CAD Models

In case you wonder (or lost a link in subscriber e-mail), here’s a link to all the .step filer related to the Rover:
https://drive.google.com/open?id=0B0VJV1qQkx0VR1hYQVEtSjVuaHM

Thanks for making these available. Just wondering if there is a BOM or parts list for those intending to self-build (or is the intention that we purchase parts from you rather than self-source)?

For example, when I look at the wheel assembly, Part 00168 in the CAD file (although referred to as Part 00008 in the wheel assembly guide?) - the aluminium tube - is this an off-the-shelf component or one that you’ve had specially machined? COULD it be 3d printed i.e. would it be strong/stiff enough?

Likewise in this assembly, the motor unit - designated “propulsion-pololu-motor-HP” - is there a way to find the exact specification of this motor i.e. voltage, gearing, etc?

Thanks,

Hi, in the wheel assembly only 00008 (or 00168 in the new version) and 00163 are custom components. The rest is either 3d-printed or bought. Actually we tried 3d-printing the tube (00008) and it works fine - the reason we don’t do that in the manufacuring is that the loads on the tube are inline with the layrs and this may effect too much faulty parts. Then with 00163 we had issues with a torque screw ripping the layers apart (the screw prependicular to shaft axis) and the part cannot work with rubber sealings we use. If you don’t want it to be watertight, you can try printing the part and figure out how to screw it.

The motor we used: https://www.pololu.com/product/3244

Although there are some issues with gearboxes with the motor (too weak for the Rover).

Cool, thanks. I will try 3D printing these parts initially then. Have you tried/considered ABS & acetone smoothing? I here it has the effect of fusing layers together to prevent that kind of failure. I have no interest in this process due to the chemicals/fumes but I do have access to the Polymaker Polysmooth system which is a similar process except using their own PVB material & IPA instead of acetone (much safer). Not tried using it to create stronger parts but would be an interesting experiment. The only downside is, depending on exposure, parts can take days or even weeks to fully cure.

re. the motor gearbox - is this different from the motor you use in the production version? or does that version also suffer the same issues? is there a better motor that can be used?

We haven’t tried the smoothing as it’s too much to do for manufacturing. But if you do with the Polysmooth, please tell me how it worked :slight_smile:
We’re now switching to Buehler Motors (they were used previously in Turtle Rover) - it will be Buehler 1-61-077-414.
All the Pololus with higher ration gearboxed tend to have the issues. It works in nominal conditions, but then if the Rover for ex. falls - the teeth of the last gear tend to break.

I’ve contacted my local Buehler distributor, they’ve advised me that the 1-61-077-414 motor WITH encoder is not a stock item so comes with an enormous minimum order quantity. Please excuse my ignorance as a lot of things in this project are new to me so it’s all a big learning curve! Do I need the encoder? If so are they generic items, would an encoder from somewhere else suffice? Can you let me know where you are getting your Buehler motors from? thanks!

EDIT: as a new user, it won’t let me post a new reply, but Thank you for the reply!!

Ah right, sorry I didn’t tell before :slight_smile:
We use Romi Encoders now.