Should Lexan usage be banned?

The reason we are asking you to rephrase your argument is because your points are so outlandish it is hard to imagine how someone dislikes lexan

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I can’t speak for everyone, but I don’t personally own a CNC machine and neither does my school. That being said, there are public work spaces in my area that do have CNC machines that can be used for free or for a small fee granted you provide the polycarbonate. It’d be really hard for vex to encourage high level manufacturing without the use of polycarbonate, and because we live in a world filled with resources, it’d be silly to get rid of polycarbonate entirely.

The argument for teams that are at a disadvantage is also silly because nothing is stopping a team from using polycarbonate on the same level as those that do. The only thing stopping them would be either a) money or b) knowledge gaps. Both of which are things out of the control of Vex. If you make the case of money being an issue, polycarbonate is relatively affordable compared to aluminum, and it already has an area limit to the amount of polycarbonate you are allowed to use.

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It also introduces students to CAD Software which may increase productivity.

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Or even then, aid in the replication of the engineering process VEX strives to promote. CAD is a huge thing in engineering, and learning to use it properly can make the actual building process of VEX a lot smoother

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O I agree, I was just saying that about some cases

Pretty much anything that can be cut from lexan with a CNC machine can be cut using tinsnips and a dremel if someone really wants too. It won’t be nearly as pretty unless you’re an artist or something, but it will still function the same way.

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Taran keeps changing his argument. Connor originally brought up the discussion of how since using a CNC to cut your polycarb is legal, should 3D printing be made legal. Taran responded to this saying that since he couldn’t afford a CNC, that he would be in favor of disallowing CNC’s to be used for Vex.

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The problem with this is that Vex can’t prohibit certain tools from being used to modify polycarb in the same way that other tools, like a bandsaw, would. Once Taran realized this, he changed his argument to completely ban polycarb.

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Completely banning polycarb just because not all teams have access to a CNC is ridiculous. If teams can afford to compete in Vex, then they most likely can pay $200 for a CNC and if they can’t, then they can go to a maker space in their area to get it cut there. Regardless, using a CNC to cut your polycarb doesn’t give a huge advantage. The hood assembly that 169 used for the Turning Point worlds robots was cut with a CNC, but the hood assembly used on the states/WPI robots was all cut with a bandsaw/file. The picture that people like to share of 1961’s polycarb was completely done for aesthetic reasons.

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A good example of polycarb that was cut for weight saving reasons was 4001A’s slider from Tower Takeover, which they did with a drill. They could’ve used a CNC and it would’ve looked a lot prettier, but just drilling the holes was good enough.

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TL;DR - CNC’s arent that important and if you really need one go to a maker space near you

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I guess you could make that argument, but there is no doubt a CNC will be geometrically perfect (for most vex applications, the tolerances on most CNC machines are practically perfect). Doing this by hand won’t ensure anything because of parallax error (which could be mitigated I guess, but you won’t know for sure, even with very precise measuring tools).

TL;DR a CNC machine does provide an unfair manufacturing advantage to those teams that know how to use them.

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I’m not gonna lie this may be one of the worst threads I’ve seen, and I’ve seen Coolyo bot . Definitely allow lexan it’d be dumb not to.

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Not really. I’ve known many teams that have had nearly perfect cuts which are equivalent to a CNC machined lexan piece by simply printing out a template of the part and taping it down onto the Lexan sheet. All you need is some time, a good file, a drill, and a coping saw.

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This is a really good idea, I never thought about that. How would you go about printing a template from a CAD file? I’d imagine you print out one of the faces of the part you made on CAD right?

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I do believe this has crossed the line between objective debate and pointless name-calling.

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Do a sketch of the part that has a 1:1 scale and print that out

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This lexan guide for our flywheel was cut out with a coping saw and smoothed out with files and sandpaper. Sure- it would’ve been much easier with a CNC, but with enough patience, you don’t need heavy machinery to make a functional final product.

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Forgive me if I duplicate anything someone else has said, but these Lexan/CNC/3D printing threads have jumped around a lot. I’d like to throw out my opinions for consideration. (Note I am a 2-year VEX coach and 8-year BEST Coach)

Lexan: I have no problem with using it. It has a history of use in VEX

3D printing: I don’t agree with the stated reason for disallowing 3D printing. Given the cost of VEX components, there already is an inherent access difference for teams. Some teams can’t afford extra aluminum, meccanum wheels, sensors, pneumatics, spare motors, V5, etc. This has not stopped VEX from allowing them to be legal.

CNC: Our teams do have access to a Shapeoko 3 CNC that we bought for BEST robotics. It’s a much bigger investment than a 3D printer and has been a great asset for BEST. It definitely gives us an advantage, but it also changed our design process. I thinks team should be encouraged to use or seek out this resource, but there really isn’t much you can do with it that you couldn’t do by hand with enough care. The CNC is just faster and more precise.

I find it hard to reconcile that VEX allows CNC machines but disallows 3D printing due to a cost/access barrier. In my experience, more students have access to 3D printers than CNCs. If a team is looking to expand its tools, a 3D printer is a much smaller investment than most CNC’s. In fact, a decent number of my VEX team members already have their own 3D printers at home.

One thing I love about BEST is that the kids design and build almost every part of the robot. It is not just a kit. It can be a big barrier for some, but when that lightbulb goes on and they realize how creative they can be, it is awesome. A CNC and 3D printer bring it to another level.

Maybe VEX could institute 3D printing in the way BEST has (They resisted it for the same reasons for years). BEST allows a maximum of 2 individual 3D printed parts that fit a certain size constraint. Not 2 assemblies of parts, but 2 distinct parts. This allows for creative designs and ingenuity while keeping the “advantage” of 3D printing to a minimum – but then again, the amount of advantage you get all depends on what you do with it.

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The one thing I’ve taken from this thread is the only advantage a CNC provides is saving time.

I personally agree with this. Our school (including a lot in our counties and neighboring counties) also has an abundance of 3D printers. All the students have to do is expand how they can use the tools allotted to them.

This… I love this quote. When I first got into 3D modeling and CAD (which was only really last year) I had dreamed of the ability to machine custom Lexan pieces with pinpoint accuracy. Only this year did I have the option to bring that into reality, and it really does shape how students think in designing and what is possible.

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Mostly, yes, with an increase in precision. But it also changes how you think about the design process a little. You are more inclined to make creative parts. But then again, you can do this by hand also. It is just easier to master the skills needed for a clean part on the CNC than it is to do it by hand - for most kids.

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You gotta admit excluding the use of lexan would hinder the competitiveness of many good teams, especially last year

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I 100% agree. Thank you for stating it better. However, my point was not about your opinion but what was actually said.