I’m curious: What does everyone think about part cutting? How often do you use cut parts in your design? Do you plan to cut parts ahead of time in CAD, or do it as you build if you realize that the standard C-channel won’t suit your purposes? Does it effect reusability of your parts in the long run?
The reason I ask is I find that the robot design we have finished probably has the most cut parts I have ever heard of on a VEX robot, not to give too much away.
I think the answer of most teams would be “too much”.
I think a small bit of cutting is part of the design process and necessary to get everything figured out and designed, but quite a bit can be avoided. Especially when prototyping, who cares if the robot is 20" long so you can use full length pieces, and then cut it down if everything works and fits.
I also think that simpler robots need less parts cutting, as they can be designed much better in detail before building. Also, on larger more complex systems not everything ends up fitting the way you want it to.
I think more cutting is generally required for the 15" college robots, but we try to cut as little as possible. When we do cut parts, we try to cut in multiples of five and sometimes sevens (from the 35 unit metal). I also let it influence the CAD design in order to minimize custom metal, especially for prototypes.
When I first saw how wasteful cut parts became post season, and how imprecise customization can be, I challenged myself to never cut parts, but rather find another sequence of materials which can achieve the same effect.
For the high school setting, I believed it was adequate, after all we advanced without aluminum and pneumatics, but I’ll admit it made designing a lot tougher than it could have been. But throughout that ordeal, I realized that the vex engineers put enormous thought in their designs which create a load of compatible combinations.
As a result, the last time we bought metal 3 years ago. However, we have to break our streak due to our lack of aluminum.
We’ve found it easy enough to use cut parts on new robots, especially if there are an even number of them. Of course, going from 12" Toss Up robots reaching 24" goals to 18" robots reaching 60" is going to render a lot of shorter metal useless.
We try to never cut stuff, but if we have to cut something we try and find an already cut peace to cut once again. Metal isn’t the most expensive of VEX parts but its still not cheap if you waist a lot by cutting too much.
Our club doesn’t have as much money as we would like to buy new parts, so we usually try to avoid using cut parts on our robots. If the design does call for cut parts, we look around the club for anything close that will work before we actually cut the parts. We have some pretty mutilated parts that have turned out to be useful in the past, so we try to avoid having to cut anything.
We always try to cut new parts from full 35 hole segments. This is a far more efficient system as long as you make sure you keep enough full length ones for when you need full length ones.
Okay so imagine a 35 hole. You cut it to be 20 long. Then you cut it to be 17. If you then were to need a 14 hole long bar cutting it from the 17 or the 15 would leave a very small piece left over that is wasted. While cutting the 14 from another 35 leaves another usable piece that is 21 holes long.
If you continue to cut down pieces eventually you will be left with bits of 3 or 4 hole long pieces that are then wasted. Like how 3 holes were cut off the 20 long metal in the explanation above.
Always. Our robot(s) would not work without cut pieces. That is why I joined VEX; I love designing cool little items that work with a design. Wouldn’t VEX suck if we couldn’t design / build custom systems?
We usually have our cut items designed before-hand. Some you just don’t realize you need it cut until you actually build it. Always try to design everything 100% before you attempt to build; it will make your life a lot easier.
(Like Tabor), we cut our custom pieces from the large full pieces. It makes more sense (just make sure to save the full length pieces if you need them :p).
My team, being on a club that barely has enough money, hardly cuts metal unless absolutely necessary. Often we find that every piece we need has already been cut by other teams at some point. Like we’ve taken towers from last year that are now implemented into our new drive.
When your club is near broke and you still want money for worlds, you find that you become very efficient at using what you have.
We have a different approach. e.g. If we are in need of a 21x and we have a 23x or 27x from a previous year, we will cut the shorter piece (23x or 27x) instead of cutting a 35x. We always cut the shorter pieces shorter, and leave the longer pieces long. You have more options with a longer piece then shorter ones.
We cut everything, metal and plastic items, if we didn’t the designs would be severely restricted. When I worked in industry as a water jet programmer it was my job to get the most pieces from a piece of stock. So I have experience with cutting pieces and save the amount of cuts.
We also have a wall of cut pieces sorted out on peg board and a bin of misc cut pieces so all the students know to go there first and then cut if they cant find it.