Is there loss of detailed engraving with a more powerful tube?

[Luke Puckett]

Hello and I hope all is well with everyone. We currently have a 60W c02 glass tube on a boss 1630 laser. We have been thinking of buying a second machine with a larger engraving area and a more powerful tube. My question is if we use a 2” focal lens will there be loss of detail on our finer or more detailed logos and such if we went from a 60w to something around 120-150w?
Also, I’ve read that you can get more detail from an RF tube over a DC tube (not sure if we are ready to make that investment yet), but if we do go to a 120w tube should we seriously consider a RF tube or will the DC be close to the same on quality of engraving?
As far as detail is concerned, we engrave several hymns (only the ones in public domain) on alder plaques, so the music notes above the words can get detailed.
Any input would be greatly appreciated. Thanks and have a great day.

[John Lifer]

One thing on detail is that you CAN drop down to a 38mm lens and the dot will be finer. I use a 50mm lens most of the time with my 80W. I have occasionally used my 38mm and it does engrave slightly finer detail.
I think the issue is not the size going to a higher wattage, you can always dial back power, but there is a limit to the low end with a Chinese power supply/glass tube. I can't get good results at the bottom end of the power curve on delicate items.
my cut off is 18% on my machine. Anything less and it won't fire well. Absolute bottom is 16% won't fire at all. YMMV as to percent.

[Chris Thomason]

One issue you need to watch out for on dc glass tubes (most Chinese machines) above 80w is DC strike. When the tubes first turn on they need 100% power then back off very quickly.

the pictures are from my 100w machine. I assume it gets more noticeable with higher watt tubes. You can use different techniques to reduce the visibility but it is a consideration. RF tubes don’t have this issue

bi directional engraving. You can see a small trench around the perimeter of the letters

425837

one directional engraving the trench only shows up on one side

425838

[Martin James]

If you look at the specs for each size and brand of tube, it will probably say the max character height. I think I have General 60 and Reci 150. The 60 has the finest beam, and therefore can make the smallest letters. You might have to find these specs as rated for each machine. The 60 tube is much cheaper.

Cheers Marty

[Kev Williams]

A more powerful tube should produce a smaller beam spot, because higher wattage tubes produce a larger diameter incident beam (the beam from the laser to the mirrors), and the wider the incident beam, the narrower the focused beam spot will be with any given lens. This is why beam expanders exist... But in the case of glass tubes, the more power output, the more issues, like DC strike that Chris mentions, and the tube's unwillingness to fire consistently at lower power, which is necessary for 'dainty' work in many cases.

My big 1390 Triumph 'dumpster' (came in a 4 cubic yard box ;) ), 80 watt RECI, gives me wonderfully detailed engraving. But not "just because", I spent WEEKS fine tuning backlash adjustments at 50mm/sec speed intervals from 100 to 750mm/second, and it's very hard to tell it's engraving from my rather expensive Gravograph LS900-
This aluminum lid I Cermarked with the Triumph, that small text still surprises me how nice it turned out...
427592427591
-and this is the only machine I have with enough power to Cermark aluminum.

But not sure it wouild do a good job with detailed 'dainty' work on paper and such, as this machine starts losing consistency running below 8% power, and it engraves Rowmark nicely at 12%.

My advice, if you need a high power machine and a high-deatail machine, you need 2 machines...
(said the guy with 19 machines) :D - but seriously, you should consider it. I've never bought a machine that I later regretted...