MOPA laser and non-MOPA laser, can I get same etching appearance?

[Amy Shelton]

I have a MOPA 30 watt. To increase production and to have as a backup, I'd like to get a non-MOPA 100 watt, so I can do deep engraving faster, etc.

I am using 2000s 40p 68freq and 200Q to get the etching the customer wants. I think I had read that is what a non-MOPA would be set to.

Do you think it's probable that it would etch the same? Should I send a partially etched part to the prospective company (still not sure yet where I'm getting it) and see if they can do a similar mark? (I know each machine is different, so that may not work, plus they could etch on a MOPA anyway, just to get the sale, I guess)

Thanks!
Amy

[Kev Williams]

Never had a MOPA so I know very little about them. I just no that there's no "Q" setting on my fibers!

as to 'the look' of the mark you want to duplicate, can you engrave something- not your job files obviously, just some words or something that would 'look' the same, and on the same material, and post up some pics?

[John Lifer]

It'll be work to get the same look with different power lasers. Some jobs way easier than others, but expect to spend a bit of time (might be minutes, might be an hour or two) to get things close. I spend about an hour changing from a 20 to a 50watt for about 6 different materials. I just did a polymer job I do every month or so and I spent about 10 minutes to get the non hatched engraving right. Had to change not just power, but frequency and number of loops to get it the same. But I was able to. I WOULD buy a JPT source over a cheaper Raycus as you have a larger frequency spread on the JPT and that can help depending on your material.

[Amy Shelton]

450568

Here's a picture. There's nothing really remarkable about it... to me it looks like a white etching, but sometimes it has a gold look to it in certain lighting.
I think it could be sort of easy to duplicate? Ha, maybe not. It took me a long time to get the settings for this.

There are SOOO many variables, not counting all the settings, but it can be in or out of focus (+ or -) and like John said, the number of passes. Fortunately, this one just took one pass. JPT is what I already have, and the one I'm leaning toward is also JPT.

There's a possibility for a recurring job, that will require deep engraving of "challenge coins" or really, commemorative coins. Someone said a 50 watt regular laser could be as strong as a 100 watt Mopa, as far as deep engraving. Is that right? Doesn't sound right.

Thanks!

[Kev Williams]

That can be done easy enough with a non-MOPA, the issue I run into is, it's very easy to overheat the stainless, which results in the gold tint. I get the best results using a wide 4 or 6 angle hatch, fairly fast, low power and the lowest freq for your machine, which would be equal to your laser's max output (30w machine, 30kH freq, etc)

I did this on a 'near' mirror polished stainless switchplate-

one of the issues with engraving metals, and especially polished metals is that the engraving takes on the color of the background reflections-

This is with plate aimed toward the wood ceiling in the basement when I took the pic-
450584
Even the plate itself looks gold--

Things are not always as they seem, this is with the plate aimed toward the concrete wall--
450585
much better :) --this looks to be a pretty good match,
3 x-hatches @ 30-60-90, hatch spacing @ .1, follow edge on the last hatch only, 2000 speed, 30 power, 30 freq, one pass-

A closer hatch or hotter power likely would've created a gold tint...

[Amy Shelton]

Thanks, Kev! You confirmed that I should be able to duplicate it well enough with a non-mopa.
Yeah, it's really hard to take pictures of highly reflective things.
I still haven't ordered another laser. But hopefully I will get it ordered this week. Decisions, decisions!