The computer is mounted on a CNC machine body and vibrates heavily. How should we select and install it so it lasts?

Vibration kills drives and connectors before it kills the board, so deal with it in three layers. Selection: use a fanless machine (a fan is a mechanical part and fails early under vibration) and only SSD or mSATA/M.2 storage, never a hard disk. Check the shock and vibration section of the datasheet — typically stated as MIL-STD-810G testing, for example 5 Grms random vibration and 50 G shock, and usually only valid with an SSD fitted. Machines with soldered RAM tolerate vibration better than socketed modules. Installation: bolt the machine to a rigid plate and use rubber anti-vibration mounts or a sprung bracket; avoid bolting directly to the CNC housing where possible. Tighten to specification and use locking washers so bolts do not back out. Cabling: leave a service loop and clamp each cable 10–15 cm from its connector so vibration is not carried into the pins. For ports that tend to shake loose, prefer screw-locking connectors (M12, D-sub with jack screws) over plain RJ45. After a month of running, re-check torque and connectors.