COMPETENCES
The Department for Production Engineering (DPE) conducts scientific research in the field of production procedures and modern mechanical engineering technologies. This Department consists of three chairs: Chair for Polymers Processing and Casting, Chair for Chip-forming and Deforming, Chair for Welding and Surface Protection. The Department has 11 staff members (3 full professors tenure, 1 full professors, 1 associate professors, 3 assistant professors, 1 postdoctoral researcher, 1 assistant, 1 research associate).
- Chair for Polymers Processing and Casting. The research is focused on the following areas: polymer processing technology (especially injection moulding of polymeric and composite materials), compounding, testing, processing and application of polymeric nanocomposites, rapid prototyping and rapid tooling technology (RP & RT), adhesive bonding technology. In the field of casting the scientific-research activity is focused on the investigation of influence of technologic parameters on the residual stresses in pressure castings: the influence of the most important technologic parameters, the temperature of casting, the rate of filling the mould with an alloy, increase of pressure in the filled mould, and the rate of cooling of the injection system after removing it from the mould.
- Chair for Chip-forming and Deforming. The research is focused on the following areas: non-traditional machining procedures (abrasive jet cutting, laser cutting, and smoothing), ecologically acceptable machining procedures and traditional machining procedures. In the field of metal forming research activity is concentrated on the investigating the effects of process parameters on mechanical properties of bent sheet metal plates, especially the effects of process parameters on the amount of elastic sheet metal spring-back. Finite element analysis (FEA) have been using for numerical simulations.
- Chair for Welding and Surface Protection. The research is focused in the area of welding technology application, surface material protection and in the field of introduction of integrated management systems in Croatian companies. Some important research subjects are: investigation of cost effective joining processes of thin materials, investigations of practice-oriented contemporary welding processes (LaserHybrid welding, MAG-STT welding, CMT process, FastRoot process and plasma welding) and their application. Also, the application and further developing of on-line monitoring system for main welding parameters acquisition and data processing at different fusion and pressure welding processes has been investigated.
LABORATORIES
Due to the complex field of expertise, Department has 6 laboratories that are used for education, scientific and research activities, as well as for cooperation with the economy:
- Laboratory for Casting is used in the education process (undergraduate and graduate programme) for the courses dealing with the casting technology in order to make students familiar with the casting production.
- Laboratory for Machining. The primary function of the Laboratory is education, including testing needed for writing term and final papers, as well as scientific research work, and doctoral theses. The most important research activities are: introduction of modern technological processes and cutting tools in the production, improving the process of chip-forming machining (with respect to ecology), control of cutting tools (to achieve better cutting characteristics), analysis of chip-forming cycle, control and optimisation of technological parameters of treatment and dynamic measuring of cutting forces, noise and acceleration in the process of chip-forming machining.
- Laboratory for Polymer Processing is used for education purposes, as well as for scientific-research projects, and cooperation with the economy in the field of polymer processing and advanced adhesive joining technologies. It offers different services, such they are: identification of polymer materials, fabrication of polymeric and composite injection moulded parts (up to 6 g) on high-speed, microprocessor-controlled injection moulding machine, simulation of rheological processes in the mould cavity at injection moulding, design of polymer products, moulds and tools by using analytic and numeric methods, and especially testing of sealed joints.
- Laboratory for Materials Surface Protection deals with corrosion testing and protection of engineering materials. The Laboratory offers a number of possibilities: corrosion testing in artificial atmospheres, testing of engineering materials and protection systems in salt and wet chamber, testing of protection coating characteristics, determining thickness, adhesiveness and other properties of all protection types, corrosion stability testing of engineering materials and welded joints (testing of riddled corrosion resistance, testing of inter-crystalline corrosion resistance, testing of stress corrosion resistance, etc.), design and control of corrosion protection by coatings.
- Laboratory for Welding with the equipment for basic electric arc welding processes and similar procedures (flame cutting and plasma cutting, soldering and thermal spraying), is used for scientific-research projects and cooperation with various companies.
- Laboratory for Metal Forming, Tools and Devices is used for testing of plastic flow stress, determination of material behaviour during forming, measuring deformation of metal samples, and for designing different tools (e.g. for punching, bending, deep drawing and forging), cutting tools and devices.
