choosing the right laser module.. pls help

So I am thinking of converting my old 3D printer into a laser engraving machine. My goal is to be able to engrave plywood and leather. Anodized aluminum would also be great but it is not a must. However, I would also like to be able to cut plywood/MDF up to 4-5mm (no worries if a lot of passes are necessary, speed is pretty much irrelevant).

So what laser would be best for the task? I am looking for something that works and doesn't cost a fortune.. I have read a lot of forum posts on the topic but I still cannot figure out what I need. Some people claim that a Chinese 2,5W 450nm laser is perfect for cutting 5mm mdf in multiple passes, others claim that even 1,6W is enough while some suggest that the quest should start at 5W.

The price difference between 1,6W and 5W is huge, so I am feeling kinda lost here.

So please give me some practical advice - what type of laser do I need to perform simple cutting tasks if speed and number of passes is not a priority? Thanks

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Self-sourced Mendelmax 2.0-based Reprap Machine -- Ramps 1.4 & Mega 2560 -- DRV8825 ([email protected], [email protected], [email protected], [email protected]) -- genuine E3D v6 direct setup -- 350W custom silicone heated bed -- ABS 1,75mm -- Marlin 1.1.0-RC7 -- Cura 15.04.6

... be carfully with the stated powers of the chinese laser modules! They often gives not the laser output power, but the drawn electrical energy, what's something like 3x the optical power (so a "10Watt-diode" is often an overdriven 2W- or a 3.5W-diode).

A blue (445nm) 2Watt diode is better for accuracy (finer spot) ... a 3.5W-diode has a slghtly bigger spot, but a bit better for cutting plywood. 3-4mm plywood is doable with both of them with several passes, 5mm is much harder.

Look too into CO2-lasercutters with 40Watts of power - more than enough for 5mm plywood -- and good for MDF and clear acrylic too ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org]
Call for the project "garbage-free seas" - [reprap.org]

I bought one of the inexpensive Chinese 2.5W lasers. No TTL (PWM) control. I expected that I wouldn't be able to do grey scale type burning, but that's OK. My question, The 'modules' take 12V, and don't have TTL input. I assume I can't just feed the module with PWM'd 12v from something like the bed heater supply? The constant current circuitry inside the module won't like it?

What Laser modules (with TTL) are people buying for GRBL or RAMPS boards? Any Banggood modules worth it?

Thanks.

... depends on the current controlling/limiting circuitry inside the diode housing (if it's the common build) - with a LM317 inside you could remove the driver an "PWM" the LM-chip directly with around 3 Volts more voltage, than needed for the diode ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org]
Call for the project "garbage-free seas" - [reprap.org]