As a high school student fascinated by CNC milling technology, I embarked on an ambitious project to build my own machine from scratch. Commercial mills were far outside my budget, so I decided to create a Mostly Printed CNC (MPCNC) variant, using 3D printed parts for structure and standard hardware for motion. The result was a fully functional machine capable of carving wood, producing over 50 personalised gifts, and teaching me the foundations of mechatronics along the way.
Discovering the MPCNC Platform
I spent weeks comparing open-source CNC designs, weighing trade-offs between cost, achievable accuracy, and required tooling. Most community designs at the time relied on machined aluminium, which would have driven the build cost close to commercial desktop machines. The MPCNC community showed a different path: use a 3D printer to fabricate the complex geometry, pair it with stainless steel tubes for rigidity, and leverage standard bearings and hardware.
This decision locked in my goals. I could keep the frame lightweight, customise the working envelope, and iterate quickly because reprinting a failed part was far cheaper than re-machining aluminium.
Printing and Preparing the Components
Printing dozens of structural parts tested both my patience and my 3D printer. The build required motor mounts, corner blocks, tool holders, cable carriers, and reinforcement plates. Across several days of continuous printing I learned to trust my slicing profiles, monitor for warping, and perform quick turnarounds when a print failed. Only one part needed a reprint, which reinforced the importance of bed adhesion and consistent extrusion.
Sourcing Hardware and Electronics
Gathering the non-printed components was comparatively easy. Stainless steel tubes formed the X, Y, and Z rails; standard bearings provided smooth motion; and NEMA stepper motors delivered torque. The electronics stack was built around a motion controller and stepper drivers, which I wired manually. Keeping the bill of materials within budget forced creative sourcing but also pushed me to understand the specification of each component.
Assembly Lessons
Mechanical assembly took roughly one and a half nights. The primary challenge was aligning the dual-axis rails to maintain perpendicularity. Getting the bearings to glide without binding required iterative tightening and reference measurements. The experience highlighted how 3D printed tolerances interact with metal hardware.
The electronics stage reminded me that mistakes are expensive. I accidentally reversed motor polarity, causing axes to move incorrectly, and I destroyed an initial control board within seconds by miswiring a stepper driver. Replacements cost time and money, but they cemented my debugging discipline.
Software, Calibration, and Toolpaths
Once the mechanics were moving, I focused on the motion control stack. Estlcam provided the firmware and control interface, while Fusion 360 handled CAD and CAM. To bridge the two ecosystems I added a post-processor that translated Fusion toolpaths into Estlcam-compatible G-code. Calibration involved squaring the gantry, tramming the spindle, and iteratively tuning feed rates until the machine cut smoothly without chatter.
Results and Production
The finished mill produced more than 50 custom gifts for friends and family, ranging from engraved boxes to small decorative parts. Each run validated the repeatability of the mechanics and the reliability of the electrical system. The machine now doubles as a research platform for experiments such as CNC painting and large-format lithophanes.
What I Would Change Next Time
- Rigid base structure: Modifying the cutting area to hang below the primary frame made levelling the spoilboard difficult. I would instead extend Z travel by lengthening the legs.
- Precision during setup: Even a small deviation from 90 degrees on the X and Y rails introduces oval patterns. A more precise initial alignment would reduce calibration time.
- Electronics safeguards: Adding fuses and labelled connectors would protect the control board from accidental shorts.
Skills Gained
- Practical digital fabrication, from CAD to G-code to finished parts.
- Structured troubleshooting of electronics and motion systems.
- The ability to document processes for reuse in future automation projects.