Author Archives: Rene K. Mueller

3D Design: Slices on Canvas (Parametric Canvas)


  • 2024/01/26: published
  • 2024/01/20: adding more examples and mounting tool/ruler
  • 2024/01/15: starting write-up


Since a while I was wondering how to create large(r) scale 3D prints like 1m / 1000mm or more, and I thought to use wood planks as slices and make “parametric wall” like sculptures. In order to get an idea of the procedure, I started with “parametric canvas” or Slices on Canvas.


I used OpenSCAD to put together a few examples with 200×150 in size, and settled for 40 slices, which are then scaled up for 400x300mm canvas, the actual size is 340x240mm giving on each side 30mm margin to the edge of the canvas.

3D Printing Slices

In order to test the concept, I used 3D printed slices printed with cold-white PLA+ in order to get a strong contrasts to the black canvas:

Each slice is 240mm wide, and 2.5mm thick and various height depending on the model.

After printing 40 slices finished, I mounted them on the canvas:

As shown on the photo, I used a mounting tool / rulers, also 3D printed, which helped me to keep the slices well aligned and spaced to each other – then glued each slice on the canvas.

40 slices with 240mm width and 2.5mm thickness takes about 20hrs to print (4 slices ~ 2hrs print time) and ~520g of filament like for the Sinus themed sculptures.

Raw slice bundles: Smooth Sinus Meadow, Quarter Drop, Drop each bundle apprx. 520g PLA+

With 2.5mm thickness x 40 and 340mm canvas width, it’s about ~25% or 1/4 of actual volume of the model, and the rest is empty space in between.

Sinus Mountain Range



Smooth Sinus Meadow

Various Examples


It’s relatively easy to create a Slices on Canvas (parametric canvas) but it takes its time to print and assemble – due the thin slices the sculpture changes its appearance drastically depending on viewing angle, and so is an eye catcher.

It certainly is a viable approach for larger scale sculptures, the saving in material is compensated with additional manual work like aligning and fastening the slices.


  • LabSlicer: used to slice the model into SVG slices (PrusaSlicer also supports this functionality)
  • Prynt3r: for printing the individual SVG slices directly

3D Design: 3D Lissajous


  • 2024/01/22: published without much reflection & conclusion as research is ongoing
  • 2023/12/02: adding more examples and refining details
  • 2023/10/22: start writeup


While studying continuous fiber 3D printing and its main nature is to find ways to lay fiber without interruption. In order to refresh my memory I revisited the Lissajous forms, which until recently only knew in their 2D form, the swirling strings or lines – and now extending it into 3D as well.

The main idea is to realize how a line, string or fiber can be used to fill non-planar and circumvent a 3D structure and how angular shifting in Lissajous context affects such form.

3D Lissajous

  • angle: 0 .. 2pi or 0 .. 360°
  • p, n, m: 0 .. 1000, the amount of loops
  • phi0, phi1, phi2: the angular offsets 0 … 2pi or 0 .. 360°
  • X = sin(angle*p+phi0)*r
  • Y = sin(angle*n+phi1)*r
  • Z = sin(angle*m+phi2)*r

I did a lot of experimenting – I could post hundreds of forms – but let me focus on one a bit closer, which got my attention:

It is a very interesting transition, 8/13/21 with phi0=0° gives almost a cube-like structure, and shifting the X loop to 90° we get a tetrahedron:

Spherical Lissajous

While playing with 3D Lissajous, I thought to adapt the cyclic nature, but apply it to a circle laying in the XY plane and then rotate in X axis, and Y axis as well, and optionally cyclic translation as well:

  • d: diameter
  • angle: 0 .. 2pi or 0 .. 360°
  • p: amount of loops as in X=sin(angle*p)*d/2, Y=cos(angle*p)*d/2
  • q: amount of X rotations: rotateX(angle*q)
  • r: amount of Y rotations: rotateY(angle*r)
Spherical Lissajous 12.23 with spreading struts

The model was printed with MSLA white resin at XYZ 50um resolution with 120mm diameter, with a few support structures near the bottom:

Spherical Lissajous with Translations

Using the Spherical Lissajous and extend it slightly:

  • [A,B,C]loop/offset/radius: translate([ sin(angle*AL+AO)*AR], sin(angle*BL+BO)*BR], sin(angle*CL+CO)*CR ])

which spreads the ribbons away from the spherical surface origins.

Spherical Lissajous 5.11 AL=3, AR=5

Spherical Lissajous 5.11 AL=3, AR=5

It’s symmetric X- and Z-wise, in Y-axis it isn’t.

The model was printed with MSLA white resin at XY 35um / Z 50um, at 60mm in Z height, ~94mm width; with a some support structures:

Spherical Lissajous 11.15 AL=2, AR=5

A more elaborate form is 11.15 AL=2, AR=5:

Spherical Lissajous 11.15 AL=2, AR=5 with spreading struts

So, there is no X-, Y- or Z-wise symmetry.

The model was printed with MSLA white resin at XY 35um / Z 50um, at 60mm in Z height, ~94mm width; with a some support structures:

and printing it larger with ~200mm width with manually positioned support:

That’s it (for now).


Misc: Formnext 2023


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


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”.

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.

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.

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.

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.


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.

Random Impressions


3D Printing: MSLA printing Triply Periodic Minimal Surfaces (TPMS) – Gallery


  • 2023/07/25: adding 20mm/40mm TPMS photos
  • 2023/03/12: starting write-up, and published

20mm cubes of several Triply Periodic Minimal Surfaces (TPMS) as explored at Generative Parametric Infill Geometries printed with MSLA (Anycubic Photon Mono 4K) at 35 μm XY, 50 μm Z:

Most of the cubes were printed without support, the cylindrical and spherical projections required supports.


20mm and 40mm cubes of TPMS mounted on canvases:


3D Printing: Parametric Generative 3D Infill Geometries


  • 2023/02/09: finally published
  • 2023/02/08: worked on text and illustrations a lot, many sample prints, multiple visualization approaches, details on f1 + f2 vs f1 * f2 and cylindrical and spherical transformation of TMPS
  • 2023/01/05: adding mesh/voxel renderings, slicing geometry to generate G-code
  • 2022/12/11: first FDM G-code generated using 2D / contour approach
  • 2022/12/07: included many suitable periodic minimal surfaces
  • 2022/12/02: start with implicit surface focus

As I progress I will update this blog-post.


Infill geometries are geometries which are continuous, repetitive or periodic; they fill a boundary defined geometry aka outer form often defined via meshs. Let’s dive into some of the simple geometries and then looking at some more complex structures:

The Implicit Geometries

Implicit geometries are geometries defined via f(x,y,z) = 0 defining their surface, the boundary between inside and outside and they are ideal to define repetitive or periodic 3D infill geometries.


Sphere: x2 + y2 + z2 – r2 = 0

When you ever tried to compose a sphere as a mesh, you know there are many ways to do so, and all are more complex than this simple description, and as you realize, the formula is perfect, it’s not an approximation – this is the nature of implicit formula. When you try to visualize an implicit formula, then you need to discretize and there the approximation takes place, as a mesh or as voxels.

