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Fivetide
04-01-2021, 03:32 PM
So I'm looking at hooking one of these lasers onto my 1040 cnc.

Says it can cut ply single pass 8mm was skeptical but then saw someone demo it on YT (https://www.youtube.com/watch?v=i46UlmwELhY)

I think at that price I will take a punt , really mostly doing some etching for my daughters Etsy wooden stuff. And a few ply coasters for a friend. Anyway I'll let you know how it goes.

29339

Specs

30W General Specification:
Model:NEJE Module 30W
Heatsink Material:Aircraft Aluminum + Brass Shell
Luminous Color:Blue
Section Size:40mm x 40mm
Cooling Mode:Temperature sensor intelligent control + 10000 rpm 40mm cooling fan
Dimension:60 * 40 * 40mm
Adapter Plug:5.5 2.1 port
Can Engrave:MDF/Balsa/Paper/Wood/Fabric/Plastic/Leather/Plywood/Foam Paper/Anodized Aluminum
Can Not Engrave:Metal/Glass/Stone/Ceramics/PCB/Stainless Steel/Reflective Material/ Transparent Material
Technical Parameters:
Module Input:20-30W
Optical power output:7.5W (7500mW)
Wavelength:445-450nm
Beam Shape:Dot (Focusable)
Working Voltage:DC 12V
TTL&PWM Modulation:YES, Compatible with Both TTL & PWM Modulation
Input Voltage:DC12V 3A
PWM/TTL Input:DC3.3V-12V
Input Interface:PH2.0-4Pin (+,-, PWM/TTL, Temperature), 3Pin (+,-, PWM/TTL) , 2Pin+2Pin (+,-) + (PWM/TTL,-)
NOTE:Temperature interface can be disconnected,NEJE provides text instructions for temperature acquisition on wiki.
Drive Mode:External ACC
Safe temperature range:<60 ℃
Module weight:202g ( The lighter the weight, the smaller the move inertia, the better the performance )
Life Time:10000-20,000 hours

Doddy
04-01-2021, 06:56 PM
Watching with interest. I'm not quite flush enough to punt 130 on a whim, but it you report good things then it's a good option.

Can I advise - get a thin sheet of ali to sit on the bed of your CNC - various materials cut tend to leach either resins or chemicals, which can mark the bed.

m_c
04-01-2021, 07:38 PM
I'd personally not put a sheet of ali under an unenclosed laser. I'd put down a sheet of something sacrificial that'll absorb the laser, not reflect it around!


One thing you'll want to add is a small fan to blow fumes away. It doesn't have to be strong, just enough airflow so the smoke/fumes aren't able to rise straight back up and coat/obscure the laser lens.

Doddy
04-01-2021, 07:43 PM
I'd put down a sheet of something sacrificial that'll absorb the laser, not reflect it around!


Then keep a fire extinguisher handy :)

You'll lose coherency on anything other than a polished surface, the amount of energy reflected back into the LED - there'll be some, but not a huge amount. Air assist and extraction all good ideas of course.

Fivetide
04-01-2021, 08:29 PM
I'm actually excited to have a go, the CNC has been in packing boxes for the last 18 months. But now I have my new home office big enough to get it built in, I'm going to do "stuff" lol
I'm on CAD atm working out a stand and enclosure to hand over to the smithy to make. Only problem is, hes use to making agricultural machinery so it will be made with battleship armor. I'll have to get some photos of some of the stuff he makes.. seriously over engineered lol

I have an idea for a low pressure cyclone air filtration system. I saw one at a factory I visited last year and it worked really well.
As for fire, I have a plan for that already.

Fivetide
17-07-2021, 09:39 AM
So just to bring this up to date.
It looks like these lasers only work with NEJE's own controllers.
Which they don't state on the sales page on AliExpress or Amazon for that matter.
They are simply an upgrade.
Waste of $100.. be aware of this.

Doddy
17-07-2021, 10:00 AM
I thought (only 5 minutes casual googling) that the laser was controlled either by a TTL or PWM signal? But I'm struggling to find the spec of the PWM signal (frequency, and active level, 0%/100% reference pulse widths)

What are you driving the PWM from? (e.g. a PWM output from a BoB?) In which case there may be a general sensitivity to the PWM frequency (and you might need a mini interface to take PWM of one frequency, and re-present that at another). That's all do-able and a cheap ardi (that you already have) could be brought to bear to achieve that.

