NASA CHAMP Clamp (THE GREY)

grabcad

**02-15-2015 I'm considering this design finished for now, I've uploaded all the files. In summary, the design intent behind this clamp design was to have something SIMPLE, STRONG and ROBUST and function by way of a simple clip, with NO EXTRA TORQUE applied by other means like a screw or lever. I also wanted to exploit the fact that you can use infill with the 3DP process to keep the overall weight down, but still have descent structural integrity. It's a beefy design yes, but that doesn't mean it weighs a lot, only 68grams. As for the Aesthetics, knowing the end purpose of the clamp was for the space industry, I wanted to keep the surface simple and clean, free of logos and unneeded pocketing where dust and bacteria can collect. Also, the need for pocketing wasn't necessary as you can adjust the weight through infill with 3DP. All the models I printed and tested used only 30% infill!!!! could float on water, but held upwards of 90+lbs! I respected the rules on radiused edges and tried to apply them as closely as possible to this specific model. Anyway, I feel I was very successful in achieving this goal with this design, and I learned a lot in the process, like how to orient 3DP parts for maximum strength, due to weaker layer bonds from the 3DP process. I tested the clamp using a 90lbs static weight running perpendicular to the rail without failure, I estimate I could have increased it to over 100lbs. I tested with 35lbs static weight running along the handrail before the seat track stud slipped out, the clamp held in place. The video's of these specific load testing experiments are posted below on 2-13-15. The main file to print is: CHAMP_TheGrey_3DPR_Withpin.STL This file has been optimized for printing with slic3r/Pronterface software and included everything you'll need to make the clamp, all in one print. It has been repaired and re-scaled. Each machine is different and sometimes the scale needs to be reset. If so, just down convert to mm from inches or vice versa. I've attached a list of the print settings I used in my gallery. All other file formats are attached and can be modified and fresh STL files can be created from them. *The pin for the hinge can be printing separately, and if needed, higher infill can be used on just the pins. I'd like to Thank NASA, GrabCad and the community for giving me an excuse to waste some plastic on my new 3D printer! :P There are tons of great designs, good luck to everyone, don't forget to have fun and ALWAYS where you safety glasses! Check out my research progress below, starting from 1-23-2015 up to now. It will give you a good idea about all the iterations and troubleshooting I had to go through to lead up to this final design. All the printing was done with a Lulzbot Taz4 and Lulzbot mini 3d printer. Cheers! **02-13-2015 I reprinted the handrail on the Lulzbot mini loaner printer so that it would slip into some bar stock. I created a better jig that held the hand rail in place so I could do some static weight testing on the clamp. To sum up, I managed to get 90lbs of weight to hang off of the seat track stud successfully. Mind you at this point, the clamp was showing signs of stress and fatigue but it was holding. Actually, it looked like the seat track area could still take more weight and the clamp would probably fail before it did, which was surprising, I figured it would be a weak point. It should be noted also that this print was only 30% infill!!! I was actually blown away by how much weight the clamp had on it without failing, I predicted it would fail after only 20-30lbs but it held on great. I just want to emphasis that 90lbs is seriously heavy, you can see all the weights in the bucket at the end of my videos, I could barely lift the bucket, and all that weight was supported by the clamp, and I have yet to test with more weight to see where the breaking point is. Really fun experimenting with this. The following video shows the live testing, this first video I ran out of weights, maxed out at 78lbs. http://youtu.be/qSjkhVO4QL4 this quick video just shows the clamp supporting 90lbs. As is, it could probably be pushed to 100ish but would probably need modification to hold more. http://youtu.be/NhuUC6JYVmc This video shows the static load being applied ALONG the hand rail, I made it to 35lbs but the seat track stud slipped out, surprisingly the clamp stayed put. http://youtu.be/5GM_wwOvM44 **02-12-2015 Lulzbot sent me a replacement printer on loan while I wait for replacement parts.. I was able to finally print out the new test hinge pin, printed horizontally, it's in yellow... aside from being a bit too large, it worked great! Time to move onto further testing... Some video's: http://youtu.be/5fzb1BQKjBA http://youtu.be/HkeTsAOGNrw **02-07-2015 My printer hot end died today. I'm without a printer at the moment and can't test anything. Great timing. **02-05-2015 (CRITICAL DESIGN FLAW DISCOVERED) 15:00:00 Just starting printing the full scale clamp design. I'm excited to see how it will turn out. Still a few hours left.... video1(1.5hrs into print): http://youtu.be/Mr4kF_yzdO4 video2(3.25hrs into print): http://youtu.be/ug7GxhWpI3U Print finished, played around with it for a few minutes, snapped it onto the handrail a few times, tried putting some force on it, twisting it etc.. and the pin gave out, the layers sheared...an issue I was wondering about. The pin will have to printed separately, sitting longways on the bed then pressed into the clamp afterwards. Damn, wanted that all in one print distinction! stay tuned... here's a video describing the issue: http://youtu.be/QeI88668h54 **01-26-2015 WIP Just finished printing vers 1.4( I call it version 3 by mistake in the video) of my test clamp, as outlined in my descriptions, learning from the three original prototypes I figured out the best way to design the Clip mechanism. This test print works amazingly well, it's snaps and locks into place with lots of force, it doesn't slide along the rail at all ( test print is only .5" thick, the real print will be 4"!! so it will hold even tighter).... and now, the clip releases with ease, I was even able to release it with my pinky finger, not much force required at all! Video demo: http://youtu.be/l1bxu1eesa4 **01-26-2015 WIP Just added a collage image of the testing of vers.1.2 and Vers.1.3 (thinner arm). The flexibility in the arm with vers.1.3 help to release the clamp but it also weakened the clamp force slightly. I wasn't satisfied with the results so after some thought, I'm taking a new direction, please refer to the sketch, should have a test model for the new clip design soon. ***01-24-2015 WIP I printed out vers.2 of the design, taking into consideration what I learned from the first proof of concept. I've attached a video with an explanation. I was surprised how well the clip holds the clamp in place, it's a very tight and strong fit --->>going to stick with the concept and tweak it to perfection. **01-23-2015 WIP Just playing around with a concept, test printing a small cross section today to test the concept, trying to work with a clip in design but doubt it will work or be strong enough. If I can't get it to work, I'll use a threaded bolt.....stay tuned.. Video: http://youtu.be/wVMU_HIVlcw