New to K40 - Hello from Malaysia!

Hi guys,

A little about me I’m AJ from Malaysia, I’ve just purchased a new laser which will be arriving in a couple of week’s time, I’m purchasing this machine as a new business venture (I’ll share more on this later).

My journey so far:- I have been reading about the K40 laser (on blogs, sites & forums) for about close to 6 months now and I was initially planning on getting the standard blue and white 3020 K40 40w machine (because of the expandability and ability to be moded to a bigger cutting area) but the local supplier that I am purchasing the machine from changed to the red and grey ones. I have instead opted to purchase the bigger brother, a 4040 50W

The nice thing about this machine is that it comes with a bigger bed compared to the 3020 and also with a motorised bed.

I have also done my due diligence on the machine and have ordered these following items:-

To be purchased (do let me know if i’ve missed out anything important) :-1:t3:

  • Flow Sensor
  • A water pump (waiting to see if the stock pump is any good)
  • A new set of switches
  • Mirrors
  • Lense

The other thing that I am looking to do in the near future is to replace the stock M2 board that comes with the machine because I would like to use the lightburn software, but looking at the cost (the Malaysian exchange rate sucks) going for a Ruida or Cohesion3D is going to cost me a kidney, hence I am leaning towards getting the Makerbase MKS DLC or MKS Robin, but for some strange reason there does not seem to be a lot of content and write-ups about the Makerbase boards being used with the K40 or other laser machines, if anyone has any experience with the Makerbase boards, I would appreciate some guidance.

Signing out for now, till my parts and machine arrives.




At least three things to keep in mind:

  • Cooling: Overheating the tube is quickly fatal to the tube.
  • Air assist: If the unit doesn’t come with air assist, you’ll want to add it. [Edit: i see it does come with air assist, good!)
  • When you get a new laser, always test alignment right away

More information is available for each of those in the K40 Intro linked at the top of the page.

Here is a recent wiring diagram from someone using a MKS DLC 2.1 with a K40.

You might want to test your laser with #k40:meerk40t before replacing the controller, especially if you end up needing vendor support to resolve problems.

I’d suggest considering a 32-bit controller instead of the MKS DLC. That’s an 8-bit controller. If you will be using gocde and especially if you will be cutting any arcs, one of the inexpensive 32-bit controllers would be a much better choice.

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WOW! I’m blown away that there is FINALLY an upsized K40. You had me all confused when you were talking about the larger laser format needing an analog meter and having the M2Nano since all the K50 machines, until now, came with a $1500 price and Ruida controllers.

Since looking at your 4040 machine I even found a 6040 for ~US$700 with the larger case and bed and same control system. These are new to the market!

As Michael mentioned you’ll want to read the K40 Intro section at the top of this page. Things to watch for are the water temp( < 25C ), water flow indicator and current limiting until we know more about the power supplies and tube quality. There are 3 applications I know of which work with the M2Nano controller: K40 Whisperer, Meerkat and VisiCut.

Looking forward to seeing more about your machine.


Thanks for the welcome @mcdanlj !

Yes i have to keep in mind the cooling as the average ambient temperature in the room i’m setting up my machine is 28-30 degrees celsius, for now my setup will most likely be a bucket with distilled water and containers of ice inside.

The unit comes with air assist, that takes some away some fiddling around.

The alignment is on my to-do list, also a once over on the general electrical system.

Also with regards to the controller, the two that i’m looking at, both of which are 32bit controllers:-

@dougl Yes! It’s an upsize K40, and it comes with a motorised Z axis and air assist!


Also to add, K40 whisperer will be what i’ll start off with.

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Ah, the DLC32 is new to me. Glad to see it exists. ESP32 with an external antenna for probably better reception than the on-board antenna.

