FR4 Machine Shield

FR4 Front Spindle-1.jpg
FR4 Front Spindle-1.jpg
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FR4 Machine Shield


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The FR4 Machine Shield is one machine with many possibilities.   Like a 3D printer, the head can move side to side, front to back, and up and down. The kit can be assembled to act as a shield, cape or hat to be used with an Arduino, BeagleBone, or Raspberry Pi. So far, we have tested the FR4 as a milling machine, a microscope, and a laser engraver. With it’s open source design, the possibilities are endless! 

For open source files and user's manuals, click here.


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Why FR4

The Machine Shield is made from FR4 composite, known to most people as PCB(printed circuit board).  It is a woven fiberglass cloth with an epoxy resin binder. The top and bottom of the composite sheet is coated with a thin layer of copper. This allows us to route wires beneath the white paint on the surface of the structure, reducing loose wires and points of failure. It also allows us to mount components like limit switches and LED’s to the structure without additional fasteners or brackets. All of the Machine Shield structure is made from a single 18” x 24” sheet of FR4. By soldering individual cutouts from the larger panel together, we are able to create a very rigid structure.

How it works 

The Machine Shield plugs into an open source microcontroller, such as an Arduino Uno, to access the digital input / output pins.  This allows the machine to be computer controlled and makes it very accurate.  In the world of open source microcontrollers, such hardware may be known as a shield, cape, or hat depending on the controller type. This is where the name Machine Shield is derived from.  

The Machine Shield ships with a brushless 3 phase milling attachment but it’s capable of so much more! Tool heads, similar to the milling tool head, are interchangeable so the Machine Shield can be used for more than one function. For example, by switching out the milling tool head for a laser tool head, the user can switch from carving to engraving. Users can design and build their own tool heads, or purchase ones made by Pocket NC.

We have many tool heads in the works. We plan to start selling some of the following as soon as machines start shipping:  

-3D printer  

-Laser engraver  


-Circuit board pick-and-place  

-Hot air Reflow

The FR4 moves using the same machine language as a 3D printer called Gcode.  For each different tool head application, this code may look slightly different. As part of the Kickstarter campaign, we plan to create step-by-step work flow tutorials demonstrating how to generate this code for each different type of head.

Open Source

The FR4 Machine Shield is a open source shield that attaches to the Beaglebone, Arduino Raspberry Pi, etc, providing 3 axis functionality for any project. As soon as we begin shipping machines, we will release the files for the design on our website. This will include the PCB files for the machine and drivers, component STL files, a complete part list, and the assembly manual.  

We were inspired to make this project open sourced by many existing projects that have helped move us along. Open source projects that directly contribute to the FR4 include:  

-  Arduino  

Raspberry Pi  

- Beagle Board  

-  GRBL  

Universal Gcode Sender  

-  Machinekit

See the story on Hackaday.

Swap Drive

Motors on the FR4 are controlled using swappable drives, we call them Swap Drives for short. Each Swap Drive holds all the components necessary to control one device such as a motor or laser. Each drive plugs into a 64pin card edge connector mounted on the surface of the FR4 Machine Shield. Because the Swap Drives have a dedicated pinout, users are able to design new Swap Drives that will work on every machine. Technology advances quickly, and this system allows the drives to be upgraded at a low cost. The Swap Drive system is also “hot swappable” meaning users can plug in and unplug drives without having to turn off the machine.

What's included?

- FR4 Machine Shield Assembly Manual  

- FR4 Circuit Board components  

- Solder  

- X, Y, and Z motors, rails, and lead screws 

- Power supply  

- Electric components(Stepper drivers, connectors, power jack, etc)

- Fasteners  

- Tools (allen wrenches and tweezers)  

- Spindle (cuts plastic, wax, and wood, micro machines aluminum)

- Spindle Motor

- Spindle Driver

 - Cutting Tool

Note:  the kit does NOT include an Arduino or soldering iron, they can be purchased separately.

Assembly Details

The FR4 structure is composed of many circuit boards that are soldered together to make a 3 dimensional machine. Brass nuts are soldered onto the structure to allow mounting of external components. Homing switches and card edge connectors solder directly to the structure to reduce loose wires. Funding for the Kickstarter campaign will enable us to compile a full assembly manual in detail to ship with each machine.

We estimate the complete assembly process will take 4-8 hours, depending on your skill level.

Machine Stats

X Axis  

Max Travel  ~125 mm

5 micron resolution  

Rapid speed ~600mm/min  

Hall Limit Switches  

Y Axis  

Max Travel ~75 mm

5 micron resolution 

Rapid speed ~600mm/min 

Hall Limit Switches 

 Z Axis 

 Max Travel ~50mm

5 micron resolution 

Rapid speed ~600mm/min 

Hall Limit Switches 


Nema 17 Brushless 3 phase spindle With Back EMF 

30 Dba ( not engaged) 



Card edge Swap drive system

 The Machine shield is not limited to one controller or user interface, It will function with any motor controller application designed to work with Beaglebone, Arduino or Rasperry Pi. Our favorite Opensource UI is Universal Gcode Sender. 

Autodesk Fusion 360

We are excited to be partnered with Autodesk who offers their software, Fusion 360, free to enthusiasts and supports this machine with a post processor. Fusion 360 is cloud-based design software that includes both CAD and CAM and is compatible with Windows and OSx. Just download the trial version and once it expires, sign up as enthusiast to continue using it for free. If you have a different CAD/CAM combination that you’d like to use, the FR4 accepts standard G code so that won’t be a problem. In some cases, a post processor will need to be generated. We will do our best to facilitate that as needed for our users.