SMC 10-CDUJB8-20DM-F8N | Clean Room Mini Free Mount Cylinder CUJ Series 8mm Bore 20mm Stroke Double-Acting Magnetic Piston Non-Rotating Rod

The SMC 10-CDUJB8-20DM-F8N is a clean room specification mini free mount cylinder with non-rotating rod from the CUJ series, featuring an 8mm bore and 20mm stroke. Part number decoded: CDUJ = CUJ mini free mount, B = basic, 8 = bore mm, 20 = stroke mm, D = double-acting, M = magnetic piston, F8N = non-rotating rod. This is the non-rotating variant of the CDUJB8-20DM, adding angular position control of the piston rod to prevent rotation during extension and retraction.

Why specify non-rotating rod on an 8mm micro-cylinder? In miniature clean room automation, end-effector tooling mounted to the rod must maintain precise angular orientation between every cycle. Even small rotational displacement at 8mm scale can cause misalignment in micro-part insertion, oriented pin driving, angled probe contact, and miniature fixture positioning. The F8N internal guide mechanism locks the rod's angular position without requiring external guide rails or bushings that would increase the overall actuator footprint. The 20mm stroke is the longest available at 8mm bore for extended travel with orientation control. The magnetic piston supports D-M9P auto-switch for end-of-stroke position detection, and the free mount body enables any-direction installation in tight clean room tooling.

The CDUJB8-20DM-F8N adds non-rotating rod to the max-stroke 8mm CUJ. For the same bore/stroke without anti-rotation, the CDUJB8-20DM costs less. For non-rotating in larger CUJ bores, see CDUJB10-F8N or CDUJB16-F8N. Clean series (10-) Particle Grade 1 for semiconductor and medical micro-assembly. RoHS compliant. Free mount body accepts screws from any surface direction.