What do you mean by “lubricating dies”?

Dies are lubricated to reduce the friction and wear that occur upon contact between the die-holder and the actuation device thereof. The contact surface should be lubricated using special grease, which should be periodically removed and replaced to ensure the wholeness of the surfaces. To overcome these bothersome maintenance operations, OP interposes, between the die-holder and the actuation/lock piston, some strips with self-lubricating material that does not require any additional lubrication.