Volumetric Flow Rate Test 2 - Toolhead

Today I was trying to beat my previous best flow rate of 83mm3/s (1000mm/s).

Here's what I did (in this order):

• Ti shield wrapped in Kapton tape
• Swapped in a 20mm LDO stepper
• Increased the current from 0.8A to 1A
• Decreased the fan speed from 40% to 30%
• Increased the hotend temp from 300°C to 330°C
• Increased the chamber temp by 5°

All of these things combined weren't enough to reliably pass 87mm3/s (1050mm/s) or 91mm3/s (1100mm/s) tests. These speeds failed instantly the last time. Now, the skips only started 3-4 loops after bumping up the speed, so there was a minor improvement.

Considering that I barely saw a flow rate drop with a 0.4mm nozzle (instead of the 0.5mm), which was doing high 70s, everything points to a maxed-out melt zone. The filament just doesn't spend enough time inside the hotend to melt thoroughly. This is an SLM steel block that's slightly shorter than a Chube Conduction, so this flow rate is perfectly in line with reasonable expectations.

In the next episode, I'll compare mid-air extrusion flow rates with and without an 8.5mm copper MZE to verify my suspicion and also to see what the extruder can do with a slightly longer melt zone.