live shaft and dead shaft rollers can be used for the same application and the choice is a function of the machine’s mounting system. But at other times, the differences between the two designs mandate a clear choice.
Dead Roller Shafts:
- Roller design is bearings pressed into the ends of a hollow tube (the roller body) with a long shaft running through the bearings and extending out the ends of the rollers.
- The roller is considered to be a “dead shaft” because the shaft does not turn. The shaft is fixed to the machine or frames mounting system by clamping or bolting and the roller body turns about the shaft via the bearings.
- Roller shells can be steel, aluminum, or carbon fiber and many times are thin-walled, making them ideal for light load and high-speed web applications.
- Commonly used as idler rollers due to light-weight, low-turning inertia and the availability of low friction bearings which reduce roller drag.
- Roller rods must be web or nip driven because there is not a rigid connection between the shaft and the roller shell.
Live Shaft Rollers:
- Roller design is typically steel journals/headers welded into the ends of a hollow tube or roller body. The journals (or rod) turn with the roller body.
- The roller is considered to be a “live shaft” because the journal ends rotate with the roller. Commonly mounted to a customer’s machine or frame through the use of external bearings such as pillow block bearings.
- Roller shells can be steel, aluminum, or carbon fiber and can be lightweight thin-walled rollers, but also – and more typically – are heavy steel-walled rollers for high load industrial applications.
- Commonly used in steel, paper, and other industries requiring strong robust roller designs and often use heavy-duty pillow block bearings for mounting on the journals.
- Rollers can be driven via keyways machined into the journals, therefore, allowing for the use of various drive systems to turn rollers.