APPLICATIONS
Department for Production Engineering was involved in 5 national scientific research projects, funded by the Ministry of Science, Education and Sports of The Republic of Croatia:
- Project title: Increase of the Efficiency of Casting Procedures – Croatian Perspectives Project coordinator: Professor Ivan Budić (Ivan.Budic@sfsb.hr)
- Project title: CAD/CAM Method of Modern Tool Construction for High Strength Steel Plates in 4D Project coordinator: Professor Branko Grizelj (Branko.Grizelj@sfsb.hr)
- Project title: Advanced Technologies of Direct Manufacturing of Polymeric Products Project coordinator: Professor Pero Raos (Pero.Raos@sfsb.hr)
- Project title: Advanced Joining Technology in Light Mechanical Constructions Project coordinator: Professor Ivan Samardžić (Ivan.Samardzic@sfsb.hr)
- Project title: Advanced Cutting Techniques for Environmentally Friendly Manufacturing Project coordinator: Professor Antun Stoić (Antun.Stoic@sfsb.hr)
RESULTS OBTAINED
The results of the project Increase of the Efficiency of Casting Procedures – Croatian Perspectives in years 2010/2011: The research was focused on the influence of technological parameters on residual stresses in die castings. The influence of following technological parameters was investigated: Temperature of pouring, filling speed of mould with molten metal, pressure increase in the filled mould, cooling time of castings with pouring system after breaking the casting out of the mould. The research results are used for improving the casting processes. As a result of this investigation, a PhD thesis was successfully finished by a young researcher on this project, Daniel Novoselović. PhD thesis was defended on 16 July 2010. The results of these investigations have been published in journals and conference proceedings. The textbook entitled: “Osnove tehnologije kalupljenja – Jednokratni kalupi I. dio, II. Izmijenjeno i dopunjeno izdanje has also been published. Continuous detailed analysis of castings is being done in some foundries: Lipovica d. o. o. – Popovača, Plamen International – Požega and Faculty of Mechanical Engineering and Naval Architecture – Zagreb.
The results of the project CAD/CAM Method of Modern Tool Construction for High Strength Steel Plates in 4D in years 2010/2011: The effects of process parameters on mechanical properties of bent sheet metal plates have been investigated (especially the effects of process parameters on the amount of elastic sheet metal spring-back).FEM method was used for numerical simulations. Elastic spring-back is very important for every process where sheet metal is processed in order to maintain desired dimensions and tolerances after the forming process. Since there is a trend of using high strength/low mass ratio of new materials, mostly high strength steel metal plates are used in the forming processes all over the world. Data for investigated processes were collected and some conclusions were made regarding the behavior of high strength sheet metal plates. Also the tool for the experimental investigation was designed and modeled for future research. The goal is to investigate behavior of high strength steel sheet metal plates in various sheet forming processes, with various forming parameters. During the last year, the hydroforming processes were also investigated by FEM method. Hydroforming is a process of forming where fluid transfers pressure on every part of the metal surface thus forming it. It can be done as forming of the tubes or the forming of the sheet metal plates onto the die surface. With die and hydroforming of high strength steel sheet metal plates, most of the car parts are made: hood, fenders, and various curved metal parts which need to ensure high rigidity and low mass of product.
The results of the project Advanced Technologies of Direct Manufacturing of Polymeric Products in years 2010/2011: Part of the rapid prototyping research is the analysis and systematization of RP procedures and rapid tooling (RT) based on the shape of the basis material, the mechanism of forming and the type of procedure. The main characteristics, advantages and disadvantages of certain procedures are analysed. The use of RP and RT in engineering and medicine are investigated in detail. A number of products was designed and technologically produced by using the computer for rapid prototyping by 3D printing, and the hybrid procedure (OBJET) and the STL files were prepared. Design characteristics of all the selected products were analysed in detail (based on the type of procedure). The influence of moulds made by rapid prototyping, i.e. material, on the characteristics of the final product (cast) is investigated. Therefore, the prototype moulds were made by chip-forming and rapid prototyping. By adapting the existing software (Moldex and CadMould), the possibilities of computer simulation of injection pressing were tested on the moulds made by RP. The possibilities of RP of individual medical implants (custom made implants) are being extensively investigated. Medical CTs and MRIs are processed by using the computer software 3D Doctor in order to make CAD medical models as the basis for making RP implants. Based on these models, the characteristics of making implants by using 3DP and OBJET were tested.
The results of the project Advanced Joining Technology in Light Mechanical Constructions in years 2010/2011: The research areas were as follows: During the investigation of cost effective joining processes of thin materials, the emphasis was put on cost efficiency as an important criterion in joining technology selection. The practical examples of modern welding processes application in production processes like LaserHybrid welding, MAG-STT welding, CMT process, FastRoot process and plasma welding are analysed. Also, the application and further developing of On-line monitoring system for main welding parameters acquisition and data processing at different fusion and pressure welding processes was investigated. Practically developed On-line monitoring system was applied, as well as other laboratory methods for the same measurements as a confirmation and validation of data recorded by On-line monitoring system for different welding processes. Based on obtained results, it is possible to conclude that presented monitoring system is suitable for practical application. This monitoring system was applied in order to evaluate the influence of different welding process parameters variations on the stability of the welding process. The weldability and the influence of welding parameters and welding conditions on the properties of the weld joint are investigated through weld thermal cycle simulation, investigation of mechanical properties and by macro and micro analysis of the weld zone.
