Fabrication

FIRST General Forum
1

We’ve all heard the arguments of in-house fabrication vs outside fabrication, and we know the answer depends on what your goal in FRC is and what your team wants to do. However, there is a point where things are taken too far.
FRC provides an engineering experience in designing and assembling a robot. However, the emphasis here is design. My team has become a team of fabricators. Our team does not do design, we design around the parts we fabricate. We avoid outside fabrication because fabrication is “the fun of robotics” I’m not arguing that fabricating parts is fun, but if you solely want to fabricate and not design, that is not engineering.

Has this problem occurred to anyone else, and has it gone to the other extreme?

2

This year, we did very little in house fabrication. Everything had to be designed, before it was sent off to the machine shop. While I do not like having so little fabrication done by students, I feel we made up with it by have a 20 times better CAD and design process this year. Though I do not like the process we took this year, it was necessary in the advancement of our team. We do not have enough space for any kind of large machines, namely mills and lathes. This year, because we did so well in LA, we hope to get more space and funding for next year, and do more in house work than we have ever done before, while still having a complete design process.

3

This is a topic that comes up every season, if not 5-10 times a season. The answer to this question is simple: There is not a right answer to the question. Every team must answer the question based on their goals and the resources they have access to.

The real problem come when teams decide their answer is the right one and those who do not do it their way is wrong.

4

our team designs the bot, and we also mostly do in-house fabrication with VERY few parts being sent out to be made. we do run into a few challenges with this, as we tend to finish very, very close to ship date every year because we spend too much time designing before we actually get to building. we have debated sending more parts out for fabrication, but I feel it’s part of being a part of FIRST to learn how to machine the parts we design too, and everyone can learn the maximum amount that way. However, that’s my take on it, and the standpoint of most on our team.

5

The Cheesy Poofs are able to do a lot of in house work. Part of it is a fast design process, and basically starting to machine on the first day of build. They can do this, because they know what type of drive train they are going with, and no the process of what they will have to machine. By adapting the same drivetrain to each game, they can already start to machine on day 1. By standardizing in this way, you can start machining much earlier, and have more time for practice and programming.

6

Different teams have different philosophies; there is no right or wrong. If the team exists, and students are inspired, then I would consider that they have the right philosophy.

7

the only time they might be “doing it wrong” is if their design/fabrication process costs them so much time that they don’t get the robot done. The hard lesson learned isn’t real inspiring.

8

As we all strive to create new engineers, it is important that we try to expose them to both the design and fabrication aspect of creating these machines. Every engineer must design within the limits of the fabrication resources that they will have, and the best way to understand those limits is to experience the fabrication process for yourself. An engineer must design the nitty-gritty details of what is possible and economical to make, which is hard to do if you have never seen or done it for yourself. I find that my (limited) knowledge of fabrication options effects nearly every detail of every design decision that I make. Most designs that I consider to be “bad” or not workable are such because they are unnecessarily difficult or impossible to make.

When I was a brand new graduate engineer in my first job in industry, my company put us through a months-long apprentice program in the machine shop/toolroom where we worked along side toolmakers and learned basic machining and shop techniques. They knew we couldn’t possibly send valid design work to the shop if we did not understand the details of what it took to make the stuff we designed. I realized then that it was something that was missing from my college curriculum. One of the biggest frustrations for those that have to work with new engineers is the new engineer’s lack of understanding of what can and can’t be made, or made economically. It is something that simply takes years of experience to develop.

Most FIRST mentors have the experience of having bright, enthusiastic students come to us very excited about their design idea, only to find out from us that it cannot be made. Learning to adjust your design hopes to the reality of what can be fabricated is one of the most difficult and important skills an engineer can learn. There is no better way to begin learning that lesson than to experience making parts for yourself.

Whatever your team’s fabrication resources are, your students will need to learn to design within those resources. If your team is lucky enough to have fabrication sponsors that can do higher-level fab work for your team, take students on a field trip to the sponsor so they can see the work being done. Even if they cannot do the work themselves, seeing what it takes to create the parts they dream up will give them valuable insight.