Another nifty property of the sphere, it is the minimal surface to circumvent a volume, and through this blog-post, the minimal surface will become a common theme.


Cube: max(abs(x),abs(y),abs(z)) – w/2 = 0


Plane: z = 0

As I render only -10 to 10 to each axis, it creates a small plate:

Triply Periodic Minimal Surface (TPMS)

Let’s move to the world of minimal surfaces, so called Triply Periodic Minimal Surfaces (TPMS), those can be expressed in implicit form and have some properties as sought for infill geometries.

In differential geometry, a triply periodic minimal surface (TPMS) is a minimal surface in ℝ3 that is invariant under a rank-3 lattice of translations. These surfaces have the symmetries of a crystallographic group. Numerous examples are known with cubic, tetragonal, rhombohedral, and orthorhombic symmetries. Monoclinic and triclinic examples are certain to exist, but have proven hard to parametrise.

Wikipedia: Triply Periodic Minimal Surface (TPMS), retrieved 2023/02/08

Schwarz P aka Primitive

One of the simplest yet powerful formula:

Schwarz P: cos(x) + cos(y) + cos(z) = 0

increasing the frequency or scale of the structure:

By extending the formula with +a, we can animate it:

animating a: -1..1, transits from octahedron to cuboctahedron
Schwarz P 4x animated a: -1..1

Schwarz D aka Diamond

Schwarz D: sin(x)*sin(y)*sin(z) + sin(x)*cos(y)*cos(z) +
cos(x)*sin(y)*cos(z) + cos(x)*cos(y)*sin(z) = 0


Neovius: 3*(cos(x)+cos(y)+cos(z)) + 4*cos(x)*cos(y)*cos(z) = 0

C(Y) Surface

C(Y) Surface: sin(x)*sin(y)*sin(z) + sin(2x)*sin(y) + cos(x)*sin(2y) + sin(2y)*sin(z) + sin(2z)*sin(x) + cos(x)*cos(y)*cos(z) + sin(2x)*cos(z) + cos(x)*sin(2y) + cos(y)*sin(2z) = 0

Fischer Koch

Fischer Koch: (cos(x)*cos(y)*cos(z) + cos(z)*cos(x)) –
(cos(2x)+cos(2y)+cos(2z)) = 0

S Surface

S Surface: cos(2x)*sin(y)*cos(z) + cos(2y)*sin(z)*cos(x) +
cos(2z)*sin(y)*cos(y) – 0.4 = 0


Gyroid: cos(x)*sin(y) + cos(y)*sin(z) + cos(z)*sin(x) = 0


FRD: 8 * a*cos(x)*cos(y)*cos(z) + b*(cos(2x)*cos(2y)*cos(2z)) –
c*cos(2x)*cos(2y) – d*cos(2y)*cos(2z) – e*cos(2z)*cos(2x)

Let’s explore this form more thoroughly, we animate a, b, c, d, and e and see what it does, essentially we animate -1 to 1 in sinus, 0 eliminates of the chunk of the formula:

animating a (-1..-1)
animating b (-1..1)
animating c (-1..1)
animating d (-1..1)
animating e (-1..1)

Gyroid Skeletal

Gyroid Skeletal: 10*cos(x)*sin(y)+cos(y)*sin(z)+cos(z)*sin(x)) –
0.5*(cos(2x)*cos(2y)+cos(2y)*cos(2z)+cos(2z)*cos(2x)) – 14

P Skeletal

P Skeletal: 10*(cos(x)+cos(y)+cos(z) –
5.1*(cos(x)*cos(y)+cos(y)*cos(z)+cos(z)*cos(x)) – 14.6

By changing the last substraction of 14.6 to 10 or 8, the structure get more dense – ideal to use.

P Skeletal, animating main subtraction -14.6(thin)..5.4(disconnected)

The P Skeletal connects 6 arms to each other.

IWP Skeletal

IWP Skeletal connects 8 arms to each other.

Schwarz D Skeletal

Schwarz D Skeletal connects with 4 arms to each other.

The above “skeletal” minimal surfaces are ideal for lattice structures, likely most usable in context of voxel-based 3D printing approaches, such as SLA, SLS, SLM and so forth, but less ideal for traditional FDM where the lattice is sliced Z-planar again kind of defeating the overall purpose of lattice structures.

D Surface

D Surface: cos(x)*cos(y)*cos(z) – sin(x)*sin(y)*sin(z)

As Juergen Meier created a variant, adding a, which gives these variants:

providing a structure using 4 arms to connect each other.


Using Implicit Geometries as Infill Structures

Slic3r and Prusa Slicer are providing gyroid infill pattern since early version, but beyond that it seems no to little development happened since (2022/12).

Let’s see how implicit geometry can be transformed into slices (FDM) or voxels/pixels (SLA, SLS etc)

Algorithm A: 3D Cache

  • create point cloud of surface of implicit geometry
  • create surface of implicit geometry using marching cube
  • (optional) determine x, y, z size where it repeats itself
  • slice surface for infills at certain scale
    • clip inner surface with outer perimeter of slice


  • with caching: fast lookup of infill geometry


  • many steps
  • x, y, z repeatability must be given, hard to determine programmatically from outside
  • clipping to perimeter can be computational expensive depending

Algorithm B: 2D Cache

  • create 2D point cloud of a slice of implicit geometry based on clipped 2D area / slice
  • convert 2D point cloud to polylines (FDM) or pixels (SLA)


  • reduction to 2D problem at first stage
  • fast 2D point cloud creation as only one z-level is used


  • create 2D point cloud at arbitrary resolution, loss of curves unless refitted
  • caching without knowing repeatability of the geometry makes little sense

FDM G-code

Here some early G-code for FDM 3D printer using PyImplicit tool tracking the implicit surface as 2D contour:

Meshs & Voxels

The implicit surfaces only define the surface, either:

  • inside vs outside – a solid; or
  • certain thickness of such surface

In order to create watertight meshs the volume needs to be limited with a boundary box, and Marching Cube is performed from outside to get proper mesh to post-process afterwards.

Now you may wonder, what’s the fuss with all those forms, why doing this complicate implicit form, why not just create a few forms as meshs right away and repeat them orderly – well, here it comes why:

Frequency or Scale Gradients

Changing the frequency or scale s0 and s1 can be achieved by:

znorm = (z-zmin) / (zmax-zmin)
s = (1-znorm)*s0 + znorm*s1 or
s = lerp(s0, s1, znorm)
f = surface(x*s, y*s, z*s)

This shows the power of generative geometries, we simply can define the scale or frequency of a geometry at any point, given we transit within reason and not too sharply to cause discontinuty.

Thickness Gardients

Alike changing thickness:

znorm = (z-zmin) / (zmax-zmin)
t = lerp(t0, t1, znorm)
f = abs(surface(x,y,z)) – t

Form Gradients

What looks very complex is done quite simply with:

znorm = (z-zmin) / (zmax-zmin)
f = lerp(surface1(x,y,z) , surface2(x,y,z), znorm)

This is quite powerful property, to be able to morph from one implicit form to another with such a simple formula.

