Laura Griffiths speaks to Jens Ertel (JE), Head of BMW Additive Manufacturing, and Markus Lehmann (ML), Head of Installations Method, Robotics, about BMW’s design and deployment of customised 3D printed robotic grippers.
TCT: Inform us about that first iteration of the 3D printed robotic gripper. How did BMW determine this as a possible utility for additive manufacturing?
JE: The BMW Group manufacturing system is continually evolving, and there may be all the time a drive to combine new improvements, for instance to optimise time, value, and CO2 emissions. The instance of the gripper for the CFRP roof dealing with in plant Landshut reveals that for the very light-weight roof, a really heavy gripper was used. It was subsequently clear that there was huge potential to minimise the load of the gripper. In fact, there are further forces just like the mass of the management models and actuators that the gripper should stand up to. Nonetheless, we had been very assured that we might obtain a major weight discount. After performing a topology optimisation, one of the vital essential instruments for calculating light-weight designs, the consequence confirmed a somewhat advanced form. Lately, new printing applied sciences have change into more and more obtainable on a big scale, so that enormous, topologically optimised parts like giant grippers can now even be manufactured utilizing additive manufacturing.
TCT: The gripper has been optimised with a brand new ‘bionic design.’ Are you able to discuss us by the optimisation course of?
JE: For the topology optimisation we first wanted a so-called design house. That is the area or quantity inside which the optimisation algorithm is allowed to distribute materials to be able to discover the optimum structural design. The design house represents the obtainable bodily house or area the place the construction will be positioned. Moreover, the non- design areas are outlined. These are principally mounting plates which can be wanted to later fasten add-on elements and to connect the gripper to the robotic and that will likely be built-in within the bionic construction through the optimisation. After that, the forces and torsional moments appearing on the gripper are estimated and the allowed deformation is outlined. Additionally, the fabric properties and a minimal strut thickness are set. With all these values and a few further particulars the topology optimisation will be began. Via the intelligent mixture of two completely different optimisation approaches, the ensuing geometry of the optimisation is already of such prime quality, that solely minor guide modifying of the design is critical. The normally time intensive redesign of a topology optimisation result’s changed by an automised workflow, that accelerates the design course of enormously. The optimisations of the bionic grippers had been achieved within the software program Synera.
TCT: The gripper makes use of a mixture of completely different types of 3D printing. Why had been every of those processes chosen?
ML: The gripper for the CFRP roof manufacturing on the Landshut plant utilises a mixture of completely different 3D printing processes to reap the benefits of the distinctive advantages that every expertise provides. The collection of these processes was pushed by the technical and financial concerns for the precise parts of the gripper. The method is to not merely ‘print all the pieces’, however somewhat to make use of the 3D printing expertise that gives essentially the most advantages for every particular person part. This strategic method ensures that the general gripper design is optimised for each technical efficiency and cost- effectiveness. For the vacuum grippers and the clamps of the needle gripper used to carry the CFRP uncooked materials, the selective laser sintering (SLS) course of was chosen. SLS permits for the manufacturing of those intricate and sophisticated elements with the required precision and sturdiness.
However, the massive roof shell and bearing construction of the gripper are manufactured utilizing large-scale printing (LSP) expertise. LSP is well-suited for producing giant, stiff parts in a cheap and sustainable method. Moreover, in a subsequent optimisation step, the load of the bearing construction was lowered even additional. This was achieved by using aluminium sand casting expertise, the place 3D printed shapes and cores had been utilised. This method allowed the complete potential of topology optimisation to be exploited, resulting in a major discount within the total weight of the gripper.
Extra BMW additive manufacturing tales:
TCT: Why was weight optimisation such an essential issue for this specific utility?
ML: Mainly, we need to scale back the weights of grippers within the manufacturing system, as this could scale back the transferring lots and thus additionally the cycle instances, power consumption and CO2 emissions. As well as, the service life is elevated and smaller robots can be utilized sooner or later. When optimising manufacturing processes, set up sequences can change in order that increased hundreds should be moved with the prevailing setup. The discount of the gripper weight additionally permits versatile adaptation right here. In particular circumstances, weight discount is not the one goal, it may also be the rise of the stiffness of the gripper system.
TCT: This type of utility encapsulates how additive manufacturing doesn’t essentially should imply direct printing in a manufacturing surroundings. How does this gripper story display the potential for AM as an enabling expertise?
ML: Primarily, we don’t merely need to print all the pieces, however somewhat utilise expertise the place it gives the best technical and financial advantages. 3D printing is one other device within the expertise arsenal that enhances and helps different applied sciences. Developments in expertise and supplies open up new technological and financial purposes. As seen in varied thrilling 3D printing tasks on the BMW Group, 3D printing expertise generally is a key to success. Within the case of bionic light-weight grippers, the complete potential of topology optimisation can solely be realised by the 3D printing applied sciences employed, permitting the utmost potential for weight financial savings to be exploited. Software-free manufacturing permits speedy and economical deployment in addition to accelerated iteration cycles.
TCT: What has been the impression of this bionic design and has it influenced any additional developments alongside the manufacturing line?
ML: Using additive manufacturing within the manufacturing system has been established for a while now. The primary hybrid grippers, the place, for instance, solely particular person, smaller parts had been printed, have additionally been in use for a number of years. This was additionally an initiator for the primary trials with the printed large-format grippers. The CFRP roof grippers on the Landshut plant have now change into a everlasting a part of the manufacturing, so that each one CFRP roof grippers for this manufacturing step are produced solely by 3D printing. To totally exploit the potential of topology optimisation, there was an additional growth in the direction of the bionic gripper, which is manufactured utilizing sand casting and printed moulds. Along with the Landshut plant, this sort of gripper is now additionally used within the Munich plant for the manufacturing of the BMW i4. Additional grippers are deliberate for added crops.
TCT: Talking extra broadly about BMW Group’s deployment of AM – greater than 400,000 elements had been printed final yr worldwide. How would you characterise 3D printing’s significance throughout the BMW Group manufacturing system?
JE: 3D printing has now change into a vital and integral a part of the product growth course of and the manufacturing surroundings of the BMW Group. The supply of 3D printers within the particular person crops has considerably elevated the creativity and modern energy on-site. Via the brief distances and the quick, native manufacturing inside a number of hours and even minutes, customised options will be applied shortly. The crops are related in a good community, during which purposes and experiences with 3D printing are exchanged. This permits all places to profit from mutual assist when it comes to concepts, applied sciences and supplies. Total, 3D printing has change into firmly established all through the BMW Group. The variety of purposes and the penetration of the expertise throughout all crops is steadily growing. This manner, 3D printing contributes decisively to the rise of effectivity, flexibility and modern energy in manufacturing.
This text initially appeared inside TCT Europe Version Vol. 32 Concern 5 and TCT North American Version Vol. 10 Concern 5. Subscribe right here to obtain your FREE print copy of TCT Journal, delivered to your door six instances a yr.
