't cut metals). still, i use my laser with some paint to help make the acid etch. it's a crapload easier than all this business with borrowing the ladie's clothes iron. i never got the hang of that...


some powders engrave much better than others. look through my work and you'll notice some are average or less, and some are brilliant (literally, bright)





and more laser assisted pedals in my gallery: http://www.dazatronyx.com/gallery/

[tyzjames]

Woah, thanks for all the info. Definitely got a better idea now. Will probably give a small batch a go and hope for the best!

darron: Cool stuff! how much did that laser marker cost you?

[darron]

the epilogue mini was exactly AU$20,000.00 (AU = about US dollar). there are different versions now so it's probably a lot cheaper. also, they are made in the states so they are probably half that cost if you live there

lemme know if you want any specific help. not sure where you are in the world, but if you can get boxes to melbourne australia then i can try some samples for you before you make any big leaps.

[defaced]

this is using a co2 laser however, NOT the kind defaced is describing.

I wasn't discussing any particular type of laser, just stating basic physics involved with lasers and my experience with the results from the different kinds I've seen. 

[tyzjames]

Thanks for all the info, guys! Just wanna share the outcome:


I passed the supplier a 'tiger sparkle red' enclosure and a 'black textured' enclosure from mammoth electronics. The black textured turned out very well after lasering, but the tiger sparkle red just looks burnt and blotchy.. I suppose that is due to the laquer on the enclosure.

[darron]

HEY tyzjames! Any development on this? I was researching something and came by this post. any good results to show off?

I wasn't discussing any particular type of laser, just stating basic physics involved with lasers and my experience with the results from the different kinds I've seen. 

mot of the guys here are using a co2 laser which can't scratch metals in the slightest with a thousand passes.

i did look into lasering copper PCB years ago, which obviously won't work for the reasons you've outline, and it was pointed out to me that even the lenses of a lot of the machines are made with copper and can't be lasered. there are exceptions i think if you really want copper done.

[The Tone God]

mot of the guys here are using a co2 laser which can't scratch metals in the slightest with a thousand passes.

i did look into lasering copper PCB years ago, which obviously won't work for the reasons you've outline, and it was pointed out to me that even the lenses of a lot of the machines are made with copper and can't be lasered. there are exceptions i think if you really want copper done.

CO2 laser do not have a optimal wavelength for metal absorption. You can cut metal with a CO2 laser but you would need a laser rated in the hundreds of watts and usually O2 injection. In the industry though most of the time they used a YAG or fibre type laser for engraving metals. Depth control becomes the next issue as lasers have pretty much none. This is not optimal.

I have tried painting boards then lasering the paint off. It can be done but its tough. Raster engraving is not the great here if you need tight resolution like with SMD parts. Vector engraving is much better but most low wattage (<100w) CO2 laser do not offer vectoring or just basic not suitable for the complexity of circuit boards. One of the thing people tend to not notice is even when lasering off paint is there is still a very thin layer of paint on the material. Enough to still stop etchant. I tried using a very mild solvent to take this layer off hoping it would still leave enough of the un-etched paint but one swipe too many and you start taking the main paint off wasting all your work. Not very consistent. It okay if you have a design with large part/trace tolerances but anything fine you will start to have problems.

Really if you want to mechanically etch your own boards go with a CNC router. Cost and quality will much better.

Andrew

[newvoodoo]

I am REALLY interested in moving to a more professional appearance in my devices as far as finish and markings are concerned.  I currently use various things, from stickers to waterslide decals to even hand-painted stuff (depending on the device).
I am considering a number of options from smaller C & C machines to laser engravers.

1)Does anyone have any information or experience with the engravers available now in the lower end of the market?
(id literally want to buy the LEAST expensive possible option.  20,000$, for example, would be a REAL close call as far as endangering the entire venture)

2) It appears that some engravers are also cutters. Is this right? For example, could I find somethign that I could use to engrave panels and front pieces AND to cut holes and other designs into, say, clear acryllic panels?

3) Are there any attendant costs I should be aware of that sales materials will not mention?
For example, do these machines require, say, an oil/lubricant, or lenses, or some other part or maintenance that normal use would require often that I should be considering when considering the cost?

4) are there any differences in the cost as far as materials they can etch/cut, etc?  For example, if I buy a 10000$ machine but it allows me to use 1$ acryllic panels (just making that up) whereas a $2000 machine would only allow me to use certain panels, perhaps 10$ acryllic panels, so that in the long run the 10k machine actually ends up costing us LESS to use?
(the above may sound nutty but ive actually run into that issue with another piece of equipment recently purchased which I dnt want to mention and give ANY marketing to)

Thank you fr ANY help you can provide, I FIRMLY believe that the more I know and the more knowledgeable I sound to sales managers & reps--the better a deal I wil find and the less likely I am to have someone try to mislead me.

[pickdropper]

I use an Epilog Mini18 to etch.  It's 30w and more than capable if burning off powder coat.  It's about $10k new.

In raster mode it etches, in vector mode it cuts (although you can reduce the power and etch on vector mode).

