Ultimaker
Lifting a 12-tonne tank with a 2kg link
The strength of a material is typically tested by engineers using a tensile testing machine. A small sample would be printed and put under a large force until it snaps. The force projected on the part divided by surface of the centre intersection at the time of breaking will express its strength.
But UltiMaker, Covestro, and the Royal Dutch Navy have decided to take an unconventional approach to understand how strong 3D printed parts can be. They wanted to lift something heavy. When it came to decide what heavy object would be lifted, it was the Royal Dutch Navy who asked the question: “Why not an armoured vehicle?”
To lift a heavy vehicle using a 3D printed part, the engineers first needed to analyse the hardware. The Royal Dutch Navy had a special lifting tank at its disposal, which used two openable steel rings to connect to a crane and to the cables attached to the lifted vehicle. An elongated O-shaped link would be needed to connect the two metal rings and lift the tank.
After importing the geometry of the steel rings into the CAD software, UltiMaker Application Engineer Lars De Jongh was able to create the initial design for the link. For the design to work, the link required a flat side for a stable 3D print and needed to be printed with layer lines in the same direction as the forces projected the part. The interacting surface of the part and the metal rings needed to be as large as possible to spread forces evenly.
Ultimaker
CAD Geometry of the O-shaped link
The engineers needed an extremely strong material that could absorb short peak forces. They looked on the UltiMaker Marketplace, which contains hundreds of materials, each with a unique combination of properties, and decided on Addigy F1030 CF10 from Covestro, which matched the set requirements. This is a nylon-based polymer, loaded with carbon fibre and can be printed using the UltiMaker S5 and CC print core.
Before the heavy vehicle could be lifted, the engineers needed to verify the part’s calculated strength physically. Two designs were generated for two sizes. The first was a 1kg link, estimated to withstand 12 tonnes. The second, weighing close to 3kg, was estimated to withstand 38 tonnes.
The testing was done with an on-site industrial tensile tester belonging to the navy, which is able to project up to 343 kilonewtons of force on an object.
The difference between the tested results and the simulated numbers was close, being only 1% off on average. This made the workflow accurate, and profitable in time-to-market and increased performance.
After several months of designing, printing, testing, and planning, it was time for action. On a Dutch army base in the south of the Netherlands, the 13th Light Rhino Brigade assisted the teams with their armoured recovery vehicle. The Leopard 2 “Buffalo” has a crane mounted on the front and is designed to recover heavy vehicles such as trucks and battle tanks.
Ultimaker
Lifting a 2-tonne vehicle with a 1 kg link
As a warm-up, the 1kg link was used to lift a military version of a Mercedes jeep weighing over two tonnes. This vehicle was lifted easily.
The 2kg solid carbon fibre reinforced link was then placed between the M113 armoured tank and the Buffalo crane. The metal rings were tightened in place, and four cables were attached from the lower hook to the vehicle. The 12-tonne vehicle was slowly lifted up, hanging form the 3D printed link. The Buffalo drove around in different directions, with the link holding up perfectly.
In September, the merger between Ultimaker and MakerBot was completed, which saw the two companies announce the new name that they would be operating under is UltiMaker.
In August, Covestro's additive manufacturing business was acquired by Stratasys, with the integration into the company expected to take early next year.
