Spherene | XYZ dims *

Updates:

2024/10/23: finally published
2024/10/11: ready for publishing
2024/01/26: starting write-up

Introduction

At Formnext 2023 I spent some unexpected time to discover a new class of procedural structure called “Spherene” (“sphere” + “graphene”), it’s a name as introduced by a company with the same name.

It’s main feature is isotropic (“all directions”) distribution of forces. Their service provides the creation of this structure based on:

density (ratio of material vs empty space), hence their term of Adaptive Density Minimal Surface (ADMS)
form
wall thickness

where all of them are freely definable in 3D space contained within an overall boundary. Their service “renders” a mesh which complies with such, like defining at some point a lower or higher density, and transits in 3D space from one to another.

Spherene Metamaterial in Simulation-Based DFAM: CDFAM NYC 2024 (Video Presentation)

Patent

My immediate impulse was to code the Spherene aside of the existing TPMS’s, but I realized their business core is the service of creating meshes based on their procedure as described in a patent:

Method of Additively Manufacturing a Minimal Surface Structure (Original, 2023), PDF available
- Method of Additively Manufacturing a Minimal Surface Structure (2023, PDF OCR processed / machine readable)
at its core it describes 6 steps (abbreviations added for clarity)
1. creating envelope
2. creating density field
3. adaptive Voronoi tesselation (AVT),
4. 1st skeleton graph (SG) associated to AVT (SG-AVT1)
  - generated from the edges of the Voronoi cells
5. 2nd skeleton graph associated to SG-AVT1 (SG-AVT2)
  - generated using Delaunay tetrahedralization
6. minimal surface from SG-AVT1 and SG-AVT2, using equidistant from both skeleton graphs, with minimal wall thickness requirements
Abstract: A method of additively manufacturing a minimal surface structure of a three-dimensional article includes a computer executing the steps of recording, in the computer,
- an envelope of the three-dimensional article; generating a density field across a volume enclosed by the envelope with densities of the density field corresponding to local requirement values of at least one physical parameter at respective positions of the three-dimensional article;
- generating an adaptive Voronoi tessellation of the volume using the density field;
- generating a first skeleton graph associated with the adaptive Voronoi tessellation;
- generating a second skeleton graph associated with the first skeleton graph; and
- generating a digital minimal surface model from the first and second skeleton graphs.
The method may further include a 3D printer additively manufacturing the minimal surface structure according to the digital minimal surface model.

I think if Spherene is truly as significant for Additive Manufacturing, and an essential invention, it has to move beyond the grip of a single company and its patents – time will tell.

Samples

Daniel Bachmann from Spherene Inc. kindly shared with me a few samples, 20x20x20mm cubes, and 20mm diameter spheres with Spherene infills, illustrating their properties:

A few support structures were required for the spherical samples, the cubic samples did not require such:

Lychee Slicer: spherical spherenes required support structure due overhangs

Additionally I printed a few cubic samples with FDM on my CoreXY Ashtar C without supports at 40x40x40mm scale.

Subtractive Manufacturing & Molding Usage

The structure cannot very well machined with subtractive manufacturing processes – or only if the piece is sub-divided so all indentations can be milled, and sequentially fused or welded again.

Another approach comes to my mind is to form dedicated bricks, e.g. for large scale application like a building, and have a limited kinds of bricks depending on their position and use case, and have molds to form those limited kinds in larger quantities.

In order to produce a mold one would inverse the original model, the negative volume, that would be produced using additive manufacturing and then produce lost-form casting molds, or highly simplify the form so one can remove the positive without destroying the mold.

References

Updates:

2023/11/13: published
2023/11/11: starting writeup

Introduction

Another year, another November in Frankfurt (Germany) and Formnext – this is the main event of the year professionally for me. As I reside in Switzerland the travel is fairly easy and short and the 770 exhibitors in two halls (11 & 12) with two floors each is so overwhelming that even 4 days attending is not sufficient.

Day 1 (Tue, Nov 7): I spent an entire day to explore hall 12.1 alone, which turns out a good choice as it was a dense populated hall with many smaller companies
Day 2 (Wed, Nov 8): visiting with a client half of the day to review some of their possible competition, and then explore 12.0
Day 3 (Thu, Nov 9): some schedules meetings and then explore 11.0 and 11.1
Day 4 (Fri, Nov 10): revisiting 12.1 and 11.1 briefly, visiting with another client some selected booths to check products on display

I surely missed a few booths in 11.1 and 12.1 still; whereas 12.0 and 11.0 were more large scale industrial AM solutions, mixed with university and regional focused booths which I didn’t have time to explore in detail.

Personal Selection

I feature some companies according my personal professional interests:

Spherene (Math)

I made contact with Spherene before via LinkedIn but I realized I missed the point of what Spherene actually “invented”, at their booth Daniel Bachmann took the time to show me the features of their new class of minimal surface model and it was challenging for me to follow him despite of my own experience with Triply Periodic Minimal Surfaces (TPMS) – after apprx. 20 mins I realized the scope and some of their depth of their “invention”.