Contineous Transitions:

  • Schwarz D – Schwarz P
  • Schwarz D – Neovius
  • Schwarz P – Neovius
  • thickness: IWP Skeletal – Schwarz P
  • thickness: IWP Skeletal – Schwarz D

Discontinueous Transitions:

  • IWP Skeletal – P Skeletal
  • IWP Skeletal – Neovius
  • solid: IWP Skeletal – Schwarz P
  • solid: IWP Skeletal – Schwarz D

Combining Implicit Surfaces


Algebraic addition has the effect of apply one geometry within another, alike recursion:


Algebraic multiplication has the effect of clipping, or geometrical intersection:

Mapping Implicit Surfaces

One can map the coordinates, and create a cylindrical gyroid, where former X & Y become distance and rotation angle, and Z remains as is, and so spherical projection is possible as well, or even feed coordinates through implicit formula itself:

Next blog-post(s) I will go into further details utilizing TPMS in Additive Manufacturing (AM) like FDM/FFF, SLA, MSLA, SLS, MJF or SLM – each one of them have unique features and limitation for using those Parametric Generative Infill Geometries.

Appendix: Visualization

In case you wondered of the different styled visualization through this blog-post, let me show you the different approaches to discretize implicit defined surfaces.


The code is rather simple with OpenSCAD yet rather slow: either skin is true or false, and delta determines the thickness of the skin if enable:

t = 1;
r = 20*t;
st = 1/2;
delta = 0.2;

function schwarz_p(x,y,z,s=1) = cos(x*s) + cos(y*s) + cos(z*s);

skin = true;

      for(z=[-r:st:r]) {
         f = schwarz_p(x,y,z,360/20/2);
         if(skin && abs(f)<delta)           // -- skin only
            translate([x,y,z]) cube(st);
         else if(!skin && f<delta)          // -- inside/outside
            translate([x,y,z]) cube(st);

Rendered via voxelation:


Rendered in OpenSCAD via marching cube algorithm with Level Surfaces:

Volumes & Surfaces in OpenGL GLSL

Following experiments were done with Spirula/Implicit3 within the browser, the implicit formulas are rendered in realtime at 100-500 fps using OpenGL’s GLSL (GL Shader Language):

One has to clip the formulas with a cube in order to have a limited set, otherwise you get a full screen looking at infinite X, Y & Z, here Schwarz P:

Spirula/Implict3 realtime rendered Schwarz P TPMS in the browser

Meshs with Marching Cube

In order to create a mesh, I developed PyImplicit which utilizes Numpy library to calculate the implicit formula fast, and then run a Marching Cube algorithm over the result in order to get a discrete mesh like STL, OBJ, or 3MF to process further for 3D printing.

Foreground: 1st row: 90mm cube clipped of frequency gradients on Schwarz D, Schwarz P*,
surface gradient between Schwarz D to Schwarz P (top) at certain thickness or solid,
2nd row: 2x IWP skeletal 90mm cubes at different frequency;
Background: various 30/40mm cube clipped Triply Periodic Minimal Surfaces

*) some of my larger prints I attach RFID tags, e.g. as on top of the variable frequency Schwarz P print, which I store the print UID from my Prynt3r job which logs all my prints with all settings and webcam snapshots. In future blog-post I will illustrate my NFC/RFID setup.

And Polyviuw is a small mesh viewer using Polyscope Python as backend to display it as mesh:

It is easy to create huge files when exporting an implicit generative infill geometry and one ends up with a 700MB binary STL file, which becomes hard to view at least on my system. To handle complex outer forms, with complex inner geometries I estimate reaching multiple gigabytes large files – let’s see.


Misc: Formnext 2022 Review


  • 2022/11/21: published
  • 2022/11/19: starting writeup


Formnext 2022 was a 4 days Additive Manufacturing (AM) event in Frankfurt (Germany) November 15-18 2022, and it had ~750 exhibitors, two huge halls numbered 11 and 12 each with two floors. I attended the 4 days and it was pretty overwhelming. I try to give an overview, for myself to process what I saw, and perhaps for you who couldn’t attend.

E3D Online

E3D is an old timer among 3D printing enthusiasts, so I start with their booth:

I was surprised to get to know E3D manufactures for UltiMaker their CC printcore.


Duet3D is a small UK-based company, but very influential due their excellent and often praised customer support and support forum aside of their slowly expanding board selection:

I met Tony Lock, and we discussed current state of multi-axis support in Duet/RepRapFirmware, and he showed me the Open5X by Freddie Hong printing non-planar as crafted by

I briefly pitched my new tool VirtualGcodeController (vgcodectl) which sits between printing program and the device, and able to change G-code on the fly, transparently bi-directional – as I was told Duet has an alike infrastructure called Duet Software Framework (DSF) which I wasn’t aware of.

Also check this brief interview by Mihai Design:


At german-based Multec booth I saw a multi-printhead setup with a rotating seal to prevent the inactive printheads leak filament – and a precise mechanism to lift the inactive printheads (patented):


Dutch-based company providing infrastructure to mix and extrude your own filament, not just for mixing different colors, but also different materials and achieve custom material properties – the only downside is the price-tag of those desktop filament extruders starting at 10K EUR – which is too high for its functionality for prosumers, and seems to aim for R&D departments of larger companies.

Commercial Slicers

As I have been entering slicing development more seriously, and closely paid attention to possible competitors or collaborators – and interestingly, the majority responded positively when I approached them:


A small danish company, who recently patented interlocking (Z-offsetted layers) printing patterns.

I had a brief chat with Folmer Gringer Brem about industrial slicer capabilities and customer needs, and what I have researched the past year.


A new french company is providing non-planar 5-axis slicer with a nice GUI, and were open enough to give an actual demo and I was impressed by the responsiveness of the GUI but were tight-lipped to reveal anything about the internals – 5-axis slicer with infill patterns:

FreeD Printing

A small 2 person german company, a spin-off from the university Bochum, also coding 5-axis non-planar slicer, showing a small desktop 6-axis robot to print an overhang model, their own logo, and it has infill – which means, they actually did properly slice 5-axis G-code. They were reluctant to go into the details, as their IP represent their core asset as a company:


AiBuild has a huge booth, lots of advertising, has been very secretive last year as they didn’t want to demo their software without NDA to anyone – but while attending Formnext 2022 I was able to get to talk to people who purchased the software, and all of them have been giving me strange feedback: a sort of underwhelming sensation – the software is costly and not deliver what is advertised: you need to know a lot of slicing in order to use the software – there is nothing “Ai” (Artificial Intelligence) as the company name implies, at least not with their slicing software.

On their booth they had the usual non-planar printed pieces, but none of them had infill, so they all are printed in vase-mode or single wall.

One feature I saw though impressed me, it was the live quality control they implemented, having a nozzle camera and machine learning / AI to determine over- and under-extrusion – something which I would say one should have under control, but perhaps it was to illustrate the detection mechanism.


Poland-based 5-axis printer manufacturer has progressed in hardware and software, and developed their own 5-axis slicer – the simulation shown as the actual printer prints – overall well designed.

