Actuators for static and dynamic product testing

Hylec can supply actuators for single or multi-axis product testing over a frequency range from 0 – 100Hz and forces from less than 1kN to >1mN with strokes from 20mm to 2m.

Three types of actuators are available for such applications.

  1. A servo-hydraulic actuator that will meet this requirement for any amplitude provided the peak velocity is below 2m per second.
  2. An electro-mechanical actuator using a ball screw as used on universal test machines can typically operate up to 5Hz at forces up to 300kN, provided the stroke is sufficient to ensure that the recirculating balls remain lubricated. If stroke is not sufficient these actuators suffer from premature failure due to loss of ball screw lubrication.
  3. A linear motor which can operate up to 80Hz and over all amplitude ranges at forces up to 10kN. These actuators have only been available the last few years, are quite expensive and care does need to be taken to ensure that the units are not overloaded causing motor burnout. These actuators find particular use in testing of medical equipment where cleanliness is essential, and the use of hydraulic oil is not acceptable.

Hydraulic actuators have a long history in applications like the above and are available in various designs such as single-rodded, doubled-rodded with either hydro-static bearings and no seals – or with low friction Teflon composition seals. The hydrostatic bearing actuators are suitable for use down to zero amplitude and the low friction seal type actuators can be used down to amplitudes greater than the width of a seal contact, which is typically about 0.3mm. Single-rodded actuators are typically used in low-frequency applications with low side load forces and where a cost effective solution is required.

It is possible to repair actuators with seals if they are operated at lower than desired amplitude or if wear is due to the dirty environment causing dirt to cover the rod of the actuator. These actuators are available as a load cell mounted on the rod end, a position transducer mounted in the rear of the rod and a servo-valve to control the action of the actuator. The system also requires a constant pressure hydraulic supply and a digital controller suitable for either force or position control.

Electro-mechanical actuators subject to excessive wear due to high frequency or low amplitude operation generally cannot be repaired and must be totally replaced, if worn.

Typical applications for such test systems include static and dynamic; packaging testing, transportation testing, mechanical component and machine strength and fatigue testing.

Hylec can supply actuators, servo-valves, hydraulic power supply, and multi-channel servo controllers which is also suitable for data acquisition. We can also supply complete systems which can be commissioned either in Hylec’s works in Auburn, or on site.