What the order code is, and what it weighs
The 1FK7042-5AF71-1DG3 is the Siemens 1FK7 COMPACT SYNCHRONOUS MOTOR — a brushless servo in the 1FK7 family built for high-dynamic positioning where the loop has to hold the micron shot after shot.
Class context and what a 1FK7 compact servo is specified for
The 1FK7 compact line is Siemens' short-stack synchronous servo family — sized for machine-tool axes, feed drives, and packaging / converting lines where the motor has to accelerate, hold position, and reverse cleanly inside a tight panel footprint. On a CNC retrofit or a 5-axis machining centre, a motor in this class is paired with a SINAMICS drive over PROFINET / EtherCAT and an absolute encoder on the shaft; the deterministic comms and clean feedback are what keep following error and following-error variance down run after run.