New and latest development in 3D Printer Technology is always about improvement of Main Head 3D Printer which are Extruder and Hotend Part. For basic these two parts have 2 (two) configuration which are Bowden style with separate extruder and hotend at some distance and Direct Drive extruder which is both are integrated together.
This 2-parts Main Head combination cannot be separated especially when user try troubleshooting after problem coming like clogging or flow problem. Some of function setting also locked together like user cannot feed (moving motor) extruder if hotend temperature is set at least 170C. It’s some kind of protection so head will not damage by accidentally extruder move with not melted material.
Direct-Drive Extruder vs Bowden
Here are the pros and cons of those 2 models:
Direct Drive Extruder: Direct Drive Extruder Actually Extruder Part (the one who feeds Filament wire) close together with Hotend Part (the one who melt the Filament wire). Very close so it looks as one set of part.
- Precise control of Filament extrussion.
- Less Retraction - very smooth surface can be achieved.
- Easy to print Flexible Material.
- Low-Torque Motor is sufficient to feed material.
- Can Print all material including Flexible and High Temperature.
- Heavy since motor mount on X-axis Gantry - big concern of moving print head.
- Slow Printing due to heavy part.
- Difficult to maintenance.
- Cooling Problem on every part on Hot Chamber 3D Printer.
Direct-Drive Extruder/Hotend (Source: TriangleLabs)
Bowden Extruder: Bowden Style Extruder actually is 2 parts of Extruder dan Hotend within a bit long distance. Usually is about 30-45cm long using PTFE Tube. The Filament pushed through the tube and on the distance hotend. It’s so simple and you can see the extrusion process of 3D Printing very clearly.
- Light-weight - very fast-moving print head can be achieved.
- Easy to assembly and maintenance.
- Can be applied easily on various 3D Printer mechanism as print head weight is not a concern.
- Heat Chamber is not a problem as the motor to feed can be installed outside chamber.
- Require additional long PTFE tube for material feeding.
- Controling extrussion is difficult.
- Require Higher Torque motor to feed the Filament.
- Very Limited material can be printed as Flexible Filament cannot be printed well and High Temp material require full metal hotend part instead of using PTFE which only can stand max at 260C.
Direct-Drive vs Bowden Diagram Mechanism (Source: ResearchGate)
Almost all Current 3D Printer now implement Direct Drive system due to the quality and can print Flex material easily.
Reduce price of small-light weight-high torque stepper motor also contributes a lot to efficient Direct Drive System.
Precision movement of extruder is important when user want to get smooth and nice surface. There are two setting to adjust which are e-step setting in Firmware and Flow setting in Slicer Software. Flow setting or some slicer software call it Extrusion Multiplier (EM) always set by default 1.00 or 100%. This setting usually untouched unless user want to change material type like abs to pla. E-step setting which is inside the firmware is more technical because it involves directly controlling your motor and gear.
Important Note: Some 3D Printer (Closed System) - e-steps cannot be adjust as the vendor already lock it. It’s normal altering Firmware can damage the Printer Head if not in proper setting.
Extruder Gear type also have significant contribution for good flow of material. The Higher of Ration Gear of extruder - less torque and cooler stepper motor.
- Single gear Extruder: There only one gear and one bearing to feed the Filament material. It’s basic setup for extruder system. Low budget system like basic Ender-3 or old printer using this setup since it’s simple and capable to feed mostly hard filament.
- Dual Gear Extruder: Dual Gear Extruder now is quite common in 3D Printer as it has better flow and better grip on Filament. The main drawback of this model is it’s bulky. Yes - Dual gear needs more gear mechanism which consume space although some of newer model are smaller.
- Planetary Gear Extruder: Latest improvement of the gear model is Planetary Gear (applied to latest Prusa I3 MK4). This model is so compact and maintain small-lightweight while maintain high ratio. More vendors will apply this for their direct extruder as it’s very efficient.
On the second part Hotend - there are two types basic hotend: PTFE Lined and Full metal hotend.
PTFE Lined hotend
PTFE Lined throat hotend using PTFE tube to guide the filament until the nozzle. This type of Hotend only capable to print below 250C as PTFE will melt and damage if temp above 250C. Low temp 3D Printing Material like PLA, PETG and Flex Filament is preferable with this type as is less problem. PTFE tube is easy to get and replace if having problem with clogging hotend.
Full metal hotend
Full Metal Hotend using all metal throat which is need extra precaution when user want to use it. First is mostly use for High Temp Material like ABS, ASA, Nylon or Polycarbonate. Printing PLA with this Hotend likely having problem as the material will get very hot and stuck in metal throat. High Flow FAN throat cooling is required and properly set-up if want to print low temp material like PLA or PETG. Longer throat and good fin cooling for this type are used as to reduce temperature near material insert on top. Why user need this kind of hotend? Higher temp of course… And also, faster speed of 3d printer require more Flow rate. So, a bit more of melted material required to adjust for more speed print.
Advanced 3D Printer Head now using CanBus system to significantly reduce number cable movement along the head. It’s very good implementation as printer head only need 4 cables instead of 16. Module board for individual function is installed on head of Direct Extruder. Installing and troubleshooting for head become much easier. But this CanBus system only applicable for newer high end 3D Printer mainboard - not for Low-End 3D Printer.