K40 40W CO2 Laser Cutter

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Generic "K40" laser cutter stock photo
Make Nashville's upgraded K40
working area of the laser
upgraded interface panel closeup
upgraded interface panel wiring
MKS SBASE V1.1 mounted and wired
MKS SBASE V1.1 pinout diagram
MKS SBASE V1.1 outline and hole pattern diagram
MKS SBASE V1.3 outline, plug, and hole pattern diagram


Generic Chinese "K40" laser cutter bought off eBay. It has been upgraded from the proprietary motherboard/firmware/software to an open source toolchain using a 3D printer Smoothieware compatible motherboard.

Here is the exact item that was bought on eBay:
High Precise 40W Co2 USB Laser Engraving Cutting Machine Engraver 300x200mm | eBay



LightBurn Software

Pay-for software, but cross-platform (Windows/macOS/Linux). There is a free 30-day full features trial. It's $40 for the version that supports G-code based open source laser cutting firmwares such as Smoothieware, GRBL, Marlin, etc. It's $80 for the version that also support the Chinese "DSP" RuiDa controllers. The software is very nice!


TODO add description and possiblly a page for a tutorial

LaserWeb/LaserWeb4: Collaborative effort on the next version of LaserWeb / CNCWeb | GitHub

Inkscape Plugin

Forest Darling wrote an Inkscape plugin that allows SVG files to be exported to G-code that can drive the laser cutter. It uses specially named "layers" in Inkscape to determine how the vectors will be engraved or images will be rastered.


We use the standard stable Smoothieware "firmware.bin" available here:


Instructions on how to flash the firmware:





Actually an MKS SBASE which is a Smoothieware firmware compatible Smoothieboard clone:

MKS SBASE V1.1 Stock Photo.jpg older MKS SBASE V1.1 that was donated and installed in the K40

MKS SBASE V1.3 Stock Photo.jpg $60.99 -- KINGPRINT NEW Smoothieware Controller Board MKS SBASE V1.3 32bit Controller Panel Board for 3D Printer

MKS SBASE V1.1/V1.2 documentation by pixel3design-hub on GitHub

MKS SBASE V1.0-??? documentation by makerbase-mks on GitHub

NOTE: post says there is no documentation yet for V1.3, I don't think it's very different from a user standpoint though:
MKS-SBASE v1.3 Schematic · Issue #39 · makerbase-mks/MKS-SBASE | GitHub

TODO: document the custom breakout board Forest Darling acid etched to adapt the original ribbon cable for the X axis and homing switches to 3D printer friendly cables. This special FPC connector was needed:

DigiKey Part A100331-ND.jpg TE Connectivity AMP Connectors 1-84534-2

Low Voltage Power Supplies

Dedicated power supplies (not piggy-backing off the laser high voltage power supply):

DigiKey Part 1145-1079-ND.jpg $17.31 -- Delta Electronics PMT-24V50W1AA

DigiKey Part 1145-1066-ND.jpg $15.45 -- Delta Electronics PMC-05V015W1AA

For wiring the 5V power supply to the Raspberry Pi's Micro-USB port:

DigiKey Part 1528-1798-ND.jpg $1.95 -- Adafruit Industries LLC 2727

DigiKey Part EP502A-ND.jpg $1.02 -- MPD (Memory Protection Devices) EP502A

Additional Power Outlets

Amazon uxcell 5pcs 125V 15A 3-pin Panel Mount Power Outlets Stock Photo.jpg $7.48 -- uxcell 5 Pcs AC 125 15A Power Connector 3 Terminals to US 3 Pin Socket

Air Assist

LightObject 18mm Air Assist Head for K40 Stock Photo.jpg $21.50 -- 18mm Laser Head w/ Air Assisted. Ideal for K40 Machine

TEN-HIGH 18mm Diameter 2-inch Focal Length ZnSe CO2 Laser Focal Lens Stock Photo.jpg $29.99 -- TEN-HIGH Diam 18mm ZnSe Focal Lens for CO2 Laser Cutting, Focal Length of 2"/50.8mm

LightObject 5mm ID 8mm OD Silicon Flex Tube Stock Photo.jpg $10.50 -- 5X8 Silicon Flex Tube for Air Assistance or Water Cooling(10ft)

Amazon Active Aqua Commercial Air Pump 60W Stock Photo.jpg $46.61 -- Active Aqua Commercial Air Pump, 8 Outlets, 60W, 70 L/min

Water Pump

The included water pump is noisy and pathetic, and a replacement is very inexpensive:

EcoPlus ECO-396 Stock Photo.jpg $23.95 -- EcoPlus 728310 Eco 396 Fixed Flow Submersible/Inline Pump 396 GPH

Banjo HB050-025 Stock Photo.jpg $3.12 -- Banjo HB050-025 Polypropylene Hose Fitting, Adapter, 1/2" NPT Male x 1/4" Barbed


NOTE: This has not been tested! This is a proposed attachment that allows the use of an in-line pump:
$5.99 -- POWERTEC 70150 Rectangular Dust Hood for 4-Inch Hose

Replacement Parts

Laser Power Supply

EBay 40W CO2 Laser Power Supply Using ZYE MYGG40W Flyback Stock Photo.jpg $65.54 -- 40W Power Supply for CO2 Laser Tubes Engraver Cutter Machine AC 110V

A higher quality alternative (with a different pinout) from a reputable US seller (still made in China):

LightObject LSR-JN40W-1V Stock Photo.jpg $205.00 -- 20W~45W PWM CO2 Laser Power Supply (AC110V) | LightObject

High Voltage Cable

LightObject LSR-CBLKIT Stock Photo.jpg $9.50 -- Laser Power Supply Cable Repair Kit | LightObject

Laser Tube

"KH Laser" 40W CO2 laser tube photos:

Interface Panel

Test fire button:

DigiKey Part EG2045-ND.jpg E-Switch PS1057ARED

TODO: post DXF for the Smoothieboard LCD interface plate.