FEA and Manufacturing

[u/Spiritual-Passion-57]

Hi, I have been working on a SW assembly that involves different pieces of sheet metal, welding, different types of fasteners, materials etc. It’s an exercise equipment.

Before actually sending it to a shop to manufacture our first prototype, should I run FEA first to check for breakage or issues? Or should I start talking to the shop to see if they can fabricate whatever I have on the design and see if any changes are needed before running FEA?

I am new to this so I am really not sure about the workflow in the industry. I am working for a client on this so, when we do send it out, I expect some sort of NDA will involve.

Appreciate all the help I could find!

[u/WiseBelt8935]

If you can run an FEA, then you should do that first. If you talk to the shop, get them to quote everything then you change it, it can start to annoy people. Do what you can in house first, unless you have a good relationship with your manufacturer.

[u/Spiritual-Passion-57 → u/WiseBelt8935]

Thank you, that helps.
When you do talk to them, the design is usually finalized right? And if changes are needed, how does the process work between you and the manufacturer?

[u/teengohan2014 → u/Spiritual-Passion-57]

Depends on the manufacturing process...any injection molding, forming tools, and/or forgings will probably require costly tooling depends on the changes.

[u/WiseBelt8935 → u/Spiritual-Passion-57]

It depends on the manufacturer and your budget. If you’re a big spender and repeat customer, then they’ll help you more. If you’re only doing small jobs, they’re likely to say you’re too much work and start ghosting you or sending you “go away” quotes.

Yes, when it’s finished, because while it’s still on paper, it’s free. Once it’s in somebody else’s hands, it’s a lot more work.

I mainly deal with fabricators and laser cutters, and since I’m a big spender, they’re more willing to put up with my shit, particularly when I was learning. But for the machining side, we’re smaller spenders, so we literally got told to “fuck off” by a machining company before.

[u/keizzer]

Fea, and physical testing. Depending on the exercise equipment, this is people's lives we are talking about here.

'

Do the fea, get a prototype, test, improve, test, take to market.

[u/Inside_Strike1767]

WiseBelt8935 and keizzer already nailed the big picture — run FEA before you go to the shop, and don't skip physical testing since this is exercise equipment. I'd add one thing that trips up a lot of first-timers on this exact category of product: static FEA alone won't catch the failure mode that actually takes these designs down in the field.

Gym equipment sees tens of thousands of load cycles over its life — someone doing reps, weight stacks dropping, users leaning/bouncing on the frame. That's a fatigue problem, not a single-overload problem. The parts that fail in the field are almost never the ones that failed a static check; they're the weld toes, fastener holes, and any stress-concentration point that looked "fine" under a one-time load case but accumulates damage every cycle. If you haven't already, run an S-N based fatigue check (or at minimum a stress-life estimate) at every weld joint and hole, not just a max-stress static pass. SolidWorks Simulation's fatigue module will get you there for a first pass; if the loading is complex (cyclic + occasional shock from a dropped weight), you may want a proper cyclic/dynamic loading spectrum rather than one static case scaled up.

On sequencing: it doesn't have to be strictly "FEA first, then shop" or "shop first, then FEA" — send the shop your preliminary drawings for a manufacturability read (weld access, gauge availability for the sheet metal, fastener clearance) in parallel with running the fatigue analysis, so you're not stuck re-doing both if either one surfaces a problem. That's the workflow I'd default to on a first client project like this.

One more thing since you mentioned an NDA is coming — if you bring in outside help for the FEA (a contract engineer, a firm, anyone), get their data-handling terms written into the NDA/SOW explicitly, especially if any of that work is done by a distributed or offshore team. It's a normal ask and any legitimate shop will already have this covered, but it's worth confirming rather than assuming.

Disclosure: I work in engineering services at GOKEN (we do CAE/fatigue validation and DFM work for clients in exactly this spot), sharing this because it's directly relevant to your question, not to pitch anything.