Hello CD community, I am the Engineering captain for 1102 and I was wondering if any teams that have used MAXSpline or SplineXL could discuss their opinions. I am designing an arm that is connected to two gearboxes on each side and it will have to lift the arm and an intake.
I want this joint to be as strong as possible with as little backlash. From what I have read here and have heard from my mentors is that spline would be better then hex shaft. However the team has not worked with either MAXSpline or SplineXL so we are unsure of witch one would provide the best quality’s. So I was hoping that teams who have experience with one or the other would be able to talk about there experience using one ore the other or how/why they decided to.
MAXSpline was released last season, and SplineXL was released earlier in the 2024 preseason.
We used MAXSpline last year on our arm successfully. Quality was good, everything fit together tightly.
I haven’t used SplineXL yet, but typically WCP sells high quality parts, and I would trust that it is just as good.
I think the SplineXL is slightly easier to machine if you were making custom parts (you can use a larger bit). No idea which one carries more torque, but they are both high enough that it probably doesn’ t matter.
Rev and WCP both have a variety of gears and sprockets for their respective ecosystem. There is some overlap and some exclusive products (for example, WCP sells #35 sprockets while REV does not).
Honestly, you probably aren’t going to go wrong either way.
We are using Spline XL for our pivot but it will be new for us too, Personally, I think the SplineXL shaft is better because you can use most rev splines products like spacers and shaft collars for MaxSpline on the Splinbe XL shaft as well as whatever products WCP has. With Spline XL you have more products to put on.
It looks like you have a fair bit of space on that arm side plate where the sprockets are and room to move your gearbox axles.
If the arm is not counter balanced I recommend # 35 chain and as large of sprockets you can fit on there to reduce loading and backlash. Fundamentally I wouldn’t put any plate sprocket smaller than 4 inches in diameter on a arm like this. (gut feel)
If your arn has a Center of Gravity that is 1 ft away from that axle and it weighs 15lbs all of a sudden that little 1 inch radius sprocket is seeing 12x the forces. Slam into a wall or other bot at 15 fps with the arm up… Let’s just say loads go through the roof. Much safer to have a larger sprocket to reduce the mechanical advantage, better yet toss some gas springs in there to help counterbalance it and take up shock loads.
The big spline systems will give you less backlash at the end effector than a 1/2" hex shaft. The reason is that for the same amount of slop in the connection, having that slop at a larger radius means you see less motion at the end of the arm.
If you are very concerned about backlash, you should be using a clamping type connection between the spline and as many of your parts as possible.
Counterbalancing, as discussed above, can be used to keep your backlash stacked up on one side, assuming your mechanism doesn’t go over center. There are ways to keep the backlash closed despite going over center, but its likely to either make things complicated or make your motors work hard.
I agree on the chain drive suggestion; large sprockets make this type of thing MUCH more reliable. As a bonus, bolting the sprocket to the arm makes a backlash-free connection. An adjustable tensioner can be used to take out the chain slop if you want that last little bit.
