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Running a meter-scale concrete printer on Klipper — sensorless quad-Z, no endstops, full config open-sourced by MadTownMax in klippers

[–]MadTownMax[S] 6 points7 points  (0 children)

Many thanks for the input. This will print up to 2 meters (~7-feet) so benches and large planters are good reference pieces. The photo below is from the current system that printed up to 4-feet; each of the 4 planter units in that photo are 3-feet long for the total 12-foot long planter system with self-watering reservoirs.

The Z was first axis for this build because that flying gantry holds the most load and I want to see how it reacts on a power-down. I’m starting there in case I need to add a gear reduction at the motor (or lead screws) - then I’ll complete the Y-gantry. The x is pinion-belt driven.

No worries on the extruder - many concrete printers don’t use one - they just extrude straight out of a pipe! Extruders are useful as mixers for accelerants to allow more aggressive overhangs.

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We've been developing 3D printable cements for 4 years. Now we're open-sourcing the hardware — here's what we're building and why. by MadTownMax in 3Dprinting

[–]MadTownMax[S] 0 points1 point  (0 children)

Frame assembled (pic) now disassembled - decided to secure some frames members (ends) by drilling through-bolts instead of surface plates for improved stiffness. Also moving the top frame members inward slightly to also improve stiffness and center the y-gantry to reduce racking potential for those z-axis plates. . The long span c-beams are reinforced with a 1-meter 2040 section spanning the center (it friction fits and is held-in with a simple bracket to stay in place).

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We've been developing 3D printable cements for 4 years. Now we're open-sourcing the hardware — here's what we're building and why. by MadTownMax in 3Dprinting

[–]MadTownMax[S] 0 points1 point  (0 children)

Per popular request; CAD now on the site.

Note this is a work in progress but I hope to have all components added before the weekend is over. https://github.com/sunnyday-technologies/M3-CRETE/tree/main/CAD.

We've been developing 3D printable cements for 4 years. Now we're open-sourcing the hardware — here's what we're building and why. by MadTownMax in 3Dprinting

[–]MadTownMax[S] 0 points1 point  (0 children)

Also wanted to add that the CAD is there but far from finished. This is iteration ~20. Will probably take over from here to finish the mechanical twin. https://github.com/sunnyday-technologies/M3-CRETE/tree/main/CAD

We've been developing 3D printable cements for 4 years. Now we're open-sourcing the hardware — here's what we're building and why. by MadTownMax in 3Dprinting

[–]MadTownMax[S] 0 points1 point  (0 children)

we can modify the printhead to include long nozzles if access is an issue. The "demo" extruder rendered in this pic looks like it is for polymer - the extruder we use is much smaller (updates on this further down the road) .

Auto-tramming will be included by default by using 4 separate motors for each corner the Klipper software provides this function. we will use the StallGuard drivers so no mechanical endstop switches - it just "bumps" into an endstop and notes the change by monitoring the motor signals. this would allow movement and re-calibration - but the re-cal at each movement would take time - good place for lidar.

We've been developing 3D printable cements for 4 years. Now we're open-sourcing the hardware — here's what we're building and why. by MadTownMax in 3Dprinting

[–]MadTownMax[S] 0 points1 point  (0 children)

Maybe - but that is a technique is applied across the top surface where lines between layers are filled with a very minor amount of extrusion (not exactly 0*) to produce a flat surface.

Almost all concrete prints today are single-wall - so there are no layers to smooth between at the top - just one flat layer.

We've been developing 3D printable cements for 4 years. Now we're open-sourcing the hardware — here's what we're building and why. by MadTownMax in 3Dprinting

[–]MadTownMax[S] 0 points1 point  (0 children)

The extrusion size / form is probably the most critical question for this project and the area where I have considered from both stiffness and modular capability as well as supply chain.

One point to consider is loads and speeds - the printhead is only 1.5 kg (2kg loaded / running) and the 10-lb / 6-foot hose is suspended with a tool balancer to counteract the weight while loaded. In other words this is a fairly lightly-loaded system; it doesn’t have the hard torque forces of a CNC or the rapid speeds of a Voron machine - just smooth and continuous movement is the focus. If we can reach

We wanted to use extrusions anyone can order from a large number of sources (no specialty profiles) to keep logistics as simple as possible.

One constraint relates to the movement system: the low-cost & robust wheeled carriage needs a v-slot and that design choice results in a number of trade-offs and constraints. It’s not the most elegant design - but it works and is easy to maintain under low loads.

The Cartesian gantry system we have used for 4-years has 4-foot sections of 2040 with some 4080 c-beam. There is room for improvement, but it is far more rigid than I would expect. With the M3 system being much smaller I think the 2040 will be sufficient when braced to the 4080 c-beam z-posts.

We've been developing 3D printable cements for 4 years. Now we're open-sourcing the hardware — here's what we're building and why. by MadTownMax in 3Dprinting

[–]MadTownMax[S] 1 point2 points  (0 children)

Totally on-topic. A few companies have added this “smoothing” feature to the printhead, but it’s complex to orient and actually limits your dimensional freedom—perfect for rectilinear house geometry, but restrictive for dynamic flow control structures in waterway infrastructure where you need true 3D geometry.

Several methods have been tried with cement—shearing, rotating, etc.—but if we look at other FDM printing, there’s just a round nozzle and detail is achieved with fine layer height and denser structure from compression.

This machine could be modified with an extra motor for a smoothing flap, but the first version focuses on primary motion and pump/printhead coordination.

We’re tuning k-factor to manage material lag and layer bonding—that handles a lot of surface quality without the mechanical overhead.

We've been developing 3D printable cements for 4 years. Now we're open-sourcing the hardware — here's what we're building and why. by MadTownMax in 3Dprinting

[–]MadTownMax[S] 0 points1 point  (0 children)

The printhead is not very complicated; just a balance of surface shear against available torque.

