Laser engraving forum

[CEPenworks]

I have a woodworking project where I want to do some laser engraving. I have a Sain Smart laser engraver that attaches to an Ender-3 3D printer. I have not had good luck with it but wanted to give it another try. It worked long enough for me to get it set up but when I went to do the actual engraving I had no laser. I am looking for an active forum on laser engraving to help me do some trouble shooting. I was hoping someone here might know of a good forum. I have found a couple forums but when you open them up and the front page has posts covering the past year and only a couple of them have one or two responses I don't think they are very active. 

Just in case someone here can help with the actual problem, here is more information. The engraver plugs into a 24V fan port on the printer. This port controls the fan by PWM. On the cable to the laser there is a small board. On my laser it looks like a custom MP1584EN buck converter. When examining this board it appears one of the IC chips may have let out a little magic smoke. I only get 0.22V out of the board. If I look at a current picture of the laser for sale on the Sain Smart website it has a very obvious LM2596 buck converter, I can find the exact same one on Amazon. I have ordered the same buck converter as on the newer ones and it will be ease to install when it arrives. What baffles me is you cannot control the laser power by PWM with the buck converter inline. I also find conflicting information if this is a 24V/12V laser of just a 12V laser. Unfortunately there is no electrical information on the laser so I can only go by sketchy documentation in website postings. If it can work on 24V why can't I just remove the buck converter?

[RPE1]

I have a woodworking project where I want to do some laser engraving. I have a Sain Smart laser engraver that attaches to an Ender-3 3D printer. I have not had good luck with it but wanted to give it another try. It worked long enough for me to get it set up but when I went to do the actual engraving I had no laser. I am looking for an active forum on laser engraving to help me do some trouble shooting. I was hoping someone here might know of a good forum. I have found a couple forums but when you open them up and the front page has posts covering the past year and only a couple of them have one or two responses I don't think they are very active. 

Just in case someone here can help with the actual problem, here is more information. The engraver plugs into a 24V fan port on the printer. This port controls the fan by PWM. On the cable to the laser there is a small board. On my laser it looks like a custom MP1584EN buck converter. When examining this board it appears one of the IC chips may have let out a little magic smoke. I only get 0.22V out of the board. If I look at a current picture of the laser for sale on the Sain Smart website it has a very obvious LM2596 buck converter, I can find the exact same one on Amazon. I have ordered the same buck converter as on the newer ones and it will be ease to install when it arrives. What baffles me is you cannot control the laser power by PWM with the buck converter inline. I also find conflicting information if this is a 24V/12V laser of just a 12V laser. Unfortunately there is no electrical information on the laser so I can only go by sketchy documentation in website postings. If it can work on 24V why can't I just remove the buck converter?

Did you look on SawMill Creek.  They have a laser forum.  I used to look on it for a while.  It was and still is very active.
RP

[iclark]

If it can work on 24V why can't I just remove the buck converter?

It has been a long time since I crawled into the details of laser diodes at the device level. That said, it seems like forward-biasing a diode (laser or otherwise) at 24V would not be a great idea.

I different question is why was the magic smoke emitted by that chip.

Is the PWM connector operating as designed? If possible, it would seem like a good idea to put a scope on the PWM output to verify its voltage and to check to see if it is running frequency-modulation or time-modulation mode.

You can go through a lot of time and money if your printer is feeding the wrong output to the laser system.

[CEPenworks]

Thanks for the responses. It seems only me and the few people that post reviews on Amazon are the only ones that bought this laser. I found 4 active sites and Sawmill Creek was the only one to give a response. It was inappropriate to the question like usual from them but at least a response. I got my new buck converters and installed one. It does a good job of maintaining the 12V even with different settings on the PMW feeding it. There is a point in which it can't maintain the 12V but that is expected. So like I though the only control over the laser is full on and full off. I also finally found some software that will output the correct flavor of gcode and it seems to be working.

[iclark]

Naive question: doesn't the PMW control how long (duration) and how often (frequency) the laser is turned on?

I would have expected that to be part of the control loop (along with print head translation speed) for getting the depth of burn that you want - sorta the grayscale control.

Does this setup not allow grayscale printing?

Again, this is new to me and I am just trying to learn (while my wallet is still telling me that it can't afford a laser printer / CNC in my shop).

[rwe2156]

If you're using Lightburn, their forum is very good.

[CEPenworks]

PWM controls the intensity of the laser beam so you can get a grey scale affect. Laser power and translational speed are the 2 things you have to play with. After finally getting this to run I have come to realize with this laser that variable power output is not needed. This is a 1.6W laser and you can get engraving at 10mm/s but with jagged edges. I have to be at 5mm/s to get something that looks decent. With the 5W and 10W lasers on real engravers they are moving around 100mm/s. I got into this only because we gave my son and Ender 3 printer for Christmas last year. This was a $50 addon for me to play with.

I did end up with LightBurn. It is a nice piece of software but does have some quirks I am still learning about.