LESSON 2.3 · 2:12 · CHAPTER 2 · THE EXTRUDER
Fibre makes the melt fight back
Adding fibre raises melt viscosity several-fold, and the pressure rises with it; temperature is the usual way to buy it back, within the polymer's processing window.
Predict · at 0:40 in the video
Plain PEI needs 10 megapascals through a nozzle at 365 degrees. Adding carbon fibre doubles the viscosity. Raising the melt to 400 degrees halves it. What pressure does the filled grade need at 400?
About 10 megapascals again. Ten, times two for the fibre, times a half for the heat. Those multipliers are illustrative.
Further reading
This course is our own. These books go deeper.
- The economics of Big Area Additive Manufacturing, Post et al., Solid Freeform Fabrication Symposium, 2016
- Additively manufactured carbon fibre-reinforced composites: state of the art and perspective, van de Werken et al., Composites Part A, 2020
About the numbers
Simulations in this lesson are our own. Where a number rests on an assumption or a single source, the video marks it with an asterisk and says where it comes from.
Up next · 2.4 · 2:17Nameplate rate vs real rate