Actually not.
My handguard saw will do as well as the sawstop non-destructively (independently tested and verified, so you don't have to take their word for it).
They do it (basically) by predicting whether your hand will touch the blade, rather than waiting until it does touch the blade.
If you wait until someone actually touches the blade, then yes, you have to operate very very fast. That is unavoidable due to physics, as you say.
But if you can gain 100ms or 250ms by proving a 100% probability that the hand will touch the blade before the person can stop it, you now have a lot more time to stop the blade.
Ive looked at the saw you mention in another comment, and in all honesty Id much rather have a safety precaution that works based on very simple physics (like sawstop) than some black-box ai hand detection algorithm.
Have you considered that they've thought of this?
Seriously.
This is company producing high end sliding table saws that cost tens of thousands.
They've been at it for over half a century.
This is not someone producing a 299 saw as cheaply as possible.
They are a German company (ie regulated heavily) and have a ridiculous number of safety standard certifications that test things like "what happens when there is dust"
do you really think they haven’t thought of the obvious basic issues and figure out what to do about them?
if so, what evidence do you have that this is true?
(Also I think you don't understand European requirements on dust extraction and allowed exposure to wood dust. This saw does not produce a meaningful anount of dust)
Finger movements are generally on the order of 1-2Hz, a hand holding a large piece of wood will generally be much lower than that, which means that at the hundreds of millisecond level most of the movement can be predicted from momentum alone. Something which identifies and tracks hands in a view and fits a second order model to the movement can likely predict accurately enough at that timescale to make for a meaningful safety improvement (especially because if it's non-destructive you can tune it to err more on the side of caution than a destructive option)
Holding a piece of wood and sliding it along a table saw (to cut it) is the canonical method for losing a finger, and you could definitely pick that out with a relatively simple bit of computer vision.
I used to have a house that backed up to a county park in Maryland. My shop was out back. I was working carefully at my sawstop (that is what I had back then), standing properly to the left of the kickback path and using a push stick and roller guides. I was just finishing a cut
A hawk decided to throw a dead animal at the window behind me hard enough to shatter it. I was startled and my hand moved enough for my palm to cross the top of the blade.
I would not have lost fingers most likely but it would have been very bad.
To your point accidents are not always foreseeable. Yeah some people work stupidly but plenty of times, It’s just random unexpected events.
also, the saws do not produce dust everywhere.
these are European saws. Dust extraction is not only required on the saw, It’s required by law in the workplace.
This saw will not operate unless the safety + extraction hood is in the proper position and dust extraction is hooked up
I can show you a video of an air quality meter sitting between the cameras and the saw hood if you want. The amount of particle change is minimal
The blade doesn't have to stop. Some saws have the entire blade assembly lower. If you walk the table saws at AWFS you'll see all types of different safety systems.
