COMMERCIAL LICENSE NOTE
This is a commercial model with an included STEP file for further customization. The license allows you to print and sell physical 3D-printed versions of this model, but does not permit reselling or redistributing the digital 3D file itself.

INCLUDED FILE FORMATS

• STEP (.step / .stp) - Fully editable CAD file for modifications and custom printer tolerance tuning.
• STL (.stl) - Standard ready-to-print 3D model file.
• 3MF (.3mf) - Pre-configured slicer project file.

DESCRIPTION
Transform your space with this fully modular, 3D-printable shelving system, now featuring an innovative under-shelf hanging drawer for even more organized storage possibilities. Designed as a high-precision mechanical constructor, this rack requires no glue, no screws, and no metal supports.

FEATURES
Designed for maximum practical organization and convenience, this model includes:

• Toolless Snap-Fit Assembly: Fits together securely using precision keys, hubs, and top caps without needing fasteners or glue.
• Under-Shelf Hanging Drawer Module: Suspended by thin 1mm U-shaped brackets wedge-locked directly into honeycomb slots.
• Smart Mathematical Grid: Highly scalable vertical tiers and overlapping horizontal joint expansions for custom configurations.
• Versatile Component Library: Features 8 leg lengths, straight and corner hubs, and rigid honeycomb panels in multiple sizes.
• High Structural Stability: Employs a diamond-profile internal skeleton pin to prevent structural separation during movement.

TECHNICAL SPECIFICATIONS
Key dimensional, functional, and structural parameters for this model are listed below:

Dimensions & Grid Scaling

• Modular Leg Heights: 8 sizes ranging from 25 mm to 200 mm.
• Panel Dimensions: Available in 100x100 mm, 200x100 mm, and 200x200 mm honeycomb configurations.
• Drawer Module Dimensions: 200 mm (L) x 170 mm (W) x 30 mm (H).
• Vertical Tier Formula: Tier Height = Leg Length + 25 mm (Hub Height).
• Horizontal Expansion Formula: Joint overlap = 15 mm (e.g., two 200 mm panels yield 385 mm length).

Structural Components

• Locking Pins: Internal 7x7x45 mm diamond-profile pins for load distribution.
• Hanging Brackets: Ultra-thin 1 mm U-shaped brackets, secured with system locking keys.

HOW TO ASSEMBLE
Follow these simple step-by-step instructions to assemble the modular frame and drawer module without tools:

1. Frame Setup: Insert side rails into the Straight or Corner Hubs.
2. Structural Core: Place the internal diamond-profile pin into the lower leg and slide the Hub over it.
3. Locking: Secure the assembly with the next leg or a finishing Top Cap.
4. Panels: Drop the honeycomb panels into the assembled frame slots.
5. Drawer Integration: Snap the U-brackets into the lower panel slots, lock them with wedges/keys, and slide the drawer in.

RECOMMENDED PRINT SETTINGS
For optimal print quality, structural durability, and functional performance, use the following slicer settings:

• Material: PLA for general usage or PETG for heavy-duty storage.
• Layer Height: 0.2 mm recommended for precise snap-fit key tolerances.
• Infill: 15-20% (Gyroid or Grid recommended).
• Wall Loops: 5-6 wall loops (increased perimeters ensure maximum durability and tensile strength for brackets and joints).
• Supports: Not required (all holes utilize a diamond profile for clean bridging).

USAGE & TIPS
Here are key instructions and assembly tips for optimal performance:

• Print legs and pins horizontally to maximize load-bearing strength along layer lines.
• Print the 1 mm hanging brackets with increased wall perimeters (5-6 walls) and near 100% infill for maximum tensile resistance.
• Choose Straight Hubs for continuous straight runs or Corner Hubs for stable turns.

UPDATES
The following updates and improvements have been added to this model:

• Split Top Cap: Added a split top cap variant designed to be printed horizontally, significantly improving layer adhesion and snap resistance while ensuring a smoother fit into frame slots.
• Center Hole Cover Caps: Added two top-inserted cover caps (a narrower cap for 3-shelf setups and a wider cap for 4-shelf setups) to seamlessly plug the unused central leg gap formed when joining shelf units into a square layout.