Titanium Deep Engrave

[Isaac Rutten]

I have a client that wants me to deep engrave their logo, which is basic text and about .125 tall. They want me to go .010" into titanium.
I didnt have any scrap laying around so i used aluminum which i read had simular properties when it comes to lasering.
The aluminum came out very nice, with straight edges and a flat bottom. When I lasered the titanium with the same parameters just more cycles to get the depth i needed, the bottom on the text looked like it was a 5th grader welding or. I sent the part to the customer and they did not approve. They are looking for a clean bottom.
My laser is a 30W chinese BM laser with EZCAD.
Parameters are:
Fill 1: 90 hatch, .05mm spacing, 35 loops, 100 power,500 mm/s,35 freq
Fill 2: 180 hatch, Same settings as above
The total cycle time was 10min per side. Had to do both sides of the part.
Anyone else ever done this or have any ideas on what to do?

[Scott Shepherd]

I haven't done real deep in titanium, but I'd say you are running too fast. I'd also be in the 20KHz range and about 1/2 the speed, maybe even 1/4 the speed you have. You might finish that with passes closer together with 80KHz. Just throwing out ideas. May or may not be closer to working.

[Isaac Rutten]

I do have a finish pass in there just didn't include that. I finally got some scrap pieces so I will try this out.

[Tim Bateson]

I agree, multiple clean-up passes are very important. At a higher KHz, lower power and faster speed. Also, that seems like a LOT of passes. If you need that many passes, you may want to mix in additional hatch angles. So same number of passes, but a better mix of hatch angles.

[Kev Williams]

I don't do "loops". I do repeat passes. Why not loops? It doesn't make sense to me to repeat engrave the same .05 spaced lines 30 or 40 times before changing direction. It's like digging the same ditch over and over... the spaces between hatch lines never actually get engraved until the angle of the hatch (or the hatch spacing) gets changed.

When I deep engrave I usually use one of two methods:

1- 3 hatches: 15, 135, 255 degrees, and then however many repeats works. This works great because the with the laser sweeping different angle each pass it's always cutting down the high-points of the previous pass. Sometimes the 3rd hatch will be a cleanup, but usually I run cleanup passes afterwards, I'll just set up a different color for cleanup duty, then just change the color of the graphic.

2- run a single auto-rotate pass, usually at goofy intervals, like 31 degrees, for as many passes as needed. Unless a few hundred passes are necessary, cuts will never repeat. Usually makes for a very smooth bottom.

[Isaac Rutten]

I set it up with 125mm/s speed, 20 KHz and .002mm spacing. Did the auto rotate pass and set it up for 40 passes.
Finished up with a clean up cycle and it looks like a dream. Sending it off for customer approval.

Now that it looks great my cycle time is atrocious, almost 20 min per side on this 30W. How much faster would a 50W be able to do it? Ballpark estimate?

Thanks for all the information! Just getting into the this kind of stuff.

[Kev Williams]

I set it up with 125mm/s speed, 20 KHz and .002mm spacing.

--Is .002mm correct? or did you mean .02mm? .002 is a bit extreme for engraving (good for annealing tho)

[Isaac Rutten]

--Is .002mm correct? or did you mean .02mm? .002 is a bit extreme for engraving (good for annealing tho)

Yes .02mm. Used to working with inches. Machinist by trade.

[Scott Shepherd]

Yes .02mm. Used to working with inches. Machinist by trade.

Switch it to English. No more metric to deal with. It's easy.