DIAGNOSIS: Yeah, this one's common. That grinding or rattling noise is almost always caused by hair, lint, and product buildup getting sucked into the air intake near the handle and winding around the fan blade.
FIX: Unplug the dryer. Look at the circular air intake grille near where the handle meets the barrel. Use a bright light and maybe a pair of tweezers to carefully pull out any visible hair or debris wrapped around the fan shaft inside the grille. Be gentle to avoid bending the plastic fan blades.
IF THAT DIDN'T WORK: If the noise persists after a thorough clean, the fan blade itself might have become cracked or warped from heat, causing it to scrape against the housing. At that point, the motor assembly is failing and the unit needs replacement.
HEADS UP: Regularly cleaning that intake grille every few weeks can prevent this. Also, try to use the dryer on clean, detangled hair to minimize how much loose hair it pulls in.