We have an original Rhino Trackdrive system we bought last year for ou Stronghold bot. We have bought the new Rev4 pulleys and they have a tendecy to crack even if we are not using the bot for an offseason competition. The team is tired of buying these wheels so, we were considering 3D printong the wheels, but the school only allows us to use (I just vomited a little) Inventor and AutoCAD. I hate Inventor and AutoCAD. Does anyone have an STL file that we could use to let us print these pulleys?
Thanks,
Taggerun
P.S. We are using PLA to print or would ABS would be better?
andymark provides a Step file https://www.andymark.com/Rhino-Track-Drive-Pulley-p/am-3298a.htm - you may be able to convert this to STL via cad programs.
Also, don’t knock inventor. I use both SW and Inventor and they are both pretty good. I’m curious why you have an aversion to Inventor. It’s just a tool.
Inventor will open step just fine, just save it as a STL file.
ABS is technically the better choice, but PLA should work just fine. I would try PLA first. Ensure you have a decently high infill and you should be good. If you are concerned about breaking you could always add more material to the spaces between the spokes in the cad file.
Our team would approach this dilemma by trying a pair of prints in the most strenuous part of the mechanism and then run it until it breaks or we get tired trying to break it. (We print everything with a lesser infill on our practice bot than on the competition bot to stress the parts to catch potential breaks early.)
If we do break something we know where to add/redesign/improve.
Our wheel hubs on our robots have been 3D printed for the past two years. They have not failed us yet. (It’s not all that impressive, they aren’t under that much pressure.)
Sounds good. PLA it is then.
Thanks,
Taggerun
What are you expecting to gain by 3D printing wheels over buying molded ones?
Edit: are you sure cracks aren’t being induced by, let’s say… enthusiastic assembly?
Now this is assuming you are using it only for this years game*. If you are attempting to cross defenses with entirly 3D printed wheels using the unmodified rhino track module you might have a bad time. PLA tends to be more brittle than ABS but they will both break under pressure faster than a molded piece. Robot to robot collisions should** be fine, but falling from something like a climb or crossing defenses would likely be enough force to do some damage. There is no suspension on the track module so the full force is being absorbed by those wheels. It might be fine, but I would test it extensively. Perhaps a good off season project for a team? (Not for my team however, we ‘steer’ of tracks.)
*Assuming you don’t fall from your climbs.
**There is always that chance of them hitting you just right.
Hi there,
Sorry to hear that you’re having issues with the Rhino Track Drive. Can you PM me pictures of these cracked pulleys? The Rev 4 pulleys were created to mitigate this specific issue. Alternatively, you can contact us via support (at) andymark.com and the ticket will get to me pretty quickly. We’d like to see what’s going on.
Sincerely,
Nick