Re: pic: 3D Printed Parts Contest
 

Sorry for late reply to this - I just realized I didn't answer this in my last post!
For complexity I meant rather the complexity of the task and/or the amount of different ways it can be used. The part could be able to complete multiple tasks - i.e, two birds with one stone. The previous phrasing phrasing was bad, and I have edited in the main post.

Re: pic: 3D Printed Parts Contest
 

Hmmm, those bevel gears on the intake look printed, along with the guides for the polycord. The wheel hubs look like it as well.

Re: pic: 3D Printed Parts Contest
 

I'm a big fan of our encoder mounts this year. The clip just rides between our drive motors and supports our encoders while being retained to the shaft using these clamping couplings from Automation Direct.

Re: pic: 3D Printed Parts Contest
 

I was just wondering if the parts have to currently be on the robot, or can I use ones from a previous iteration? Alternatively, I have a completely 3D printed, .254 scale, model of the robot: would that fit the criteria?

Thanks,

Re: pic: 3D Printed Parts Contest
 

Has anyone tried 3D printed bevel gears for a low load high speed application like an intake? We talked about this but we were too nervous about it. I don't know enough about the plastic properties to know if they'd be okay. I know you can buy nylon bevel gears, but I don't know how they hold up.

Re: pic: 3D Printed Parts Contest
 

The former part works - but the latter not as it did not help you complete/perform a specific task for your robot - but is rather just your robot. Can't wait to see the part(s) you submit!

Re: pic: 3D Printed Parts Contest
 

Short answer:
Yes. It works, but it isn't the BEST option.

Long answer:
This year, I prototyped a vertical extension of our horizontal roller intake after bag and tag. I made some 1/2" hex bore spiral bevel gears that transmitted power at a 1:1 ratio at a 90° angle. While the system did work, we ended up not using it due to size, placement, and vulnerability. To get the strength capabilites you need to use for just about anything, even a low torque intake, the gear tooth has to be pretty large. Also, I had to design the gears myself, just because there aren't many resources online that I could find for printed gears. Downloading the files for a gear won't give you the correct tolerances for printing. Had I already not spent some time last semester on how to design spiral bevel gears, I would have had no idea how to do it. Also, I had access to parts printed out of Ultem plastic, which is much stronger than ABS or PLA. In the end, it worked, but not as well as I would have hoped considering the time I put in it.
I would just use the bevel gear from WCP if you can, but I would also love to see somebody refine some designs for printed bevel gears.

Re: pic: 3D Printed Parts Contest
 

If anyone wants to apply their 3D Printed Parts the deadline is this Thursday, April 21st. Remember to also email a picture, render, or the .stp file to Contest3D@ligerbots.com.

We've had great submissions so far, and can't wait to see more!

Re: pic: 3D Printed Parts Contest
 

So I know I cant submit anything because this isn't for a team, but I just had too share this. this is a printed pattern for making a casting out of cast iron. it is 14" diameter +1% to account for shrinkage, sorry for off topic. https://scontent-ord1-1.xx.fbcdn.net...60&oe=57BC0450

Re: pic: 3D Printed Parts Contest
 

Don't worry - that's awesome! Do you use it often?

Re: pic: 3D Printed Parts Contest
 

You can get plastic bevel gears from MCM for fairly cheap: http://www.mcmaster.com/#bevel-gears/=121anop

We've used em for prototyping before, but never on a final robot.

-Brando

Re: pic: 3D Printed Parts Contest
 

Contest is extended until the 30th - the last day of April. Get applying now!

Re: pic: 3D Printed Parts Contest
 

Hi Everyone,

Here is the submission from Team 1965, the Firebirds from St. Joseph Prep. HS in Brighton MA.

Over the last few years we have been doing a lot of experimenting with 3D printing. We use PTC Creo and a combination of MakerBot Replicators and older Replicator 2s to build our parts. During this period we have developed enough confidence with this process that we developed a full suspension and tank drive system for the game this year. I have included a few pictures below and after the dust settles I will post the CAD files for all of the parts and assemblies.

The track design was an improved version of what I had posted before. The suspension system was design by a few of our students based on some recommendations from mentors to look at how the 1920's Christie suspension and WW2 sherman tank suspensions worked. It was modified between Northeastern District events to include the extra wheel set on the front bogie to prevent the track from collapsing when going over the rock-wall.

I will get more information posted when I have a moment but feel free to post comments and questions.

Special thanks to the Ligebots in Newton MA that saw our robot at BU and encouraged us to submit this. Pictures are below.

Colm.