K40 build-out vs. DIY from scratch

As I ponder getting a laser cutter and/or engraver, I notice that when people get a K40, they start to add things or replace things, including:

  • Interlocks
  • Control board
  • Gantry
  • Motorized bed
  • Replacing bed material
  • Mirrors
  • Head
  • Fume extraction
  • Air assist
  • Front panel, or at least parts of the front panel
  • Power supply (typically with separate LPS and 12V PS)
  • Tube since it’s a consumable

Also, I’ve seen a lot of complaints about the quality of the enclosure; cutouts not aligned, gaps, etc. Suggestions that the original belts aren’t that great and you might want to replace them even before they wear out because of inaccuracy, or even that the wrong tooth profile was shipped.

What’s left?

What is the value of the constraints of the original K40 if the general consensus is you are going to end up replacing almost the entire unit anyway? Is it just a cheap way to make your first mistakes?

I’ve always said it’s about quality versus quantity. At about $300 delivered, you would never be able to buy all the components individually for that price. If you really wanted to just set up and go, you would then purchase the more expensive version and not learn about all the nuances that it takes to support a laser.
I was not sure I would even use a CO2 laser when I purchased my first k40. The price was why I purchased it and then enabled me to know that I wanted a more reliable and bigger laser. I would have been really bummed if I spent a lot of money and learned I did not want or would use the laser.


If the budget alklows, get the next step up. A 50-60W 500X300mm bed with a Ruida controller. You will pay around $1200 but have a much better machine than even an upgraded K40.


I agree, the K40 is all about the entry price point. You can make things pretty much right out of the box at about $300 delivered.

That being said, I opted to invest around another $150 on new mirrors, lens, air assist head, air pump, exhaust fan, new bed and misc materials. That gave me a machine that wasn’t fancy but reasonably capable.

Quality can certainly be a bit of a crap shoot with these machine sometimes.

Given what I know now, I do wish I had invested in a bigger machine from the start.


One of my kids has been in a program at a local museum and a couple days ago when the topic of laser cutters came up in the family, he started explaining his workflow with a laser cutter, which was quite a surprise to me because I had no idea he had access to one. :roll_eyes:

Today I visited the site and learned that the laser cutter in question is a 40W Dremel that retails for $6500. I looked at the construction and it really didn’t seem all that special. I think 8mm rods for the Y axis, with X on a Hiwin linear rail. 12"x20" / 300mm/500mm bed, so bigger than a K40. Bed not adjustable, head height set manually to fixed focus distance above the work piece.

Vis-a-vis a 50W or 60W, do I understand correctly that due to minimum activation energy engraving can be harder with higher-power lasers?

Still on the fence, and would want to close out some other projects first. But it’s interesting to think about at least. :slight_smile:

The issue with engraving and higher power tubes has more to do with the beam size, and the final focused size of the “dot”. The higher the power, the larger the dot size. A 40W laser can hit around 350dpi where a 100W laser will struggle to get 200 dpi.


One of the other considerations that you will need to chew on is that the “commercial” laser machines have mostly gone to cloud software and will not work “off line”. You will also have to use their propriety software only.
Most Chinese lasers use controllers that will work with third party software specifically Lightburn. You do not need an internet connection to run the laser.
For now, my Chinese laser has cost me $200.00 for laser powersupply replacements and $80.00 for Lightburn software plus yearly updates. If I wanted to stay cheap, I could use the RDworks software that came with my machine for free.
For the price of the Dremel, I could have purchased 3 of my larger and more powerful 60 watt laser.

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Oh, I’m definitely not in the market for the Dremel. Making my own from scratch, controlling it with hardware I control, is more what interests me. $6500 is very much outside my comfort zone here, too! It was more that it didn’t look intimidating to design and implement something of similar size, given other projects I’ve done.

The museum chose the Dremel over other units because the Dremel didn’t depend on cloud software to run, they told me. That’s all I know there…


When I started those K40 project, it was motivated by having a new tool in house at a small budget. As often with home tools (vs Pro) you have a moderate use of it. Size matter it take a certain amount of place in the workshop same if you would wish a larger gantry. 40W is about right for most I would do and I could always do some exceptional jobs outside.
As per mod/update I would stick with the cheap one, the most expensive being the controller to escape the Chinese software, interlock, air assist, new set of lens mirrors. The rest is just adjusting the k40 enclosure, cost very little.
Visicut is still a great piece of free software, not enough promoted here.

A K40 is a cheap entry level to CO2, the eBay price tag does not include the time you need to make it “usable and safe” with those mods. If no damage during delivery it still a good base to start with.
Your budget would be around 500$, you could spend more on adjustable bed, rotary, etc… But I would not do it , to me the K40 should stay entry level, as usual evaluate the job to chose the right tool !


It depends on what you want to do with it?

  1. Learn and build your own shop laser tool for 1/2 the price and have something to make personal stuff?
  2. Try and save money to make money (sell laser service)?

#2 is usually and a frustrating journey…

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#1 definitely! Making the machines is half the fun for me. (If it were a business, and I could build more efficiently than buy, I’d have to ask myself whether I was in the right business.)

My question was whether buying a K40 was inevitably DIY in the end, based on all the updates I saw recommended starting to look like approaching the complexity of DIY, while missing some of the potential concomitant benefits. The answers have been clear that I was extrapolating beyond common experience. It sounds like most folks end up spending less than the initial purchase price again on upgrades. That’s been definitely useful to understand.

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For me a new word of the day… :).

adjective: concomitant

  1. naturally accompanying or associated.
    “she loved travel, with all its concomitant worries”

Editorial note:
I mostly tinker with my K40’s functionality as a learning experience.
I find that I use my CNC router much more often but not really sure why.
I go hot and cold as to whether I really need a laser.
I do not do much engraving and mostly bought it for cutting acrylic. However I find I can fabricate acrylic projects by hand much faster then build a CNC program, test and then cut …


I am the opposite of Don. I cannot remember when I last touched my CNC. I can say I do more engraving with my laser than cutting.


And following up on that, looks like 60W 600x400 bed starts around $1500 with Ruida; $1100-1200 with M2 Nano and associated limitations. Good to understand the variables here. :slight_smile:

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I would definitely not plan on using the machine with an M2, the software is awful. For me, that made the machine unusable.
However, I think @NedMan is still running M2 and does awesome stuff.

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