Printing the Chassis

Stub — section skeleton authored 2026-06-27; prose to follow.

3.1 File Inventory

3.1.1 STEP Files

The upstream repository contains STEP files for the core chassis and all modular components. STEP is the CAD-neutral format; these files can be opened in FreeCAD, Fusion 360, or any STEP-compatible CAD application for inspection or modification before slicing.

This section lists every STEP file in the repository, its function in the assembly, and whether it requires modification for common builder variants (different screen size, different compute board, etc.).

3.1.2 Mesh Files

The repository also provides mesh files (STL or 3MF [VERIFY format]) suitable for direct import into a slicer without opening a CAD tool. This section lists the mesh files, notes any that correspond 1:1 to the STEP files versus any that are pre-oriented for printing.

3.1.3 Drag-Chain STEP Files

The drag-chain cable management system has its own STEP files in the repository. This section covers the drag-chain geometry, the number of links required for the sliding screen travel distance, and how the end brackets mate with the chassis.

3.2 Core Chassis

3.2.1 Main Body

The main chassis body houses the Pi 5, the step-down module, and the battery. This section covers the chassis geometry — internal clearances for the Pi 5 with the Joy-it heatsink, the battery bay dimensions for the NP-F pack, and the mounting points for the power module.

3.2.2 Sliding Screen Rail

The screen slides on a rail system to reveal or conceal the keyboard. This section covers the rail design, the tolerance requirements for smooth operation, and any post-processing required to achieve consistent slide action.

3.2.3 Rear Module Attachment Points

The rear of the chassis provides attachment rails for expansion modules. This section covers the attachment geometry, the USB rail pass-through points, and the shoulder-strap mount positions.

3.3 Drag-Chain Parts

The drag-chain manages the cables that must flex as the screen slides. This section covers the complete drag-chain assembly: link count, end brackets, mounting hardware, and the cable bundle that runs through it (display cable, any signal wiring crossing the sliding joint).

3.4 Module Components

3.4.1 Trackball Module

The trackball sits in a dedicated right-side module. This section covers the module’s printed parts — the shell, the trackball aperture, and the PCB mounting provisions — and how the module attaches to the core chassis.

3.4.2 Left Connection Module (WIP)

The left connection module provides external device ports. Its mounting geometry is established in the chassis, but the wiring is not yet complete in the upstream reference build. This section documents the module’s printed parts and the intended interface, with honest WIP status.

3.4.3 Scrolling Handle (WIP)

The scrolling handle provides ergonomic navigation for vertical and horizontal panning. Its mounting geometry is established; wiring is not yet complete. This section documents the printed parts and intended function.

3.5 Print Settings

3.5.1 Material

The material choice affects structural integrity in a workshop environment that may experience elevated temperatures. This section covers the reference build’s material [VERIFY from upstream docs], the tradeoffs between PLA (easy print, lower heat resistance), PETG (better heat resistance, slightly harder to print), and ASA/ABS (high heat resistance, warping risk).

3.5.2 Layer Height and Infill

This section covers the recommended layer height, infill percentage, and infill pattern for the structural chassis parts versus the cosmetic panels.

3.5.3 Orientation and Supports

Some chassis parts require careful orientation to achieve the correct layer-line direction for structural loads. This section covers the orientation recommendation for each significant part and where supports are required versus where the geometry is self-supporting.

3.5.4 Bed Adhesion

Large flat parts and parts with fine features may require specific bed adhesion settings. This section covers the adhesion approach for the DFCD chassis parts.

3.6 Post-Processing

3.6.1 Support Removal

This section covers the support removal process for each part that requires it, with notes on any features that are difficult to clean cleanly.

3.6.2 Fit and Tolerance Adjustment

Sliding mechanisms and snap-fit features may require light sanding or reaming to achieve the intended fit. This section covers where builders typically need to do this work and by how much.

3.6.3 Surface Finishing

Optional surface finishing (sanding, priming, painting) is outside the scope of the functional build but noted here for builders who want a finished appearance.

3.7 Alternative: PCBWay Manufacturing

For builders without 3D-printing access, PCBWay (https://www.pcbway.com/) offers 3D printing from STEP files as a manufacturing service. This section notes the steps required to order chassis parts from PCBWay using the upstream STEP files, material selection on the PCBWay platform, and approximate cost considerations [VERIFY].