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Pretty nice machine…

Keep in mind that it’s only 900mm in width. This is from Think Laser:

    55 x 800mm = 40 watt tube
    55 x 1000mm = 50 watt tube
    55 x 1200mm = 60 watt tube
    80 x 1200mm = 80 watt tube
    80 x 1400mm = 100 watt tube

Are common wattage for a 50mm and 80mm co2 tube. My China Blue is advertised at 50 watts and measures about 45 watts, about right for a 880mm tube.

To get a 60 watt tube in that case your extension would have to 1/3 the size of the case…

Just be aware, I’m sure you’ll have a great time with it…

Good luck


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You need a 30 mA ammeter, not a 30 A one.

If you replace the digital control panel with a potentiometer and a momentary switch, you’ll need something like a 3-wire 4/5-digit voltmeter if you want some kind of readout.

In my opinion, the digital control panel is perfectly fine if you install an ammeter.

See if you could get a (sort of Ruida) Ryxon KT322N for a reasonable price. They usually cost about half as much as a Ruida RDC6442G/S.

A Mini Gerbil could be also an option.

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@tomatsu thanks for highlighting that i ordered the wrong ammeter, since my machine is supposed to be a 50W laser, wouldn’t i require an ammeter higher than 30mA? (Managed to cancel the order… phew… I can order the right one now)

Yeah, I realised that I purchased the wrong voltmeter earlier :man_facepalming:t3: … I’m not really confident with these cheap ass china panels so I would rather go ahead with removing the digital panel.

The Ryxon cost about as much as a Ruida…

Ruida RDC6445 - $260 (MYR 1,100)
C3D - $230 (MYR 972)
Ryxon KT332N - $198 (MYR 837)
Robin Nano V3 - $74 (MYR 314)
DLC32 - $40 (MYR 172)

The reason i left out the Mini Gerbil is because it can only control 2 axis, the X & Y only, it would seem to be a waste since my machine already comes with a motorised Z axis, so i might as well get a controller that does just that…

Watts = Volts * Amps; Amps = Watts / Volts. Volts to the laser on your system will be somewhere near 20,000 and that’s the circuit you are measuring current on. CO2 Laser tubes are about 20% efficient at best, so 45W optical power delivered would be about 225W electrical power consumed. 225 / 20000 = .01225 or about 13mA. That’s a bit lower than what you’ll actually consume but wanted to give that math to show why 30A would be the wrong range. :relaxed:

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The difference has been discussed quite a bit on the Lightburn site. I have a document from Ruida that states the KT322N is one of their products. Of course, I can’t read Chinese to check the stamps, but…

For what it’s worth…



30 mA works for a pretty wide range of tubes. E.g. a CR70 tube (rated: 60 W, peak: 80 W) has a max working current of 20 mA. So, a 30 mA ammeter would be still okay.

But if the tube got a max working current of 25 mA (e.g. a CR90), I’d go with a 50 mA ammeter.

It’s pretty much just a glorified potentiometer. When it works, it works.

A bit cheaper: MYR 729.35 (Shipping: MYR 52.50)

For what it’s worth, the cheapest LightBurn-compatible DSP controller is a TopWisdom TL-A1 (same as WaveTopSign WT-A1 or LightObject A20). I’m currently upgrading to one of those. It supports 3 axes, got a small color screen, and you can use Wi-Fi and U-Disk in addition to USB.

Unlike most of the other DSP controllers, this one doesn’t use a separate panel which you just plug into the controller. The panel is the controller which makes wiring quite a bit more challenging with most chassis types.

Since I’m not done with the upgrade, I won’t recommend it just yet.

Sort of. It uses an AC motor for that. So, you’d need a stepper motor, a stepper driver, some mount for the stepper motor, and you may also need some pulley which matches the shaft of your motor. If it uses a chain instead of a belt, you may need to change a few more things.


Awesome, I guess i’ll go with a 50mA… We’ll just call it future proofing… lol…

What are the advantages of a DSP vs G-Code controller? There must be some long ass debate thread in here about there, if there is, could someone point me into the right direction?

