Updates:

• 2021/03/14: more detailed references, published
• 2021/03/11: starting write-up with basic illustration

Introduction

I thought to compose a summary of the features of 3 types of 3D printers I currently work on, and its relations to print 90° overhangs – main motivation to go beyond 3-axis 3D printing:

Functionality Commonalities

• a 5-axis printer PAX has the same features as a 4-axis printer RTN and 3-axis printer plus it can print at any tilt angle, printing 90° or more overhangs
• a 4-axis printer RTN prints conic- or angled sliced models so it can print 90° overhangs in all directions (conic slice) from a central point or single direction (angled slice); the tilt angle is fixed at 45°; Z sliced horizontal layers must be post-processed¹⁾ to be printable in acceptable quality but good quality cannot be achived in my opinion
• a 3-axis printer by default cannot print 90° overhangs without support (unless it’s tilted 45° as for belt-printer, then only in one direction), but may print conic sliced models with 20-25° cone angle, hence print 90° overhangs from a central point, and behave partially like a 4-axis printer

1. a suitable Z_rot must be calculated and added to extrusion commands of the G-code, see this example.

Printing an Conic Sliced Overhang

Conic Sliced on 3-axis

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A well tuned and well designed part-cooler is prerequisite to print conic-sliced models at cone angle of 20-25°, and currently there is no conic slicer which can properly segment sub-volumes yet (2021/03) to switch from horizontal- and conic-slicing (with two modes of outside/inside cone) where suitable.

Conic Sliced on 4-axis RTN

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Conic- or angled slicing is recommended in order to print with Rotating Tilted Nozzle (RTN) or post-processing of existing horizontal sliced G-code is required to provide additional Z_rot information to print in good quality.

Conic Sliced on 5-axis PAX

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and nearly the same with PAX90 (tilt angle 0..90° only) with shorter arm:

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A 5-axis Penta Axis (PAX) supports other slice methods than horizontal-, angled- or conic-sliced, but any variable build-orientation, but will make the slicing software very complex to recognize those sub-volumes suitable for advanced slicing methods.

This also means, a 5-axis PAX slicer with proper settings can produce G-code for 5-, 4- and 3-axis 3D printers with combining the horizontal-, angled- and cone slicing for sub-volumes or segments.

Traditionally Horizontal Layers

Slic3r 1.2.9 and Ultimaker Cura 4.8 as comparison:

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References

• Conic sliced (non-planar) printing 90° overhangs on 3-axis 3D printer
• Conic Slicing for 4-axis Rotating Tilted Nozzle (RTN)
• 4-axis Rotating Tilted Nozzle (RTN)
• 5-axis Penta Axis (PAX)

That’s it.