September 25, 2017

Prof. Saša Zelenika become an expert evaluator of the European Commission!

Our member prof. Saša Zelenika was selected as an Expert evaluator of the European Commission (EC) of research infrastructure proposals submitted to the Horizon 2020 EU framework programme calls! Evaluation was held in Bruxelles, Belgimum from June 12th to June 16th 2017.


Laboratory @ CMNST Equipping Sponsors

Laboratory equipping was supported by infrastructural ERDF project no. RC.2.2.06-0001: “Research Infrastructure for Campus-based Laboratories at the University of Rijeka – RISK”

         Europska unija

  Ulaganje u budućnost


Bruker Dimension Icon Scanning Probe Microscope (SPM)

  • AFM and STM modules in one device.

  • Supports contact and tapping mode (closed loop control keeps the force (deflection of the beam which holds the tip) constant, which limits the contact forces to < 200 pN, i.e. a value far lower than the tapping forces of other devices – PeakForce tapping).

  • Enables measurements of elasticity modulus, adhesion, lateral force (LFM), spectroscopy and force modulation, electrochemical analysis, electric field and magnetic forces, surface potential, piezoelectric force; enables also nanolitography, …

    Option to measure in liquid for biotechnical applications and measurements with heating/cooling of the samples, …

    Imaging of measured data on 5’120 x 5’120 pixels.

  • Samples fixed to the support via a vacuum chuck can be up to few millimetres in size, with bidirectional positioning repeatability of 3 mm on a scanning area of up to 90 x 90 mm.

  • Includes heat (creep < 200 pm/min) and vibration isolation (1” Si damping cushion + compressed air → < 30 pm RMS), microscope and CCD camera, control SW, …

  • PeakForce Tapping™ is an AC imaging technique, i.e., the cantilever is oscillated but well below resonance.

  • This results in a continuous series of force-distance curves.

  • In addition to direct force control by keeping the peak force constant, a multitude of material properties can be extracted and quantified from the force-distance curve at each pixel within an image, such as modulus, adhesion force, and deformation depth.

Examples of measurements – mechanical testing of orthodontic archwires (topographies of NiTi, Rh NiTi and N NiTi):


Examples of measurements – ball element and sliding surface of linear guideways:


Keysight G200 Nanoindenter

  • The device is thermally as well as dynamically (and acoustically) isolated.

  • Electromagnetic actuation (voice coil principle), i.e. load generation: max 0.5 N with a 50 nN resolution; additional built-in high-load system with 0.1 mN … 10 N load range. Loading system stiffness (guided by leaf springs): 5.106 N/m.

  • Capacitive displacement measurement: resolution < 0.01 nm for > 500 mm displacement range. Obtainable straightness in a

    100 mm range is within 10 nm.

  • 4 samples in a 100 x 100 mm sample holder with a scanning resolution of 0.1 mm and 1 mm accuracy; automatically controlled (closed loop based on incremental encoders). Measurement of elasticity modulus and hardness according to ISO 14577.

  • Enables LFM with a ≤ 2 mN resolution and max lateral force

    ≥ 250 mN. Low-force measurements enable obtaining surface topology after indentation.

  • Berkovich, cube corner, conical, spherical and Vickers tips. System for sample visualization (10x and 40x zoom), microscope with CCD camera and data analysis SW.

Examples of measurements – mechanical testing of orthodontic archwires:

Stratasys Fortus 250mc 3D printer

  • For models with dimension of up to 254 x 254 x 305 mm, with 178 mm layer thickness and positioning accuracy of 240 mm.

  • 2 heads (building and support material).

  • FDM (Fused Deposition Modelling) technology (heating and extrusion of thermoplastics); material: ABSplus (acrylonitrile butadiene styrene).

  • Import of STL (Standard Tessellation Language) 3D models from CAD + SW for printing process optimization (including support structure optimization).

  • An additional 3D printer (Stratasys Connex 500), capable of using up to 14 different materials with different stiffness properties, available at the Faculty of Civil Engineering on same U. of Rijeka campus → PolyJet technology: similar to desktop inkjet printers, with photo polymer material hardened under UV light; printing resolution down to 16 mm.

FDM process:

  • Advantages: laser not needed, fast and secure procedure, lower power consumption, unnecessary cooling and ventilation, simple usage, low investment, low maintenance costs, small size (additional room not needed), warping effect minimised.

  • Disadvantages: surface can be rough and models can have a certain porosity, model functionality is limited by the used material, in many cases the support structure has to be used, additional mechanical processing needed, lines between layers can physically be seen, hardness of the product is lower in the direction of the printed layers, oscillations in temperature during the printing process can lead to delamination of the product; upon warming, melting and solidification processes, ABS can shrink up to few %.

Examples of 3D printed structures:


DAVID SLS-2 (Structured Light Technology) 3D Scanner

Structured Light Technology: The distance and the angle of the camera with respect to the projector are known, i.e. distortion of the reflected light pattern (fringes) depends on object’s geometry. Projector + camera + calibration panels + rotating table.

  • 500 mm scanning area,

  • resolution/accuracy 1‰ of the object size,

  • includes SW environment,

  • mobile with tripod,

    enables exporting data to formats compatible with standard CAD SW (e.g. STL).

Examples of measured 3D structures – dental casts:


Shimadzu Autograph AGS-X micro-tensile machine

Measurement of mechanical properties (hardness, elasticity modulus, …) of metals, ceramics, polymers, rubber and composites up to 5 kN with 2 mN and 10 µm resolutions.


