The NICHIA NDV 4542 diode in a laser CNC

[John1a]

Hello.
I am planning on another X-Y laser engraver. This one is not made by printer and cd drive parts, but with parts I bought myself to ensure a big enough working space, enough motor torque and for the joy of assembling all those by myself.

Being a newbie in laser diodes I almost end up on this site while doing my queries in google.
The questions:
Having read many topics here I found out that 405nm wavelength is what I need. So while looking on ebay I found the NICHIA NDV4542 diode in to38 casing. It is a 200mw 405nm diode. But everyone is selling it as "used". No new found.

Is this diode what I need? It is quite low power but I am experimenting with all this so I don't want to spend for a more powerful diode right now.

How (and why) does a diode die? I am really worried about killing my first diode...

The datasheet figures 3 pins. I know (electronics/soldering and all those are my field) that a diode has 2 pins. What is the third one and what do I have to do with it? I believe it is the can ground but I am not sure.

I am gonna use the LinuxCNC (EMC2) to run my CNC (it is all set waiting for its laser). There is a package of software that makes EMC2 to support lasers (formally CO2 I believe). This package (you can find it at sourceforge) uses PWM to control laser power, as well as PPI (Pulses per Inch -really crazily cool). Is the PWM gonna hurt the diode? At what mA do I have to drive it to ensure no harm?
(extra bit on this: the on/off switch is on the supply-driver connection and it is a Darlington TIP120 Transistor with collector to the drivers ground and emitter to the supply's ground)

I am using an LM317 driver with a trimmer, diode, and cap. A standard build that has flooded the internet. What test load circuit do I need to test the Amperage? (how many diodes before the resistor?)


Any answer can be helpful
Thank you all in advance!

 

[LarryDFW]

John1A;

Forget the 200 mw LD.

You need more power and reliability.

I would look at the 9mm 445 LD from DTR (~$70) or

the NDB7A75 for even higher power @ $210.

With decent optics, they will be a good match.

Properly designed PWM is fine for any 445 or 405nm LD.

I am also looking at some X-Y stages & software for a slighly different application.

Mainly, you will need good heatsinking for longer run times required.

Don't forget safety goggles !

LarryDFW

 

[John1a]

When is a PWM source properly designed?
I haven't forgotten the goggles, I will buy a pair when I choose the diode.

First of all, I want a first meeting with "laser diodes" so I can't spend that much (70$) for something I am not sure how to use...

Can you please answer me some of the rest questions?



If you need any help in CNC software I may can help you. While doing my research on what I need I found lots of CAD/CAMs and experienced the most well known CNC controllers (EMC2 and MACH3).

 

[ChaosLord]

When is a PWM source properly designed?

First of all, I want a first meeting with "laser diodes" so I can't spend that much (70$) for something I am not sure how to use...

Well, you aren't going to find a diode powerful enough For cnc for cheaper. I can understand you're hesitant. I would suggest getting a cheaper diode and search around the forum and learn all you can about them. Play around with cheaper ones till your ready.

 

[John1a]

Hello! Thank you for your interest!
The diode has been bought, has arrived and has been in my CNC for some time now.
It works perfectly for engraving wood real deep (gets a very black line) and almost cuts cd case plastic (I believe that running at lower speeds will do the trick).

I even made an instructable about it in instructables.com
Here you are: (clicky).
Of course I referred back to LPF as a source of information about lasers generally in step 5.

Thank you for your feedback!

 

[LarryDFW]

It works perfectly for engraving wood real deep (gets a very black line) and almost cuts cd case plastic (I believe that running at lower speeds will do the trick).

I even made an instructable about it in instructables.com
Here you are: (clicky).
Of course I referred back to LPF as a source of information about lasers generally in step 5.

Thank you for your feedback!

Looked at your instructable. Good job.

Liked the HD Rack & Pinion.

Glad you put a fan on it,

because the smoke will end up on the laser lens if you don't.

LarryDFW