I'm building a claw machine. I have noticed that people are using servos for the gripper. I was wondering, isn't it bad on a servo to stop it before it reaches its programed limit?
Definitly. Usually the gears loos teeth, so you will have toprovide some meansof stress relief.
That's called stalling the servo and you're right it doesn't do it much good. But most hobby servos can take being stalled for a short while and most hobby grippers aren't used for very long. So you get away with it for a while then you buy a new servo.
There are techniques to avoid some of the problems (mechanically or by programming) but they can be complex.
Thanks, that answers my question!
A gripper mechanism should have a spring to limit the force (torque) on the servo ideally for the reasons you give. Metal bodied servos are much more likely to survive abuse as they can lose heat more rapidly. Servos
fail by cooking themselves at high current when stalled. There's no reason a servo cannot be designed to sustain stall indefinitely, but most cheap ones are not specially robust. Higher quality servos may have high current and high temperature cutouts implemented.
A quality gripper design would probably have current sensing to enable force control, so you would simply avoid
setting too large a current in the first place.