Drilled stock nozzle to 0.5mm almost doubled print speed!

Hi, since I’m using my vertex mainly for (small series)mechanical parts that I’m printing in 0.2 layer thickness with no very small details (minimum wall thickness 0.8mm or two perimeters), I was looking for more speed. I tried printing at higher temperatures (pla up to 220°C), but eventually the heat from the nozzle came into the isolator and after an hour or two and the chances for blockages became very real.

So I ordered some drills(packages of 10 pcs, they break very easily) from Ali, 0.4, 0.45, 0.5 to gradually increase nozzle diameter.

The nozzle is made out of brass material and drilling with my dremel freehand was not so easy, it costed me a few nozzles. A drill stand is recommended. I brought it to 0.5 (or a bit bigger because of hand drilling).

The results are great, I could double the filament speed from 4-5mm³/s (SLIC3R software) (0.2mm layers) to a safe 8mm³/s (0.4mm layers) on a mechanical complicated part with +32 filament retractions per layer (contributor to nozzle blockages). Main observations is that the standard heater block has no problem melting the filament fast enough. I could even lower the (pla)filament temperature to 190°C. It seems highly unlikely it will block in this setup. Wall and surface finish is not much different to printing with stock setup.

With 8mm³/s the filament is really flying out of the extruder, and I’m not at the limit I think 10mm³/s on simple parts will be no problem.

It would however be easier if Velleman would offer multiple size nozzles…

Good post, it will be interesting to see how this develops over time. Please keep us posted.

The Vertex is a good kit printer, but Velleman should maybe look into the various modifications that have been suggested in the forum here & see if they can bring those into the design. Or offer them as mod kits. :slight_smile:

Dear TLS,

from physics point of view, the fluid behaviour can be approximated by the Hagen-Poiseuille equation (a special condition of the Navier-Stokes equation for round pipes), which can be written like that:

                dP = 8µLQ / πr⁴

with dP the pressure drop across the nozzle

    L    the length of the nozzle channel

    Q    the volumetric flow rate

    r    the radius of the nozzle.

In your case you have increased the radius of the nozzle, according to this equation you can apply a four times higher volumetric flow rate when applying the same maximum pressure drop.

As you already mentioned, the limiting aspect will be the heating capacity of the hotend, mainly the thermal contact from heat block to nozzle. Here I would recommend a good thermal grease which is still stable at temperatures above 150°C. This is he specification limit of most of the available heat pastes!

For the risk of blockage I personally would recommend to print always with fan on to have a sufficient cooling of the Isolator and the inner PTFE tube. It would be less critical printing at this high speed.