Step 4 of 9
Max Volumetric Flow
Find the maximum amount of filament your hotend can melt and extrude per second without under-extrusion. This sets the real limit for your print speeds.
⏱
Time
20–30 min
📊
Difficulty
Intermediate
⚡
Impact
High
Typical hotend limits
E3D V6 standard
~11 mm³/s
E3D Revo
~14 mm³/s
Dragon HF / Rapido
~18 mm³/s
Bambu hotend
~32 mm³/s
Volcano
~25 mm³/s
Obxidian / CHT
~35 mm³/s
Extrusion Test — Increasing Flow
SAFE FLOW RANGE
Clean extrusion
Clean extrusion
TOO HIGH
Gaps, missing lines
Gaps, missing lines
ℹ️
Why this matters: Exceeding your hotend's max flow causes under-extrusion, weak prints and inconsistent layers. Knowing your limit lets you set realistic speeds and line widths for perfect results.
1
Follow These Steps🔥
Heat up
Heat your hotend to your normal printing temperature.
🖨️
Print the test
Print a max flow test from low to high increasing flow rate. OrcaSlicer: Calibration → Max Volumetric Speed.
🔍
Inspect the results
Find the highest flow rate before under-extrusion starts — gaps, rough surfaces, or missing material.
🔢
Enter the value
Enter that flow rate in the calculator. Apply 10–20% safety margin for reliable results.
⭐ Pro Tip
Use the same nozzle, filament, temperature and cooling you use for real prints.
2
Calculatormm³/s
The highest value before under-extrusion first appears.
%
10–20% recommended. Higher = safer but slower.
Max speed at your settings
Formula: Flow ÷ (layer height × line width) = max speed mm/s
3
What to Look For✅
Good Extrusion
Lines are smooth, connected and consistent. Even surface, no gaps.
⚠️
Starting to Fail
Lines look rough, gaps appear between lines or corners look rounded.
⊗
Under-Extrusion
Missing lines, big gaps, thin walls or inconsistent extrusion. This is your limit.
Too Low
WeakPerfect Range
Strong, cleanToo High
Gaps
WeakPerfect Range
Strong, cleanToo High
Gaps
Increasing Flow (mm³/s) →
⊗Common Mistakes
⊗Using a test with inconsistent line width
⊗Printing too cold (lowers max flow result)
⊗Not using the same cooling as real prints
⊗Ignoring the first signs of under-extrusion
⊗Setting the limit too close to the maximum
⭐Pro Tip
A lower layer height and wider line width require more volumetric flow. Stay within your limit for consistent prints.
⬇️ Layer Height
↔️ Line Width
🚀 Speed
→Next Step
Pressure Advance
Eliminate corner bulges and improve accuracy at high speeds.
Go to Pressure Advance →