Any documentation with the laser?

Doddy
17-07-2021, 10:02 AM
Deleted post - not convinced that the laser module isn't just driven by TTL-signal from the missing PWM controller. (ignore image that I can't figure out how to remove)

Fivetide
17-07-2021, 05:43 PM
I understand

Doddy
17-07-2021, 05:51 PM
It's hard to assess performance and operation from a web-based forum. That you can test-fire the laser fire suggests a constant demand generates full optical power (and absence is off), and that suggests the laser diode itself is "working" (and for the supplier, that's probably the position they're aligned to). The only question I would have is the operation of the control circuit built into the laser assy - that allows the diode to be modulated with the TTL input. It **should** be a case that "on" is lase, "off" is don't-lase, and that is simply and exactly what an Arduino PWM output will produce. If the laser assy is questionable, then that can be assessed with passing a variety of signals into the laser and observing the resulting laser output. Similarly, you should be able (with equipment) to monitor the PWM output from the Arduino, that under GRBL it generates a pulse with variable mark-space ratio up to full-on (or near-as-dammit). Without testing these it's difficult to throw blame at either the laser or the arduino/GRBL.

Doddy
17-07-2021, 06:01 PM
Here's a question or two:-

1) Can you write software on the Arduino?, such as to test the PWM interface to the laser without the GRBL software?

2) If you have an Arduino sketch, can you Upload (compile, link and install) the software into the Arduino?


If Yes/Yes, that's your answer. If No/Yes, then I'll knock something up for you - if you're interested.

Fivetide
17-07-2021, 06:17 PM
Just bought one of these

https://www.amazon.co.uk/1-3KHZ-Voltage-Module-Digital-Converter/dp/B0789738RC/ref=sr_1_5?dchild=1&keywords=PWM+To+Voltage+Converter+Module&qid=1626541965&sr=8-5

- looks simple conversion. But I'd hope for PWM control or TTL as its more accurate for shading etc. But.. saying that - I might buy another laser just for etching as I bought the 30w mainly for cutting hopefully it can achieve that. Apparently u get better focus and accuracy at lower power with diodes

Doddy
17-07-2021, 06:25 PM
Hmmm, that module you linked converts (or claims to convert) a PWM signal into an analogue signal. All three input methods on the laser control board are TTL/PWM. If your intent is to use that board with the laser to control power, I don't understand how the laser is intended to take an analogue voltage.

Edit:

Consider also the Arduino PWM outputs, if using the built in libraries (counter driven PWM) operate around 500Hz.. That module claims 1kHz -> 3kHz operation. Just a health-warning on compatibility.

Fivetide
17-07-2021, 06:32 PM
I'm amusing via the PWM/TTL imput?

Fivetide
17-07-2021, 06:34 PM
Hmmm, that module you linked converts (or claims to convert) a PWM signal into an analogue signal. All three input methods on the laser control board are TTL/PWM. If your intent is to use that board with the laser to control power, I don't understand how the laser is intended to take an analogue voltage.

Edit:

Consider also the Arduino PWM outputs, if using the built in libraries (counter driven PWM) operate around 500Hz.. That module claims 1kHz -> 3kHz operation. Just a health-warning on compatibility.

I'm getting confused.. on the laser board it only says TTL not PWM I thought it may need a PWM to TTL conversion.


https://youtu.be/hhlSpaA8an4

Doddy
17-07-2021, 06:41 PM
Aha, get where you're coming from. That board does convert PWM into 0-10V analogue, but that's to support the spindle's VFD 0-10V analogue input. That makes some sense. But the interface to your laser remains a PWM-driven TTL-level input. I'd cancel the Amazon order if I was you for that board.

Fivetide
17-07-2021, 06:45 PM
Aha, get where you're coming from. That board does convert PWM into 0-10V analogue, but that's to support the spindle's VFD 0-10V analogue input. That makes some sense. But the interface to your laser remains a PWM-driven TTL-level input. I'd cancel the Amazon order if I was you for that board.

