Tuesday, 15 March 2011

FMP - Eight (10/03/11 - 15/03/11)

To be honest, progress has slowed down a bit over the past 2 weeks in getting the base finished, but at least I can proudly say that all the work and time has paid off, as the CAM works! It's been sanded down to create a smooth track, so of course I assembled the bits I have to give it a test run. I didn't attach the motor, so it was rotated by hand, but nonetheless it worked. The masking tape represents the different height changes as it's rotated:

As you can probably tell, the rod going round isn't one of the ones I've made. I tried the ones I made on it last week (before the CAM was probably sanded down) and it snapped the ends off, probably due to catching on some protruding filler:

As I mentioned this was last weeks attempt, since having sanded down the CAM, the ones that still have the ends work fine. But this problem has highlighted the issue for me, so even if I stick with the tyre idea there's a good chance of them snapping and there's nothing I can do to fix it. So to prevent this I'm going to sand the ends down into half a sphere, just like on my prototyping. This instantly strengthens the end tenfold, and is a lot less fiddly than the tyres. It's worth noting as well that I was only using the tyres when the CAM was only 5mm thick with guides either side so that it couldn't rotate, but now it's almost tripled in width and there are no more guides this idea wont work.

The new design to prevent them from rotating is to simply thread a bar through the poles and have two pieces attached to the base, so that they prevent the pole from rotating, this picture should clear that up a bit:

To end on a good note, here's a video of it working (keep your eye on the masking tape):

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