Parametric Hollow Sections Cover cup

This is a Parametric Snap-Fit Cover Cap for Hollow Sections. It is specifically designed to plug rectangular tubes or hollow profiles, providing a clean, professional finish while ensuring a secure mechanical lock.

Purpose

The code generates a customized end cap that snaps into the open end of a hollow structural section (HSS). It uses four flexible tabs with integrated locking wedges to grip the inner walls of the profile, preventing the cap from falling out due to vibration or gravity.

Typical applications include:

• Furniture building: Capping steel or aluminum square/rectangular tubing.

• Industrial frames: Sealing the ends of T-slot or hollow profiles to prevent dust ingress.

• DIY Projects: Finishing touches for racks, stands, or handles.

Key Features

1. Flush-Fit Flange: The outer dimensions create a decorative lip that covers the raw cut edges of the hollow section.

2. Rounded Exterior: The flange_radius ensures the cap has smooth, safe corners that won't snag on fabric or skin.

3. Self-Centering Tabs: The tabs are positioned based on inner dimensions, which should correspond to the internal cavity of your hollow section.

4. Optimized Snap Action: The locking wedges use an equilateral triangle profile with a rounded tip, allowing the cap to "click" into place smoothly without requiring excessive force that might snap the plastic.

5. Durable Design: Filleted wedge bases reduce stress concentration, making the tabs less likely to break during repeated insertion or removal.

How to Use

1. Measure Your Profile:

   • Measure the outer dimensions of your tube (use these for outer_width and outer_height).

   • Measure the internal cavity of the tube (use these for inner_width and inner_height).

2. Adjust Tolerances:

   • 3D printers often print slightly "fat." If the cap is too tight, decrease the inner dimensions by 0.2mm - 0.4mm to create a clearance.

3. Refine the Grip:

   • For a tighter grip in metal tubes, increase wedge_size slightly.

   • For thicker-walled tubes, you may want to increase tab_thickness for more rigidity.

3D Printing Recommendation

• Orientation: Print with the large flange face down on the heatbed. No supports are needed for the wedges as they are small and have a 60-degree slope.

• Material: PETG is ideal for this application because it is UV resistant (for outdoor frames) and has the "springiness" required for the tabs to flex without deforming permanently.

Added 40x30 Hollow Section cover as an example