Here are some of my favorite ways to keep robots light:
As mentioned previously, getting rid of this can sometimes drastically reduce total weight, but sometimes a few well placed cylinders can accomplish things lighter and better than motors.
Where ever you can, try to stick to aluminum fittings instead of brass. I can’t find exact PNs right now but they are available online.
Use an appropriately sized manifold. If you know you only need 2 cylinders, get a 3 port base instead of a higher number (1 overhead is usually good for later additions).
Don’t use those giant pressure gauges or inline pressure regulators that come in the KOP and require brass fittings. Automation Direct has some really small and light push-to-connect legal variants you can find here.
The standard FRC Viar compressor sold by AM is really good, it mounts well and is pretty robust. If you are really in the need for weight savings, there is this Thomas compressor. Be warned - it is more expensive, difficult to mount, and requires the use of bent metal tubing to be FRC legal.
This is a weird one but for the 2020 season we only used 5/32’’ tubing and fittings on components post manifold. We found over previous seasons this worked well in select applications compared to the 1/4 standard variant and provides weight reduction, which can be important if you end up having pneumatic actuators on mechanisms with long tube runs.
More of a design thing, but try to keep the battery, main breaker, and PDP close to each other. This reduces the length of large gauge wire that needs to travel between these components.
When looking around for non-specific items, look for components with non-metal cases and the right amount of ports that you need. A good example of this is this Monoprice Ethernet switch we recently switched to vs this Netgear Ethernet switch that we used back in 2016/2017 because it was the first thing we found on Amazon.
Echoing what a ton of people said earlier, don’t skimp too hard on your drive train. Make sure your gearboxes are bulletproof and that the system will be able to keep up during competition. That being said, we have successfully used 1/16’’ wall box tubing for front/back frame rails. We have also switched out colsons/pneumatic wheels in the past for AM HiGrip wheels. We love them to death, even though they can sometimes get a bad wrap, and weigh a significant less compared to other wheel alternatives.
You can see the HiGrips and the front drive rail that we swapped out for 1/16’’ tube to get some weight back at a competition.
Don’t get too crazy with it, but something we found helpful was “scalloping” the edges of plates. All this is doing is getting rid of unnecessary attachment points between the plate and what it is providing rigidity to, which can net you good weight savings.
You can get away with 3D printing pulleys in a lot of cases. This not only helps with part procurement and integrating designs together, but also allows you to use belts and pulleys in a more creative way that can allow for a lighter mechanism than just using gears. A good example of this was in 2016, where the pulleys driving our wheels were printed out of PLA. They held up all season without any problems.
People often design intakes with large rollers on them or lots of different wheels, with a giant hex shaft going through the middle. You often don’t need that shaft. Try to replace smaller wheels with a more lightweight roller supported on both sides and either a dead axle system, or a way to get rid of the middle unused portion of the hex shaft.
You can see inside the bottom transparent roller that the hex shaft driving the roller extended from the 3D printed tube insert to the bearing on the far side of the plate, retained on both sides by snap rings.
Lots of cases where bushings would be a lighter weight, better solution than bearings. Good examples are intake pivots, mechanisms that drop down once a match, and other low load rotary points.
Thunder Hex from VEX has been a real game changer, but you don’t need to use 1/2’’ hex everywhere. VEX also sells a 3/8’’ variant which is perfect for intakes, rollers, conveyors, and standoffs.
Every shaft on our 2020 intake was 3/8’’ thunderhex, would have weighed a lot more with the 1/2’’ variant.
Thanks @JackTervay for reminding me about this one.
They weigh a lot, don’t use them.