Cancel thanks :)

So how do I increase the bandwidth of the PWM to 1khz - 2khz @Doddy ?

Fivetide
17-07-2021, 06:53 PM
I'll give this a go tonight when I get 20 mins spare then report back


https://youtu.be/gMB88fXOZ-g

Doddy
17-07-2021, 06:53 PM
FiveTide - I've offered you my phone number on PM. Or we can continue this thread here. One way is faster than the other.

Ignore the frequency - that's a characteristic of that board that converts PWM to analogue. If you've cancelled that order, that issue is off the table.

I really need to understand from you how much you understand what PWM is (a variable mark-space signalling standard) and TTL levels (simply a digital 0/1 representation though there are particular voltage level connotations that we can probably safely ignore given the rail-to-rail drive of the Arduino outputs). The question that needs to be resolved is: If you tie the TTL input to 5V, does the laser emit 100% power, and if tied to 0V does the laser emit 0% power (off). If that's happening, then the laser is fundamentally working.

Next, we need to establish - if your GRBL is trying to lase at 100% power, is the PWM output from the Arduino substantially "on" (maybe > 95% mark/space). And similarly at each power level (e.g. 50% = 50% mark/space). That confirms the behaviour of the GRBL controller.

Then you plug them together and check that still works. Back of my mind I'm cautious about any loading from the laser onto the Arduino output. TTL implies a current source level that the Arduino can comfortably handle. But the proof of that is scoping the D11 output signal. I'm also hesitant for any voltage droop on the PSU under the full load drive from the laser. Again, that's a scope job.

Doddy
17-07-2021, 06:54 PM
.

Doddy
17-07-2021, 06:55 PM
I'll give this a go tonight when I get 20 mins spare then report back


https://youtu.be/gMB88fXOZ-g

Yeah, that's a good test set up.

Fivetide
17-07-2021, 07:21 PM
FiveTide - I've offered you my phone number on PM. Or we can continue this thread here. One way is faster than the other.

Ignore the frequency - that's a characteristic of that board that converts PWM to analogue. If you've cancelled that order, that issue is off the table.

I really need to understand from you how much you understand what PWM is (a variable mark-space signalling standard) and TTL levels (simply a digital 0/1 representation though there are particular voltage level connotations that we can probably safely ignore given the rail-to-rail drive of the Arduino outputs). The question that needs to be resolved is: If you tie the TTL input to 5V, does the laser emit 100% power, and if tied to 0V does the laser emit 0% power (off). If that's happening, then the laser is fundamentally working.

Next, we need to establish - if your GRBL is trying to lase at 100% power, is the PWM output from the Arduino substantially "on" (maybe > 95% mark/space). And similarly at each power level (e.g. 50% = 50% mark/space). That confirms the behaviour of the GRBL controller.

Then you plug them together and check that still works. Back of my mind I'm cautious about any loading from the laser onto the Arduino output. TTL implies a current source level that the Arduino can comfortably handle. But the proof of that is scoping the D11 output signal. I'm also hesitant for any voltage droop on the PSU under the full load drive from the laser. Again, that's a scope job.

Thanks for the offer, I'll try and adjust the PWM output via the Arduino library's as in the video above. If unsuccessful I'll call you probably tomorrow evening if that's convenient ?

m_c
17-07-2021, 11:45 PM
One thing I've not seen mentioned, is how are the laser and arduino powered, and are they suitably connected?

If both are powered from the same 12V supply, they should already share a common ground, but if you're powering them independently (i.e. 12V to the laser, but relying on USB power for the Arduino), then you'll need to connect the Arduino ground to the laser/12V ground. Without that connection, the TTL/PWM control circuit won't be complete, and nothing will likely happen.

Fivetide
18-07-2021, 12:35 AM
FUCK ME m_c your a genius !! I owe you one. Tapped the power off the laser 12v power + earth and ... now works. :)

Doddy
18-07-2021, 09:38 AM
A useful reminder to me to not ignore/assume the basics

peterhend
13-08-2021, 12:43 PM
Looking at different things, sometimes you realize that for everything you need a lot of money.

CharlieRam
19-08-2021, 09:43 PM
I'm curious....did you get chance to test the laser power? Does it manage to cut through 8mm ply in one pass?