I had a brief chat with Adam Wajda about the state of their hardware/software stack, very open and friendly exchange.


Hungary-based startup with a dual delta setup printing upside and downside at the same time. They were present last year Formnext 2021 already but with an inactive printer, and this time showing the printer in action:

Beside reducing print-time the printer also is able to print pieces which otherwise are hard or impossible print when layer orientation is given and surface quality is of high priority.


The newly merge Ultimaker + MakerBot = UltiMaker had no booth again, hardly any presence – the marketing / sales department seems in hybernation to skip such as event without their own booth, no hardware innovation on display, perhaps there is nothing (new) to show.

I visited the 3dimensional booth and someone showed me how to print “metal” (just steel as it turned out) with BASF metal filament on a Ultimaker S5, and having everything needed in a nice box and then send off to wash & sinter.


Snapmaker announced a new machine called Snapmaker Artisan: single head operation, yet changeable heads: FDM head, CNC head, laser head – very sturdy desktop machine, using linear motors:


Bleeding edge high temperature resisting materials, and to show the applications they built a most precise FDM printer I have seen so far – Chiara Mascolo briefly showed me the machine and samples:


Massive SLA and SLS machines shown:


The Formlabs booth was well visited, and it was hard to take photos until the last day of the expo – so just a brief video of the Form 3+ printing below:


German-based startup printing with 7 different light curable materials at the same time, drop size / resolution at 60um with the NovoJet C-7 – quite impressive, with the ability to blend drops or let them cure side-by-side giving new possibilities of material gradients in 3D space:

They also provide a station for fluid testing & development, so you can engineer your own material to print with. Even though this was a small both it was for me from a technical point of view most innovative I have seen so far.


As I was looking at resin printheads, I was approaching Global Inkjet Systems (GIS) – a subdivision of Nanodimension:

  • Fabrica 2.0: impressive 2um resolution, but as consequence 1mm height / hr print speed, SLA/DLP
  • Admaflex 300: 35-88um XY resolution, 10-200um layer height, up to 60mm/hr height print speed, resin combined with ceramic/metal printing


A massive industrial resin jetting 3D printer, build-volume at 500 x 250 x 200 mm printing with wax as support material. It is a closed-loop system, it prints, cures and measures the actual layers and adjusts live for the next layer – achieving 100um precision, yet only for industrial application due the cost of 1M USD per machine.

They developed their own packing algorithm in order to achieve high density packing ratio.


Italian-based “Betron Genesi” 4000 x 1900 x 1300mm build volume along with high volume extrusion (~20mm nozzle, layer height ~4-5mm based on my own photos) having excellent extrusion precision, along their real time temperature control:

Additionally is is a hybrid able to run also CNC milling on the same machine for post-processing.

Phaetus & DropEffect

Visited Phaetus expecting to just meet sales people instead I ran into Maximilian Arnold, owner of DropEffect which designs hotends under his own brand but also for chinese-based Phaetus as R&D director. I showed him photos of my early prototype of a Multi-In Mixing Hotend supposed to be printed in Aluminium and he immediately commented on my design and gave me useful input – unexpected interesting and fruitful exchange.

A brief interview with Max conducted by MihaiDesigns:

XAct Metal

This booth impressed by the samples they showed:


France-based company combining FDM and CNC together:

What you achieve with this is incredible precise plastic pieces at 20um precision, while maintaining 500 x 500 x 500mm respectively 1000 x 500 x 500mm build-volume. They are milling with a round drill bit – CNC toolpath is calculated by Autodesk’s Fusion 360 though.


Turkish-based company wire arc welding with 6-axis robot:

Bloom Robotics

Massive ABB 6-axis robot FDM printing on a rotating 2-axis bed . . . with shiny cyan/pink/violet lights, a bit of an overkill with the lights, but the setup was impressive:



It has been overwhelming expo for me, 4 days in noisy halls, constant audible and visual stimuli grown tiresome for me as I was eager to absorb all; I can say I looked at every single booth, and decided within few seconds if something caught my attention, and I knew to lookout for things I did not know or a company I did not recognize – for new companies in the arena of Additive Manufacturing. It took me a single day to roam both floors of a single hall, so at least it takes 2 days to explore two halls of the expo – and if you happen to explore a booth for more than a few mins, you end up with 3-4 days attending easily.

So, the overall impression of mine has been:

  • 3D printing / Additive Manufacturing (AM) specializes into niches more and more
  • resins printed as drops at high resolution & precision
  • paste-like materials get printed in high extrusion quality
  • metal printing showing incredible wide-variety in regards of materials
  • industrial machines are still pricey but seem to me become more affordable, instead of 10M’s they are becoming 100K – 1M while maintaining same functionality
  • multi-axis FDM with robots become more established to print large scale parts
  • in-process/live quality control and logging/documentation for FDM and powder-based processes
  • many startups still coming up with new or refined existing processes
  • gap between prosumer and affordable industrial machines is closing
  • quite open atmosphere, people are willing to share and discuss their technology, collaboration seems more important than eyeing on each as competitors

Some impressions of Frankfurt (Germany) . . .

That’s it.

3D Design: Parametric Mixing FDM Hotend with Metal Printing

Status: early prototype, metal printed model, temperature testing, no extruding yet


  • 2023/01/09: iteration 2 testing results
  • 2022/11/22: early heating tests, no extruding yet
  • 2022/11/21: iteration 1: SLM AlSi10Mg metal printed photos added
  • 2022/11/19: published finally
  • 2022/09/10: adding photos of PLA+ prototype
  • 2022/09/02: starting writeup

This blog-post will be updated as I progress.


I experimented with the Diamond Hotend in the past, but I was limited with the setup given – and adding another color or otherwise change the design seemed impossible, but it has changed now.

Metal 3D printing has been a niche and high priced application the past years, but in 2022 many 3D printing services support:

  • stainless steel: low heat conductivity 15W/mK
  • aluminium: good heat conductivity 210W/mK, yet low melting point 660C°
  • inconel: low heat conductivity 15W/mK
  • titanium: low heat conductivity 17W/mK

at relatively low price and all of the sudden designing a FDM mixing hotend, where multiple filaments are mixed together before exiting the nozzle – like with the Diamond Hotend – can be printed in metal, like with aluminium – so, I started to design a Parametric Mixing Hotend.


  • parametric design with 2 up to 6 filaments inputs
  • combine heatblock, heatbreak and heatsink, make it compact
  • permit ordinary nozzles (MK8/E3D V6), using M7 thread
  • orient heat cartridge vertically (like a E3D Volcano) to support up to 0.8mm nozzles
  • single 30mm fan for heatsink
  • using PC4 M10 or M4 pneumatic couplers as intakes


  • mixing colors: 2 to 6 colors, CMY(KW), actual true color printing
  • fast switching of materials, given they have similar extrusion temperature


  • filaments must be present in order to withstand backpressure even if not printed
  • filaments must be printed eventually, otherwise ‘bake’ in the hotend


  • controlling actual mixing in the chamber, e.g. creating turbulence to mix properly
    • creating turbulences may limit retraction, which is anyway not easy with mixing hotends


The filament channels:

Mounting options, plain mounting holes 3x 20mm, or plate with 3x 40mm holes:

and adding my Parametric Part Cooler:


Early prototype printed in cold white eSun PLA+ 0.25mm layer height (~1h 20m print time):

Adding nozzle, heat cartridge, heat thermistor, heatsink fan and pneumatic couplers PC4 M6:

and just testing my Parametric Part Cooler using 50×15 blower fan:

which very likely leads to have a some sort of thermal insulator aka silicon sock for lower part of the heat chamber and nozzle.

