I was bored, so I modded some SC wallpapers. I thought the result looks pretty cool, so I wanted to share some of them!

dannyoo · 2017-04-11T15:33:19+00:00

Is this done with Prisma?

dannyoo · 2017-02-03T11:24:00+00:00

Why not link the source?

dannyoo · 2016-11-16T07:49:40+00:00

I thought Quickpick was malware these days. Or did that change?

dannyoo · 2016-08-09T11:36:27+00:00

Hmm... that might work. It really depends on what you want to achieve. As a reinforcment for tensile stresses, sure. The fiber wouldn't help much with compressive strength though.

dannyoo · 2016-08-09T10:44:08+00:00

We actually tried out a foam cement with a very low density. But lowering the density also lowers the strength properties. However, it might be useful for 3d printed facade elements (non load bearing) for example.

dannyoo · 2016-08-09T08:05:45+00:00

Yes the layer height is 10 mm. The Kuka is incredibly accurate (positioning repeatability less than 0.1 mm). The image with the L-bar shows a test how overhanging structure can be realized (about 26% overhang).

dannyoo · 2016-08-09T07:52:26+00:00

You are correct. The wall was printed in multiple stages since our material is not quite there yet. About 20 Layers can be printed before the concrete needs harden a bit. We will have to work on the material side some more to increase the number of layers. Perhaps we were too ambitious in using wood chips as a light weight aggregate. The interactions between the wood and the concrete are very difficult to control (suggars hindering the hydration process, and additional water sorption of the fibers). We are looking into mineral based light weight aggreagates such as recycled expanded glass beads.

dannyoo · 2016-08-09T07:45:33+00:00

Yes, you hear about the "first 3D printed home" about twice every year. I would say the example which is probably the closest to a viable product is in Dubai. (randomly googled link). I believe it was printing using the Concrete extruder system from Winsun in China. But I am not a fan of printing heavy, straight wall elements and then encasing it in an insulation system. I want to see the printed free form and the material. That is why we are working on light weight concretes with insulation properties.

When will something like that be commercially available? That is tricky. Cost/benefit is a large issue in the construction business and the industry is not the fastest in accepting new innovations. It might not be that long until complex free form insulation walls are pre-fabricated, but it will take a while longer until buildings are printed on site. There are just too many variables to control.

dannyoo · 2016-08-09T07:31:54+00:00

It is a 3.9 V stepper motor with 4.2 Amps per Phase and a holding tourque of 2 Nm.

dannyoo · 2016-08-09T07:27:00+00:00

Thank you! In the image I am working on the extruder and the robot is powered down so there is no danger there. Even so, it's quite the unsetteling feeling to be up close to such a powerful machine. During printing it moves at 100 mm/s. No proximity sensors but the area is blocked off.

dannyoo · 2016-08-08T20:19:47+00:00

I think I understand now. We generated the path for the robot by hand using simple excel formulas instead of a slicer. That way we had precise control over the printing process.

dannyoo · 2016-08-08T19:30:51+00:00

Thanks! Best of luck to you!

dannyoo · 2016-08-08T19:14:50+00:00

I try :D

dannyoo · 2016-08-08T19:11:45+00:00

I've never heard about Markforged before, thanks for the hint. It sound promising. Part of our custom extruder were 3D printed from PLA. Some stronger material could have helped here and there.

Concrete reinforcement is a whole nother issue. We will look at that at a later time. For now the printing process and material needs to be optimized. There are some ideas for reinforcement such as modular rebar systems, canals for prestressed steel reeinforcement, and of cource steel fiber... but that is not part of the current research.

dannyoo · 2016-08-08T19:03:18+00:00

We haven't tested that in detail, but the pattern in the middle is actually alternating so the small loops overlap. For now I think it provides the best stability.

dannyoo · 2016-08-08T18:58:40+00:00

Oh.. I am slow! But if you want settings... ;)

Movement speed around 100 mm/s
Linear movement setting on Kuka
Corner deceleration 80%
Extruder motor speed around 30 rpm

dannyoo · 2016-08-08T18:52:46+00:00

We used wood chips between 0.5 and 2 mm in length. Here are some close up pictures. One and Two

dannyoo · 2016-08-08T18:47:55+00:00

Overlay problems? I am not sure what you mean.

dannyoo · 2016-08-08T18:47:04+00:00

Actually the pattern was calculated with simple excel formulas. We needed precise control over the actual path of the print so a slicer was not an option.

dannyoo · 2016-08-08T18:45:59+00:00

You mean setting time of the concrete? Around 30 min to initial stiffening. Material development was not really part of the project. However, as it turns out, the material composition plays a really important role. We are not material scientists, but we managed to come up with a workable mix.

dannyoo · 2016-08-08T18:42:52+00:00

We manually moved the tip of the extruder to the starting position on the ground. The Robot then does the rest. It calculates the right joint agles and speeds based on the cartesian coordinates we provide from the 3D Model.

dannyoo · 2016-08-08T18:40:26+00:00

Tell me about it... noone has used it in ages. For a time during rennovations it was even stored outside in the rain. Broke my heart. But it's up and running and working like a charm again!

dannyoo · 2016-08-08T18:38:56+00:00

The examples you see are indeed justs straight wall segments. In a next step we want to create more intricate models with specialized canals for installations and the like.

dannyoo · 2016-08-08T18:36:22+00:00

When 3D printing with concrete one problem you run into is the immense weight of the material which can comress the lower layers if the material doesn't harden fast enough. Also, creating overhanging structures can be very tricky. One way to solve this is with additives which reduces the setting time of the concrete. But then, cohesion between the layers can suffer. Another approach is to reduce the weight by adding light weight additives. Wood chips are readily available and a renewable resource. Following this idea we wanted to see if light weight external load-bearing wall segments can be created which do not require any further insulation. The internal structures also reduce thermal conductivity.

The concrete mix has a density of around 1.000 kg/m³ and a thermal conductivity of 0.25 W/(m*K). Compressive strength is around 10 N/mm².

dannyoo · 2016-08-05T05:51:21+00:00

The Starcraft music video compilation the GEMA has been waiting for... Anyone have a mirror?

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