The Anatomy of Filament-Based 3D Printers

MicroCenterMaker · March 2023

As 3D printers continue to become more popular and more people are introducing 3D printers into their everyday life, understanding how the technology works is more important than ever. While there are a number of printers out there such as the ANKERMAKE M5 that offer reduced setup and systems, designed to limit the need for user intervention during prints and general use, the majority of printers on the market still require some setup and hands-on time to get them printing consistently.

And in honor of spreading that knowledge, we'll be breaking down some common parts and what they do. Some parts have changed slightly over the past decade of printing but there are a large number of parts and principles that are common in today’s consumer-grade filament printers. While there are a number of popular movement styles such as CoreXY and Delta, for the sake of this article we’ll be using the ever-popular Cartesian movement which is found on popular printers like the Ender 3 series.

The Frame

The first important piece to understand is the frame of the printer. A solid frame can ensure that any artifacts of movement don’t show up in the final print. Many printers require assembly so it’s important to make sure you follow instructions and tighten things appropriately.

The frame is what the moveable axis and beds are mounted to with roller wheels. Frequently, the filament is mounted to the frame, on an arm attached to the side or the top. Similarly, motors, electronics, and any screens are also mounted directly to the frame.

The Bed

Naturally flowing from the frame, we move to the next biggest piece: the bed. The bed, in the case of the Cartesian printer, is often mounted to a metal plate. Some printers will use four adjustable, spring-tensioned screws for adjustments. Others opt for a self-leveling bed, using BL-Touch, inductive, resistance sensor technology. Ensuring the bed is level is important for having a good first layer, which can make all the difference between the print being successful or not. We have a few tips and prints for checking your bed level over here!

The surface of the actual bed plate also plays an important role in how well the filament sticks and your print comes out. Many printers are now coming with removable, flexible build plates that have special coatings such as PEI (Polyethermide). Additionally, most printers now come with heated beds which makes bed adhesion much easier, especially for more complicated printing materials such as ABS/TPU and PETG.

Image: Bed Leveling Probe CR Touch

Motors, Belts, and Lead Screws

Motors and belts are the crucial pieces that enable movement in 3D printers. The use of stepper motors allows for precise movements over a standard DC or Servo Motor. At minimum, a printer will have four stepper motors to move the x-axis, y-axis, z-axis, and finally the extruder, where filament is pushed through to the hotend. Belts are put around geared pulleys and stretch the length of the axis that it’s moving, normally the X and Y. The Z axis is normally moved by rotating a lead screw up and down.

On the x and y axis, it’s important to have proper belt tension. Without proper tension, the head may skip during printing or cause layer offsets and your print will be ruined. It’s good to check that the belts are tight enough that the teeth on the belt don’t jump over the gears but not so tight that the axis can’t move freely when the printer is turned off.

Extruder motors may be attached to the frame away from the hotend or may be integrated into the hotend. If it is attached away from the hotend, it is considered a Bowden tube-style printer. Many printers can be modified to get the motor directly in line with the hotend, which is considered a direct drive motor. Direct drive motors are important for printing with more flexible filaments as they greatly reduce the distance between the motor and the hotend, minimizing the chance for the flexible filament to bind up.

Image: Stepper motor

The Print Head

The print head has many components and is where a lot of the magic happens. It is possible, as mentioned above, that the extruder motor is part of the print head. However, that is not always the case. If the extruder motor is not integrated, you'll find a range of other components in its place, like the fan shroud.

The fan shroud is normally what encases the majority of the parts and holds one or more fans to the overall assembly. These fans cool the components and the heatsink, preventing overheating. The filament travels through the tube to the heat sink first normally. This allows the filament to stay solid and be pushed all the way up to the point of the heater block.

Image: Hotend Assembly

The heater block is where the filament is heated to its melting point. This is done using a heater cartridge, which is connected back to the mainboard. Also attached to the heat block is the thermistor. This temperature gauge connects to the mainboard and sends temperature readings to the mainboard, telling the mainboard exactly how much power is needed at the heater block to maintain the correct temperature. The hotend is usually shrouded in a silicone sock. That silicone sock is not there just to protect you, but also other components around the nozzle from heat creep.

The final major piece in the print head is the nozzle. The nozzle is what takes the - on average - 1.75mm filament and reduces it down to the finer diameter that is required by printers. The material the nozzle is made up of, as well as the diameter of the outlet on the nozzle, can affect how well a material prints and how fast.

Image: .4mm Nozzle

The Electronics

The final major components to explain are the electronics. Normally the mainboard, the power supply, and a control panel or touch screen make up the bulk of the electronics necessary to run the printer. The mainboard is what houses the microprocessor that controls the logic and sends commands to the stepper motors via motor drivers. The mainboard also houses the connectors for power, connection to the thermistors for the heated bed and hotend, and the heater cartridges for both the hotend and the heated bed. It may also have a USB connector for computer hookups and/or an SD card slot for loading and running STL.

Image: Mainboard

Power is routed from the power supply to the mainboard before being sent to the other components. It’s important when getting a new printer to make sure the power supply is set to 115v power, as many printers have a small switch for either 115v or 240v, allowing the same model to be shipped to every corner of the world.

The touchpad or screen also operates off of the mainboard and gives users a visual/tactile way of interacting with the printer. Some printers only have a single rotary dial that can make basic selections and adjustments.

Image: Control Screen

FINAL

Hopefully knowing the names of the parts of your printer will give you more confidence in using the printer as well as troubleshooting it. As you grow more comfortable with your printer, these basics can serve as a springboard for modifying and upgrading your printer.

If there are any parts you feel we've missed, let us know in the comments below!