The Ultimate Guide to Extruder 3D Printers

3D printer extruders are one of the most important components of any 3D printing setup. The extruder is responsible for melting and depositing the plastic filament in precise locations to build up each layer of the 3D printed object. Choosing the right extruder for your 3D printer can have a major impact on print quality, speed, reliability, and capabilities. This guide will provide an in-depth look at the different types of 3D printer extruders, key specifications to consider, top extruder recommendations, and tips for getting the most out of your extruder.

How a 3D Printer Extruder Works

The extruder is the part of a 3D printer that handles the plastic filament. It has two main jobs: to grip and feed the filament, and to melt it. Here’s a quick overview of the extruder components and how they work together:

• Feed Mechanism: This is typically a wheel with teeth or ridges that is pressed against the filament and rotated by a stepper motor to pull the filament into the extruder. It provides the force needed to push the plastic through the hot end.
• Hot End: This is where the filament is heated to a molten state so it can be deposited. It contains a heater, a temperature sensor, and a nozzle. Heaters are often a cylindrical resistor, while nozzles range from 0.2mm to 1mm.
• Cold End/Heat Sink: This is a metal component that dissipates heat from the heater to prevent too much of the extruder from getting hot.
• Extruder Gear: A gear driven by a motor that provides the rotational force to push the filament into the hot end consistently. The teeth mesh with the feed mechanism.
• Cooling Fans: Fans direct air at the filament right before it enters the hot end to help solidify it quickly after being extruded.

In action, the stepper motor turns the extruder gear, which meshes with the feed mechanism and pushes filament down into the hot end. The filament is heated to a molten state and forced out of the nozzle onto the print bed, where it solidifies. The extruder must do this consistently and smoothly to create good prints.

Types of 3D Printer Extruders

There are several common types of extruders used on 3D printers today:

• Direct Drive Extruders: In a direct drive, the extruder gear is mounted directly to the motor shaft. This provides maximum torque and force for pushing filament. Direct drive extruders excel at flexible and soft materials. The downside is they can be heavy on the print head.
• Geared Extruders: These use a gear reduction between the motor and extruder gear to increase torque while reducing weight on the print head. Geared extruders are common on Cartesian and delta style printers. They aren’t as good for flexible filament.
• Bowden Extruders: Named for the Bowden cable used, filament is fed through a tube to the hot end. This keeps weight very low. Retraction and flexible materials can be challenging.
• Dual Drive Extruders: These have two geared wheels working together to grip the filament. They provide more force and reduce slipping.
• Titan Extruders: Very high torque direct drive extruders optimized for flexible filaments. Named after the Titan stepper motor.
• Multi-Material Extruders: Allow printing with multiple filaments by having multiple hot ends or unique feed mechanisms.

Key Extruder Specifications

Several key specs determine an extruder’s performance and capabilities:

• Thrust/Force: Measured in kg or lbs, indicates how much push force it can apply to filament. Higher is better.
• Gear Ratio: Gear reduction between motor and drive gear that affects torque. Around 3:1 is common.
• Filament Compatibility: Most use 1.75mm filament, some 3mm. Important to know max filament diameter.
• Nozzle Compatibility: Nozzles have standard thread sizes like M6 or M7. Ensure compatibility.
• Maximum Temperature: The max temp the hot end can reach, usually over 240°C.
• Cooling: Fans should provide adequate airflow over the filament. Dual fans are ideal.
• Motor Type: Nema 17 motors are standard. LargerNEMA 23 motors offer more torque.
• Weight: Lighter extruders put less strain on print heads for faster prints.

Top Extruder Recommendations

With so many extruders to choose from, here are some top picks for several types and budgets:

Beginner/Budget

• Creality MK8 Extruder: Simple, effective, geared extruder for Creality machines like the Ender 3. Just $15-20.
• BIGTREETECH MK8: All metal, basic direct drive extruder. Great value at around $25.
• Zonestar Direct Drive: About $35, quality aluminum alloy geared extruder. Great starter upgrade.

Enthusiast Grade

• E3D Hemera: Top of the line, all-metal, dual-drive direct extruder. Amazing performance for $99.
• Orbiter 2.0: Dual-drive, lightweight extruder designed for high speed printing. $149.
• Bondtech BMG: Proven, precise geared extruder. Dual drive grips filament tightly. $89.
• Slice Mosquito: Innovative lightweight and compact hot end. Starting at $180.

High Performance

• E3D Titan Aero: Benchmark in flexible material printing. High torque direct drive. $199.
• E3D SuperVolcano: High flow hot end for ultra fast printing. Starting at $230.
• Flexion HT Extruder: High temperature extruder for filaments like PEEK. Up to 455°C. $299.
• Slice Engineering Copperhead: State-of-the-art heat break and cooling. Starting at $480.

Dual Extrusion Kits

To print with multiple colors or materials, you need dual extrusion. Here are some top options:

• E3D Chimera: Twin independent hot ends in a compact package. Starting at $199.
• Gulfcoast Robotics Dual Direct Drive: Affordable kit with dual direct drive extruders. $189.
• BIQU H2: Dual-nozzle hot end with two geared extruders. Just $129.
• Trianglelab Dual Extruder: Well-integrated kit with dual hot ends and fans. $159.

Tips for Getting Great Results From Your Extruder

To get reliable, high-quality 3D printing, you need to understand how to optimize and maintain your extruder. Here are some key tips:

• Calibrate your extruder steps per mm and flow rate for each new filament. This ensures it’s pushing out the right amount of plastic.
• Keep the feed mechanism and gear clean. Check for stripped filament dust and buildup.
• Monitor for slipping or grinding and adjust spring tension on the feed mechanism.
• Maximize cooling over the filament right before the hot end for clean prints. Upgrade fans if needed.
• Print slowly under 50mm/sec for the first layer to get a solid adhesion.
• Adjust the retraction distance and speed for clean travel moves and color changes. More for Bowden, less for Direct.
• Use a filament oiler kit if printing with flexible materials like Ninjaflex. Reduce friction and tangling.
• Swap nozzles to match print requirements. Larger nozzles for faster prints, smaller for fine details.

Your extruder is a mission critical component of your 3D printer. Investing in a quality extruder and learning how to optimize it will take your print quality and capabilities to the next level. Use this guide to demystify extruder selection and maintenance.