I’d like to propose a potential rule update regarding structural parts in High School VEX competitions. Currently, functional parts like chassis braces, mounts, and other supports must be cut from polycarbonate sheets or metal, which can be time-consuming, difficult, and sometimes limits accessibility for teams without certain tools.
Proposal:
Allow 3D-printed structural parts under the following conditions:
Thickness: Must be 0.064 inches thick, the same as standard polycarbonate sheets.
Orientation: Parts must be printed flat to mimic polycarbonate’s strength and behavior.
Usage: Only replace polycarbonate structural parts; no changes to function beyond fabrication method.
Inspection: Thickness can be verified using a VEX-issued measuring tool or a built-in feature in the official inspection process, ensuring compliance is consistent and straightforward.
Reasoning:
Fairness: Maintaining thickness and orientation ensures parts are functionally equivalent to polycarbonate.
Accessibility & Cost: Teams can more easily and inexpensively translate CAD designs into real-world parts without cutting or wasting polycarbonate sheets.
Inspection-Friendly: Using a VEX-issued or built-in measuring tool ensures consistency and enforceability without ambiguity.
Innovation & Efficiency: Encourages additive manufacturing, modern engineering skills, and reduces material waste while maintaining competitive integrity.
The goal is not to give an advantage, but to make structural fabrication more accessible while maintaining safety, fairness, and function.
I’d love to hear thoughts from the community—support, concerns, or suggestions for improvement. If enough teams are interested, perhaps the GDC might consider officially allowing this in the future.
In practice, I don’t really see this happening unless there are similar restrictions to how many individual parts may be used. It’d be nice to have more accessible manufactured plastic parts, but I think the new polycarbonate rules were put in place to explicitly prevent teams from overusing manufactured plastic. Furthermore, 3D printed filament material like PLA is far more likely to snap in half at such thicknesses compared to polycarbonate. Not saying that I am against this idea, just that it probably won’t happen (there are many discussions on this matter in the past spanning hundreds of replies that went nowhere, so fair warning).
It would be too easy to get some extra thickness then attribute it to an error of the machine. it could be used strategically to gain thickness, or an inexperienced team could be required to get rid of a vital part over print tolerances (if that’s the right term).
It would be treated exactly as poly carbonate and add to the plastic limit. Stronger materials can be used (petg, cf pla) and this would be a cheaper way for teams to make precision plastic parts similar to polycarbonate without spending thousands on a lazer cutter or cnc.
I think you have good intentions. Honestly, 3d printers are definitely more available than laser cutters and CNC machines. However, the good old scissors is also more available than 3D printers. and it looks like the GDC aren’t going to change their minds any time soon…
Well, 3D printed parts may not be as reliable as the issued VEX parts. One is metal, the other is PLA (or another material). By the way, I totally undertand the reson behind your “cost” category. However, safty always comes first. VEX issued their parts because they knew they are reliable. If your robot discombobulates during a match, it’ll be your fault. Not VEX’s. We’ve never seen VEX parts snap during matches unless they were axles. But you cant 3D print a reliable axle. (Correct me if I’m wrong). Bottom line, in some cases, 3D printing is unreliable for structure. Now, as somebody thats been competing in VEX for 5 years now, my teams have had 3D printed nametags, or little charms on the machine. Thats fine. But making the machine’s structure out of any 3D printed parts is risky. But anyway, enjoy your year of competing.
What I’ve learned from using 3D printed VEX parts… (not just ploycarb replacement)
I occasionally have students use 3D printed VEX structure in my engineering class (NOT on V5RC competition robots). The reasons are usually:
They want lighter parts
They need something custom (ex: 120 degree c-channel couplers)
They want discontinued parts (I only have 4 wheel legs)
These parts are much weaker and often fail unless redesigned to be thicker, have ribs added, etc. I don’t think a single printed VEX part has worked well without some modification.
If you have enough teams in your community you could try an off-book event. Competition models grow from public endorsement. If you have enough support you could host an unofficial hybrid event where you amend a few rules specifying the material, volume (weight), maximum part size, quantity of parts, etc.
You could host it during the gap that often happens between your last tournament and regionals, or regionals and worlds.
The REC Foundation is usually interested to hear about innovative competition models. It may not influence the established core V5 competition but if enough teams are taking the time to fabricate parts, it may lead to something new.
My proposal is different. Rather than allowing 3d printing in general, I am suggesting simply allowing 3d printing as an optional replacement for polycarbonate.
ugh, it is NOT a direct replacement as the processing for polycarbonate sheets is much different than 3D printing using PLA/PETG… One facet of plastic rule is non-shattering requirement due to safety, with the myriad of printing technologies and media that can not be assured on a scale at all V5RC events.
I find it interesting that you think it will be inspection friendly - far from it, it adds more complexity to the process. Let’s not get started with it being less wasteful material wise - have you see the waste buckets next to 3D printers of failed print
I agree with James on this one, you are beating a dead horse with this one. Your proposal is the same - “Let us use 3D printed parts for our robots in V5RC” - nothing had changed.
It wouldn’t be a direct replacement to polycarb because 3D printing is a lot more weaker than just using polycarb. As @lacsap said in his above mesage, it makes the general process of inspection at any event. Also, this year they also cut down on polycarb because of the inspection process for it and how many pieces there were per bot i think.
It would be a very hard process for the inspections because if there’s a limit on infill or some other settings, it’s hard for them to make sure it’s legal. Thickness would also be horrible to inspect because just because the piece is a certain thickness, it may not be on certain robots.
For fairness, there are some things that many teams can do to be able to avoid or manipulate these rules. How would one inspector know that they didn’t print it vertically or any other way?
In conclusion, it is NOT inspector-friendly, whereas it just makes their job harder to do by adding these rules. There are so many factors that are regarded are in here for teams to follow these rules and can possibly lead to some accidental thickness added into their part. It would just be insanely harder to implement into the competitions.
To add to @99976D 's myriad of causes of failure (and slicer configurations!):
Two words - Printer Hygiene
A lot people get preparing a clean build plate right. Many have go to solutions = hair spray, glue, painter’s tape … the list goes on. If you are consistent with your prep, the likely print fails are reduced.
Other factors come to play - old humid filament yields flawed or failed prints. The use of dryers, proper storage techniques, heaters - all help mitigate.
All this to say when you introduce 3D printing, you are introducing a wide range of inconsistencies to the finished product - while the traditional sheets of polycarbonate are manufactured with more consistency and the techniques of cutting and shaping are pretty well understood.
Why does VEXU get 3D printing? Their robots are complex so bad of inspection. The answer is simple - fewer teams, fewer events, more sophisticated technology at the college/university. Very different quality of work than can be produced on a $200 3D printer.
Layer shifts are unlikely to be a concern for parts with a height of only 0.064 inches. Bed adhesion should also be sufficient, as most components will maintain a significant contact area with the build plate while keeping both mass and height low. The same applies to potential knock-off issues. Any clogs are generally a matter of user technique.