Sorry, just woke up and about to run out for a haircut, hence i’ve not used the “into the 6 hour rabbit hole (search) button” yet…

They have a color screen which can show you a preview etc (except for a few exceptions), you get top-notch raster performance, there are jog/frame/origin controls, settings can be changed via a menu system, and there are usually a few additional connectivity options like Ethernet, U-Disk, and Wi-Fi.

You can usually run jobs “offline”. I.e. from a stick or internal memory.

They usually also support RF/metal tubes (with or without pre ignition).

Some of them can control two laser sources. E.g. there are machines which use a beefy DC/glass tube for cutting and a less powerful RF/metal tube for raster engraving. And there are other machines which got two heads and tubes for quicker batch runs and redundancy.

They usually have at least two outputs which can be used for all kinds of things. E.g. the “Ultimate Air Assist” mod requires a job running and an air assist output.

They usually pause the job when the interlock/chiller/whatever switch trips. You get a somewhat descriptive error message and then you can resume the job once you’ve taken care of the issue.

Some of them can resume the job after a power outage.

Some of them keep track of some statistics. E.g. how often you’ve run a particular job, how far each axis has traveled, or how long the tube has been firing. It’s kinda neat.

Overall it’s a way more polished experience, but there are some caveats. DSP controllers are kinda expensive (well, mine was quite a bit cheaper than a C3D LaserBoard), you need the more expensive LightBurn license, and if you upgrade from an M2 Nano, you’ll need a bunch of other components which you wouldn’t need with super convenient options like Mini Gerbil or LaserBoard. It’s also quite a bit of work.

Either way, I recommend to first check what kind of components you actually got with your machine. It could be an M2 Nano with external stepper drivers, for example. That would be convenient. Or it could use that flexible flat cable (FFC) like my K40 does, which is kinda the worst case scenario when you want to upgrade to a DSP controller.


Some goodies arrived today, i got a little trigger happy and purchased a12v and 5v power supply without knowing if my machine comes with a12v psu :rofl::rofl::rofl: if it does, I guess i would have to buy more led light to put around the house… lol


@tomatsu thank you for taking the time for the detailed write up, I guess we’ll have to wait for my machine to arrive first before i make more unnecessary purchases… :sweat_smile::sweat_smile::sweat_smile:


Using a 50ma meter on a system that the max recommended current at 21ma, is a poor selection.

Bigger isn’t always better especially when you loose resolution in the trade off.

At current readings that will ruin your 50 watt tube, you will be using just over 40% of the meter scale.

Meters are $8 or less. A 150 watt tube has a recommend current of 30 ma. If you go with a tube > 150 watts, the $8 for a new meter won’t even be missed, considering the cost of the new tube and laser power supply.

It only takes a couple of minutes to change out a meter.

You asked for suggestions, everyone here has suggested a 30 ma for a reason.

Noticed you have a couple of flow meters, how do those hook up?

Good luck


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There are also digital ammeters. They cost about the same. I think I paid about $6 for my digital 5-digit 50 mA ammeter.

Digital ones are way more precise and easier to read, but they only update about 3 times per second. When you raster engrave, they just jump around while an analog one would smooth it out and display some sort of averaged value.

Well, in my opinion, that’s not really a problem. I only need it to figure out where the limits are and at what current I’m cutting. I can do that with a digital one just fine.

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Ok ok… i cancelled the order and got a 30mA one… hahaha

The Flow Meter basic little acrylic box with a wheel that spins to show that the cooling water is actually flowing goes to before the laser tube inlet. Also houses the temperature sensor. Check out this you tube vid

The Flow Sensor connects before the flow meter, and it connects to the interlock… no water, no laser…

@jkwilborn this is what you were asking about right? Just in case I misunderstood your question.

I use a flowmeter that actually shuts down the HV supply rather than relying on having to constantly watch the meter.
I don’t know if this one is permanently out of stock or not but it provides and example.

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