Servo Press System eases assembly

A part is pushed into a recess, which is slightly undersized causing interference. The fit is made possible by the material elasticity, which gives rise to a compressive force between the part and the recess. The join is maintained by the friction, which is usually a function of this compressive force. Kistler has expanded its range of NCF servo press systems with the introduction of the NCFT-B for low force interference fit processes, for forces below 1 kN. The actuators include a piezoelectric force sensor and a rotary encoder to measure and control position and are linked to a servo controller and a monitor. The NCFT has been used where the limited position and speed control offered by pneumatic systems, is inadequate. The force sensor mounted on the end of the shaft eliminates any force measurement uncertainty due to friction in the bearings. The piezoelectric force sensor offers two selectable calibrated force ranges, allowing the same NCFT-B to switch between operations with differing force requirements. Most applications have been on plastic parts with a high quality requirement, such as drug delivery devices. Maintaining and running a pneumatic or hydraulic circuit usually has a greater energy demand and therefore higher operating costs than equivalent electrical systems. An electrical system has the benefit of only using energy when required, which greatly helps to improve its energy efficiency.