An OpenSCAD parametric funnel with several options, including:

• Outer diameter, base diameter, base length, and taper angle
• Air gap
• The "turbine" fins

This is a vase-shaped model, so it only requires a few grams of consumables and has a fast printing speed. If a funnel gets messy and can't be cleaned, it won't waste much plastic.

Print:

• UseVase mode
• 将Set the extrusion width to 0.7 mm
• Set the bottom layer to 0

Notes on the "turbine" fins

I want to comment on those turbine fins: I think they're basically useless. Some people believe that vortices can accelerate flow, but this only holds true under certain conditions: for example, when pouring water out of a bottle. The vortices form a stable airway in the center, so air can enter and liquid can be poured out. Without vortices, rising bubbles would interfere with the descending liquid. The same problem also arises when pouring some liquid into a bottle and the funnel covers the entire bottle mouth. Then, the vortices can play a helpfulIfIt's powerful enough to actually form an airway. I've seen some "turbine" funnels, but the "turbine" features in them are too shallow to make the vortex reach a high speed. Most of the designed vortex fins actually become very steep at the bottom, which slows down any vortex movement...

If the funnelThe bottle cap wasn't sealed properly， the air can escape from the side, without the need for a vortex. In fact, this is counterproductive, because centrifugal force will counteract the water's descent.

My conclusion is: if your funnel can seal the bottle mouth, please use a funnel with a built-in air gap.

However, I implemented the turbine fins for two reasons:

• Here's for you to try and see if they really help with the funnel. I've also implemented a version where the fins aren't quite vertical at the bottom.
• These fins are also useful for filtering. They filter the liquid while maintaining the gap between the filter and the funnel wall. Many coffee machines also use these fins.