I got a couple of new pieces today but I’m not completely satisfied!
I’ve misunderstood how the printing resolution works. I thought it would affect the surface roughness, but not the measurements.
This resulted in too thin material at the connection points
I’ve been doing a lot of work since last time and there have been some changes in the design as well!
After I assembled a couple of parts in FreeCAD I realized that I had miscalculated (in my head) the size of some of them 🙁
I had to flip the base plate upside down to make room for the steering cradle and remove the friction wheels, because they wouldn’t fit anymore. I also had to make the propel wheel larger to get better grip and to make the ball go a bit faster.
The approximate speed is now somewhere about 10 km/h, which is a quite good speed I think.
The base plate front view – with motors and steering craddle and its servo
Another post is up, about the propel system this time!
I have this idea that the ball will be driven with a motor and a small wheel inside a bigger ring, with a friction wheel underneath.
Sorry for my bad sketch
Finally I think we nailed the printing tolerance measurements! We also changed from white to black ABS filament, which seems to behave more accurately than the white one does.
I added some snap connections and push fittings to the new test piece so we can see if the printer has an accurate repeatability
Today I got my first “missing” parts to propel my ball 🙂 I’m going to make a simple and cheap speed controller by using two 30A brushed plane ESC, less than $9 each.
A couple of days ago I got a mail with an attached film clip of the first printed piece of the skeleton.
The day after, “Dubbear” came to my place and I got it in my own hands so that I could look, bend, squeeze and feel the first printed part of my very first CAD-project!
We took a look at my CAD-files and “Dubbear” showed me that my parts wasn’t made as solids. I had simply misunderstood how to build the parts in a correct way!
Later on I did some googling and it turned out that it wouldn’t be as much work as I feared to fix the parts into solids.
It’s been quite some time since I last wrote something here, before the last post that is 🙂 so it’s about time I do so!
Since I’ve got a lot of R/C parts laying around I figured it wouldn’t be too expensive to gather the rest of the electronics needed, a DC motor and an ESC.
In the instructable the author used a 7″ (17.8cm) hamster ball as the housing for his ballbot. 7″ is quite small if you want to fit sensors and other fun stuff into the ball and really make it into a robot, not just a radio controlled ball. Continue reading