🧠 Design Concept and Intended Use

This model is a keychain-style bottle enclosing cap designed to cover the mouth of glass bottles (such as beer or beverage bottles) after opening.

Its purpose is to protect the contents from contaminants like sand, insects, dust, and other debris — especially when outdoors.

It is not a sealing closure; it serves only as a protective cover.

There is a risk of leakage or accidental opening, so keep the opened bottle upright at all times.

The greater the number of cuts, the higher the flexibility — try different versions and use the one that fits your preferences best.

🔧 Update – Printable Spring Mechanism (Improved Version)

I’ve developed an improved variant with a built-in, fully printable spring that stabilizes the carabiner mechanism, prevents permanent deformation, and keeps it working reliably over time.

v1.2 → stronger spring, stiffer feel, higher resistance.

v0.8 → more flexible spring action, easier to operate with lighter force.

🔒 Improved Latch (Carabiner Mechanism)

The latch has been redesigned to increase reliability:

Anti-lateral shift: the geometry prevents the arm from sliding sideways under load.

Self-bracing negative angle: when force is applied, the latch locks against itself instead of slipping open, allowing higher usable force without deformation.

🧾 Material Compatibility

The model has been tested with PLA and works very well.

However, flexibility depends on material choice and version:

Versions v1–v2 → May be difficult to remove and can break easily when printed from PLA or other rigid materials. For these, use PETG, or other flexible filaments.

Versions v3–v8 → Optimized for PLA printing – they maintain proper fit and flexibility even with stiffer materials.

Spring variants (v1.2 / v0.8) → Choose material to match your preferred feel: PETG/TPU for more resilience; PLA is workable but stiffer.

🖨️ Printing Suggestions

Material: PLA, PETG, or other slightly flexible materials

Layer height: 0.1–0.2 mm

Infill pattern: Gyroid or low infill percentage for improved flexibility with rigid materials

Top/bottom pattern: Concentric (recommended for both)

Print orientation: Place the top surface of the cap facing the print bed — this orientation is optimized for best results

Supports: Not required

Brim: Optional (if needed for adhesion)

After printing, test one piece for proper fit. If it’s too tight or too loose, adjust the scale slightly and reprint.

🧩 Assembly Instructions

No assembly is required — the model prints as a single ready-to-use piece with an integrated carabiner-style loop for attaching to keys or bags.

After printing, gently press the movable carabiner arm inward toward the center to free the latch and set its working position — the mechanism is sufficiently elastic and this step will not damage the part.

Just ensure that the fit on the bottle mouth is snug but not overly tight.

☕ Support & Follow

If you like my designs, follow me — there’s more to come!

I’m working on other practical everyday models such as reusable caps, accessories, and functional 3D-printed tools.

You can buy me a coffee simply by printing and boosting my files — nothing more 😉

Most of my uploads are completely free, so I’ll be genuinely happy if you decide to reward my work in any way.

If you’re interested in commercial use of this model, please contact me by leaving a comment.

Enjoy printing and using it responsibly! 🧴🔑

Practical, fun, and easy to print — ready to protect your bottles anywhere!

Beer cap, beverage cap, carabineer glass bottle enclosing

0.2mm layer, 2 walls, 15% infill