Metal Printing

The first attempt to order with WeNext using SLM failed, they were not able to find a way to print it without support, which was surprising as powder-based metal printing1) – the removal of support was not guaranteed, so I canceled the order.

  1. SLM powder-based printing requires support structure to counter act geometric distortion when sintering, when the piece shrinks.

The 2nd attempt with PCBWay – disclosure: they approached me a couple of weeks later to sponsor metal printing process, which I agreed on – also using SLM AlSi10Mg at first looked good at first, but then they also needed to add supports once the production step came close, and then I followed up and approved the production. The order was submitted November 5, and 14 days later the piece was at my door.

  • the print quality is excellent, the supports have been removed pretty much with little remains (between the cooling plates a few spikes remained but they have no functional influence)
  • a bit rough surface overall, more than I expected; which means, the inner holes are also rough and likely add friction to the motion of the filament

Preassembled with MK8 0.4mm nozzle, 30mm fan, heat cartridge and thermistor:

and 2x PC4-M6 threaded, with PTFE tubes:


My test rig:

  • Mellow Fly Super8 V1.2 running RepRapFirmware with two stepper motors attached driving two extruders in Bowden style
Test rig: Mellow Fly Super8 running RepRapFirmware 3.4.1, two steppers/extruders with custom mixing hotend printed in SLM AlSi10Mg (Aluminium)

Pass 1: First results

I heated to 50C°, 80C° and 100C°:

  • thermistor does poor job to measure actual temperature at the heatblock ~20C° off
  • heat conductivity to nozzle is very poor, barely heat up at all (when thermister reports 100C°) – very surprising
  • heat piles up from the heart cartridge cables
  • the fan cools barely, could be better

Pass 2: Adding thermal paste

  • adding thermal paste for the thermistor and nozzle thread
  • running M303 for 100C° and keeping it at 100C° for 10mins
  • lowest heatsink fin reaches 50C° – also connects to heatsink fan
  • nozzle looks cold (but when touching it it is hot), filament will definitely melt above
  • heat block has consistent heat distribution

Pass 3: Setting 150C°

  • heatblock is at ~120C° while thermistor reports 150C°
  • the filament pipe above the heatblock is at 100C°
  • the nozzle looks cold, but is hot at 105C° when touching with 2nd thermistor, an issue with reflective brass not properly showing proper thermal reading

Pass 4: Lowering Fan

As the lowest fin heats up significantly, as a first remedy I lowered the heatsink fan a bit:

  • lowest fin is cooler, also overall better air flow; the fins seems a bit too thick, thinner would be better
  • lower end of heat block has near set temperature, delta of just ~5C°

Conclusion Pass 1-4

  • make heatbreak section of pipes thinner
  • optionally have PTFE tubes until lower end of heatsink for smooth motion of filament
  • make fins thinner
  • lower heatsink fan by one fin

Iteration 2

After the tests, I changed the design slightly:

  • thinner pipes to lessen heat transfer to the heatsink
  • a few wings on the fins to increase heat dissepation
  • thinner fins so the air flows better

Submitted to PCBWay 2022/11/29 for manufacturing review, a day later I was informed of thin walls of the pipes near the heatbreak (<1mm) and I gave OK to manufacture.

Iteration 2 of Parametric Mixing Hotend

The thin heatbreak walls seemed to help:

  • ability to heat up to 210°C nominal, some parts reach 220°C, but nozzle is around 210°C
  • 30mm fan performs well
  • 40mm fan removes too much heat, no possible to reach 210°C anymore
  • heatbreak pipes are still too thick, too much heat flows away (hence 30mm vs 40mm fan)
  • first extrusion worked, but after 1-2min both channels are blocked, near lowest fin of the heatbreak, to clear the blockage, I removed the fan and heated to 180°C and allow entire hotend to reach ~90°C, then with 0.4mm needle and 1.8mm copper wire was able to clear the blocked section


Heatbreak is most critical, and has to be short and has to be a hard cut temperature gradient-wise – and 0.5mm wall thickness is still too much. So, regardless of cooling fan on the heatsink, if the heatbreak is too thick, too much heat creeps up or away – it’s not a matter of cooling capacity, but conductivity.


  • metal printed version (aluminium), done 2022/11/21
  • heating tests (on-going)
  • test prints with multiple filaments
    • 2 inputs, e.g. complementary colors (Black/White: Grey Shades, Yellow/Violet: Red Shades)
    • 3 inputs, e.g. CYM: saturated colors only
    • 5 inputs, e.g. CYMKW: full spectrum colors
  • silicon socks for all variants, as part cooler will introduce otherwise heating instabilities


Misc: XCR3D 3in1-S1 aka Bigtree ZSYong 3in1 (Switching/Non-Mixing) Hotend


  • 2022/09/10: designing part cooler for its
  • 2022/08/29: starting


The XCR3D 3in1 S1 aka Bigtree ZSYong 3in1 is a neat 3 in 1 out switching hotend (non-mixing):

XCR3D 3in1-S1 – 3in / 1out (switching, non-mixing)


  • cost effective with EUR 20-24 (2022/09) complete with heat cartridge, thermistor, 3xPTFE tubes, 30mm fan


  • nozzle / heatblock asymmetry: the heatblock extends right-side ~2mm
  • clumsy fan fastening between heatsink ribs
  • slightly overengineered otherwise, too much mass for the basic functionality

XCR3D 3in1-S1

BigTreeTech ZSYong 3in1

NF THC-01 3in1

Very similar, but with symmertric E3D V6 heatsink:

Clones of Clones

It seems to me, the this 3-in-1 hotend with hexagon heatsink, was cloned from NF THC-01 3in1, and likely engineered by a small company, and now brands like BigTreeTech, XCR3D and others purchase in bulk the hotend black/red anodized and their white brand stamp on the hotend.

What makes things truly confusing is that the hotends from China have terrible naming, e.g. “3in1” and “2in1” are used for switching and mixing hotends, which are quite different functionalities, and otherwise the name does not distinct designs.

Part Cooler

I adapted the Parametric Part Cooler using 50×10 blower fan for the XCR3D 3in1 S1 as well:

Download Part Cooler

As you can see on the illustration and photos, put the part cooler on the heatsink, and then 30mm heatsink fan on top. The part cooler itself requires 50x15mm blower fan.

It is a bit fiddly as there are no clear threads for the screws on the heatsink, so the first mounting is crucial to thread properly.

