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Laser engraving

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GA Gyro

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#1
Hi all,

I was not sure where to put this... after looking at all the forums, chose this one.
MODS: If there is a better forum, please feel free to move the thread.

One of the reasons I am setting up a machine shop, is EAB (experimental amateur built) aircraft... in my case gyrocopters.

I have some friends at the airport that want me to make parts for them... and am thinking of a way to identify the parts I make... A co logo and serial numbers.

And the thought came up: How to put these on metal parts???

The first thought was a laser etching tool... and then was thinking of liquid acid and a template.

Looking for ideas.

Most of the time, the metal will be 6061-T6, sometimes hot or cold rolled, and sometimes 4130.

THX for any input, appreciate it!

John

Edit... looks like a typo in the thread title... MODS: Can you remove the df at the front of the title, THX.
 

Terry Worm

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#2
I corrected the title and moved this thread to the Classic car, planes, trains, helicopters & rockets forum, although it may not be the best fit either. If we had a forum for etching and engraving, I would have put it there.

Sadly, I know nothing about laser engraving, so cannot be of much more help.
 

rgray

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#3
I always prefer the items that have a stamping or engraving. This lazer marking stuff is for the birds.
Taps that are stamped you can read....lazer marked just wears off before the tap wears out.

Wrenches that have the size stamped are much preferable to the lazer marked ones.

Not sure if your parts could withstand a stamp. Some probably could easily while some like hollow tubes would not.

The old pantograghs intrigue me...but take up alot of space..there are old engaving machines that work much the same and are a smaller foot print...some of the little desk top CNC engravers look interesting for this type of job.
 

Ebel440

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#4
The only laser engraver I have seen are cnc and expensive. You could possibly use some type of acid or electrical etching. Also could use a stencil and sandblaster.
 

GA Gyro

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#5
THX for the replies!

I kinda figured a laser etching machine would be costly... I looked on Amazon and found a couple under $1K, then upwards of $1.5K... lots of $$$ for simply putting a co name/logo and serial # on a metal part. And the cheap ones said not recommended for metal... ooops...

The goal is to place a company logo (or name) on the parts, as well as a serial number. Most of the parts will be small to moderate size... most would fit in a 3-4" cube... some are longer and smaller.

Any ideas as to a way to place these things on metal parts (mostly 6061-T6) would be most appreciated!

THX

John
 

CNC Dude

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#6
Laser engravers have come down in pricing considerably! When I bought mine, the cheapest was around $15K. Now you can get similar stuff for around $3K. In less than 10 years!

Anyway, here is all you will need to know about laser engraving:

1. A laser engraver (like most CO2 lasers out there) will NOT touch metals. How do they engrave then?
2. Metals can be engraved if they are anodized first. Since anodizing often involves the deposition of an ink, the laser can vaporize the ink and then you will get your artwork embedded into the metal. This artwork will last a life time on most parts, but if they are going to be handled, as mentioned before, you may wear out the artwork, not because it will wear out the artwork, but because the metal will wear out, removing the thin layer where the art work was laid.
3. Another option is to use a ceramic element better known as Ceramark. The stuff is expensive and hard to work with, but once that thing gets lasered in, rest assured only by melting the metal will you be able to remove the laid artwork. What you end up with is basically ceramic grafted into the aluminum. Good luck removing that!

If you want a laser to directly touch the metal, CO2 laser engravers are not what you are looking for. You should look into YAG, which are preposterously expensive and far from hobby world reach. But that thing will change the metal, so that is as close to a stamp as you will get with a laser.

Needless to say, another option is actually engraving the metal with an engraving tool (similar to a mill, but more like a needle which removes material). Not cheap either, but pretty much any CNC Mill should be able to do the trick, and there are some out there which are quite affordable.
 

Chips4Lips

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#7
The "CNC Dude" is right about what is being defined. A good part of the reason for promoting the "Cermark" process is that the alternatives ARE expensive and geared far more towards the larger commercial and military use because they cannot have a failure like one of the other readers mentioned where the graphics come off before the tap is worn out. I don't believe those examples are from the Cermark process but I would agree that their retention on the base metal is really poor and won't last at all with any handling.

I use the "Cermark process" on a lot of aluminum parts (as well as some other non-ferr. materials) and the durability is remarkably good when the parts and process is followed. On anything with a medium to high polish, the contrast will look great because the end result is a solid black image against what will serve as a good contrasting color with the aluminum. The whole point of this process was to put a durable and high contrast marking option in the hands of others with existing laser capabilities.

The commercial users (those with deeper pockets) will opt for the YAG laser but are often limited by the working envelope being on the smaller side, so "if you're writing a letter to someone" you'll need to be brief!

Typical laser engraving on anodized surfaces also provides a crisp, clean image on almost anything that you can get into the work area. The durability is expectedly a little less than the Cermark parts due to the relatively thin deposit of color on the aluminum. That can be addressed somewhat with heavier coatings but that means more $$ as it's time in the anodizing tank in a batch oriented process.

It all boils down to what you want to pay and the durability you're likely to be satisfied with. There are a lot of creative options for the "1-offs" - Thanks.

- Chips4Lips
 

GA Gyro

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#8
THX for the explanations of laser engraving...

It does seem to be expensive to set up for permanent markings on metal... ooops.