The results of the project Advanced Cutting Techniques for Environmentally Friendly Manufacturing in years 2010/2011: The test samples for turning tests were made of heat treated steel. Two different structures with significant difference in hardness were obtained on test samples which enables monitoring and comparison of conditions of cutting hard and soft materials. These tests were conducted at different cutting regimes (cutting speed, feed rate and cutting depth). Digitalized images of microstructure of chips and the analysis of particle shape in the analysed surface were performed. Microstructure measurements are determined by the baseline thickness of elementary lamellae, on the basis of these data and the frequency of creating fins. Laboratory measurements of components of cutting force and acceleration in the processing of test samples were recorded. Micro-hardness measurements were conducted on machined surfaces, as well as on rough surfaces. Mathematical models were created to determine the frequency of changes of stress on the results of microanalysis of single particles and the geometric size of test samples. The machinability (according to the wear of tools) of Inconel 718 was investigated (e.g. dry machining, MQL, liquid nitrogen, gaseous nitrogen, classically cool). The results of comparative cryogenic treatment (liquid nitrogen) as compared to conventional processes were experimentally verified by analysing: cutting force, tool wear, temperature and cost. Cryogenic technology has high potential for cost reduction, creating less waste, and it also has lower environmental and social impact. Studies have been done by measuring the quality of the cooling flush and lubrication. In collaboration with the Head of the LABOD from Ljubljana, Prof. Janez Kopač who was a subcontractor on the project, a research on the utilization of alternative coolants and lubricants (liquid nitrogen) was conducted. The research project is an important contribution to a PhD student and two students of postgraduate professional studies. Achievements have been published in the Journal of Mechanical Engineering (CC) and in the journal Technical Gazette (SCI-expanded). Experience of Hungarian colleagues from Kecskemet was helpful when using MQL equipment. MQL equipment was purchased from the German suppliers and activities planned for research in the field are being realized, especially in the factory Đuro Đaković.
INDUSTRIAL SECTORS OF APPLICATION
- Raw material extraction
- Refining
- Light industry
- Heavy industry
- Construction
- Transportation
- Technological research, design and development
ACCOMPLISHED INDUSTRIAL APPLICATIONS
Project title: Testing the durability of gas pressure regulator membrane Project coordinator: Professor Pero Raos Project ordered/funded by: HEP-PLIN d.o.o. Osijek Short description: The investigation deals with testing of gas regulator auxiliary membrane durability. In experimental investigation, the period after which auxiliary membrane loses its initial properties was identified. A new, non-built membrane was taken as a referent for monitoring the properties of membranes. Testing of specimens’ ductility led to the conclusion that it is advisable to check the quality of the membranes every 8 years.
Project title: Analysis of the project of energy efficiency and use of renewable energy sources Project coordinator: Dr. Štefanija Klarić Project ordered by: SOLING d.o.o. Short description: The analysis of the project of energy efficiency and use of renewable energy sources for municipality buildings in Okučani and Stara Gradiška was performed Research results show that energy efficiency has increased and CO emission has reduced after the renovation of buildings.
Project title: Non-destructive Corrosion Testing Project coordinator: Professor Stjepan Aračić Short description: Examination of corrosion resistant non-metallic and metallic coatings in different aggressive media. Investigation of resistance of organic coatings on a variety of effects (exposure to chemicals, weathering etc.). Determination of the speed of general corrosion of metals or alloys in specific corrosion environment (gravimetric, polarization measurements, measurements of dissolved metals in the corrosion environment in the closed-pressurized system). Determination of resistance of metals and alloys in various forms of corrosion (galvanic corrosion, inter-grain corrosion, corrosion in the gap, dimple corrosion …)
Project title: Sealing of threaded pipe joints in municipal gas pipelines Project coordinator: Professor Pero Raos Project ordered/funded by: Ministry of Science, Education and Sports of The Republic of Croatia Short description: Contemporary approaches regarding to infrastructure are more and more directed to new materials development for natural gas and other installations. The most recent development and application of the new materials pertain to sealant materials for sealing of threaded joints in gas pipeline installations and installations for other media. Based on provided analysis by HEP-PLIN Ltd Osijek, gas leaking on threaded joints in home metering and control units sealed with hemp was affirmed. Considering that in practical work in the case of hemp, sealing threads are made by a thread tool and during threading, the tool lubricates, the influence of impurities on sealing with anaerobic sealant compounds has been tested. Experimental work included testing of three different anaerobic sealing compounds with three material combinations in threaded pipe joints (steel – brass, brass – brass and brass – aluminum) on three different temperatures (-20 °C, 25 °C and 100 °C).