Marlin 2.0.x Configuration

In Configuration.h one has to update the thermistor type:

#define TEMP_SENSOR_0 5    // changed from 1 to 5


#define PID_FUNCTIONAL_RANGE 25   // changed from 10 to 25

recompile, upload/update firmware and then run via G-code console the autotune PID procedure:


and after 3-5 mins or so, when the autotune is done, save settings in EEPROM:


and one is done.


I really struggled to get decent quality prints first, as somehow the temperature reports were off by 40C°, and various Google searches gave the same wrong answers, the seller did not give proper detailed information about the thermistor either. Eventually at Amazon one customer gave the relevant information ATC Semitec 104GT-2/104NT-4-R025H42G and defining TEMP_SENSOR_0 5 in Marlin gave sane results.

Retraction settings are in my case 3mm at 70mm/s with apprx. 500mm long Bowden tube on my Ashtar C (CoreXY 400x400x380) and also Ashtar K #3 (300x300x360).

Ashtar K #3 with XCR3D 3in1-S1 hotend with 3 rolls of filament

I really like the switching filament solution close to the hotend, compared to other multi-material solutions where materials are switched far away from the hotend; e.g. switching material is faster, but one has to still purge one material/color by 30-50mm filament – so I tend to use the multi-material/color feature for fast switching colors for single material/color prints.

Following procedure I use when switching material:

  • heat up nozzle
  • purge 30-40mm regardless
  • retract 55mm at 70mm/s
  • switch to new material/color (e.g. “T1“)
  • push 55mm at 70mm/s forward
  • extrude/purge 30-40mm filament
  • start actual print
  • [ … ]
  • end print
  • retract 55mm at 70mm/s
  • switch to “T0
  • push 55mm at 70mm/s forward [note: not purging material/color transition]

so by default “T0” is ready to be printed. In order the print with the other materials, I have two macros with Print3r e3-t1 and e3-t2.

print3r --printer=ashtar-c-1 print cube.stl @e3-t1
print3r --printer=ashtar-c-1 print cube.stl @e3-t2


prepend_gcode="G91\nT0\nG1 E20 F100\nG1 E-55 F3000\nT1\nG1 E55 F3000\nG1 E30 F100\nG90\nG92 E0\n"
end_gcode="G1 Y{$machine_depth-10} F6000\nG92 E0\nG91\nG1 E-2 F2000\nM140 S0\nM104 S0\nG1 E-55 F3000\nT0\nG1 E55 F3000\nM84\nG90\n"

and ~/.config/print3r/macro/e3-t2:

prepend_gcode="G91\nT0\nG1 E20 F100\nG1 E-55 F3000\nT2\nG1 E55 F3000\nG1 E30 F100\nG90\nG92 E0\n"
end_gcode="G1 Y{$machine_depth-10} F6000\nG92 E0\nG91\nG1 E-2 F2000\nM140 S0\nM104 S0\nG1 E-55 F3000\nT0\nG1 E55 F3000\nM84\nG90\n"

The way it is composed: start_gcode + prepend_gcode + slicing G-code + end_gcode.

Sourcing / Purchase


As it happened to me several times, the hotend clogs up and the reason is often the filament is not hot enough, and when pulling back/retracting it forms a long pointy drag, and might break and the next cold filament jams in further down, but not enough to melt – it clogs up eventually.

First solution is to heat hotend at 240C° at least, not more than 250C° because of the PTFE – and try to push with filament on top, eventually some of the clogging might melt and free the nozzle.

Second solution is removing the lower part with heatbreak, heatblock, by opening the worm screws at the heatsink, and review the PTFE intake:


Misc: More Materials – Testing JLCPCB 3D Printing Services 2022


  • 2022/10/26: published finally
  • 2022/09/27: adding measurements and verdict
  • 2022/09/15: starting write up


Beside Fused Deposition Material (FDM) /  Fused Filament Fabrication (FFF) aka extruding hot filament, there are more methods to 3D print:

  • SLA (stereolithography): resin based printing
  • SLS (selective laser sintering): laser sintering, like polyamid powder
  • MJF (material jetting): deposite material and binder in one go
  • SLM (selective laser melting): metal laser sintering, aka metal printing

and I choose JLCPCB which provides all four of them, whereas SLM only stainless steel is available as of 2022 – other 3D printing services provide wide-range of metals as well.


I ordered Pulley 20T 6ID (GT2 20 teeth 6mm inner diameter) as created via OpenSCAD Customizer, a piece which requires high accuracy and is mechanical stressed when in use, in following materials:

  • 8x PA12 aka Nylon aka Polyamid, black reflective (MJF), 1.04 EUR / pc
  • 8x 9000R resin, natural white (SLA), 1.04 EUR / pc
  • 8x 3201PA-F aka Nylon, dark gray matte (SLS), 1.04 EUR / pc
  • 1x 316L stainless steel (SLM), 8.30 EUR / pc

after 3 weeks the pieces arrived:

The overall quality of all pieces are excellent, regardless of automatic warnings I received while requesting the 3D printing task.

MJF: PA12 / Polyamid / Nylon

MJF has a nice finish, slightly reflective, deep dark, slightly grainy surface, and the top of the pulley is uneven, otherwise very precise.

  • diameter 16.1mm (+0.62%)
  • height 15.5mm (+0%)
  • cost EUR 1.04

SLS: 3201PA-F / Polyamid / Nylon

3201PA with SLS is a very good piece, dark gray matte, grainy surface, very precise.

  • diameter 16.05mm (+0.31%)
  • height 15.6mm (+0.65%)
  • cost EUR 1.04

SLA: 9000R Resin

9000R resin with SLA produced a very nice piece, best finish at the top (near perfection), milky white color (vs cold white or warm white), but as it turns out not very precise:

  • diameter 17.75mm (+4.68%)
  • height 16.1mm (+3.87%)
  • cost EUR 1.04

It is very surprising to see the SLA having the biggest imprecision of all the samples.

SLM: 310L Stainless Steel

316L stainless steel with SLM produced a nice piece as well, the top of the pulley is good, some unevenness where the top goes over the gear:

overall it’s grainy surface – indicating powder-based additive procedure. Holding the piece in the hand feels heavy compared the other materials.

  • diameter 16.0mm (+0%)
  • height 15.5mm (+0%)
  • cost EUR 8.30


The SLA / resin piece looked most smooth but it had the biggest imprecisions with over 3% in height and diameter – very surprising to me, it should comparatively be as precise as SLS and MJF. I cannot determine if it’s from the JLCPCB resin printer, or inherent of SLA.

SLS and MJF with Nylon performed expectedly very good, very sturdy and precise.

SLM stainless steel surprisingly very precise, yet unsuitable in real life application due the heavy weight.

