K40 and Lightburn - Whats needed to make Lightburn work please?

Hi there.

I have a few diode lasers that I play with and I am thinking of picking up a K40 but I know these do not work with lightburn out of the box directly.

Can anybody in the forum point me in the direction of whats needed to make one work please on Lightburn apart from the Cohesion board which is a little out of my budget at the moment.

I was hoping for something a little cheaper and if I like the K40 then move up to a cohesion board later.

I am also aware of grounding issues, length of tube ie 30 watt and not 40 watt and to avoid the digital models but I cant seem to finds the “D” models on ebay in the UK which seem to be the best of the bunch from reading articles, there is also a big price difference between Amazon and eBay european shops for a K40 when they are both based in europe and I am not sure why Amazon is more expensive, Markup?

I assume the colour orange or blue is no difference.

Basically I want to get a k40 use it with lightburn and see how I get on and then either offload my diodes and buy a much larger C02 machine or stay with the diodes.

Thanks Neil

The only comparable replacement for the C3D is a Mini Gerbil from Awesome Tech - it’s mostly a drop-in replacement, though you should check as I’m not sure if they have the connector for the ribbon cable or not, or they require you to rewire the end stops.

Another option would be any Smoothieboard running Smoothieware or GRBL-LPC, but those are going to require figuring out the wiring yourself, cutting and splicing connections, mounting, etc.

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Using a $5-10 ‘middleboard’ allows you to wire any controller into a K40

Is there a reasonable priced controller you could recommend at all that works with your board.

At the moment I want to keep things to a budget, If I like the co2 lasers then in the future I will be going for a 100 watt machine but I want to start small for the time being, I already use several powerful 445 diode lasers and have used them for a couple of years and know them inside out but nothing on C02.


thanks Oz.

I assume the other alternative is replace with a cohesion board but thats expensive ?

Depends on the K40 as to how hard it will be to make a 3D printer board(MKS sBase v1.3) work. My analog K40 only required I convert the 3 wire endstop cable(sig/gnd/sig) into two 2 wire(sig/gnd). But it helps to know what’s going on like how stepper motors are wired and how to test your end stops.

I’d tested my machine using K40Whisperer which worked with the stock M2 controller and after a few months upgraded the controller and software to LightBurn.

As I said in the last post “ allows you to wire any controller into a K40”

Any being the operative word :slight_smile:

There are hundreds, from Arduino 328-powered with a CNC shield through to the Cohesion3D and Smoothieboard, Duet3D and other pieces of exotica.

I like the LPC1769-powered boards. Huge amounts of processing power, and a number of different firmwares, Ethernet, display screens, usb, sd card, on-the-fly changes, strong stepper drivers.

If you’re looking to budget, the MKS Sbase V.1.3. If you want to splash a few quid and support the community, a Smoothieboard 3XC or similar.

The ribbon cable is used for M1 and two end stops - easily rewired using a couple of lengths of light cable and a custom length of 4-wire motor cable (depends if your manufacturer used a hard-wired or socketed stepper - you will need to check)

thanks for the clarification, I know nothing really about the K40 setup and I am trying to learn over the next week of so, thats for that it enables me to move forward now. Would never of thought a 3d printer board would work as a laser controller! I guess at the end of the day they are all XYZ controllers.

You got it. The difference is in the speed. A basic CNC controller can drive a laser if you only want to cut, but it will struggle with engraving.

If you want to engrave, you’ll really need one that takes advantage of the advanced modes Oz coded into Smoothieware and that means an LPC1769 based board

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If you use the older, analogue version with the Ampmeter installed, you will have the ribbon cable.
If you don’t want to solder on your own and don’t want C3D, you have two alternatives:

  1. Buy the MiniGerbil (abt. 90$) which has a ribbon connector already on, but only 2 axis or
  2. Buy a middleman board and use any other controller.
    For 2. I would recommend to purchase a MKS SBase 1.3 and run it with GRBL.
    (according to what I read, GRBL is better in rastering, but the board could also run Smoothieware)
    The board itself costs something like 30$ and I strongly recommend to purchase also a 24V power suplly as the on original installed is quite weak. Connections to be done between MKS SBase (for GRBL!):
    From 24V power source into power in with GND and +24V
    From MKS SBase to original power supply: GND (the one the new power supply goes in) to GND on the old power suplly (3rd most right PIN). Minus port of the bed Mosfet (PIN 2.5) to the TL PIN (far right) of the old power supply. (Smoothieware uses PIN 2.6 as far as I know, which is E1 on the board)
    Y Stepper directly to the corresponding port of the MKS Sbase
    X Stepper from middleman board to X Connector on MKS SBase and
    End Stops from middleman board to X min and Y min to MKS Sbase.
    You also need + and - 5V going into the middleman board in order to power the end stops.
    (Can be taken from one of the Endstop connectors)

And you still have Z and E0 (A-Axis) also available if you want to add motorized bed and/or a rotary attachment.

Wit this setup you have the same functionality like Cohesian 3D, just 140$ less in price, but not to hide it 20Mhz slower processor. (30$ for the MKS, 10$ for middle man and 20$ for the 24V power supply)

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Bo, thanks for your comments, is it possible you could point me in a direction of a particular board please that doesnt take weeks to arrive as I typed in that and got a lot of different boards and as this is not my strong point I do not want to get the wrong one. thanks a lot. Neil

thanks very much for your detailed reply. I might come back to you with some questions once I have gone through this with my friend if that is ok, many thanks. Neil

Sure, if you need the GRBL settings don’t hesitate to ask.
This combination works great in my K40 and I used the MiniGerbil before.

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@spiritburner you NEED to read all of the FAQ at http://k40laser.se if you want to learn about the K40, how to make it safe and reliable, how to mod it for better operation and what it can and can’t do.

I really felt like I could hit the ground running after reading that before my K40 arrived.

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@Roy I had purchased the analog version and it did not have a ribbon cable. So it could be that it will really depend on the luck of the draw if you experience the opposite.

In fact, mine came with motor connectors which fit right onto the MKS sBase v1.3 motor connectors and the 3 wire M2 endstop connector only needed to be broken into 2 2-wire end stop connectors. Even that was probably overkill as only one ground wire was probably needed on the MKS sBase v1.3 for the end stops.

I do recall one of the motors was wired differently than the others but I was able to just remove two wires connector from the housing and swap them.

Not any more.

Lightburn has ‘cluster mode’ support for Cohesion’s version of Smoothieware which is significantly faster than GRBL at rastering.

The MKS Sbase v.1.3 board, Smoothieboard 3XS, Cohesion’s boards, MiniGerbil all run LPC1769 chips and support smoothieware.

IMO that is the best firmware for K40s.

I can’t tell you where to get them - I assume you’re in the USA and I’m half a world away with different sources and supply routes.

If you go for the MKS, don’t assume the 1.4 and 1.5 are ‘upgrades’ to the 1.3 - they’re completely different boards and won’t run Smoothieware.

The key is finding a board that runs the LPC chip.

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Hi Bo thanks for your reply I’m based in Spain in europe if that helps at all? thanks

I think Smoothie boards are made in Brest - although a little more expensive than their clones, you are supporting the industry/hobby and getting decent support into the bargain.

However, it looks like there are no V1 boards for sale anywhere, so unless you want a V2, you will have to buy a clone.

MKS V.1.3 is a decent one

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