Naivete about what can and can’t be made is one of the most common obstacles for a new engineer. We are giving our FIRST students an enormous head start in understanding that lesson. It is one of the many things that will set them apart from their peers.

9

I understand that knowing and experiencing the fabrication process is important, and I would not be complaining about in house fabrication if it weren’t for the attitude that building a robot is not about design, but fabrication. I don’t know if I made it clear in the first post, but what is happening is that our team is not designing by engineering drawing or CAD. What we do is say what drivebase and type of manipulator we want and we come up with the dimensions while we are fabricating. As a result, the entire frame has parts mis-measured, inaccurate, and the robot does not work because things weren’t pre designed, they were designed while being placed on the robot. As a senior on the team, I want to see my team go through the design process and design something before starting any fabrication.

10

Many people have already said that there is no right or wrong answer to this question and I agree. But I might add that things are not always what they seem. I do not believe there is really much pure engineering or pure fabrication out there. Engineering is an applied science so it must and does take into account all aspects of finished product including fabrication. And performing the simplest fabrication process can sometimes shed light into good design practices.

Any good mechanical design has to take into consideration how the parts will be fabricated. The choice of materials, aluminum vs. steel, sheet metal vs strut, drilled and assembled plates vs machined bar stock, bolting vs welding, etc. Even if you never leave the CAD station and outsource all of your fabrication to a machine shop, some amount of your design does need to rely on a significant knowledge of your fabrication process. How you come by that knowledge can vary, but it must be there to become a really good designer.

The same is true in the other direction. Experience in fabrication cannot help but give you a boost toward becoming a better designer. I believe you can become a great designer without ever drilling one hole in a piece of aluminum. But that does not mean that time in a machine shop at some point does not help you more quickly and efficiently learn some important lessons.

Most machinists have had no formal design training, but most have a acquired a significant degree of design knowledge almost through osmosis. This is not the best way to learn some things and can lead to some significant holes in your knowledge if it is not supplemented by detailed study in the basics of statics, dynamics, properties of materials, and all the rest. But do not underestimate the vale in knowledge obtained in this manner.

Perhaps in these days of CNC, EDM, LASER and water jet cutting, etc. there seems to be less connection between fabrication and design. But occasionally there is just no substitute for having a intuitive knowledge of what is easy and difficult to machine, the order of how things actually need to be machined, and even what the machinists themselves might be able to teach you.

11

Failing to plan is planning to fail.

In industry, building without a drawing is extremely rare. And engineers who do their own building are almost as rare. This is because close to 95% of engineers would simply turn the part they need over to manufacturing. (The other 5% are likely classed as engineering technicians.)

So the normal process is to design, then build and refine the design.

We just had this discussion in one of my senior-level college classes today actually. Apparently, back in the 80s, at least one company designed by fabrication–they focused entirely on ease of manufacture. This cost them a lot of business because once built, the product could not be serviced easily. Fabrication drove their design process, and this damaged the company. They have since refocused to designing with all the other factors (and believe me, there are a LOT of other factors!) in mind, and are producing better products.

If I were your team, I would go to a local but large engineering/manufacturing company, and have them spend a day there shadowing the engineers and possibly the fabricators and talking to them. I think it would be an eye-opening experience for the team leadership. Sometimes, it’s not all about the fun.

12

In before thread close…

13

Anupam,

If I’m correct, you are not concerned about how much direct fabrication your team does or how much an outside shop does. You are talking about “designing” a robot vs. stumbling through “making” a robot.

I think that your problem is one that most “capable”/“established” teams have either bypassed altogether, or solved many, many years ago. Others are stuck.

Many teams start out by taking the KOP, asking “what can we build with this stuff” and starting out making something right away. When it doesn’t work, they rebuild. If it works, then that’s what goes on the robot. “Prototypes” become the actual systems that make it onto the robot. Electronics are added as an afterthought, and the whole thing barely gets programmed.

