From university to the test bench: tribology applied to REGNER microactuators
Regner® Editorial Team
Aiguaviva -
06/08/2026
Oriol Garay, who is studying for a Bachelor’s degree in Materials Engineering at the Universitat Politècnica de Catalunya (UPC), has joined REGNER on a work placement. During his time with us, he will take part in an applied tribology project to characterise and optimise a critical interface within our microactuators: the connection between the lead screw and the nut.
The contact between the lead screw and the nut also determines performance
In a linear microactuator, the lead screw and nut assembly converts motor torque into axial force. In this process, friction is not a secondary consideration. It directly affects the torque required to initiate and maintain motion, the mechanical efficiency of the assembly, heat generation and wear.
The coefficient of friction cannot be considered an isolated material property. It is the result of the complete tribological system, including the materials in contact, surface topography, lubrication, thread geometry, axial load, speed and duty cycle. Consequently, an apparently minor variation in the surface condition of the lead screw can alter the behaviour of the assembly and how it evolves throughout its service life.
When resistive torque increases or shows excessive variability, the torque margin available from the motor is reduced, power consumption rises and motion consistency may be affected. In applications involving hundreds of thousands or millions of cycles, the issue is not only the initial friction value, but also its stability and how it changes with wear, temperature and actual operating conditions.
A critical variable for precision dosing
In analytical instrumentation, diagnostic equipment and laboratory automation systems, microactuators are often used to drive piston pumps, motorised syringes and other positive-displacement mechanisms.
In these architectures, the linear displacement of the piston is directly related to the volume aspirated or dispensed. Dosing performance depends on the system as a whole, including its mechanics, control system, sensors and fluid circuit. However, the stability of the linear transmission is one of the conditions required to maintain repeatable behaviour.
Variations in friction can affect the velocity profile, increase the difference between breakaway and steady-state motion, and alter actuator response during slow approaches or short-travel movements. In systems operating with small volumes and repetitive cycles, these deviations can ultimately affect process consistency, reagent consumption or calibration frequency.
Characterising the interface between the lead screw and the nut is therefore not simply a matter of reducing friction. The aim is to achieve controlled, stable and reproducible mechanical behaviour throughout the intended service life.
From surface to functional behaviour
The project will investigate the extent to which different surface treatments and finishes can reduce and stabilise friction, limit wear and improve the functional consistency of the assembly without altering the thread geometry or specified tolerances. The objective is not simply to achieve the lowest possible surface roughness, but to identify the solution that delivers the most stable performance under the actual operating conditions of the microactuator.
Starting from an untreated reference configuration, different solutions will be compared, including electropolishing and the application of low-friction coatings. Their effects on surface condition and assembly behaviour will be evaluated by measuring torque, current draw and temperature, as well as by analysing noise and motion consistency.
The tests will be carried out under conditions representative of the intended load, speed and duty cycle, with the aim of relating surface characteristics to friction, wear and functional repeatability. The results will support a technical recommendation based on experimental data.
Turning academic knowledge into engineering decisions
For Oriol, the project brings together several areas of Materials Engineering, including surface characterisation, tribology, wear, corrosion, metrology and experimental validation. The outcome will be a technical analysis directly linked to the performance of an industrial product.
For REGNER, this collaboration will generate internal technical knowledge about the relationship between the manufacturing process, surface condition and functional performance. The conclusions may help define process specifications, acceptance criteria and design decisions for future generations of microactuators.
If the results demonstrate sufficient consistency and technical potential, this line of work could subsequently develop into a final-year degree project (TFG).
Taking academic knowledge to the test bench, testing hypotheses and turning results into engineering decisions is exactly the kind of collaboration we want to foster.
