Longer LK4 Pro

The Longer LK4 Pro is an FDM 3D printer from Longer with a 220 x 220 x 250 mm build volume.

Specifications

The Longer LK4 Pro is a compact, budget-friendly FDM (Fused Deposition Modeling) 3D printer designed to compete directly with market standards such as Creality's Ender 3 Pro. While sharing a similar build envelope, the LK4 Pro distinguishes itself by offering several factory-installed upgrades that users of other brands typically have to purchase separately.

• Hotend (Hotend): The machine utilizes a Bowden-style extrusion system feeding 1.75 mm filament. The extruder stepper motor is mounted on the left side of the frame, pushing filament through a PTFE tube to a lightweight carriage on the X-axis.

Calibration

Achieving accurate dimensions and clean surface finishes on the Longer LK4 Pro requires systematic calibration. Use the following 8-step guide:

• Glass Build Surface Cleaning:

Oils from fingers can prevent first-layer adhesion, leading to warping. Clean the glass surface with isopropyl alcohol (IPA) when cold before starting a print.

• Expected result: A pristine build surface that guarantees strong first-layer adhesion.

Common defects

• Hardware defects and mechanical weaknesses
• Cracked Plastic Extruder Arm:
• Symptoms: Random under-extrusion, layer voids, or the extruder drive gear slipping and grinding.
• Cause: The stock plastic extruder tensioner arm cracks on its underside under spring tension.
• Solution: Replace the plastic extruder housing with an aluminum dual-gear or single-gear extruder kit (MK8 style).
• POM V-roller Flat Spots:.

What it is used for

Best use-cases:

• Quiet Apartment Printing: The silent TMC2208 board allows the printer to run in home environments without high-pitched motor whine.
• Small to Medium PLA/PETG Prototyping: Ideal for printing electronic enclosures, brackets, and fixtures.
• STEM Education: The color touchscreen and simple mechanical design make it a great teaching tool.