I’m looking at a new concrete 3D printer that seems to be able to accomplish builds I’ve never seen with other concrete 3D printers.
Concrete 3D printing is a new niche that is heating up as builders gradually realize the potential of the technology. While there have been a number of highly questionable ventures in this area, there are several legitimate operations in the field.
Twente Additive Manufacturing Concrete 3D Printer
One very interesting venture is Netherlands-based Twente Additive Manufacturing, or “TAM”. The company seems to have launched only a year or so ago, so they may be considered a startup venture.
Their claim to fame is a 9-axis concrete 3D printer.
Like smaller thermoplastic 3D printers, there are multiple deposition approaches used in concrete 3D printers. Most seem to use either a scaled up 3-axis Cartesian system or some form of polar-oriented swing arm. TAM does something different.
They employ a 6-axis robotic arm, equipped with a concrete extrusion toolhead. How do they get nine axes? I think it is done by mobilizing the robotic arm, thus adding potentially three more axes to total nine.
You can see their machine in operation in this video:
Concrete 3D Printing Overhangs
If you watched the video, I’m sure you must have noticed their system’s unusual ability to 3D print overhangs. This is a capability I have not seen in concrete 3D printers previously. While the amount of overhang possible seems to be slight, it is sufficient to allow them to 3D print large arches and similar structures.
Overhangs in concrete are a devilish problem because unlike thermoplastics, concrete does not instantly solidify when extruded. It can take hours or days for the material to “set”, whereas PLA freezes almost instantly, allowing overhangs to be attempted.
While this is an amazing capability, I am very curious about the concrete mix used by TAM to permit overhangs. Concrete is notorious for its variability in strength, mostly due to the mix composition and setting procedure. In fact, concrete is typically measured regularly on construction sites to ensure it is suitable for building. You’ll see technicians measuring the “slump” of a concrete glob to understand the likely strength of the finished material.
If TAM has made adjustments to the concrete mix to allow for overhangs, would those adjustments affect the ultimate strength of the finished prints? Could it be affected positively or negatively? They don’t seem to say.
This is perhaps an important aspect for the company, since most concrete builds are for human use, where the build must meet stringent engineering standards. That’s why engineers must certify plans and execution on construction sites.
TAM Concrete 3D Printer Resolution
Another interesting aspect of TAM’s concrete 3D printer is the toolhead.
By using a robotic arm they are in a way limiting the size of the toolhead as compared to some other concrete 3D printer implementations. In other words, their extrusion bead seems smaller than some competing systems.
This is not a bad thing; it just means that the TAM system is likely capable of more detailed 3D prints than their competition. On the other hand, prints could take longer with less extrusion volume per second. If a large concrete structure were attempted, perhaps a different concrete 3D printing system might be optimal, at least as far as speed is concerned.
You can see an example of the detail possible with TAM’s extrusion system here, where they have built a wall section with an interesting and complex pattern. This would not be possible with a larger extrusion tool.
Here they have produced a 3m tall cone, which they say is their “tallest continuous wet-print in one session”. Again this is impressive because concrete tends to slump. How they achieved this is beyond me.
It looks like the concrete 3D printing niche is heating up.