Uploaded January 2026 | Updated September 2026, 2 weeks ago

---

In this video, I explain why laminar flow is essential in 3D printing and what actually happens to molten plastic inside the nozzle.
Using a simple Reynolds number calculation, I show that during FDM printing the flow is extremely laminar, and why this remains true even at much higher printing speeds.

This helps to understand:
• why extrusion is pressure-controlled
• why turbulence never occurs in a nozzle
• why stable, predictable flow is important for print quality

No CFD, no overcomplication — just practical engineering logic.

❤️ Support my work

If you like my work, please support the video with a 👍 like or 🔁 share — it helps a lot.
If you want to support me financially, donations are always welcome:

☕ Buy Me a Coffee: buymeacoffee.com/mytechfun
❤️ Patreon: patreon.com/mytechfun

Thank you for your support!

Mentioned in the video:
Density website: kg-m3.com
Dynamic viscosity source: doi.org/10.3390/polym14132721
Roetz 4.0: youtube.com/@Roetz40

⏱ Chapters

0:00 Introduction
0:51 Why laminar flow matters?
2:04 Reynolds number
2:56 Calculation
4:35 Conclusions

🏷️ Tags

#3Dprinting #LaminarFlow #ReynoldsNumber #FDM #FFF #3DPrintingBasics #Engineering #FluidMechanics #PLA #NozzleFlow