Waterjet vs. Manual Build Process?

[Kevin Leonard]

A few notes.
CNC or Waterjet equipment is NOT NECESSARY to be competitive. 5254 was highly competitive the past two years despite using almost exclusively COTS parts from VEXPro.

However, these things can be helpful if used right, and provide a huge learning opportunity for students, especially if your team also uses CAD heavily. I vividly remember seeing our 2013 shooter plates on 20 being waterjetted using RPI's waterjet, and it was inspirational (and effective as well).

Advanced manufacturing techniques are not necessary to build a good robot, but they can help make some difficult tasks easier and provide a unique learning experience for students.

[RoboChair]

Originally Posted by Kevin Leonard

A few notes.
CNC or Waterjet equipment is NOT NECESSARY to be competitive. 5254 was highly competitive the past two years despite using almost exclusively COTS parts from VEXPro.

I 100% agree that they are not necessary. Our 2013 robot was built in a 20' shipping container with a tabletop mill, a small amount of outsourced mentor machining, and a box of scraps; made it to Einstein. 2014, same container, added a Bridgeport mill and a Harbor Freight mini lathe, nearly beat team 254 for the World Championship Title. 2015, actual shop space with reasonable manual machines, all CNC parts outsourced to sponsors, won Champs. Needed, no, but it can make life go smoother some times.

[adciv]

I've got a few different views on this, mind you I'm from the programming side of the house. Also, waterjet/CNC, consider what's more appropriate. A waterjet is nice but may require significantly more maintenance and upkeep than a CNC. Look at the sustainment costs for each before deciding. I think a waterjet starts at $80k, if you can get one for significantly less please tell us.

1) On the loss of hands on. I've had some debate with one of the other mentors on this who thinks everything should be done by hand. In the real world you will not be cutting everything manually. In fact, you would likely be fired for attempting this. It's not always worth it to build everything by hand or from scratch.

2) You don't have to give up hand cutting entirely. This year about half our robot was hand cut (or could have been, would have to check) and half was waterjet/CNC. Our main frame was box tubing and wood ribs. A few pieces were water jet and bent with a brake. One of our components was right angle aluminum and was hand cut with a hack saw. Determining which is the most appropriate method is another part of engineering (I can build this and it costs X or I can go to home depot and it costs Y).

3) Beware the CAD Trap and Prototype. One thing we've sometimes become trapped by is the design trap of trying to get the robot fully designed and then building it. If we came across an issue, sometimes it would be too late into build season to fix. Hand building can be easier if you don't have as much of a delay for prototyping. Our original drive train this year got stuck on the moat and we did a quick redesign to fix it. This wouldn't have been as easy in years of heavy dependency on CNC/waterjet where we send the components out for manufacture.

On a different note, if you don't do it already I recommend you build a practice robot in addition to the competition robot. If you do, try to build the practice first and use it for prototyping, programming, and learning how to build the competition robot. Your programmers will thank you and the build quality of your competition robot will greatly improve.

[BeardyMentor]

My day job is implementing an integrating CNC and other computer based manufacturing techniques in existing manufacturing processes. The correct answer here is; Do what works for you. Some parts the only way to make them is to have them done on a 5 axis CNC. Others, can and should be done with a drill press and a jigsaw. It depends on complexity and the tools and skills you have on hand. If you have easy access to a waterjet, use that. but if you just need a rectangular spacer with a 1/4" hole roughly in the center, a waterjet is overkill and the set up time will be longer than just using a drill press. For each part spend a SHORT period of time evaluating your options and use what makes the most sense.

I guarantee you that not every part can be made with the waterjet and some handwork is going to be required anyway. There will be plenty of hand work no matter how much stuff you get made on some flavor of CNC.

[Gdeaver]

Water jetting is wonderful if you have a local business that will help. We design in Solid works. It wasn't free. We spent about 400$ total on water jetted parts. It was well worth the budget. 1 day turn around as apposed to days and days to make them in house. The smaller parts - gussets, shaft adapters, motor mounts and other plates were done in house with a X-carve router. Last year we held classes teaching many students cad and design. This year over the summer we intend to cover cam with Hsm express. We are going to have a project with the cad cam and mechanical teams to design and build a 3d printer. The goal is to ingrain modern manufacturing methods and the maker mentality in the team and get away from the tedious hand crafted robot parts. It does take money. Find sponsors and fund raise. It's easier to get sponsors when you bring them in on a busy build night and they see kids hunch over the lap tops cading and the cnc stuff running full tilt. Of course there is always those parts that need careful hand crafting.