Yag laser etching for marking parts

We do a lot of engraving on our VMC's for part numbers, lot numbers, vendor identification etc. We have had some parts laser etched (subcontracted) usually around $2. each in lots of 100 when engraving was impractical. We are seriously thinking of buying a marking laser, but don't know about operating costs and possible limitations. Not the trophy shop desktop models, but a Yag laser for part marking. Anyone have one that would care to enlighten me? I'm thinking around 20K to get into one, but what does it cost to run, any expensive consumables?

I have a friend that has a yag...it believe it cost $110k range. But he is marking polished steel parts in high volumes, so his might be a bit fancy.

I've been told that fiber laser is the way to go for part marking...I think you can get into one for $30k-ish.

We use a CO2 laser since our marking volumes are relatively low. With some marking compound, we can mark on steel and stainless as well. You can get into a CO2 laser for well below $20k. Send some sample parts and ask the laser marking OEMs to show you what they can do.

Operating expenses on the CO2 are pretty much nil...we've been told that we have to replace the tube every so often. If we have a large job to mark, we buy a bag of ice for the coolant tank. The marking compounds are quite expensive.

No a YAG or YVO4 laser does not have any consumables. Assuming you are not marking on especially hard materials or highly reflective materials you could get a YAG or YVO4 for around 20k - 30k. However you can get a laser that can easily mark on tool steel/carbide for around 50k. I actually happen to be an engineer for a laser marking company these days so feel free to ask me anything you like. With the right laser you wont have to use any marking compounds or anything. We have a green laser that can even mark effectively on gold without any compounds. Are you talking about marking or actual engraving with a laser? Two very different things. If you just need a mark then you can get a pretty cheap laser but if you actually need to engrave then you will likely need a fiber laser with more power otherwise it will just take too long to engrave to be very practical but still may be.

Timely topic.

Can you educate us (OP and me) on how they differentiate between marking and engraving? We need to look at getting a laser for marking purposes. Stainlesses and Titanium. What types are we looking at? What kind of price range?

My needs are a permanent mark that does not build up on the surface at all. It can erode very slightly ( .0002" max deep) and be easily readable. Materials hard and soft steel, stainless,aluminum, flat and cylindrical. Character size from 1/16" to 1/4 inch. Cannot cause any rust or corrosion or dis color (other than the marking).I'm not sure if you would call that marking or engraving.

Generally the difference is that marking is very minimal in it's affect on the material. Marking usually just changes the color of the material. For anodized aluminum it will vaporize the dye from the surface. Stainless it will heat the spot to change the color and so on. Where as engraving is more about material removal, or ablation, and will leave a groove just like traditional engraving .001-.004 deep. One of the other benefits of marking is the pulse duration is so short that the mark will have almost no affect on the surrounding material. Most of our lasers can pretty easily mark stainless. We have alot of knife manufacturers who use our systems for their logos and part numbers. If you are marking titanium frequently then I would say go with a 20 watt or so simply to reduce the marking time. More power means less passes required to get a defined mark. RJT you say you need to mark on cylindrical parts. Do you need to mark around the circumference or are you marking on one spot on a cylinder? I ask because we have rotary system that can mark around a cylinder but if you don't need that then you can usually get away with marking on a cylinder as if you were marking on a flat surface without too much distortion in the mark. Fiber lasers are terrible for this the focal point is very precise but the U-20 has about an 1/8" focal range which for everything but small diameter parts usually works fine. I have attached some pictures of sample marks we have done. All of these images are laser marks so the depth of mark is less than .0002, there is absolutely no buildup and very small heat affected zone.

One of the Knife marks

Or here is our promo video from youtube which actually shows the different lasers marking on different materials in real time.
http://www.youtube.com/watch?v=iNkwQNAepf4

We are everyday CAD users (Auto CAD, Inventor, Master CAM) so I don't see that as a problem. What kind of setup / programming time to do 30 characters, 2 lines of text on a flat piece? Trying to deceide if I would use it for just a few pieces, or go back and forth with CNC engraving. I can see we would need the rotary axis also.

RJT the setup time will be minutes at most generally. Basically what you would do is open the software create a text box and enter the characters you want. Then we have two diodes in the system one is obviously the marking diode but there is also an aiming diode. Which will create a red preview image of your mark on the actual part and when you hit mark it will switch diodes and mark exactly what it was previewing. This makes alignment really easy as you can just visually line it up which is excellent for marking a wide variety of parts as I am sure you are. It can get a little more involved when switching between materials as you will want to change the power settings and possibly other marking settings but these are pretty easily adjustable and when you find a butter zone you can save the settings for different materials. There is also a operator mode which keeps them from changing settings leaving the fine tuning to you.

We have switched to Fiber lasers. Our 20w units ran bout ~$30-$40K. We do engraving in a high volume, automated situation. Part numbers, 2D matrix, arrows, boxes, etc. Cycle time on a box, filled arrow, 20 character part number and a 10 x 10 2D matrix is about 7-8 seconds in aluminum. The great things about fiber lasers.. Fast, No chilled water required, runs off of standard 110V single phase, and they are pretty small units. I strongly suggest you get a Fumex vacuum system for any laser you install. Laser ablation generates fumes, especially if you are doing aluminum. These fumes can be dangerous, and they will degrade the laser lens in a hurry also.

Laser Fume Extractors for laser cutting & laser cutters

Second what Tony said about the Fume Extractors. Unfortunately the laser will not have any consumables but the fume extractor does need filters replaced.

If we collect the fumes and filter them, do you exhaust the discharge outside or inside? We already have a dust collector system for our small surface grinders (dry dust from dressing and grinding) that we filter and return so we don't lose heat or A/C. Would it be the same kind of unit (Torit) or something different?

We exhaust to the inside with our fume extractors. Yes it is probably similar as I know Torit makes fume extractors for welding. We use Bofa extractors here but anything rated for welding should do fine for marking as well.

With about 45,000-50,000 parts a week, we change our Fumex filters every 3 months I think. It's on a PM so it isn't something one thinks about much. We started using fumex about 2003 and have yet to have a unit fail for any reason, and they run 24/7.

What's the nature of the fumes toxicity, is it something that persists?.

It all depends on the material really. When it comes to plastics though I wouldn't do anything without a fume extractor.