What is a hard bearing and a soft bearing What is the difference between them?

Answer 1

There are two primary types of balancing machines, these are hard-bearing and soft-bearing machines. The difference between them, is in the shaft / bearing suspension and not the bearings.

In a hard-bearing machine, balancing when preformed is done at a frequency that is lower than the resonance frequency of the machine suspension. In a soft-bearing machine, balancing when preformed is done at a frequency higher than the resonance frequency. Both types of machines have various advantages / disadvantages. Hard-bearing machines are generally more versatile and can handle pieces with greatly varying weights and because hard-bearing machines are measuring centrifugal forces this then only require one-time calibration. Only five geometric dimensions need to be fed into the measuring unit to be ready for use. Therefore, ideal for low- and middle-size volume production and in repair workshops.

Soft-bearing machines are not so versatile with respect to amount of rotor weight to be balanced. Preparation of a soft-bearing machine, individual rotor types is more time consuming and needs calibration for every individual part. It is very suitable for high-production volume and high-precision balancing tasks.

Both types hard and soft-bearing machines can be automated to remove weight automatically, example such as by drilling or milling. Hard bearing machines are generally more robust and reliable. Both machine types can be integrated into a production line and loaded by a robot arm or gantry, requiring very little human control.