Upkeep is part of laser engraving.  The laser tubes do wear out over time.  Going by memory, I think the Epilog requires a new laser tube approximately every 3 years or so, depending on use.  The tubes are $1500 or so.

As far as cutting , I but acrylic on it all the time and it does fine up to 1/4" thick.  I have to rotate the part and so more passes on anything thicker.  Higher power lasers can cut through thicker material and cut thinner material faster.  You cannot cut PVC/vinyl on it and there are likely other things you can't cut as well.

The stock optics will do 600dpi, but you can add a 1200dpi lens for $250 or so.  I'd recommend going with the stock lens first and seeing if you need more .  Often, the 600dpi setting seems to look better anyway.

On an upkeep level, you will want to learn how to take it apart and adjust it, or you'll end up paying somebody else good money to do it.  Luckily, it's really not that complicated.

[newvoodoo]

thanks for taking time to respond. I appreciate it.  Were considering taking out a loan to get that particular model..hwever we have ZERO debt at the moment and im hesitant to acquire any unless necessary.  Ive got one of my guys searching the net fr used ones, maybe we'll get lucky and find one close by that we can try out and is going for a reasonable price.

thx again, I REALLY appreciate the info re: replacement of tubes, etc  thats invaluable b/c the salespeople are unlikely to mention that unless I bring it up

[darron]

sorry for the massive delayed response after re-spiking the thread. i'm really interested in all this.

I have tried painting boards then lasering the paint off. It can be done but its tough. Raster engraving is not the great here if you need tight resolution like with SMD parts. Vector engraving is much better but most low wattage (<100w) CO2 laser do not offer vectoring or just basic not suitable for the complexity of circuit boards. One of the thing people tend to not notice is even when lasering off paint is there is still a very thin layer of paint on the material. Enough to still stop etchant. I tried using a very mild solvent to take this layer off hoping it would still leave enough of the un-etched paint but one swipe too many and you start taking the main paint off wasting all your work. Not very consistent. It okay if you have a design with large part/trace tolerances but anything fine you will start to have problems.

that's how i make all my PCBs lol. yeah, it's not as exact a science but i etch a whole sheet at a time and 90% of them work out. like you said, there's always a film. here's how i combat it:

- always use a flat black enamel paint. not acrylic.
- let it dry for as long as possible. 2 weeks is good.
- just use plain water and cloth/paper towel (i use toilet paper lol) to clean up as much of the remaining film. i used to use isopropyl alcohol and other solvents but as mentioned too much rubbing would wash into the traces you want.
- after it's been in the etchant for a while take it out and wipe it down some more to get the areas you missed with a tiny bit of film. do this a few times during the etch.

i'm made some really high detail stuff.



i'm getting a bit sick of lasering powder coating though. i'm after some higher contrast results. right now I'm experimenting with lasering and then filling the engraved area with chrome powder coat and putting it in for a final bake. this has been meaning 3 or 4 trips in the powder coat oven though!

[The Tone God]

that's how i make all my PCBs lol. yeah, it's not as exact a science but i etch a whole sheet at a time and 90% of them work out. like you said, there's always a film. here's how i combat it:

- always use a flat black enamel paint. not acrylic.
- let it dry for as long as possible. 2 weeks is good.
- just use plain water and cloth/paper towel (i use toilet paper lol) to clean up as much of the remaining film. i used to use isopropyl alcohol and other solvents but as mentioned too much rubbing would wash into the traces you want.
- after it's been in the etchant for a while take it out and wipe it down some more to get the areas you missed with a tiny bit of film. do this a few times during the etch.

i'm made some really high detail stuff.

i'm getting a bit sick of lasering powder coating though. i'm after some higher contrast results. right now I'm experimenting with lasering and then filling the engraved area with chrome powder coat and putting it in for a final bake. this has been meaning 3 or 4 trips in the powder coat oven though!

I did use flat black paint but I only let it dry overnight. It was just an experiment so I didn't want to put much time into it. I did use isopropyl alcohol but I didn't try water. I also touched up areas using a normal sharpie. I could decent detail but not what I needed. It would be good for maybe DIP parts but as I am mainly doing SMD these days its not enough. I even wondered if the laser was refracting off the copper making lines even more fatter and/or random. I just can't do say TTSOP parts or even SOIC. It was better then laser transparency toner transfer I usually do but only as long as I could get that thin layer off. I wonder if lasering off laser toner would work. I did do an experiment awhile back using metal blue dye, vector lasering that off, then etching through that. It did not too bad but it wasn't circuit board material that I etched. Might be worth a try sometime.

I do laser off the powder coat for the TubeUlent warning labels and serial numbers now. I use a textured powder though so filling would be difficult and I'm just not a fan of multi bake cycles with texture or satin finishes. Its ok with gloss and maybe a low temp clear which I do with flake jobs but those are rare for me. Too much messing around for my tastes.

I have some other ideas I am trying but I still have to do some testing.

Andrew

[haveyouseenhim]

I tried the same thing, but I used a lacquer paint as the resist. I had the same problem with the thin layer of paint left over. I was thinking of using some super thin adhesive vinyl to cover the board and laser that. If there is residue it can be cleaned with solvents with little chance of damaging the vinyl (hopefully).