Polymer Concrete Composite – Preparation of Testing Samples

Presented article is focused on manufacture of composite materials based on polymer concrete mixtures. Article describes the very essence of polymer concrete as well as the properties of its individual possible components. In the second part, the paper deals with specific materials, machines and utilities, which are used in the manufacture of composite. The third part of the article describes the manufacturing process itself and the individual stages of production. Conclusion includes the acquired knowledge of the production as well as other possible improvements of the process

Eddy current testing of artificial defects in 316L stainless steel samples made by additive manufacturing technology

Additive manufacturing has many positives, but its incorporation into functional parts production is restricted by the presence of defects. Eddy current testing provides solutions for their identification; however, some methodology and measurement standards for AM (additive manufacturing) products are still missing. The main purpose of the experiment described within this article was to check the ability of eddy current testing to identify AM stainless steel parts and to examine the data obtained by eddy currents variation under the influence of various types of designed artificial defects. Experimental samples were designed and prepared with SLM (selective laser melting) technology. Artificial defects, included in the samples, were detected using the eddy current testing device, taking the important circumstances of this non-destructive method into account. The presented research shows significant potential for eddy current testing to identify defects in AM products, with a resolution of various types and sizes of defects. The obtained data output shows the importance of choosing the right measurement regime, excitation frequency and secondary parameters setup. Besides the eddy current testing conditions, defect properties also play a significant role, such as their shape, size, if they are filled with unmolten powder or if they reach the surface.Web of Science1519art. no. 678

Study of High Feed Cutting Efficiency of Aluminum Alloy AW – Alzn5,5mgcu

Presented article is focused on the study of high feed cutting of EN AW - AlZn5,5MgCu material. Experimental part describes the study of the efficiency of high feed milling of the specified material and its subsequent comparison with conventional methods and standard tools. This part describes the realization of five milling options, 4 of which are realized by the HFC method and the last alternative is realized by conventional milling. The conclusion is focused on complex assessment of the efficiency of machining of the specified aluminium alloy from economic and technical point of view and the comparison of individual HFC alternatives with the conventional milling method

Surface Integrity Evaluation of Brass CW614N after Impact of Acoustically Excited Pulsating Water Jet

AbstractPresented article is focused on surface integrity evaluation of brass CW614N form the sight of surface topography, structural changes in surface layers and strengthening character in subsurface layers after impact of acoustically excited pulsating water jet (PWJ). Surface topography was evaluated using optical profilometry. Structural changes in subsurface layer were observed based on mass material removal Δm [mg/s] and maximal depth of penetrance of PWJ hmax [mm]. Nano indentation measurement according to Berkovich were used to examination of strengthening character in subsurface layer. Disintegration of experimental samples was performed under constant technological conditions: hydraulic power of plunger pump Ph = 19kW; round nozzle diameter d = 1.6mm; feed speed rate v = 0.75mm/s; pressure of plunger pump p = 38MPa, stand-off distance of nozzle from target material z = 45mm; ultrasound frequency f = 20.29kHz and as variable factor was set power of ultrasound P on values 340, 360 and 380W. In terms of surface topography experimental investigation proved that PWJ under selected conditions is not suitable for precision machining. Evaluation of the surface characteristics indicates that the chemical composition has a significant effect on material weight loss Δm [mg/s] and a maximum depth of penetration of PWJ hmax [mm]. Evaluation of characteristics of subsurface layer was observed strengthened area with lower elasticity

Implementation of Computer-Aided Design of Fixture in the Educational Process

This article describes the implementation of Computer – aided design of fixture in the educational process. The introduction of this article describes the drilling technology and the fixtures in a theoretical approach. In the second part of this article, the current state of drilling technology and fixtures is analysed. Described is a part for which it is necessary to design a fixture for the drilling process. The third part of this article is focused on the description of fixture design creation for selected part. The design is created in the Autodesk Inventor which is integrated into the educational process at the Faculty of Manufacturing Technologies. The final part of this article provides an overall evaluation of suggested solution from the practical and educational point of view

