BMW Group
BMW 3D printed "bionic" robotic gripper
The BMW Group says it produced more than 300,000 parts with 3D printing at its Additive Manufacturing Campus in Germany last year, with a further 100,000 produced across its global production network.
The German automaker has been using additive manufacturing (AM) technologies since the early 90s for everything from concept models to end-use parts, and significantly for the use of production aids.
"The increasing use of additive manufacturing in the BMW Group production system has many benefits," says Jens Ertel, Head of BMW Additive Manufacturing. "For example, we are able to quickly, economically, and flexibly produce our own production aids and handling robots, which we can individually adapt to specific requirements at any time, as well as being able to optimise their weight. Less weight allows higher speeds on the production line, shorter cycle times and reduced costs. Plus, smaller robots can be used in the medium term, which also cuts CO2 emissions and costs."
The company recently shed light on its use of 3D printing for customised, lightweight robotic grippers at its Lightweight Construction and Technology Centre in Landshut, where a particularly large gripper element, used on a press in the production of all CFRP roofs for BMW M GmbH models, can be produced in just 22 hours, and weighs roughly 20% less than a conventional alternative. While the vacuum grippers and clamps for the needle gripper to lift the CFRP raw material are made using selective laser sintering, the large roof shell and bearing structure are manufactured using large scale printing, which uses injection moulding granules and recycled plastics. Compared to the use of primary raw materials, CO2 emissions when manufacturing the gripper are roughly 60% lower.
However, last summer BMW was able to develop an even lighter ‘bionic’ version which employed topology optimisation software Synera (which BMW iVentures has strategically invested in) to produce an optimised bearing structure. The new gripper is a further 25% lighter than its predecessor, meaning the entire process of manufacturing a CFRP roof of the BMW M3 can be performed with just one robot, rather than three.
BMW is also using 3D printed grippers in chassis construction, for example, for dealing with doors at BMW Group Plant Regensburg. But at its parent plant in Munich, the grippers are being used to hold and move the entire floor assembly of a BMW i4. For the floor assembly gripper, 3D printing is used to create a sand casting mould, which is filled with liquid aluminium. The bearer is optimised for weight and maximum load capacity, and weighs just 110 kg - roughly 30% lighter than the previous, conventional model.
Markus Lehmann, Head of Plant Engineering and Robotics at BMW Group Plant Munich commented: "At the Munich plant, we are continuously expanding the use of production aids created through additive manufacturing. When it comes to the field of gripper and handling systems, we use 3D printing to equip our established grippers with individual, printed attachments and are already replacing complete gripper systems with highly-integrated and weight-optimised bearing structures. When handling the full BMW i4 floor assembly, this allowed us to reduce the weight of the complete gripper by 30 percent – 50 kg – and thus to extend the service life of our facilities."
As an early 3D printing adopter (EOS even built its first machine to BMW's specification), BMW has continued to invest heavily in its in-house AM capabilities. Back in 2018, the BMW i8 Roadster featured the first metal 3D printed parts on a commercial vehicle, and its MINI Yours Customised campaign used polymer 3D printing to allow customers to add personalised icons and fascia to their cars. Last year, ExOne revealed how BMW is using its binder jet 3D printers out of its Landshut Light Metal Foundry for Series 3 & Series 4 engine cores, while BMW also hailed the success of a three-year project with various industry partners called POLYLINE, which was set up to automate an AM production line for polymer parts at scale. More recently, the car manufacturer also announced plans to use wire arc additive manufacturing for vehicle production, having already undergone extensive testing with components such as a suspension strut support.
