The K40D is well known for beeing one of the better K40 versions out there, with it´s upgraded controller board (HT Master) and the famous gold-ish styled gantry.

Is it really possible to upgrade this beast? sure, or, maybe? let´s find out!

This project will be massive with deep diving into most of the stuff the laser is made up of, everything from the controller, water cooling, electric and buttons and so on.

Even if you have a regular K40 you can follow the ideas and solutions in this project, as most of it will be custom made and changed completely!

Here´s a list of the upgrades

New gantry in aluminium and MGN12/15 sliders

No friggi´n wheels on this gantry, at all, ever 🙂
Some of you have probably seen my hate for the plastic wheels that exist on the regular K40 and some of the upgrade versions found on the web. I do not like it and will not use it in my project.
20×20, 20×40 and maybe some other types of extruded aluminium aswell as MGN12/15 bearing sliders will be used. (the ones i got now is probably not genuine MGN, will be changed later).

400×550 travel size – or close to it.

Depending on what i can spare in the driving setup of the gantry i will try to maximize the avalible space for the laser to work with. It will be bigger than 200×300 anyway!

External case for electronics

With a external case i can control the cooling for the power supplies better, as it´s a well known fact that electronics do not like heat so i will take the knowledge i have from building custom PC´s into the project.

New lid and panels

As the laser is widened the lid has to go and i will install a new lid aswell as control panel for the machine.

Installation of Cohesion3D Mini

This one is pretty straight forward, as there is no guide on how to install it on a K40D, i will show it here.

Arduino security system

This is my product i sell in my store (not at the moment though), similar can be found on Github and other places. It controls fans, pumps, water flow and has a myriad of sensors and detectors to prevent the machine from commiting suicide 🙂
In the guide i will show how you can build your own from parts and products from Ebay/Aliexpress.

Custom changable bed with different jigs.

I do 99% cutting of acrylic, and i need special jigs and beds for this.

Part 1 of the video

Just a speeded version of the tear down.

Your ideas!
Do you have knowledge, ideas or suggestions? feel free to put them in the comments below, or on the youtube-video. All feedback appreciated

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could you tell me where to wire in a water flow safety switch on k40

Brian Field

I purchased one of the flk40D machines, it has manual bed lift air assist and a very funny looking lens head, i would like some advice on but can’t upload a picture on here, machine works ? runs a 12mm lens, and came with a 36mm focal tool cuts are crisp engraving is nice. Purchased an ma meter from you, fitting tomorrow.


Dear Mr HP Persson i need to replace my board moshiboard 4.7 to cohesion3d do you have the diagram for how to do that

Alf Hansen


Shortly ordering one. Any suggestions for a ebay version that is the better of K40?


where can i find this upgraded version? what is the name of the version?
best regards 3ddiys


thank you! do you have a drawing on your gantry? i´d like to build one myself 🙂