Throughout my college ME design courses whenever we used the waterjet I'd always run into the same problem — the holes never came out to spec. They'd consistently cut oversize, and the geometry was never a clean circle. Feel as though I am always told these machines give precision accuracy, but I have never experience it. Might be a user error, lol. Every single time I ended up having to go back and model it undersized to then drill press to open them up and clean them out before they were usable.
My most recent random fun project was a layered aluminum ashtray cut from 1/8" 6061 sheet. Same issue, different waterjet. Had to re-drill every hole on the drill press before tapping them at 82° to get the flat-head screws to sit flush. Not a huge deal on a project like this, but it made me wonder if everyone just quietly accepts this as part of the waterjet workflow or if there's something that can be dialed in to get cleaner results.
Is it a kerf compensation issue in the CAD setup? Lead-in/lead-out placement? Or is drilling to final spec just the standard practice when you need a clean hole off a waterjet?
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