No Ooze Nozzle

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Revision as of 03:24, 18 February 2017 by Quenta (talk | contribs) (How it Looks)
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No Ooze Nozzle

Release status: experimental

No ooze photo.jpg
Description
nozzle end to stop ooze
License
Author
Contributors
Based-on
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Categories
CAD Models
External Link

Introduction

The No-ooze-nozzle is a hotend with a mechanical valve, which opens only when there is pressure from the extruder cold end.

Oozing is a universal problem of FDM 3D printers, which perhaps all users experience. Not only is it just a little annoying for single extrusion machines, it is a critical problem for dual (or more) extrusion machine. The oozed plastics mess the model, and demands the use of intricate countermeasures. Countermeasures means both hardware & software countermeasures.

One hardware countermeasure is the one that shift the nozzle from the printing position so that the ooze doesn't touch the model. However it's a hefty load for your hotend and neither does it stop the nozzle from oozing, so you still need the prime pillar or the ooze shield.

Another measure is to have one nozzle to extrude multiple filaments, like the Diamond Hotend or the E3D Cyclobs. However because the plastics mix in the barrel, you still need software countermeasure, namely a prime pillar.

You could also cool down the idle hotend, but it doesn't totally prevent oozing, and it takes time to reheat when printing again.

So with dual extrusion you are likely to waste materials and time anyways. Another shortcoming is, the significant weight increase on your hotend caused by the toolchanger. It will result slower speed, so it's likely that you'll also have to compromise your single-extrusion speed, too.

No More

So it's best if you could simply stop the nozzle from oozing, and the no ooze nozzle is what you want. This attempts to eliminate the following:

  • ooze shield
  • prime pillar
  • tool change retraction
  • cooling the idle hotend
  • tool changer (like a servo)

How it Looks

The No ooze nozzle has a lean structure which comprise only 4 components. Below is a Makerbot hotend nozzle compatible design example.

How it Works

The gimmick is simple. the nozzle is closed when there is no pressure, and open when there is. Note that some retraction is needed, as residual pressure does leave the valve open. The opening force of the ball valve is adjusted to about 1N.

Notice

The shortcoming of this nozzle is that you will need some higher pressure to jerk the valve open, relative to normal hotend nozzle. The valve & the spring are also obstacles of the plastics flow. High power geared extruder motors are recommended. With PLA, the author has attained 80mm/sec at 0.2mm layer height and 0.4 diameter nozzle.

Availability

It is not yet commercially available. You will (typically) need the following tools to machine out a no ooze nozzle:

  • boor-bank
  • 2mm drill
  • 3mm drill
  • 2mm reamer
  • 3mm reamer
  • 2.5mm ball-end cutting router end

Purchase these BOM items from your locally available stores.

  • 2.5mm ball
  • spring (length = 4, 5coils, OD=2.6mm, 1N/mm)
  • M6 acorn nut
  • M6 plain screw, (length = 13mm)
  • 2.5mm ball router cutting bit

Video

The demonstration video is recently under preparation.