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•Advantages,

-requires only one surface of a part to grasp

-a uniform pressure can be distributed over some area, instead of concentrated on a point

-the gripper is light weight

-many different types of materials can be used

•Disadvantages,

-the maximum force is limited by the size of the suction cups

-positioning may be somewhat inaccurate

-time may be needed for the vacuum in the cup to build up

11.1.3 Magnetic Grippers

•Can be used with ferrous materials

•Electromagnets,

-easy to control, requires a power supply, and a controller

-polarity can be reversed on the magnet when it is put down to reverse residual magnetism

•Permanent magnets,

-external power is not required

-a mechanism is required to separate parts from the magnet when releasing

-good for environments that are sensitive to sparks

•Advantages,

-variation in part size can be tolerated

-ability to handle metal parts with holes

-pickup times fast

-requires only one surface for gripping

-can pick up the top sheet from a stack

•Disadvantages,

-residual magnetism that remains in the workpiece

-possible side slippage