Filament for parts in VEX U

In your experience, what would be the most suitable filament to print parts in VEX U?

Most of the time, it’s whatever you can buy the cheapest! :wink:

You need to evaluate the properties you’re looking for, and compare to what’s available. Good stuff to document in your engineering notebook.


It really scares me that the vibration ends up splitting the pieces

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You’re selection of fill density/infill can have huge effects on properties, just as much, or perhaps even more, than the particular material. You might need some trial and error experiments for your particular part, and, of course, if you’ve got your model in SolidWorks, you could do some stress analysis on the design to optimize it.


Vibrations splitting a piece a part is something that should never happen, that should be the least of your worries, however what you do want to be mindful of is whether or not a piece could potentially take an impact from another robot or from running into something.

As for filament, it doesn’t matter too much, PLA is one of the most common materials that people print in, so that’s always a good place to start. If you’re wondering about specific brand, take the time to read some reviews and determine what price is best for you. I’ve heard that Hatchbox filament is pretty good though.


Spend some time watching this youtuber’s videos on achieving strength for hints and tips. Filament can make a huge difference, of course, but spltting along layer lines suggests you want to be running the nozzle some balance of hotter, slower and lower layer heights to smoosh the plastic together. Can you share a part that you want to print and approximately what it’s for without giving away competitive advantage? We may be able to comment on printing for strength in your specific design. I have a MK3S so I can try something if I get time.


Oh hey, and photos of parts that have split.

[attempt at humor]
Be sure to get waterproof filament, water resistance will not suffice for future games.
[end attempt at humor]


TL;DR : unless you’re looking for some specific property, PLA is our usual go-to

PLA is pretty sufficient for most parts

In my experience, you can push PLA prints really fast and it’ll still be super forgiving.

We use eSUN PLA+ and Hatchbox branded PLA

ABS is nice because you can easily solvent weld it with acetone.

One of our departments completely 3D printed a multirotor with ABS (minus the electronics and propellers), crashed it, and gave up on it. Little bit of acetone later and it was flying again.

Personally I have a spool of MG Chemical branded ABS

PETG is nice because it's more elastic than PLA or ABS

I 3D printed a passive cone intake with PETG during ITZ.

PETG layers also fuse very well, during stress testing the cone intake actually split through the part diagonally rather than along a layer.

My spool of PETG is Inland branded

TPU is pretty self explanatory

Compliant wheels, custom timing belts, flexible wrench to mess with people, etc

One of our members brought in the spool of TPU and I can’t recall the brand off the top of my head

Nylon is strong and wear resistent but honestly kinda hard to print

Be careful when printing nylon, almost all plastic extruder lining (PTFE) deteriorates at around 260°C, nylon is usually printed at 240-260°C

My spool of nylon came off a spool of 0.065" trimmer line

There’s also tons of other types of filament (just look at the list on McMaster), but these are what I’ve had experience with.


This with one addition. TPU is tough, like really, REALLY tough. If shore 95A printed solid, it is also surprisingly rigid, making nearly unbreakable prints. I personally used this to make a puncher stop during turning point which was able to last the entire season. I purchased have purchased sainsmart tpu which works very well. We have also investigated intakes and custom damping mechanisms using TPU.

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Polymaker PLA PolyMAX. Best filament I have used for VEXU parts. Been using it for 4 seasons


Density and Infill aren’t the answer for durability. Its the amount of Walls. I run 6-8 walls on all dimensions of the parts my team prints. Never had a single part break in 4 seasons of usage.



Aun estoy en planeaciones, conseguiremos todo el material para iniciar el equipo pero agradezco mucho tu intenciĂłn de apoyar

To Translate:

I am still in planning, we will get all the material to start the team but I appreciate your intention to support
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PLA is pog. Its’ probably best for most situations

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Thank heavens for google translate :slight_smile: Just realised I haven’t looked to see if there’s a good browser add on that will parse pages for unfamiliar language.

That’s what forums are for :slight_smile: I guess I’ll have less time available in a couple of weeks. When printing at critical strength, keep filament as dry as possible. I print directly from a sunlu dry box. It makes a big difference even with PLA. Moisture in the filament causes small gaps in the print from where it boiled and tried to escape. Those tiny holes cause stress concentrations that initiate cracks. My favorite cheap and easy to print but strong PLA is sunlu PLA +. When a fracture occurs, it is quite an exciting brittle fracture, so if you need something to fail gracefully so that you can see it gradually give way, basic PLA could work, or you can find the results you want in CNC kitchen experiments.

How good is google translate?
Para eso están los foros :slight_smile: Supongo que tendré menos tiempo disponible en un par de semanas. Cuando imprima con una resistencia crítica, mantenga el filamento lo más seco posible. Imprimo directamente desde una caja seca sunlu. Hace una gran diferencia incluso con PLA. La humedad en el filamento provoca pequeños huecos en la impresión de donde hirvió y trató de escapar. Esos pequeños agujeros provocan concentraciones de tensión que inician grietas. Mi PLA favorito, barato y fácil de imprimir, pero fuerte, es sunlu PLA +. Cuando ocurre una fractura, es una fractura frágil bastante emocionante, por lo que si necesita que algo falle con elegancia para que pueda ver que cede gradualmente, el PLA básico podría funcionar, o puede encontrar los resultados que desea en experimentos de “CNC Kitchen”.


Pretty good translation dude haha, I really forgot to write that answer in english haha, i’m sorry.


Seems like you needn’t apologise for having a different first language and being comfortable enough to forget. Enjoy the research!


¡No hay necesidad de disculparse aquí! Buena suerte con sus futuros esfuerzos.

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