Multibellow Suction Cup

thingiverse

Hi All This is a ABS/TPU printed suction cup that can be done with a single extruder by pausing and switching filament. The suction cup can be used on the end of a robot arm for Picking and Placing stuff. This design is meant to be a general example/starting point. No hookups are provided for a particular vacuum source. Add what you need or your own setup. Things that worked well: Bellows walls are 0.4mm thick, any more and the cup is too rigid. No more than 45 degree angle works best. 6mm long on the "Increasing Diameter" half of the bellow is about as long as you want, and even at that length the upper part starts to bend inward a bit due to plastic contracting. The decreasing diameter section of the bellow prints just fine. Sticking with .1mm layer height on the bellows worked out better than 0.2. Upping the TPU temp to 230 for better layer adhesion is recommended. You want more (AKA thicker) material on the inside of the cup lip, which provides a spring force to pull the lip back over center and prevent it from folding upward. (See video) Slicing it twice, once for ABS and once or TPU, then manually splicing the Gcode together is necessary. Beware using different layer heights. If you transition from 0.2 to 0.1, you might miss 0.1mm of the transition layer if not careful. Also note that adding extra extrusion (about 14mm for my bowden tube length of 20") is required to make sure enough pressure is immediately applied to the TPU to ensure a nice thick, well-extruded first TPU layer. Else you will get a heavily underextruded first layer, and the cup will leak, and maybe break at that layer. Fan/enclosure usage didn't seem to matter much at all to the TPU (enclosure good for ABS obviously). The TPU has been found to be extremely tough, and always goes back to its printed shape. This same accordion design could be used as a vibration isolation device. ABS to TPU layer bonding has been good so far. A test cup has been in the dishwasher for 3 weeks with no ill effects reported. Issues printing smaller diameter cups were experienced. It is believed that heat buildup and printing multiple cups at once should solve this issue. Please post your makes/modifications to this design. https://youtu.be/q1MWsZH-f90