Some teams seem to repeat this year after year.

If you are very lucky and clever, you can come up with a competitive machine, but you never reach your potential. We’ve been very lucky.

This is our first year (after 10!) using CAD to do any real planning of our robot. It has made a huge difference. The thing looks like it was planned out - designed to be the way it was, because IT WAS! Our problem was not having anyone with any CAD experience, or the time/interest in learning.

The key to getting over this hurdle is having people who can get ideas into a design that can be documented and easily and accurately communicated to everyone. Since you are concerned about it, it sounds like you’re going to have to take the initiative to make this happen.

Get some like-minded people (if you can) from your team together, get some copies of some CAD software (students can get SolidWorks & Inventor free if they are on robotics teams) and set out to learn it. There are online tutorials if you can’t get instruction from someone. When the time comes, do what you can to “stay ahead” of the fabrication. Keep in mind that your model doesn’t have to be “perfect” for what you are trying to do. It sounds like any kind of beforehand design will be an improvement.

To paraphrase Gandhi - “Be the change you want to see in your team.”

Good luck!

14

Agreed. After re-reading the original post I now see that I did not fully understand the question.

There are things to learn from both design and fabrication, and if a team chooses to emphasize one more than another that is hardly wrong. But completely avoiding the design phase is never a good idea unless you are referring to a completely trivial problem. And the more experienced I become, the more I believe that there are no completely trivial problems.

15

How is fabricating not a part of engineering?

How do you think they did it in the days before CAD? They built it and tried it out. Theres nothing wrong with it. At all. Don’t force a method on your team that they don’t want to use. If they have fun doing it, their being inspired. This is exactly how our team works. You build something, try it out, and use your engineering skills to improve it or redesign it if it didn’t work out right. I personally don’t see how people can get students into engineering by having 2 students cad it while everyone else waits around for parts.

16

While I don’t necessarily have a problem with your answer, before CAD there was Plain Old Drafting. :stuck_out_tongue:

17

Because that’s not what happens.

There’s a LOT of misconceptions about how the pretty powerhouse robots are created.

The students involved in CAD are typically CADing the drivetrain, while the other students work on designing, manufacturing prototypes, and testing an end effector, which then gets CADed, and all of the parts get manufactured in a professional shop, and then assembled by the students.

They’re involved at every step except for manufacturing of the final product. The difference between them and a majority of teams is that a majority of teams are basically fielding their prototype, rather than a finished product.

18

In their first year, I’d suggest that they don’ t try to completely CAD out the robot before any tools touch material. It will most likely take too long. As the initial model is being developed, students can be fabricating and testing prototypes, or building components that they know they will be using. As components are finalized, they can begin fabrication - even without a complete CAD model. If nothing else, CAD in parallel with the fabrication.

Make the transition with as little disruption to the way the team works as possible. Most likely, everyone will see the advantages to introducing a bit of design before fabrication begins.

Perhaps watching the Grant Imahara “FIRST Design” video might help.
[http://www.youtube.com/watch?v=YNweJ7QbF7Y](http://www.youtube.com/watch?
v=YNweJ7QbF7Y)

  • Mr. Van
    Coach, Robodox
19

Not true. We drew it. The process was no different, only the tools and medium were different. There was such a thing as design before CAD. Cars, bridges, airplanes, and televisions were not cobbled together by trial and error.

20

I can see what the OP is saying. I don’t see how they didn’t have a plan before building. My team loves the fabrication aspect. We do everything in house. They love it so much that no one has any real interest in drawing an entire robot before building. So this year I got stuck drawing portions of the robot in Inventor. Next year I hope to have some students spooled up on the program to draw the robot as we progress.

As for knowing design before fabricating? I think you need to know how to make something before you can really be a great designer. That doesn’t mean you need to actually drill a hole but you need to know its possible. It’s just more fun to learn by actually doing it.