Residual Stress Evaluation in L-PBF-Produced SS 316L Specimens

The identification of residual stresses (RS) in components made by selective laser melting (SLM) is necessary for subsequent technological optimization. The presented research is devoted to evaluating the influence of the combination of laser power (P), scanning velocity (v) and the rarely considered number of layers (nL) on surface residual stresses in SLM stainless steel SS 316L. Experimental parameters were set based on the Design of Experiment (DoE) method, with follow-up X-ray diffraction (XRD) measurements and data processing using analysis of variance (ANOVA) and regression analysis. The obtained data are a valuable stepping-stone for the subsequent design of research focused on the application of sustainable eco-friendly Abrasive Water Jet (AWJ) peening for RS modification in the evaluated material

Study of Eddy Current Testing Ability on SLM Aluminium Alloy

The detection of defects in aluminium alloys using eddy current testing (ECT) can be restricted by higher electrical conductivity. Considering the occurrence of discontinuities during the selective laser melting (SLM) process, checking the ability of the ECT method for the mentioned purpose could bring simple and fast material identification. The research described here is focused on the application of three ECT probes with different frequency ranges (0.3–100 kHz overall) for the identification of artificial defects in SLM aluminium alloy AlSi10Mg. Standard penetration depth for the mentioned frequency range and identification abilities of used probes expressed through lift-off diagrams precede the main part of the research. Experimental specimens were designed in four groups to check the signal sensitivity to variations in the size and depth of cavities. The signal behavior was evaluated according to notch-type and hole-type artificial defects’ presence on the surface of the material and spherical cavities in subsurface layers, filled and unfilled by unmolten powder. The maximal penetration depth of the identified defect, the smallest detectable notch-type and hole-type artificial defect, the main characteristics of signal curves based on defect properties and circumstances for distinguishing between the application of measurement regime were stated. These conclusions represent baselines for the creation of ECT methodology for the defectoscopy of evaluated material

Machining of Wood Plastic Composite Using AWJ Technology with Controlled Output Quality

The paper deals with the application of abrasive water-jet cutting to composite material containing natural reinforcement—wood plastic composite. The specimens were cut through the application of four flows of different abrasive mass: 150, 200, 250, and 300 g·min−1, respectively, and under different traverse speeds required to achieve the (expected) quality level Q1–Q5 (according to the SN 214001: 2010 standard). The output quality of Q1–Q5 was set in the CNC cutting programs and the real traverse speed values were calculated by machine control system according to change in the flow of the abrasive mass. The quality of surface topography was assessed using a tester (contact roughness) and an Inspectis digital zoom microscope. The results of topography–surface roughness parameters Ra presented here are compared with the values normalized for individual samples sets. The applied technology, i.e., the AWJ, eliminated the problem of tool wear and adhesion of the thermoplastic matrix to tool surfaces (compared to standard machining)

Effect of pulsating water jet disintegration on hardness and elasticity modulus of austenitic stainless steel AISI 304L

The presented article is focused on the evaluation of mechanical properties of stainless steel disintegrated using an ultrasonically modulated pulsating water jet. The experimental procedure was performed using a nozzle with a circular orifice with an equivalent diameter of 1.6 mm. The mechanical properties evaluation was based on indentation elasticity modulus E-p and nano hardness H, which were measured using nanoindentation technique. Influence of ultrasonic power and plunger pressure change on disintegrated material was evaluated. Changes in mechanical properties in dependence on distance from the disintegrated surface were evaluated. Elasticity modulus and nano hardness change were observed below and on the sides of the disintegrated surfaces. Measurements were performed until the distance of 930 mu m. The indentation was carried in three series of 10 indents with 100 mu m spacing located below the affected area, next to the affected area and in the unaffected material. Results of experimental testing show changes of nano hardness (generally an appreciable decrease) and elasticity modulus (limited increase) of material under and to the side of the newly created surface.Web of Science1075-62730271