My goal is simple...
Company name and serial number on each part...
Sadly, this seems to fall between the one-offs and permanent... which are the opposites of processes.
(The idea of laser engraving came from watching 'How Its Made'... enjoy that show.)

Seems at the other end of options would be using stamps (manual)...
Or a small engraving machine.

May research a small engraving mill... attached to a PC???

Any more suggestions... would be most appreciated.
 

fgduncan

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#9
Instead of laser engraving, you might want to consider electro-etching. This method is fairly simple and relatively cheap. You can use one to put your company logo and stamp the serial number. The markings are pretty durable since metal is removed. You might look into it as an alternative to laser marker. You have to be careful with a laser marker since eye protection is required if you image specular surfaces.
 

echesak

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#10
Back when I was working on my UG degree, I used to do a lot of work on and with lasers. As explained in previous posts, direct laser marking of metals can be expensive. Here's why. It takes a lot of laser power to melt metal. Like most things, more power costs more money. CO2 lasers are CW (continuous wave). So a 40W CO2 laser is going to put out 40 watts continuously. This is great for cutting paper, wood, foam, etc. But you need a lot more power to melt or ablate metal. To compound the problem, many metals are good reflectors, especially at the longer 10.6 micron (10,600nm) wavelength of CO2.

YAG lasers are typically Q-switched, for metal etching. This holds off the energy of the laser pulse and lets it go all at one time. The shorter the pulse, the higher the peak power. So a low-ish energy laser pulse of, say, 4 joules compressed in a pulse of 10 milliseconds will be a peak output power of 400 watts. If the pulse rate is 10 pulses per second, then the average power is 40 Watts, same as the CO2 example. But the peak power of the YAG is 10X as more. This is what makes them so effective for marking. CO2 lasers typically use a gantry or table for X-Y control, where YAG's usually use high speed galvanometers, which are usually more expensive.

If you have a CNC milling machine, why not just mark the parts by engraving. If you don't have one, you can always get a small one and dedicate it for engraving (or a small CNC engraver). I've used my Tormach for some engraving, and it does a fantastic job. But it also does some pretty fair machining (better than I can do manually). So there's a double benefit :)

Eric
 

SEK_22Hornet

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#11
If you have a CNC mill already, one other option might be a diamond point drag engraver - used without the spindle turning, if I understand the process correctly - here is one type and a little information on it -

http://www.benchtopprecision.com/engraving_tool.html

I have not done it, since I'm not into CNC at this point, but it may be an option on some things.
 

ssaxer1

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#12
In my most recent job I laser marked thousands of 17-4 and C465 medical devices. We used a YAG laser and I can make marks that are just on the surface or deeply engraved. We used the laser to mark any metal items on the floor (brass, aluminum (anodized or not), stainless steel (316,316l,17-4, C465), tool steels, titainium). With the right setup you can mark just about any metal. The key with laser marking is determining how long you want the mark to last. If you want it to be forever than you engrave it. If you want pretty colors (and you can make some really neat colors) yopu trat it a little differently.

The company I worked for had just bought a just bough a new laser marker and ti cost ~$150K. This unit had everything (8x8 X-Y stage, rotary A axis, and a clean room compatible enclosure). The laser itself cost about $30k so it is not really for the hobbiest.
 

Chips4Lips

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#13
The comments from "SE" are on track as a solution - given the massive number of listings on "x-Bay" in the past year, there are "desktop or table top" (better option) CNC systems -many using MachIII and are relatively straightforward to setup and get results. Granted their spindles and motors are often on the "frail" side for any seriously long use but if their work envelope size is adaptable to what you intend to engrave (and you keep in mind things involving your specific "setup fixtures" then taking your time with maybe 2 more passes instead of "going for the gold" with a heavier cut depth - they would give you a variety of reasonable options. One in particular that is more impressive than many others goes by the name of "Sable15" and the construction methods and spindle type do outclass many of the others listed. This machine uses a stand-alone (bolt on) spindle arrangement with the motor and drive belt and even sells this portion separately so replacing either the entire spindle arrangement or some specific component is pretty easy to deal with. Another aspect to consider in your engraving is the "tool"(s) that you're going to use. I agree that the diamond point drag engraver is a good option - especially when turning but if the steel type (or especially anodized aluminum) is the stock you want to engrave on - consider looking for some of the single lip carbide (steep angle) cutters that are also available from "x-Bay) and for really inexpensive prices in packs of 10. They are fragile but effective when used correctly and I've begun to see additional coatings offered on many of them. That too will enhance their life and help your pocketbook. The use of coolants can sometimes be helpful in extending their life and with other metals they need to be cut "dry" - although I tend to try multiple fluids (tap cutting / etc) it's surprising how much help you can get out of simply using "3-in-1 oil" and keep the layer of oil spread out over the entire cut surface. Might be a little messy, but it helps to keep the chips suspended and moving away from the remaining "non-cut" surface. Patience and close observations will tell you whether your methods are working (as will the tip on those single lip cutters.) They will either be sharp or they won't be... if you have access to a grinder with diamond coated wheels you can re-sharpen then as well. The original carbide is where the cost is and the ones you're buying are most likely turned out on a production grinder system that takes about 10 seconds to complete and another blank is loaded for the next process. I hope this is of some help to your efforts.
 
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