Tested my new laser from optlasers.com this weekend.
First test: Will it cut 6mm birch plywood ?
Yes it will, first attempt failed with 6 passes at 300mm/min, 2nd try 8 passes at 300 mm/min success (left a round mark on the spoil board too )
With better focus adjustment 1mm per pass might be possible.
Sweet!
Can you provide any additional information like which laser you’re using and how you have it mounted? Any pictures of your setup? I had read that for thicker plywood you might need blower assist to remove the ash/char after the laser passes. Did you need this or have you tried it?
Thanks for sharing!
The laser is this one (Based on a NUBM44 diode) : http://optlasers.com/en/home/78-clh-5000-engraving-laser-head.html
Since I’m using a Kress spindle the 43mm laser head fits in the same mount.
I don’t have any more pictures yet, the wires and driver is tied on with zip ties at the moment 
I did not use blower assist for that test, the seller claims that its able to cut 10mm plywood so I figured 6mm should be easy 
After checking I realized that I was actually using the 3 element lens and not the included single element lens (some kind of aspherical lens, not G2), the results might be even better with that one.
That’s pretty simple then. 12v power in and with the analog 0-5v modulation I think there should be no problem using any PWM pin on the arduino to control the output power.
Now I just need to figure out how to plop down the $340 without the wife having a go at me.
I bought it with the 7.5V psu included and used pin 44 like in the 100$ 2.8watt laser guide, has no problems with it
Just give her 340$ for clothes and it will be fine
Nice laser, I’ve had my eye on one of these for a while myself. The cost should be under $200 total. The assembled diode with 3element lens is $106 at dtr laser shop. I wouldn’t buy a cheap Chinese driver but go with one from x-wossee on eBay.He has a good rep in the laser community and sells a5amp driver for about $40. That driver should be able to run from your ramps power supply a long as it meets the current requirements.
Don’t forget to add a decent heatsink and laser goggles for another 50$ or so but that still ends up under $200 id you don’t need to buy a new power supply.
Well that I could do and I was an electrical engineer in a past life so can probably do a little more research and work out the details. Do you have any forums threads or websites you would suggest I start at?
Is this driver okay or does it need the driver you linked?
Found this “So you want to build a laser” thread
I just glanced at it but it didn’t appear to support pwm for grayscale engraving. If you only plan to cut with it then it’s fine but I’d definitely get the x-wossee driver instead if you want to do grayscale. It (x-wossee) also has lots of extra features like interlock inputs for safety enclosures and thermistor input to allow overheat cut off. I think you can tune it with a voltmeter without having to construct a test load as well.looks like a great driver.
Yes, it does have PWM. He has docs there explaining it. The site you had screenshots from is considerably cheaper than his ebay or amazon stores. I got the full 12mm module with 3 element glass lens and 4500mA driver for $160 shipped.
Now for eagle pair safety glasses $47.68 shipped and probably this heatsink $7.36 that I’ll mount a fan to that I already have.
Grand total: $215.04
I’m not so sure about pwm support on that driver. It can be driven by ttl logic , on or off, but i don’t think this will do pwm. Can you ask seller to confirm? The dtr laser shop site describes the buck drivers like the one you bought and refers you to other sellers if you need a driver with modulated input. This kinda convinces me that theirs doesn’t support it. Let us know when you find out.
For some reason the eBay listing has the most info. Basically remove the 10k SMT resistor between the enable pin and vcc. Then connect the AVR pin to the enable pin with a 10k resistor. Enable pin is on at 1.8v and off at 0.6v so that’s why the 10k from the AVR 5v PWM is needed. I will confirm with the seller.
On at 1.8 and off at .6 implies it responds only at those thresholds for on and off switching so i don’t think grayscale will be possible. I hope I’m wrong…
For the Laseerer X-drive DTR’s page mentions TTL/PWM modulation frequency of up to 5kHz:
https://sites.google.com/site/dtrlpf/home/flexdrives/x-drive. So make the mods including removing the ramp up capacitor and it looks like it PWM control should work.
I’m going to try this so KRavEN it would be really great if you could post any results here.
Thanks,
Steve
5khz frequency is the speed that it can switch at based on the input signal and it will accept ttl or pwm signal but my concern is the threshold voltages that are mentioned for switching off and on. That doesn’t imply that the output will modulate in correlation to the input signal does it? I contacted the seller myself but no answer yet. I still think the x-wossee driver is better suited for this type of thing. Those little buck drivers are tailored for handheld ray guns that the laser enthusiasts like to build:)
To be sure yes it would be best to hear from the seller but those thresholds are just TTL min high and max low specs just like you would expect for any PWM input. So if the laser can be turned on and off at that frequency then the average beam power will be proportional to the pulse ratio. Think about it like this - take a PWM TTL signal and low pass filter it. The output will be an analog signal proportional to the PWM ratio. The laser is just heating the material. The material will have a relatively long (relative to the 5KHz) thermal time constant. This will act like the low pass filter. Does this sound right?
The one thing that bothers me about the X-Drive is that the current is fixed 4.5A. I would prefer to be able to tweak it downward.
Steve
To me, ttl is different from pulse width modulation so i get thrown off when the seller recommends other drivers for modulation. TTL just means digital high and low switching doesn’t it? Oh well, if anyone gets one to do grayscale then keep is posted on the results.