Examples of measurements – measurement of presliding friction of ultra-high precision positioning device:

Examples of measurements – mechanical testing of cured ham:

CNC machine tools for sample preparation

Haas Office series machine tools characterized by small dimensions as well as outstanding performances and exceptional benefits for the end users; include user-friendly interface, HAAS/Fanuc control unit as well as technical support from the Croatian representative company Teximp d.o.o.

Haas Office OM-2A milling machine

  • dimensions within an 1.7 x 0.84 x 1.9 m envelope,

  • enables a 5-axes machining with up to 20 automatically interchangeable tools,

  • machining volume 305 x 254 x 305 mm,

  • 1 µm displacement resolution; spindle velocity of up to 30’000 rpm and 3.7 kW power.


Haas Office OL-1 lathe

  • dimensions within an 1.3 x 0.84 x 1.8 m envelope,

  • 4-axes, 12 tools,

  • turning diameter of up to 250 mm,

  • 1µm displacement resolution,

  • spindle velocity of up to 6’000 rpm and power of up to 5.6 kW.



A system for ultrasonic cleaning of samples for (ultra-high) vacuum

  • Heated (up to 70 °C) prewash with oil separation

  • ultrasound (10 PZT inverters, 40 kHz, 500 W continuous and 2 kW peak power) 45 l heated stainless steel bath for cleaning with a “soft” (pH 9.9) detergent and with filtering of media (particles’ separation)

  • 2 baths for rinsing in demineralized water with heating (1.2 kW, 30 … 80 °C)

  • drying with hot air (up to 300 °C).


Newport opto-mechanics




17th International EUSPEN Conference 2017, Hannover, Germany

Employees of the Precision Engineering Laboratory visited the 17th International conference EUSPEN 2017, held from 29.05. to 02.06.2017. in Hannover, Germany.

In the session Applications of Precision Engineering in Biomedical Sciences, our team presented a poster:

In the session Advances in Precision Engineering and Nanotechnologies, our team presented a poster:


Our member prof. Saša Zelenika was a member of the International Scientific Committee as well as the Chair of the session “Advances in Precision Engineering and Nanotechnology”.

Science Festival in Rijeka 2017

This year’s Science festival in Rijeka was held from April 24th to April 29th, 2017. The 15th festival was held in 22 Croatian cities at the same time. The theme of this year’s festival was weather/time.

Opening ceremony of this event was held at City Hall Korzo on Monday, April 24th, 2017 at 11:00.

As a part of the Science festival Precision engineering laboratory team members Prof. D. Sc. Saša Zelenika, D. Sc. Ervin Kamenar and M. Sc. Petar Gljušćić organized an open laboratory day for broader public on April 27th, 2017.


16th International EUSPEN Conference 2016, Nottingham, UK

Employees of the Precision Engineering Laboratory visited the 17th International conference EUSPEN 2016, held from 30.05. to 00.06.2017. in Nottingham, UK.

In the session Mechatronics and Control, our team presented three papers:

In the session Precision Engineering in Biomedical Sciences, our team presented a paper written together with the coleagues from School of medicine in Rijeka:


Doctoral thesis defence – E. Kamenar

Our member D. Sc. Ervin Kamenar defended his doctoral thesis entitled “Ultra-high precision positioning via a mechatronics approach” on May 19th, 2016.

Doctoral thesis supervisor vas Prof. D. Sc. Saša Zelenika.

Committee for the defense of the doctoral thesis:
  1. Prof. D. Sc. Nenad D. Pavlović, University of Niš, Serbia, Faculty of Mechanical Engineering (Mašinski fakultet Univerziteta u Nišu) – Committee Chair
  2. Prof. D. Sc. Saša Zelenika, University of Rijeka, Croatia, Faculty of Engineering (Sveučilište u Rijeci, Tehnički fakultet)
  3. Prof. D. Sc. Francesco De Bona, University of Udine, Italy, Department of Electrical, Management and Mechanical Engineering (Università di Udine, Dipartimento di Ingegneria Elettrica, Gestionale e Meccanica)

Thesis abstract:

Ultra-high precision mechatronics positioning systems are critical devices in current precision engineering and micro- and nano-systems’ technologies, as they allow repeatability and accuracy in the nanometric domain to be achieved. The doctoral thesis deals thoroughly with nonlinear stochastic frictional effects that limit the performances of ultra-high precision devices based on sliding and rolling elements. The state-of-the-art related to the frictional behavior in the pre-sliding and sliding motion regimes is considered and different friction models are validated. Due to its comprehensiveness and simplicity, the generalized Maxwell-slip (GMS) friction model is adopted to characterize frictional disturbances of a translational axis of an actual multi-degrees-of-freedom point-to-point mechatronics positioning system aimed at handling and positioning of microparts. The parameters of the GMS model are identified via innovative experimental set-ups, separately for the actuator-gearhead assembly and for the linear guideways, and included in the overall MATLAB/SIMULINK model of the used device. With the aim of compensating frictional effects, the modeled responses of the system are compared to experimental results when the system is controlled by means of a conventional proportional-integral-derivative (PID) controller, when the PID controller is complemented with an additional feed-forward model-based friction compensator and, finally, when the system is controlled via a self-tuning adaptive regulator. The adaptive regulator, implemented within the real-time field programmable gate array based control system, is proven to be the most efficient and is hence used in the final repetitive point-to-point positioning tests. Nanometric-range precision and accuracy (better than 250 nm), both in the case of short-range (micrometric) and long-range (millimeter) travels, are achieved. Different sensors, actuators and other design components, along with other control typologies, are experimentally validated in ultra-high precision positioning applications as well.


15th International EUSPEN Conference 2015, Leuven, Belgium

Employees of the Precision Engineering Laboratory visited the 17th International conference EUSPEN 2016, held from 30.05. to 00.06.2017. in Nottingham, UK.

Our team presented five papers: