My goal is to acquire a laser engraver to do granite engraving with high quality photos, while also having the flexibility to cut thicker materials efficiently.
I have the ability to get a machine with a dual laser with these various setups.
Reci W1 and Reci W6
Diode laser and Reci W6
single Reci W2
I’ve read diodes have the smallest beam dot size outside of UV lasers. I’ve also heard that 150W W6 lasers have wider beams and therefore have a harder time with precision engraving.
So would a Reci W1 with a focal lense that creates a very small beam dot be a better bet than a diode laser for image quality?
If diode is the answer, which diode head should I use with a Ruida RDC6445S controller?
Do you have a link for this? I’ve really never seen a regular diode laser mated with a co2 system…
The lenses ability to make a focused ‘dot’ is a function of the size of the beam going into the lens. So a larger diameter beam entering will produce a smaller spot.
That probably isn’t the issue. If I’m engraving something on my 40W laser at 10% power you can equate that to 4W… Usually enough for a photograph… if not I can run at 20% or 8W…
With a 150W tube, you probably can’t fire it below nearly 20%… that means the lowest power you can control would be 30W which would sizzle something that only required 4W.
All the hobby lases are driven on and off by a pwm signal from the controller. The Ruida sends a pwm for the entire time it’s running the layer and uses another signal (L-On1) to fire the laser.
You couldn’t directly drive these lasers directly from a Ruida without some external logic.
If you notice, he had to build external hardware to control the led… Didn’t say it wasn’t possible, just I’d assumed you were going to buy one configured this way… and that the led laser isn’t directly driven by the Ruida.
This board is for the user to just plug existing systems together.
The led module requires a common ground, 12V and a pwm signal. The pwm signal tells it when to lase.
The Ruida puts out the pwm all the time, so you laser would be lasing all the time… The Ruida controls the lps (laser power supply) power to the tube by the pwm signal. However when it needs to lase, it uses L-On1. Two signals…
So if you want it to turn on, you need to combine the two signals to one that will drive the led module.
The only purpose of that board is to allow your to plug in a bigger power supply. You would only use one set of inputs…
I understand now. It doesn’t seem that complicated in theory.
With all of that being said. Is it worth having a low powered diode laser or a w1 co2 laser cranked all the way down with the smallest focal lense possible?
What beam size is achievable with a w1 laser with a small focal lense?
This is definitely doable. Note, though, that adding a diode laser module to the head of a CO2 laser is going to increase the mass of the head considerably. This is likely to dramatically lower top speed of the laser which may make engraving with the CO2 difficult due to limited overburning.
Yes, it is indeed possible to run a CO2 laser and a diode laser next to each other, controlled by the RD6445G. As is already mentioned in this conversation, if you hook up the diode laser directly to the second PWM output of the RD6445G, the diode laser will also laser during idle movements. This is because the PWM signal is also sent by the RD6445G controller during idle moves, but with a low on/off ratio (duty cycle). For a CO2 laser this is not a problem since it will NOT laser below say 6-8% of it’s maximum power. As a matter of fact the low duty cycle PWM signal is meant to keep the CO2 ‘ready’ and to start lasering as soon as it is needed again.
Instead you could indeed use the L-On2 signal, to control your diode laser, but you would then loose power control over your diode laser. It would be fully of or fully on. However, by using the L-On2 signal to gate the PWM signal (allow the PWM to pass through or not), you can have a perfect working diode laser that you can control very nicely between 0W and the max output power of the diode laser.
The Lightburn software supports this fully, and you can set the offset between the laser focal points of both the first and the second laser. This allows you to combine both lasers in one job, the CO2 laser for the better cutting work and the diode laser for the fine engraving stuff just as an example).
The gating of the PWM signal with the L-On signal can be done with just one transistor and a (or a few) resistors. Costs virtually nothing.
Hope this clarifies a few things.
I haven’t finished the complete setup yet since I wrote the quoted post, but it does work. One thing I learned when mounting the diode laser on the CO2 laser head (the tube with the lense), is that you have to provide enough stiffness. Otherwise you get positional oscillation, especially where the laser suddenly changes direction. This is something I still need to work on.
Thanks for the very detailed write up! I’ll keep this handy in case I want to revisit it.
I ultimately decided to go with a 75w co2 and a 150w co2 laser. I plan on using a compound lens for the 75w and just using it as the engraving head. It should also give me a little more flexibility in the speed department and people seem to have good results with it.
If the 75w with a compound lens isn’t detailed enough I might get a diode laser and see what quality that can produce.
Ummm… not quite.
I can fire our W2 tube as low as 5% power, and get it to just mark paper, and I can fire our W8 tube as low as 7% power, and have it just mark paper.
(Our W6 tube needs 23% to just make a mark, though, but the 180 watt will just run on 7% power, ie the figures are relative to the individual machine.)
We have a dual head, w2 & w8 laser, amongst others.
I’ve just swapped out the 6442S for a 6445 controller, though the 6442 us still perfectly fine, I just wanted the extra rotary control of the 6445, without having to disconnect the Y drive,
