Deep Metal Engraving

[Brian Robison]

Anyone do this? How big of a laser is needed?
Does it need to be a Yag?

[Scott Anders]

Brian I know the stuff you are talking about. I have seen two examples in the last few weeks and it has me stumped how they do it. It has to be a laser because a mill would not be tiny enough or viable to do the detail involved. I'm not sure what type of power would be needed. it has been embossed into the material about .1mm then paint filled i assume. both the examples i have seen are stainless steel.

[Scott Shepherd]

I'm not aware of any "deep metal" laser engraving. Doesn't make sense to me. The beam of a laser is .005". Why would you want to remove .005" at a time, when you can chemically etch the entire surface in one whack. Much faster and the right tool for the right job.

[Scott Anders]

Thanks for the reply, maybe we should have both worded it better like "what process is used to do deep metal etching" you've answered our question thank you.

So the next question is "how easy is a process like this to set up?" looks interesting i've googled a bit of it but there doesn't seem to be much info on the process involved. apart from the highly corrosive chemical warnings. There is a little machine for it though... the etch-o-matic. sounds corny but looks like it does a good job. too small for the application i was thinking of.

[Mike Null]

Take a look at http://masteretch.com/

[Scott Anders]

Thanks Mike, that hit the nail on the head.

[Brian Robison]

People contact me quite often about lasering in reverse for the cavities of molds. Of course my laser doesn't have that kind of power but I'd love to have one that did.
I also may have a chance at medical engraving but the process calls out for a Yag. I was wondering if some one here was interested in doing the work short term.
I wondered what kind of wattage was needed.

[Scott Shepherd]

http://www.etchcraftline.com/index-2.html is another one I've seen at shows that has very nice looking products.

Brian, I'm still unaware of any fast process that will do what you're asking. A laser with a .005" beam is going to leave marks in the bottom of a mold, no matter what. Etching is light years faster than trying to engrave metal away, YAG or no YAG.

It's possible the technology is out there, but I haven't seen anything in the laser world that can compete with traditional methods of making molds.

[Doug Griffith]

Another method for "burning" images into metal, especially molds, is a sinker EDM (Electrical discharge machining). Extremely accurate but not cost effective for engraving.

[Brian Robison]

Scott, I don't think I explained myself. Flip a bottle over and it will have the recycle logo. That's more of what I'm after, not machining the whole tool. I'm looking into the chemical etching now and it seems very probable I'll get into doing that. Thanks for pointing me in that direction. I have a molded part on my desk that I got today with the Nissan logo molded in from a chemical etch!
Looks very good to me!!!!:D

[Scott Shepherd]

Flip a bottle over and it will have the recycle logo.

Great, now I've spilled my beer :eek:

:) Gotcha, either chemical etched, or as Doug said, EDM'd. I use to run a EDM that did that. Very slow process indeed, but incredible results.

[Brian Robison]

Hi Scott, yep I'm familiar with that also. Sinker. But you have to machine the electrode. This chemical etching is just what I'm looking for. Now for the research part.

[Scott Shepherd]

Cool, let us know how it works out. I've never done chemical etching (and don't want to), but I'd love to know how it works for you.

[Rodne Gold]

I have posted how to etch with lots of details , tips tricks , how to use your laser to do it etc
Search for my name , ferric chloride , etchant , mordant etc on this board
I wrote a whole long detailed expolanation at
www.uksignboards.com (http://www.uksignboards.com)

http://www.uksignboards.com/viewtopic.php?t=2905&highlight=ferric+chloride&sid=7e769385587538b4f50db046a1cd64a0

If that doesnt work , then search uksignboards for the same terms.

[Brian Robison]

Here's Rodney's post.
If you have a vinyl cutter , you can do doctors plaques , stainless plates, alumminiun signs and a lot of other articles in metal with lettle or no expense.
You use a technique called chemical etching. Metals are eaten away by various mordants (acids or the like) and if you protect areas of a plate the mordant does not attack them , however most of us dont really want to work with acids as they release toxic fumes and are pretty hazardous materials , but there is a relatively mild product called ferric chloride (not really an acid , used to make printed circuit boards) that is cheap and wont burn you
(It is VERY messy and will stain your hands and clothes yellow or orange, it is not completely safe , is not really suitable for flushing down the drain etc - so be carefuyl , gloves overalls , eye protection open containers of ferric in your workshop will ataack all metals (like the bearing rails of you super duper 10kw overhead router:)
This is available from just about any chemical supply house in crystal or liquid form , get the liquid and ask for about 46 baume concentration - they will know exactly what you mean or should.