Project title: Expertise of the structure of polymer-coated monofilament glass fibres Project coordinator: Professor Pero Raos Project ordered by: Mijo Veneers d.o.o., Oprisavci Short description: Expertise of the structure of polymer-coated monofilament glass fibres has been done aiming to classify this specific product for the custom purposes.
POTENTIAL INDUSTRIAL APPLICATIONS
The competences of the Laboratory for Metal Forming, Tools and Devices can be applied to design stamping tools for sheet metal products, to optimise sheet metal forming process for different goals (cheapest production or demanded quality of product, tool life etc.). Also competences of this laboratory can be used for design and optimisation of different forging tools, bending tools, to assess the amount of elastical springback of high strength steel sheets. Also through laboratory testing of metal mechanical properties it can be assessed if some metal material can be used for a specific forming process.
Laboratory for Polymer Processing offers assistance in various aspects of polymer processing and engineering industrial applications: identification of polymeric materials, design and simulation of polymer products and tools, pilot production of small injection moulded parts etc.
TRAINING ACTIVITIES FOR COMPANIES
- Metal forming tool design, calculation and optimisation
- Corrosion and Protection of construction materials
- Protection of construction materials with organic coatings
- Design of protection systems of construction materials
- Polymer Processing
- Injection moulding of polymers
- Design of plastic parts
- Design of tools and dies for polymer processing
- FEA Simulation of injection moulding
- Adhesive bonding technology
- Training course for auditing of quality management system
- Implementing basic statistic techniques for industry
AVAILABLE INSTRUMENTATION
- Ultrasound measuring instrument for the control of parent material and welded joints homogeneity
- Re-condensation strength measuring device DISA PNZ
- Residual stress measuring device HBM MTS3000
- “Solid Cast” software for simulation of metal casting
- Universal lathe TNP 160 A
- Band saw
- Electro-erosion tool machine
- Devices and equipment for acquisition and measuring technological process parameters,
- Device for measuring wear of the tool cutting edge
- Device for controlling the driving engine on tool machines,
- Device for simulation of the tool cutting edge sharpening
- Injection moulding machine BOY XS
- Temperature control unit Regloplas 90S
- Injection mould for manufacturing of ISO 527, ISO 178 and ISO 179 specimens
- “Cadmould” software for simulation and analysis of mould filling in injection moulding of polymers
- “Autodesk Moldflow Adviser” software for simulation of injection moulding of polymers
- “3D Doctor” software for processing of medical images
- Six axis industrial robot for MAG/MIG welding with robotic welding positioner Motoman
- Semiautomatic apparatus for MAG/MIG and TIG electric arc welding by impulse current TPS 2700
- AC/DC apparatus for REL and TIG welding by impulse current MagicWave 2000
- DC apparatus for REL and TIG welding by impulse TT 1600
- DC MAG/MIG conventional welding apparatus
- AC/DC conventional REL and TIG welding apparatus
- On-line monitoring system for measuring, recording and processing parameters of electric arc welding processes
- Apparatus for spot electric resistance welding
- Automatic tracking vehicle FTV 4 with remote control unit FCU-4-RC
- Apparatus for air plasma cutting Hypertherm Powermax 1250
- Apparatus for thermal spraying and cold spraying Castolin Rotec 80
- Implant apparatus for steel weldability testing
- Equipment for stud arc welding
- Equipment for testing of materials and protective coatings in salt and wet chamber
- Off-centre 50-ton press
- Gravitational hammer
- Tensile tester
- Various tools for punching, bending, deep drawing and forging
RESEARCH GROUP
Department for Production Engineering
Mechanical Engineering Faculty of Slavonski Brod
Trg I. Brlić-Mažuranić 2
HR-35000 Slavonski Brod
Contact person: Full professor tenure, Pero Raos, Head of Department (Pero.Raos@unisb.hr)
Chair for Machining and Metal Forming
Contact person: Full professor, Leon Maglić, Head of Chair (Leon.Maglic@unisb.hr)
Chair for Polymer Processing and Casting
Contact person: Associate professor, Daniel Novoselović, Head of Chair (Daniel.Novoselovic@unisb.hr)
Chair for Welding and Surface Protection
Contact person: Assistant professor, Josip Stojšić, Head of Chair (Josip.Stojsic@unisb.hr)