Filament Joining System Sunlu FC01 — filament welder for PLA/ABS/TPU repair and spool splicing

The Sunlu FC01 Filament Joining System is a compact filament welder that joins 1.75 mm 3D printing filament ends for reliable splicing and repairs. It supports common materials such as PLA, ABS and PETG, heats to working temperature in about 3 minutes and provides precise temperature control for repeatable, strong joints. The device is intended for hobbyists and small workshops who want to reduce filament waste, restore continuity after breaks and create multi-colour or gradient prints by joining different spool ends.

Advantages

The FC01 minimizes filament waste by enabling effective joining of spool ends and small scraps, allowing you to use filament until the last meter. Rapid warm-up and a short splicing cycle mean minimal downtime, while temperature accuracy and an insulated housing provide repeatable, safe results. The unit supports a range of common printing materials and offers intuitive operation suitable for users with different experience levels.

Suitable for

• Hobbyists repairing broken filament strands
• Small workshops and makerspaces joining spools or scraps
• Users creating multi-colour prints or smooth colour transitions
• Anyone aiming to reduce material waste and printing costs

When it may not be suitable

The FC01 is designed for 1.75 mm filament and may not work with other diameters. It is intended for common thermoplastics (PLA, ABS, PETG); results may vary with flexible filaments or speciality materials. Buyers who need industrial-scale splicing throughput or automated spool handling should consider more advanced equipment.

Key specifications

• Supported filament diameter: 1.75 mm
• Supported materials: PLA, ABS, PETG
• Operating temperature range: up to 240°C
• Typical PLA operating temperature: approx. 185°C
• Warm-up time: approx. 3 minutes
• Splicing time: 10–15 seconds per joint
• Temperature accuracy: ±3°C
• Power supply: 5V 2A (adapter not included)
• Housing temperature during operation: approx. 50–100°C

How to use

Prepare the filament ends by cutting them square and inserting them into the PTFE splicing tube. Connect the FC01 to a 5V 2A power source, switch it on and wait for the unit to reach the operating temperature (around 3 minutes). Align the filament ends in the heating chamber, operate the splicing cycle (10–15 seconds) and allow the joint to cool briefly before trimming excess material and resuming printing. Follow the included user manual for safety and detailed steps.

What to consider before purchase

• Confirm your filament diameter is 1.75 mm
• Check that your primary materials are PLA, ABS or PETG
• Power adapter (5V 2A) is not included
• Housing reaches elevated temperatures during operation—allow for safe handling and cooling

Usage recommendations

Use clean, square-cut filament ends and the provided PTFE tube for best results; perform a short test splice when changing material types or colours to confirm settings before critical prints.