Spherene: sphere sample with variable porousity

In essence, the sphere is used as a base form, and density, wall thickness and other features are processed in a localized manner, filling the space. The main result doing is optimizing a form to distribute inner/outer forces, e.g. the ends of the spheres are perpendicular to the surface providing ideal way to distribute them into a network of thin walled interconnected spheres providing isotropic (“all directions”) property.

The samples on display were printed with MSLA, SLA, FFF/FDM or SLM were indeed very strong in relation to the printed volume, e.g. the hallow rabbit printed with resin barely gave in when pushing on the thin outer perimeter – impressive.

Their approach is available as cloud-based GUI or as Grasshopper/Rhino plugin. The actual details of their procedure isn’t easily found but a patent (WO2020229692A1) by CEO Christian Waldvogel gives some idea.

Genera (DLP Resin)

There are many MSLA/SLA/DLP printer manufacturers, yet, I wasn’t aware of Genera and I was shown their system, an integrated workflow:

all resin vats have a lid (only applies for G1/F1 combo but not their bigger machines), which are opened only within the machine
the finished prints (still on the plate) are moved in a box into the washing machine (without any person touching resin or the resin coated prints)
once automatically cleaned and post-cured, the prints are removed from the build plate manually

In essence one does not interact with resin directly, it’s all contained within the workflow – which I like a lot. They also provide wide selection of resins: hard, soft, rubbery, opaque, transparent/clear.

Genera

My idea has been to adapt some of their approach to make my own resin printing with Photon series (4K, X2 and X 6Ks); right now I also have multiple vats, and flex-plate, but moving the printed parts and washing them are still messy.

Quantica (Resin Jetting)

Last year I already visited the booth of Quantica, and so this year again. I asked earlier for printed samples, but they declined, and again this time . . . it is bizarre to see a machine actually able to print, and they don’t hand out samples, but I was told by January 2024 I might get some. This tells me a few things, the printed pieces are very sparse or not yet at the quality they want others to experience – some samples were on display, but sealed behind a glass box unable to have in my hand. So I guess now, they are expecting or already have better and more reliable printing results where the printed pieces match other similar printing processes.

I follow their development closely since ~2 years as I consider it very innovative to print with 7 different resin-based materials at the same time and able to fine-tune material properties on the voxel-level.

Quantica / q3d.io

Duet3D (Open Source Hardware & Community Building)

UK-based Duet3D with its Duet boards and RepRapFirmware (RRF) is, as I wrote before, a beacon within the Open Source Hardware community – it isn’t just an example for other companies, and but also a great synergy provider, aiming to bring different individuals, groups and companies together.

Brandon Builds’ Open 5X version was featured on a Voron 0, and a second machine also 5-axis setup with a tool changer.

Rapid Liquid Printing / RLP (Flexible Structures)

While roaming around a small booth of RLP caught also my attention, where a video was featured of a nozzle moving in a bed filled with silicon printing rubber, and other flexible material:

Reinforce 3D (Enhancement)

Another truly innovative approach combining and enhancing existing additive manufacturing processes was shown by Reinforce 3D:

using existing AM methods such as SLM, SLA, MSLA and even FFF/FDM to make models with thin walled tunnels and then
filling or rather pushing them with strains of carbon fibres along with resin into the tunnels
and thereby reinforcing free forms by keeping the result lightweight but incredible strong due the embedded carbon fibres

A very small but significant detail is, that you can print multiple parts on a smaller printer, but once you start to insert the bundles of carbon fiber those segments of pieces get combined in a strong assembly, as the aluminium skeleton shown above.

Reinforce3D

Plasmics (Inductive Heated Hotend)

INo Trident – inductive hotend by Plasmics: fast heatup and cooldown / 3s from 20C to 220C, 10s from 220C to 150C

At the booth of Plasmics I looked at the inductive hotend and saw the heating up in a few seconds from 20C to 220C and cool-off in a small demo first hand.

The hot part of the nozzle looks like a needle, with little thermal mass, hence the fast heat and cooling-off time, and then surrounded by ceramics with the inductive coil on it.

The hotend incl. the controller board priced at EUR 400 is high for DIY enthusiasts but low for an industrial setup.

Miscellaneous

Major AM players were present:

Formlabs: industrial SLA & SLS
Markforged: 3-axis Continueous Carbon Fiber (CFF)
Nexa3D: industrial SLA & SLS
Prusa Research: the usual lower-end/lower cost printer and their industrial aimed printers of the “Pro” series
Elegoo: low-cost resin & FFF/FDM printers, resins & filaments
Anycubic: low-cost resin & FFF/FDM printers, resins & filaments
BambuLab: cost-effective quality high-speed FFF/FDM printers
Creality: low-cost FFF/FDM & resin printers
Modix: low-cost but large scale FFF/FDM printers
Polymaker: filaments
eSun: filaments & resins
many smaller filament seller
E3D: hotends, extruders

And UltiMaker (after Ultimaker & MakerBot merger) wasn’t present again; the consensus has been that BambuLab‘s printers have taken the higher quality consumer FFF/FDM printers market segment, and the air getting thinner for UltiMaker – at the same time they are doing a great service with the Open Source Cura slicer.