How do teams model fasteners in CAD? (Internal/external threads and reuse libraries)

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Hutchie.91
Hutchie.91
3
Joined: Tue Feb 15, 2022 3:25 pm

How do teams model fasteners in CAD? (Internal/external threads and reuse libraries)

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So a little personal project of mine, is to try model a full assembly of a rear wing. My own way of trying to learn NX at home since I already learned surface design in Catia when I was at uni. The reason why I'm trying to do this down to component level is because instead of doing some half-arsed CFD with some sub-optimal geometry (mainly the endplates), I would like to do some nice product renders and make it feel like a 'real thing'.

Anyway, this leads me to the actual question; how do F1 teams and automotive OEMs model fasteners in their assemblies and sub assemblies?

Obviously, over the years, a team/organisation are going to build up a library of certain fasteners they are using year on year for each new car/part. So do teams get a part file of each specific nut, bolt etc from their supplier or purchase/subscribe to a ISO/SAE standard library of fasteners, and add those part files to their reuse library, no doubt assigning those part files unique part numbers the company uses internally for reference in assembly documentation and BOMs etc? Or would a company identify which size bolts, threads, nuts etc they use often, and it would be knowledge a part designer would typically know before hand whenever they are designing a new part?

Like, if someone is tasked with designing the mainplane of the rear wing, obviously just the mainplane is going to be made of several part files that will be interfacing with each other, the actual external carbon we see, internal rohacell foam, machined endcaps which will then be mated to the end plates or to the 3-4 aerofoils in the 20mm free area for pre '22 regs etc, and obviously they will all be sharing common hole size and thread information as needed, so would the mainplane designer model those in as they go using the hole/thread commands on the geometry, or does the person responsible for the whole rear wing sub assembly, go back and model the holes and threads defining their specs, and can then go in and add the required bolt, screw or nut fastener part file to the assembly file?

When I was looking through the 2015 Caterham thread and the CAD drawings there, I noticed in the assembly diagrams, they were drawn/modelled using symbolic threads (which would make sense, modelling threads for each bolt in an assembly just ramps up computational resource demands), and this would lead me to believe that Caterham do make use of a reuse library of standard fasteners they would have needed, but then I remember Red Bull's old video of the life of a bolt, where a bolt for some sort of camber adjustment on the hub, they designed and machined in-house, where the designer modelled the threads and even test fitted the bolt in their CAD model, with the threads matching the female hole threads perfectly.

So I'm just after a bit of insight into how it all gets done in the real world and what would be the best workflow for me to try emulate that as best as I can. I've managed to get a large fastener library installed into NX, but the family part files for all those bolts and screws show symbolic threads only, meaning every time I bring in a fastener, I have to manually open the part file, activate the detailed thread and then go back to the assembly every time, which is a bit of a pain, not to mention trying to save assemblies that use part family components has been a bit of a headache and NX just isn't playing ball with me.

Obviously for my specific usecase, symbolic threads aren't ideal as when it comes to actual renders I do, obviously I want all the details in the model to make it feel as realistic as possible, if I was to do an exploded view render in KeyShot for example.

Sorry for the long rambly post, this aspect of CAD and dealing with assemblies and how every component gets modelled and managed has always been super interesting to me.

tok-tokkie
tok-tokkie
34
Joined: Mon Jun 08, 2009 3:21 pm
Location: Cape Town

Re: How do teams model fasteners in CAD? (Internal/external threads and reuse libraries)

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This is a long way from Catia & F1. It is Fusion 360. In this YouTube at 12:05 you will see a group of modeled cap screws.
At 12:12 you can see there is a Component labelled Hardware which includes Bolts.
You can download the design file.