Long Term Usage

I will update this part as soon long term (1-2 years) usage experience is available:

  • SLA: Resin 9000R: (not yet)
  • MJF: Polyamid/Nylon PA12: (not yet)
  • SLS: Polyamid 3201PA-F: (not yet)
  • SLM: Stainsteel 310L: (not yet)

Materials & 3D Printing Methods

Material vs Printing Methods

Comparing MJF Nylon vs SLS Nylon

PA12 vs 3201PA-F

Comparing Resins



Misc: MKS Monster8 Board Configuration with Marlin for Ashtar K & C


  • 2022/11/20: Linux DFU upload details added
  • 2022/09/19: adding Ashtar C M503 dump beside Ashtar K
  • 2022/08/24: extending with part cooler fan and extruder fan connection
  • 2022/08/14: starting with the notes


MKS Monster8 V1.0 board

These are just my notes for configuring Makerbase (MKS) Monster8 V1.0 for Ashtar K and Ashtar C:

  • STM32M407VET6 (ARM Cortex M4), 168MHz, 512KB Flash, 192KB RAM
  • 8 stepper drivers TMC2209, configured in UART mode
  • MKS MINI 12864 V3 display (the “V3” is relevant)
  • 12V power in/out
  • 3 hotends & bed heating
  • Price ~EUR 55 (2022/08) incl. 8 stepper drivers TMC 2209 and 12864 display


  • cost effective, EUR 55 (2022/08) incl. 8x TMC 2209 stepper drivers and 12864 display
  • 8 stepper drivers: e.g. X, Y, Z1/Z2 (on-board splitter) and 5 extruders (e.g. E0, E1, E2, E3, E4 – but only 3 hotends possible)
  • TMC 2208 or TMC 2209 silent drivers
  • good connectors on board, clean setup
  • github with Marlin source (partially preconfigured) for Arduino*) & PlatformIO


  • no RepRapFirmware
  • no Wifi (the V2.0 version has optional Wifi board to attach)
  • no Ethernet
  • requires Marlin with PlatformIO (tedious to configure, recompiling required, reupload)
  • limited documentation: actual details are scattered around

Stepper Motor UART Mode

As first putting in the jumpers on all the driver sockets, in my case I choose UART mode for each one of the 8 drivers:

Marlin with Arduino vs PlatformIO

As of 2022/08, it seems Arduino is no longer able to compile Marlin-2.x (various compile errors within Arduino), at least with this board and everybody moved on the PlatformIO, which really surprised me.

PlatformIO CLI

As of 2022/08 there is no Linux GUI for PlatformIO but only PlatformIO CLI, but it’s simple enough:

pip3 install platformio


As next download the firmware, Marlin 2.0.x source from github:

git clone


By default the board is configured for Voron 2.4 CoreXY, with 3x Z motors and Z probing in the midst of the bed and other things, so I had to edit Marlin/Configuration.h:

  • #define MACHINE_UUID "..." (use online generator to generate one)
  • #define CUSTOM_MACHINE_NAME "Ashtar K #x L8", given Lead 8×8 are used
  • #define LINEAR_AXES 3
  • #define EXTRUDERS 1 (or 2, 3 max)
  • comment out //#define PREVENT_COLD_EXTRUSION needed for calibration
  • comment out //define COREXY
  • define [XYZ]_DRIVER_TYPE and E[012]_DRIVER_TYPE
  • #define DEFAULT_AXIS_STEPS_PER_UNIT aren’t that important, as one can define it with M92 and M500 saving to EEPROM
  • comment out //#define Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN
  • test motors regarding #define INVERT_[XYZ]_DIR true or false
  • test motors regarding #define INVERT_E[012]_DIR true or false
  • #define [XYZ]_HOME_DIR -1
  • #define X_BED_SIZE 380
  • #define Y_BED_SIZE 300
  • #define Z_MAX_POS 330

and Configuration_adv.h:

  • #define NUM_Z_STEPPER_DRIVERS 1 even when two Z-stepper motors are attached
  • if you want an automatic E0 fan which turns on only when nozzle is heated: #define E0_AUTO_FAN_PIN PA1 and attach extruder fan (watch polarity) on FAN1/J12 connector

once those changes are made, build the firmware:

cd marlin\ firmware/MKS_MONSTER_Marlin-2.0.x/Marlin-2.0.x/
platformio run

After a short while (~1min) it should finish successfully (if not, edit files).

Firmware Installation

SD Card Firmware Update

Use a SD card, e.g. 8GB with simple FAT filesytem, and copy .pio/build/mks_monster8_usb_flash_drive/firmware.bin and mks_monster8.bin on the SDcard.

Insert the SD card into the Monster8 board next to the USB connector, and turn off and on the board (power cycle) – wait 5-10 seconds so the new firmware is installed, then the display should show the Marlin splashscreen eventually, and the board becomes available as USB device, in my case as /dev/ttyACM0 on Linux Ubuntu 20.04 LTS.

DFU Util Firmware Update

  • connect board with USB cable and optionally select POWER USB (via jumper)
  • power cycle board (e.g. via USB cable) while you push BOOT 0 button in the center of the board briefly (~2 secs)
  • the device will appear as a new USB device

Linux: install apt install dfu-util and then

% sudo dfu-util -a 0 -s 0x0800C000:leave -D .pio/build/mks_monster8_usb_flash_drive/mks_monster8.bin -d 0483:df11
dfu-util 0.9

Copyright 2005-2009 Weston Schmidt, Harald Welte and OpenMoko Inc.
Copyright 2010-2016 Tormod Volden and Stefan Schmidt
This program is Free Software and has ABSOLUTELY NO WARRANTY
Please report bugs to

dfu-util: Invalid DFU suffix signature
dfu-util: A valid DFU suffix will be required in a future dfu-util release!!!
Opening DFU capable USB device...
ID 0483:df11
Run-time device DFU version 011a
Claiming USB DFU Interface...
Setting Alternate Setting #0 ...
Determining device status: state = dfuERROR, status = 10
dfuERROR, clearing status
Determining device status: state = dfuIDLE, status = 0
dfuIDLE, continuing
DFU mode device DFU version 011a
Device returned transfer size 2048
DfuSe interface name: "Internal Flash  "
Downloading to address = 0x0800c000, size = 178820
Download        [=========================] 100%       178820 bytes
Download done.
File downloaded successfully
Transitioning to dfuMANIFEST state

M503 Dump for Ashtar K

Ashtar K with 300×300 bed, single extruder:

> M503
echo:  G21    ; Units in mm (mm)
echo:  M149 C ; Units in Celsius

echo:; Filament settings: Disabled
echo:  M200 S0 D1.75
echo:; Steps per unit:
echo: M92 X100.00 Y100.00 Z400.00 E95.00
echo:; Maximum feedrates (units/s):
echo:  M203 X300.00 Y300.00 Z5.00 E25.00
echo:; Maximum Acceleration (units/s2):
echo:  M201 X2500.00 Y2500.00 Z100.00 E5000.00
echo:; Acceleration (units/s2): P<print_accel> R<retract_accel> T<travel_accel>
echo:  M204 P3000.00 R3000.00 T3000.00
echo:; Advanced: B<min_segment_time_us> S<min_feedrate> T<min_travel_feedrate> X<max_x_jerk> Y<max_y_jerk> Z<max_z_jerk> E<max_e_jerk>
echo:  M205 B20000.00 S0.00 T0.00 X10.00 Y10.00 Z0.30 E5.00
echo:; Home offset:
echo:  M206 X-35.00 Y-3.00 Z0.15
echo:; Material heatup parameters:
echo:  M145 S0 H180.00 B70.00 F0
echo:  M145 S1 H240.00 B110.00 F0
echo:; PID settings:
echo:  M301 P22.20 I1.08 D114.00
echo:; LCD Contrast:
echo:  M250 C255  
echo:; Power-Loss Recovery:
echo:  M413 S1
echo:; Stepper driver current:
echo:  M906 X500 Y500 Z700
echo:  M906 T0 E500

echo:; Driver stepping mode:
echo:  M569 S1 X Y Z
echo:  M569 S1 T0 E

M503 Dump for Ashtar C

Ashtar C with 400×400 bed, 3 extruders with single nozzle:

