HAFC V2 – Hackman Automatic Filament Cutter

by Hackman3D

Here's a link to get the necessary hardware. No partnership or affiliation involved, but since the price is reasonable, I haven't asked for a commission.

HAFC Aliexpress Pack back in stock :

https://a.aliexpress.com/_EH25h7a

Operation in video :

https://youtube.com/shorts/-0ykCtMGRbw?is=eZs9yd8VRiyitJUe

🧠 Concept & Purpose

The HAFC V2 (Hackman Automatic Filament Cutter) is a fully mechanical system compatible with any FDM 3D printer using 1.75 mm filament with a PTFE tube.

I designed it to solve a very common issue:

filament getting stuck on the spool (tangles, friction, jammed spool…).

Instead of forcing the extruder:

• filament tension increases

• the mechanism triggers

• the filament is cleanly cut

• the printer pauses thanks to its filament runout sensor

👉 You just reload filament and resume the print

No electronics, no sensors involved —

everything is passive, simple, and reliable.

⸻

⚙️ What’s new in V2

This version is based directly on feedback from V1.

The main focus was improving reliability and behavior:

• more compact design

• faster to print

• improved tolerances (filament path + internal sliding)

• added return spring → automatic reset

• stronger resistance to reduce false triggers

• improved magnet alignment

• possibility to add extra magnets externally to fine-tune trigger force

The result is a more stable and predictable system, even on very precise machines.

⸻

⚙️ How it works

The filament goes through the HAFC using a PTFE tube and Pneufit connectors.

If the spool gets stuck:

• tension increases

• the sliding module moves

• the blade cuts the filament

➡️ The printer detects filament runout and pauses automatically

Magnets control the trigger force,

and the spring resets the system after activation.

⸻

🖨️ Printing

• PLA or PETG recommended

• supports already included in the 3MF / G-code

Basic settings work fine:

• 0.2 mm layer height

• 3 walls

• 20–30% infill

⸻

🔩 Required hardware

Mechanism

• 2 × M6 Pneufit (good quality recommended)

→ cheaper ones may have an internal lip that restricts filament movement

→ Bambu Lab ones work perfectly

• 1 × Bambu Lab cutter blade

• 1 × spring (0.3 × 6 × 80 mm)

• 3 to 5 × 8×2 mm neodymium magnets

Screws

• 2 × M3×20

• 1 × M3×12

⸻

⚠️ About Pneufit installation

When installing the Pneufit on the moving part:

👉 the plastic might crack slightly

This is normal and does not affect functionality.

It depends on your printer tolerances and filament.

⸻

🛠️ Assembly

⸻

🔧 Adjustment

Depending on your print, you may need to:

• slide the mechanism manually a few times

• “break in” the contact surfaces

This improves smoothness.

Some users added a bit of grease on V1 —

still an option if needed.

⸻

🔄 Compatibility

• all FDM printers

• 1.75 mm filament

• PLA / PETG / ABS / TPU

❌ not compatible with 2.85 mm

⸻

⚠️ Important

The HAFC does not replace a filament runout sensor.

It works before failure happens,

by intentionally cutting the filament to prevent a failed print.

⸻

❤️ Support

If you use the HAFC V2:

• leave a like

• post a make

• share your feedback

👉 that’s what helps improve the project

⸻

💬 Creator note

V2 fixes the main issues reported on V1:

triggering, smoothness, and tolerances.

Thanks to everyone who tested and shared feedback 🙌

The future versions will depend on the community.

// hidden signal detected

If you’re reading this… you’re not supposed to

A small batch of 8 HAFC V2 kits is being dropped to selected makers.

No public giveaway. No announcements.

Just builders who:

create

share

push the project further

If that’s you… you know what to do.

📩 Send proof of your posts (any platform) in DM.

Selection will be random… but only among those helping the HAFC grow.

// end of transmission

HAFC V2 - Hackman Automatic Filament Cutter

0.2mm layer, 2 walls, 15% infill

0.2mm layer, 2 walls, 15% infill

0.2mm layer, 2 walls, 15% infill