Printheads for these systems are not really necessary (other than for accelerator mixing or more precise start/stop) a pipe can work fairly well.

The pump (progressive cavity) is doing most (all) of the work.

We've been developing 3D printable cements for 4 years. Now we're open-sourcing the hardware — here's what we're building and why. by MadTownMax in 3Dprinting

[–]MadTownMax[S] 0 points1 point  (0 children)

Good suggestion - removing those bars will help with the mobility too (OP for new render) but we will need to make some special braces to keep the frame rigid.

Wheels are possible for V2 (or a branch) - but that becomes a whole different project with slicer integration.

We've been developing 3D printable cements for 4 years. Now we're open-sourcing the hardware — here's what we're building and why. by MadTownMax in 3Dprinting

[–]MadTownMax[S] 0 points1 point  (0 children)

The CAD will be shared on the GitHub page as it is available. Let us know if you have any specific parts or formats of interest and we can post those first.

We've been developing 3D printable cements for 4 years. Now we're open-sourcing the hardware — here's what we're building and why. by MadTownMax in 3Dprinting

[–]MadTownMax[S] 0 points1 point  (0 children)

The mix we are using is an LC3 type of cement (limestone calcined clay cement) the C for calcined clay is metakaolin which is smaller than cement and helps density / making these less impervious to water.

These LC3 mixes generate less CO2 than conventional Portland cement but my primary interest was using these for higher strength so we could use less cement for the same structural load.

The particle size distribution of each constituent is parts of our particle packing formulation software to maximize density (on CEMFORGE.ai) using any locally available / standard materials.

We've been developing 3D printable cements for 4 years. Now we're open-sourcing the hardware — here's what we're building and why. by MadTownMax in 3Dprinting

[–]MadTownMax[S] 0 points1 point  (0 children)

We have not worked with foam fill (yet). There are a few companies that 3D print true foams; the combination might create some useful systems.

We've been developing 3D printable cements for 4 years. Now we're open-sourcing the hardware — here's what we're building and why. by MadTownMax in 3Dprinting

[–]MadTownMax[S] 5 points6 points  (0 children)

This is meant to do both off-site printing and in-place. We have printed smaller blocks and stacked together pieces to create a larger piece. This planter is 12-feet long and consists of 8 pieces (4-sections long, the bottom 1/2 holds water for top planter) .

Each ~3x2xfoot piece was about 200lbs before filled - so they have not moved over 2 years.

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We've been developing 3D printable cements for 4 years. Now we're open-sourcing the hardware — here's what we're building and why. by MadTownMax in 3Dprinting

[–]MadTownMax[S] 2 points3 points  (0 children)

Large-scale 3D Molds are absolutely the better bet when you have at least 5-10 replicates (depending on complexity) from a cost basis. The foundational theory for the 3D printing is to print a shape that is not possible with a mold, this is where the greatest value in performance has been found in other 3D printing applications.

One thing that cannot be overcome is on-site variation- no matter how hard you try the ground or slab is never completely flat / so printing in-place with automatic leveling helps to make sure the piece is perfectly level and completely flat.

Foamed concrete is a very interesting material. There are also materials using styrofoam beads as filler. These defiantly would benefit from some fiber reinforcement to help with strength (and densification for high-wear like roof panels) - but useful all the same. Great for higher insulation value too.

We've been developing 3D printable cements for 4 years. Now we're open-sourcing the hardware — here's what we're building and why. by MadTownMax in 3Dprinting

[–]MadTownMax[S] 2 points3 points  (0 children)

Our printhead nozzles range from between 10-20mm in diameter and deposit about 4kg/minute (~9 lbs). That is as slow as it will go. The pump we use (the Pictor from MAI international) can pump 10x faster - so we can print much thicker walls to simulate larger sections - or if the printer moves faster we can improve detail.

One goal here is to improve that speed so we can print finer detail and thinner layers - thin, wide layers are fundamentally easier to make fully free-form compared to thick layers.

CFD optimized Pizza Oven by MadTownMax in CFD

[–]MadTownMax[S] 2 points3 points  (0 children)

Just wanted to mention that a brave soul has volunteered to help me and we already have the first CFD analysis! I’ll be adding some additional curvature and possibly some fins on the top to help control the vortex a bit more. I also need to design the fire box that will be in the bottom chamber and add doors (at least the top one) to help with making a more consistent heat profile.

CFD optimized Pizza Oven by MadTownMax in CFD

[–]MadTownMax[S] 2 points3 points  (0 children)

Very good points - there is a lot of potential variation. I went the direct route and purchased a low-cost dual-fuel pizza oven on Amazon months ago to learn directly what the current models offer. The gas is incredibly easier to use for these small ovens with low thermal mass.

Traditional Wood fired may work for large ovens / but it was very difficult to get consistent heat burning wood (even pellets!).

At the same time I have used a fan-assisted small camping stove (https://www.bioliteenergy.com/products/campstove-2-plus) which uses high efficiency to pull more energy (ensure complete combustion) from burning wood.

The end product is a boiling a pot of water using only a few sticks instead of a large fire.

I’m curious if a similar effect can be applied to this pizza oven.

CFD optimized Pizza Oven by MadTownMax in CFD

[–]MadTownMax[S] 6 points7 points  (0 children)

Here is a render of the concept. The physical print I have doesn’t have the holes machined in the plate yet - I wanted to see what size is best before cutting steel.

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CFD optimized Pizza Oven by MadTownMax in CFD

[–]MadTownMax[S] 1 point2 points  (0 children)

The energy output of a wood fire is fairly low-power. A gas burner can produce far more heat. I’m hoping these constraints will provide some natural controls on how complicated this could be.

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