Die swell relates to the expansion of the extruded material once it is expelled from the nozzle and comes into contact with the atmosphere. Not all polymers, but the core plastics are subject to this. We intentionally under-drill the nozzles by 15% to compensate for this expansion.
We usually supply 1 x 1.75mm and a 3mm nozzle, but we can supply two
3mm. In fact, both these nozzles are under drilled to allow for die
swell (expansion of the material on exit from the nozzle bore) the 3mm is
drilled to 2.5mm and the 1,75mm nozzle is drilled to 1.6mm.
If you find that your composite material tolerance is too thin, then you may want to think about drilling a larger bore. We do also supply blank dies, which you can drill yourself.