The simple steps are this
Take a sheet of the metal you want to etch , give it a good rubdown and wash with something like a scotchbrite abraisive pad , design a graphic and weed OUT what you want etched inwards , make the graphic border a little smaller then the plate. Now apply the square with the lettering or graphics removed to the plate , making sure you apply it nice and square and then roll it or squeegee it down , pay LOTS of attention to where the edges of the graphics you have cut out meet the brass , IE you are going to dip this plate in something that attacks metal , the Vinyl is the resist - thus if for example you have a bubble or wrinkle where a letter is cut out , the mordant (etch) is going to seep under it.

Then take some parcel tape or vinyl and coat the back of the plate and the exposed eges or ANY area you want to remain protected
Make sure you havent got "leak holes" or anything where the plate is taped up
The next step is to take a plastic or glass caserole type dish , bigger than the plate and fill it with enough ferric to cover the plate - if you can heat the ferric to about 40 degrees c - all the better , it works tons faster than room temp.
You put the plate in , face up (tho face down is better but more difficult to work with) and using a brush swish the ferric over the plate , using the brush to remove the byproducts of the etch , within seconds you will see the letters darken and if you leave the plate in long enough(about 15 mins with heated stuff and constant swishing brushing) and strip the vinyl tape etc off it , you will have a stunningly etched plate with crisp edges and contours an engraving machine couldn't cut , let alone a etched surface finish that a machine cant do (which aids paint filling.)
Dont try this first on aluminium as it needs a weaker ferric mix , about 1/3rd strength otherwise it fizzes and bubbles and overheats , brass is ideal
Stainless requires a longer time to etch. If you dont heat the ferric , it can take a long time to etch any metal)
At worst , to try this can cost you a few pounds , and like us , you might end up building semi automated hot spray etching machines (for our own use , I will post instructionsto build a better more production type etcher if anyones interested)

Obviously if you cant weed something , you cant etch it , thus the smallest finest detail is dictated to by your weed or cutting capability.
Etched plaques sell for very high prices and can be made very quickly , very cheaply.
There are various other nethods of doing this , some etchers screen an acid resistant ink onto the metal for large repetitve runs , we often laser engrave a polyester resist away , cos the laser can engrave VERY fine detal and then ettch for jobs where high detaill or even halftone photographs are needed.
You get various photsensitve resists you laminate onto playe and expose directly usining a possie etc.
Try it , you will be amazed

[Brian Robison]

I bought some Ferric acid at an electronics shop. Masked a test piece and swabbed the acid on the metal. I let it sit for 1/2 hour with no results.:(
I didn't heat the acid or emerse the part. BTW 40c =104f
You think the acid was too weak?

[Rodne Gold]

you need ferric chloride with a baume value of 42 , ie its like a specific gravity...most chemical places that supply ferric supply it in that form.
You have to both heat and agitate the ferric and immerse the part for any results. Non ferrous etches a lot quicker than ferrous.
However you have to have clean metal for an etch to take , even the oil left by your fingers will act as a resist.
Anodised aluminium will not etch , you need to use caustic soda to strip the anodising.

[Eric Allen]

I bought some Ferric acid at an electronics shop. Masked a test piece and swabbed the acid on the metal. I let it sit for 1/2 hour with no results.:(
I didn't heat the acid or emerse the part. BTW 40c =104f
You think the acid was too weak?


Brian, what metal are you trying to etch?

[Brian Robison]

H-13 is what I'm looking to do. My sample was ???? Beats me:rolleyes:

[Larry Alles]

Brian,

I have been engraving for 45 years and engraved the recycle logo into
hundreds of brass, aluminum and steel molds and inserts using a Deckel
3-D pantograph. I also engrave raised lettering on steel dies and carbon
electrodes using the Deckel pantograph. Metal etching is very costly and
not many people do it.

[Andy Wingfield]

Hello Folks,

The most knowledgeable person I know in regards to metals and the laser engraving process is Gary Sheriff. goggle Shertec.

Regards,

Andy Wingfield
Wanlaser

[Brian Robison]

Hi Andy,
I called Gary the other day and I'm working on some leads he gave me. Keeping my fingers crossed.

Larry, I don't know much about the pantograph regarding the detail you can do. I understand I could laser a part such as a plastic and use it as a template for the pantograph?