MMTO is a collaborative research funded by UCL’s Bartlett Faculty of the Built Environment Innovation Fund. The project concerns the metal components connecting the different parts of a building’s structure and cladding that are standard-sized, materially homogenous elements.
Using material uniformly in effect is inefficient and increases embodied energy and componentry manufacturing, transportation, and installation costs.
How can Meltio’s metal 3D printing help this problem? Keep reading and be ready to be amazed by the results.
The W-LMD technology produces parts with exceptional microstructure and a density of 99.998%, surpassing the properties of castings and rivaling those of forgings.
The origins of this redundant material use go back to times when design and fabrication techniques were different from today’s practices. Nowadays, CAD methods like topology optimization (TO) offer the possibility of reducing the amount of material in building components to a bare minimum.
The overal aim was to minimise embodied carbon. Optimisations ranged from 90% up to 10% mass reductions.
The next step following the optimisations was to 3D print (Wire Laser Metal Deposition):
- A conventional mild steel beam, and starting conservatively,
- Its 50% reduced mass equivalent in single mild steel,
- Another 50% reduced mass dual material beam with 50% mild steel and 50% tool steel.
From an environmental point of view and depending on a part’s geometry, one issue with 3D printing is the need for added supports, which in this case weighed a total of 2.9 kg. A workaround is to optimise with LMD printing constraints in the digital model.
The following step is to perform vertical load testing on all three beams at the structural testing facilities of TH Lübeck. This will verify whether the MMTO beam can perform the same as or better than the single TO and conventional beams. On the path to net zero, this approach could incur urgently needed building component embodied carbon reductions, hopefully paving the way for widespread applications of MMTO in building construction.
70% and 50% mass reduction category examples. Within each category, there can be at least ten combinations of the two metals. Indicatively, these can range from 100% tool steel to 50% mild and 50% tool steel to 100% mild steel. The highlighted beam in red is the one that was selected for fabrication.
Displacement analysis of the TO beam that was selected for fabrication (top) and the solid PE beam. The analysis was performed with a single isotropic material (SS316) for both beams and it therefore only shows how form affects displacement.
Buckling analysis of the TO beam that was selected for fabrication left and the solid IPE beam. The analysis was performed with a single isotropic material (SS316) for both beams and it therefore shows how form affects buckling.
Toolpath studies for a 40% mass reduced beam (A) and a 50% one (B). The colours represent the different toolpath orientations along different angled planes for achieving the print vertically. Having various toolpaths creates multiple joining boundaries that require close printing control to ensure a proper attachment.
These toolpaths are also non symmetrically arranged, which affects the isotropy of the part. (c) shows the 50% mass reduced beam with fool steel (grey), mild steel (black) and supports (red). When supports are added (O) the same, horizontal toolpath orientation can be used across the 3D print. (E) shows the final multi-metal 3D printed beam without supports.
Close-up view of the 3D printed IPE and single material TO beams, showing the horizontal printing layers. The print parameters for the single material TO beam were:
Robot Speed: 6.5 mm/s
Laser Power: 830 III
Feeder Speed: 8.28 mm/S
Argon Flow: 10 L/m
The amount of mild steel used was 4.5835 kg for the beam and 2.0485 kg for the supports. The print parameters for the IPE beam were:
Robot Speed: 7.5 mm/s
Laser Power: 1100 lI
Feeder Speed: 7.57 mm/s
Argon Flow: 10 L/m
The total amount of material (Mild Steel ER7OS) used came to 7.762 kg.
The single metal TO (front), multi-metal TO (back), and PE beams are going to be vertical load tested to compare their structural behaviour.
The solid IPE beam (left), bi-metal tool and mild steel beam (middle), and single metal (mild steel) beam (right). The beams are shown prior to sandblasting, with added supports and base plate for printing still in place.
Close-up view of the single TO (front), IPE (middle), and multi-metal TO (back) beams before sandblasting. The print parameters for the multi-metal TO beam were:
Robot Speed: 6.5 mm/s
Laser Power: 830 W (Mild Steel) – 830 W (Tool Steel)
Feeder Speed: 8.28 mm/s
Argon Flow: 10 L/m
The amount of steel used was 3.39432 kg (Tool steel) and 162714 kg (Mild steel) for the beam and 2.19361 kg for the supports.
Close-up view of the four 3D printed beams prior TO sandblasting and removal of the supports. The beam at the left still has the supporting 3D printed parts that attached it to the metal base for manufacturing in a vertical orientation.
Close-up view of the single metal TO beam showing the area where supports for 3D printing were removed. Also visible are the horizontal 3D printed layers.
Full and close-up views of the completed beams after sandblasting and support removal.
Tool steel is visible at the top of the beam in the foreground as it has a lighter colour to the mild steel region below it.
