The blade, called a mixing knife, in Thermomix® is engineered with a safety breakpoint outside the bowl, so the pressure required to break the knife will break the shaft before the blade. This is a safety feature so the blades in a Thermomix® do not have any pieces that could break free. If the motor is moving but the blades are not, a new mixing knife is needed, call Customer Service at 855-867-9904 for next steps.
