Laser Etching & Engraving with 405nm

[NightLase]

Hello All,

I wanted to share a few images of some of my current explorations into laser CNC etching & engraving.

I have been playing around with a couple of the cheap Chinese laser engravers that are available on eBay and Aliexpress, in particular the "K3" which has an 80mm x 80mm working area and also the Meterk / Neje DK-BL.

Its been a learning curve to say the least having worked out the difference between the "Chinese mW" and "true" measured mW. In my two engraver examples, the K3 sold as 2000mW laser and the DK-BL with 1500mW. It happens to turn out that the Chinese seem to ignore the decimal and state a power level 10x that of the truth, and seems this is how the are advertised.

Most recently, I found that Neje in particular state to be using a "Nichia NVD4642". An email to Nichia Japan, confirms this part number is counterfeit.

Recently I decided to measure the power on an Ophir Nova meter and thermal head (as my PD300 only goes to 300mW), and confirmed that in fact the powers are realistic at 150mW and 200mW (close enough).

Aside from the findings, the results are respectful and surprising. I am now in the process of porting the "K3" to GRBL. The origional software that comes with these units, to say the lest are crap.

Should anyone have a K3 engraver, I am looking to see if able to regain a copy of the original HEX data from the STM32 Processor.

Enjoy

 

[Hemlock_Mike]

Night Lase --

I have a small engraver which I have modified with a 405 laser and power supply.

It came with very simple software and I'm wondering what you use and if it can work on my simple unit.
HM

 

[paul1598419]

Yes, many of us here are aware of the Chinese mW. It is an ongoing joke around here. With only 200 mW to work with you must be quite limited in the materials you can engrave. Don't get me wrong, as I know the power density of the beam profile is determined by how small a spot you can get. But, since the BDR-209 BR diodes are available and can be pushed safely to 800 mW, I would think you might want to modify these engravers.

 

[NightLase]

Night Lase --

I have a small engraver which I have modified with a 405 laser and power supply.

It came with very simple software and I'm wondering what you use and if it can work on my simple unit.
HM

Hey HM,

I am currently porting a unit to Laser GRBL (free software)

You will need to use an Arduino and Motor drivers.. and upload GRBL firmware onto it

As you are using stepper Motors from CD/ DVD rail, you will need the low voltage motor drivers DRV8834 as you can’t run them at 12v as they will run very hot.

I’m happy to talk further with you if you are keen to work further on your system.

 

[NightLase]

Yes, many of us here are aware of the Chinese mW. It is an ongoing joke around here. With only 200 mW to work with you must be quite limited in the materials you can engrave. Don't get me wrong, as I know the power density of the beam profile is determined by how small a spot you can get. But, since the BDR-209 BR diodes are available and can be pushed safely to 800 mW, I would think you might want to modify these engravers.

Hey Paul,

Definitely I have been looking to get a BDR-209 diode.. this looks promising...

200mW of 405nm is slow, but the results are very good due to the ability to focus it to a very small point.

I also have a True measured 2.5W 445nm laser that I’m going to mount on my little 1310 CNC which I’m in the process of putting together.

 

[CurtisOliver]

The BDR-209 is also a very good single mode diode, so you can also focus it to a nice small point too.

 

[paul1598419]

^^^ Exactly.

 

[DTR]

Most recently, I found that Neje in particular state to be using a "N!ch!a NVD4642". An email to N!ch!a Japan, confirms this part number is counterfeit.

Funny I would take what they say with some skepticism.

It might be a valid part number or it might not. They do tend to keep a lot of info secret specially if asking in context to a salvaged part from a commercial product as they really have it out for harvesting and supplying for use in end products they have not approved of. I get messages all the time saying that N!ch!a denied the existence of the NUBM44 diode blocks despite the 100% proof they do. It is an effort to undermine sellers which they have a real distan for. Now there is a lot of incorrect data and made up part numbers/datasheets for Nichia diodes which is not helped by their secretive and super controlling policies.

 

[Janda]

Hi, i'm currently in the process of repairing my K3; the four H-bridge chips decided to put on a impromptu firework display, which was quite exciting to say the least. NightLase, can you tell me what chip is used on yours? I'm looking for replacements but the H-bridge chips on my board are all blank and I can't read the text from the image you provided.

I see you are converting yours for GBRL compatability, which is a fantastic idea and one that I would like to persue at a later date. Could you provide a parts list?

I also need a replacement laser, but before I invest in a BDR-209, can anyone recommend a cheap diode to experiment with? What is the practical minimum mW for a 5V laser?

I have an old DVD burner lying around and i'm tempted to extract the diode from that. Are there any disadvantages engraving at 650nm? I assume one issue is less precision, but on this engraver, would it be noticeable?

Thanks in advance.