For this week, our team developed a CNC-based zen garden machine that draws patterns in sand by moving a magnet beneath the surface using a Cartesian XY system. For this, a custom web interface converts PNG images into G-code and sends it wirelessly to an ESP32-C6, enabling real-time control of the machine. This is our group page: Group Assignment.
My contribution focused on the design and fabrication of the external enclosure, as well as the development of a custom ESP32-C6 control board. This involved integrating both the structural and electronic aspects of the system to ensure proper housing, functionality, and overall coherence of the project and user experience.
The enclosure was designed as a protective and structural housing for the CNC sand plotter, maintaining a clean and minimal appearance while containing all internal components. It was first conceptualized in Shapr3D, where the cylindrical geometry was defined to accommodate the internal XY mechanism and ensure overall stability.
Used for initial conceptual design and visualization, allowing exploration of form, proportions, and overall aesthetics.
The design process began with the creation of a hollow cylindrical base, maintaining a wall thickness of 3 mm, corresponding to the selected material for fabrication (MDF).
A top cover was then designed to fit the cylindrical base. This piece includes a recessed area on the upper surface to hold the sand. Additionally, a smaller circular feature was added on the underside to achieve a press-fit connection with the base.
To enable the MDF to bend and form the curved surface, a laser-cut flexible pattern (living hinge) was applied to the lateral walls of the enclosure.
The enclosure will be fabricated using 3 mm MDF, with a matte black finish applied to the sandbox components to enhance the final aesthetic.
This is the final render of the enclosure, where a background was selected to better contextualize and present the design within a defined environment.
Used for precise CAD modeling, defining all components and preparing geometries for fabrication.
The flexible strip was designed as a rectangular piece measuring 276 mm in width and 88 mm in height. This dimension was calculated based on the enclosure diameter (560 mm). The circumference was obtained using the relation C=πD, and the result was divided into two equal sections to fabricate two identical strips.
Flexibility was achieved through a series of cuts, where spacing and length were balanced to control the material behavior. Greater spacing increases rigidity, while smaller spacing improves flexibility but weakens the structure. Similarly, longer cuts allow smoother bending, whereas shorter cuts increase resistance to deformation.
Using the linear pattern tool in Onshape, the base geometric unit was duplicated and distributed across both the length and height of the rectangular strip, creating a continuous flexible surface.
Both the base and the top cover were designed using a 560 mm diameter circle, ensuring enough مساحة to accommodate the internal CNC mechanism.
To achieve a press-fit connection, a secondary circle of 557 mm diameter was created on the underside of the top cover. This reduction accounts for the 3 mm wall thickness, allowing the top to fit securely inside the base.
Four concentric rings were designed with an outer diameter of 560 mm and an inner diameter of 460 mm. When stacked and combined with the top cover, these rings form the sand container, defining the area where the sand is placed.
Process used to fabricate all components from 3 mm MDF, ensuring accurate cuts and enabling the flexible pattern.
Open the files in SmartCarve 4.3 and assign cutting settings such as line type and operation (cut). Go to File > Import > Select File.
Once the file is imported into SmartCarve 4.3, the DXF is positioned within the working area. The design is checked to ensure correct scale, orientation, and alignment
Configure the machine according to the material (3 mm MDF).
Place the MDF sheet on the laser bed and define the origin point (X/Y).
between the external shell and the internal mechanism.
Once the pieces were cut, they were lightly sanded to remove burn marks from the laser. For this, use sandpaper and a Dremel tool to make the process easier.
The rings and top cover were assembled using white glue, applying pressure to ensure proper alignment and prevent movement during drying.
After assembly, two coats of matte black spray paint were applied to improve the final finish.
The flexible strip was gradually glued along the outer edge of the base, ensuring that the walls remained straight during the process.
An inner layer of off-white cardstock was added to the interior walls using hot glue, improving both structure and appearance.I also used the Dremel to make a hole for the CNC cables to pass through.
Final touch-ups were made with black paint, resulting in the completed enclosure.
Likewise, I was helping in other parts of the project, such as soldering our Seeed XIAO ESP32-C6 board, which would be connected to a driver and make our CNC machine work via Wi-Fi.
All components were organized and positioned on the PCB before soldering. The soldering iron was set to an appropriate temperature (~270 °C), and flux was prepared to improve solder flow and adhesion. Also place tape on the back of the Xiao to prevent a short circuit.
SMD components were soldered by first fixing one pad to hold the part in place, followed by soldering the remaining pads. Care was taken to ensure proper alignment and avoid solder bridges.
All components were organized and positioned on the PCB before soldering. The soldering iron was set to an appropriate temperature (~270 °C), and flux was prepared to improve solder flow and adhesion. Also place tape on the back of the Xiao to prevent a short circuit.
Final touch-ups were made with black paint, resulting in the completed enclosure.
In this section, you can find the downloadable source files developed during this week.