> M503
echo:  G21    ; Units in mm (mm)
echo:  M149 C ; Units in Celsius

echo:; Filament settings: Disabled
echo:  M200 T0 D1.75
echo:  M200 T1 D1.75
echo:  M200 T2 D1.75
echo:  M200 S0
echo:; Steps per unit:
echo: M92 X100.00 Y100.00 Z3200.00 E102.00
echo:; Maximum feedrates (units/s):
echo:  M203 X500.00 Y500.00 Z2.00 E120.00
echo:; Maximum Acceleration (units/s2):
echo:  M201 X9000.00 Y9000.00 Z50.00 E10000.00
echo:; Acceleration (units/s2): P<print_accel> R<retract_accel> T<travel_accel>
echo:  M204 P1500.00 R1500.00 T1500.00
echo:; Advanced: B<min_segment_time_us> S<min_feedrate> T<min_travel_feedrate> X<max_x_jerk> Y<max_y_jerk> Z<max_z_jerk> E<max_e_jerk>
echo:  M205 B20000.00 S0.00 T0.00 X10.00 Y10.00 Z0.20 E2.50
echo:; Home offset:
echo:  M206 X0.00 Y-5.00 Z0.15
echo:; Material heatup parameters:
echo:  M145 S0 H180.00 B70.00 F0
echo:  M145 S1 H240.00 B110.00 F0
echo:; PID settings:
echo:  M301 P22.20 I1.08 D114.00
echo:; LCD Contrast:
echo:  M250 C255
echo:; Power-Loss Recovery:
echo:  M413 S1
echo:; Stepper driver current:
echo:  M906 X700 Y700 Z1000
echo:  M906 T0 E700
echo:  M906 T1 E700
echo:  M906 T2 E700

echo:; Driver stepping mode:
echo:  M569 S1 X Y Z
echo:  M569 S1 T0 E
echo:  M569 S1 T1 E
echo:  M569 S1 T2 E
echo:; Tool-changing:
echo: Z2.00


Part cooler fan is plugged into FAN0/J11, and if you enabled extruder fan (temperature dependent), plug it in FAN1/J12.

Part Cooler Fan (FAN0/J11) and Extruder Fan (temperature sensitive) FAN1/J12
  • Part Cooler Fan (FAN0): cools the extruded filament, the filament which becomes the part you print
  • Extruder Fan (FAN1): cools the heatsink near the heatbreak, when attached to FAN1/J12 it only runs when the hotend is hotter than 50C° as defined in Marlin.

The jumpers are needed next to the fan connectors to define the voltage, either Vin (left) which is 12V-24V depending on the power input of the board, or 12V (middle) or 5V (right).

MKS Monster8 V1.0 Pins
MKS Monster8 V2.0 Pins

Multiple Materials/Colors

With 8 stepper drivers one is able to run:

  • 3+1x motors for X, Y, Z(2)
  • 5x extruders (colors or materials), the board supports 3 hotends (3 different temperatures)

Monster8 V1.0 vs V2.0

The boards differ in physical layout such as connectors, but the firmware is the same, incl. the pin for the hotend cooler fan (which switches on conditionally when hotend heats up).

Update V2.0

Board Comparison 2022

As of 2022 (I intend to update this) following boards are suitable for my cases:

MKS Monster8 V1.0/V2.0 & 12864 displayMellow Fly Super8 V1.2 & 12864 displayDuet 3 Mini 5+ & Duet 3 Mini 2+Duet 3 MB 6HC & Duet 3 Expansion 3HC
Price55 EUR80 EUR155 EUR (120+35)385 EUR (255+130)
Stepper Drivers887 (5+2)9 (6+3)
Stepper Connectors9 (dual Z)879
Hotends345 (2+3)6 (3+3)
FirmwareMarlin 2.xMarlin 2.x
RepRapFirmware 3.4.x

Alternatively, there are Duet 2 & 3 clones available on the market:

Duet 2 WIFI CloneDuet 2 WIFI OriginalDuet 3 6HC FYSETC Clone with Duet 3 3HCDuet 3 6HC Original with Duet 3 3HC
Price30-50 EUR2)175-185 EUR1) 225 EUR (150+75)385 EUR (255+130)
Stepper Drivers559 (6+3)9 (6+3)
Stepper Connectors6699
Hotends227 (4+3)6 (3+3)

  1. either WIFI or Ethernet
  2. without or with display
  3. MKS Monster8 V2.0 has Wifi module option

As of 2022, RepRapFirmware has become quasi standard in professional level 3D printing; while a lot of people run Klipper & Marlin together I can’t see the point doing this*) but rather have a more capable microcontroller like the Duet boards have to run the printer and manage WIFI / Ethernet at the same time. The only reason to run Klipper on a Single Board Computer (SBC) setup like Raspberry Pi is cost and enhance simple microcontrollers functionality this way.

MarlinKlipper & MarlinRepRapFirmware with Duet
CPUs1x Simple Microntroller1x SBC + 1x Simple Microcontroller1x Capable Microcontroller
ConnectivityUSB onlyUSB, Ethernet and/or WIFIUSB and Ethernet or WIFI
Configuration3x .h files, recompiling requiredsingle .cfg filesingle .g file**)
Boot Time3sKlipper 30s, Marlin 3s3s

*) running different kinematics on the SBC converting G-code on the fly might be a reason
**) multiple .g file can be used optionally

If you are cheap, buy the Duet clones, if you want to support Open Source and Open Hardware community, buy from direct, pricing is +45% of the clone prices, whereas the Duet resellers add another +15% (Clone: EUR 150, 220 EUR, Reseller 255 EUR)

RepRapFirmware: Mind the SD Card

Whether to run an original Duet board or a clone, one thing though one might pay attention to is the SD card, it is the weakest link as far I can tell:

  • SD card needs to be present at all time to provide configuration
  • SD card is not written regularly to unless the logging is enabled

After power-cycling the board, as it was in a strange state no longer responding to G-code properly, the display remained blank, no response to G0/G1 – after investigation it turned out, a single file vanished from the SD card: config.g – the main configuration file, and that is bizarre. The board appeared to be broken, when in truth, the SD card came to its end of life of operating reliably already after only ~1.5 years. The SD card was the one originally shipped with. In this light, a Marlin-based board requiring no SD card being present operates more reliable, unless one uses an industrial grade SD card.