Hi I would need to laser engrave really fine text (Patent Numbers) on a cylinder steel product 40mm or so in diameter, and the engraved text only occupies 15 degrees at max. Do I need a rotary chuck, and do you guys have any recommended machines?
At 15 deg you might be able to get away without a chuck. If you are marking steel you will need a fiber laser.
You can mark steel with a typical plasma-excited CO2 laser by painting it first with cermark (or molybdenum-bearing moly lube or sulfur-bearing things like mustard; examples of both you can search for here), but to engrave it you’ll need a fiber laser or RF-excited CO2 laser. I’d choose a fiber laser.
The difference between the high and low point would be only about 0.17 mm.
If you set the focus between the high and low point, it’s off by half of that in the worst case.
@mcdanlj is good advice. I use
Here is a stainless mug using that product.
Maybe this is or isn’t what he was thinking, but …
It’s relatively costly (IMHO) around $5 an ounce (spray can, 12oz) and I seem to wash most of it away.
This mug had to cover more than the image area to ensure an even cover. You can see how much was not used and went down the sink. There are other options that are lower cost if you chose this method, but require mixing and spray equipment for more of an initial investment.
It’s sensitive to how thick it’s applied. I think the recommended thickness is about 0.05mm. If it’s thicker, it takes more power to get the similar results and you lower the possible lpi/dpi.
You didn’t mention how tall the characters are, relating to lpi that may be a problem.
It’s doable with a co2, but if it’s commercial I would highly suggest a fiber, as that’s what they do and there’s virtually no ‘prep’ of the material. For the cost of a fiber laser and how much I use it, I’ll stick with the spray on stuff…
Another thing with rotaries are maintaining a good registration of the material. I have a configuration file for just the rotary where all the acceleration and limits are very low.
So slow, it’s almost painful.
You see this problem more with vector files, since it’s rotating and changing direction as quickly as possible.
Trying to rotate a mass too quickly has it’s own set of issues. I’ve read that even the chuck rotaries have some problems here. Never had one, just reading before I purchased mine.
In a ‘wheeled’ rotary once set, you don’t have to change anything if you go from a 4" cup to a 6" cup.
On a chuck rotary you have to take into consideration the diameter of the material every time it’s changed and change the software to compensate.
Let us know what you chose and how it works out, so the next person will get better advise.
Good luck, take care.