ENGINEERING FOR RURAL DEVELOPMENT Jelgava, 24.-26.05.2017. 121 MACHINING OF POLYMERIC COMPOSITES BY MEANS OF ABRASIVE WATER-JET TECHNOLOGY Miroslav Muller 1 , Roberto D´Amato 2 , Anna Rudawska 3 1 Czech University of Life Sciences Prague; 2 Universidad Politecnica de Madrid, Spain; 3 Politechnika Lubelska, Poland muller@tf.czu.cz, r.damato@upm.es, a.rudawska@pollub.pl Abstract. The water-jet cutting technology represents an effective cutting tool for diverse materials. It is prospective in the area of composite materials, which represent a combination of a hard and a soft component. An advantage of the water-jet cutting is that the cut (the material) is not heat affected, namely at the polymeric materials. The abrasive water-jet with a dash of pabrasivum (a garnet MESH 80) was used for the research. The research was performed on the device AWJ CT 0806. The aim of the research was to evaluate the cutting area and delamination of the matrix and the reinforcement (a filler). The research based on the SEM analysis proved that the AWJ technology was a prospective method for cutting polymeric composite materials. Keywords: cutting, delamination, epoxy resin, fibres, particle, scanning electron microscopy. Introduction Dividing of a material is a common attribute of production companies. Classically applied methods of machining are not always technically and economically the most suitable for machining of new materials [1]. Classic technologies use cutting tools above all, on the other hand, unconventional (modern) technologies use flexible cutting tools such as ultrasound, plasma, laser-jet, liquid-jet etc. [2- 5]. Various mechanical and physical principles depending on the single machining method are used in the unconventional machining method. The technology of the abrasive water-jet can be ranked among modern and effective machining methods of wide spectrum of materials [6]. Creating of so called “cold cut” belongs to the main advantages. It does not come to heat affecting of machined materials, to evaporation and degradation of the material. The temperature is a problematic factor mainly at machining of polymers and polymeric composites. The liquid-jet is the working tool for machining. It is completed with an ingredient of abrasive substances at the abrasive water-jet (AWJ) technology. The AWJ technology consists in a principle of generating high water pressure going through a nozzle of a small diameter so the water gains very high kinetic energy similarly as at the water-jet [1; 6; 7]. Abrasive particles several fold increasing its effect are added into the high-speed water stream [7]. AWJ cutting, due to its various distinct advantages over the other cutting technologies such as no thermal distortion, high machining versatility, high flexibility and small cutting forces, is being increasingly used in various industries [7]. Specific advantages of AWJ to machine difficult-to-cut materials without inducing thermal stresses have complemented this technique for machining composites [7; 8]. AWJ was used at the research, i.e. abrasivum was added into the water-jet. Manufacturers, designers and engineers recognise the ability of composite materials to produce high-quality, durable, cost-effective products [9]. Composite materials are found in many of the products used in our day-to-day lives [9]. Composites are broadly known as reinforced plastics [10- 13]. Specifically, composites are reinforcing fibres in a polymeric matrix. Most commonly, the reinforcing fibre is fibreglass, although high strength fibres such as aramid and carbon are used in advanced applications [9]. A distinct advantage of composites, over other materials, is the ability to use many combinations of resins and reinforcements, and therefore custom tailor the mechanical and physical properties of a structure [9]. The composite materials are widely used in the technical practice [10; 14]. The polymeric particle composites find their application in a form of so called liquid metals [14]. Not only their adhesion at the production but also at another processing, such as, e.g., methods of material dividing into required dimensions, is important at these materials. The composites are of fibres, of particles, based on natural and synthetic fillers [14-16]. The AWJ technology is suitable for machining composite materials. This method has its advantages as well as disadvantages at machining of the composite materials. A serious damage of the material surface as well as its inner structure can occur at an encounter of the high-speed liquid with the abrasivum with the surface of the workpiece [8; 9]. Delamination is a major component defect when machining DOI: 10.22616/ERDev2017.16.N021