What Happens Inside Your Hotend?
The hotend of a 3D printer is where the magic happens. It is responsible for melting and extruding the filament, creating the intricate layers that form the final printed object. Within the hotend, the filament travels through a heated chamber, gradually reaching its melting point. The molten plastic is then pushed through a tiny nozzle, precisely depositing it layer by layer to bring your designs to life.
Have you ever been curious about what’s happening inside the hotend of your 3D printer? It might seem straightforward: filament melts, it’s pushed out, and repeat. But is there more to this story than meets the eye? Well, a team of researchers led by Marc Kreutzbruck from the University of Stuttgart decided to dig deeper into the mystery by using a CT scanner to peer inside the inner workings of a 3D printer’s hotend. Let’s dive into their findings.
What’s Inside the Hotend?
What’s Inside the Hotend? In a recent study conducted by Marc Kreutzbruck and his team at the University of Stuttgart, they used a CT scanner to explore the inner workings of a 3D printer’s hotend. Their findings revealed a complex system of components and processes that go beyond the simple melting and extrusion of filament. Discovering the intricacies of what happens inside the hotend sheds new light on the fascinating world of 3D printing technology.
To uncover the hidden secrets of the 3D printing process, the team set up an experiment using a Bondtech LGX extruder and an E3D V6 hotend mounted to a static frame. Unlike typical 3D printing setups, this one didn’t require any X-Y-Z motion control. Instead, they added a load cell to measure the extrusion force. The filament they used was a special blend of high-impact polystyrene (HIPS) mixed with a small amount of tungsten powder (just 1% by volume) to enhance X-ray contrast. The entire system was compact enough to fit inside a micro CT scanner, which provided both 360-degree computed tomography images and 2D radiographs.
The Surprising Observations
The results of this unique experiment were quite enlightening. One key takeaway was that higher filament speed leads to less contact area between the nozzle wall and the melting filament due to the presence of an air gap between the solid filament and the nozzle’s metal surface. Additionally, they noticed that the incoming filament had a greater tendency to buckle at high extruder speeds, which aligns with the experiences of many 3D printing enthusiasts.
Perhaps most interestingly, the researchers found that filament speed had a more significant impact on print quality, as measured by extrusion force, compared to heater temperature. While both factors play a role, their recommendation for achieving higher print speeds was to optimize the hot end’s geometry, specifically by extending the barrel to allow for adequate melting time.
Your hotend is more exciting than you think
What Happens Inside Your Hotend?
One key takeaway is that higher filament speed leads to less contact area between the nozzle wall and the melting filament due to the presence of an air gap between the solid filament and the nozzle’s metal surface. Additionally, the incoming filament has a greater tendency to buckle at high extruder speeds, aligning with the experiences of many 3D printing enthusiasts. Most interestingly, filament speed has a more significant impact on print quality, as measured by extrusion force, compared to heater temperature. To achieve higher print speeds, the researchers recommend optimizing the hot end’s geometry by extending the barrel to allow for adequate melting time.
While the findings might not be earth-shattering, it’s certainly refreshing to see a systematic study on the inner workings of 3D printing hotends rather than relying on anecdotal observations. This research sheds light on critical factors affecting 3D printing quality and opens doors for further exploration and optimization in the world of additive manufacturing. Plus, the CT scanner images are undeniably cool!
Source: Science Direct
