hi gang!here's a 3d printed sprocket that i both designed and printed.i made it for my sparking bike. it's turned by this chain,so that it can turn the disks of this wimshurst machinewhich creates the sparks. in this video i'll show you the steps that i wentthrough
3d printing impact on supply chain, to make that 3d printed sprocket. i first looked online on websites like thingiverse.comand sure enough there were some there. but i wanted to try my hand at designing myown. so using blender 2.71,a free 3d modelling and animation software
that i use a lot,i drew up the sprocket. in the scene panel i set the units to metricto keep things easy. and then i set the scale to 0.001. i used the smallest sprocket on the back wheelof my bike to get all the measurements.as you can see it's a fairly simple part, with a nice flat bottom and no overhangingpieces. the underlying mesh is also fairly simple. when it was ready, i exported it as an .stlfile. i did my printing at the university of ottawa'smakerspace,
and the printers there are various versionsof makerbot's replicators. i opened my .stl file in the makerbot program. i next brought up the settings window.the infill is how much of the inside is filled in.here's what it did with my selection of 50% infill.this saves on plastic and printing time. since it was a sprocket, i wanted at least50%, for strength. but even more important i think was this numberof shells. that's this outline of material it puts here.as you can see, that just happens to fill in the teeth ofthe sprocket,
making them strong.4 shells seemed to work well. that's all i modifiedso the next step was to bring up the export window.that calculates an estimate for how long it'll take to print.if it's too long then you can go back and change the settings for less infill andso on. when i exported it, it created an .x3g file,which i put on an sd card to put on the printer. it starts by printing some bottom layers,called a raft. once the raft is done, it starts on the actualpart, my sprocket. notice the 4 shells being laid down, alongwith the infill.
and after a whileit gets working on the part which the shaft will go through.until finally, it's done. the whole thing is stuck to the bed but onceit's removed, i can take it home and work on it some more. the first thing is to remove the raftand extra material from the bottom. then i have to sand the teeth.both sides need to be sanded, while constantly checking the fit in the chain.but after around 15 minutes sanding, it fits great. next i drill out the hole through the middlea little more,
so that my bolt goes on with a tight fit,not requiring anything else to grip on. and there's the finished sprocket. i then remove the old crank from the wimshurstmachine and put on the sprocket.it works! once it's on the bike,i put on the chain. and once it's outdoors, you can see the endresult works great! well, thanks for watching! see my youtube channel, rimstarorg for morefun videos like this. that includes the one where i show more ofmy sparking bike in action,
and more on how i did it all.another on using a peltier module to do thermoelectric cooling.and one on using nitinol wire, a shape memory alloy.
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