Additive technologies are increasingly widespread in the aviation industry, medicine and implantology. It is essential that the parts manufactured for these applications meet the highest requirements not only as far as their strength, but also surface quality. Thus, high importance should be attached to performing analysis of the manufactured part's surface morphology to ensure optimised functionality, and to selecting appropriate post-processes so as to arrive at the required external surface structure. The paper aims to establish the influence of technological parameters (chiefly of the laser power) of the selective laser melting (SLM) process on the morphological properties of the manufactured surfaces. The changes of characteristics of the Sa and Sq parameters in the laser power P function are non-linear. However, for some values of laser power P (150, 175 W), the Sa and Sq parameters are considerably higher than that in case of the remaining laser power values. The change of the laser power has a strong influence on the structure of individual surfaces, as evidenced by the fact that the highest values of the Sa and Sq parameters were achieved at different laser powers (175 W for the top surface and 150 W for the side surface). The results are shown in graphic form of 2D and 3D morphology profiles and charts. Based on the analysis of parameters describing surface structure properties, optimum values of laser power during SLM process are established. The study also revealed that surface structure analysis should not be focused solely on basic parameters such as average height (Sa) or root-mean-square height (Sq), but also on parameters such as kurtosis (Sku) and skewness (Ssk), which yield important information on surface stereometry. Precisely established surface stereometry allows assessing properties such as wear resistance, corrosion, tribological properties, and the ability to integrate medical implants with live organism tissue.
Apart from accuracy, one of the parameters describing industrial robots is positioning accuracy. The parameter in question, which is the subject of this paper, is often the decisive factor determining whether to apply a given robot to perform certain tasks or not. Articulated robots are predominantly used in such processes as: spot welding, transport of materials and other welding applications, where high positioning repeatability is required. It is therefore essential to recognise the parameter in question and to control it throughout the operation of the robot. This paper presents methodology for robot positioning accuracy measurements based on vision technique. The measurements were conducted with Phantom v2511 high-speed camera and TEMA Motion software, for motion analysis. The object of the measurements was a 6-axis Yaskawa Motoman HP20F industrial robot. The results of measurements obtained in tests provided data for the calculation of positioning accuracy of the robot, which was then juxtaposed against robot specifications. Also analysed was the impact of the direction of displacement on the value of attained pose errors. Test results are given in a graphic form.
Abstract. The subject of this article is the assessment of measurement uncertainty with the kinematic telescopic bar QC20-W in the accuracy test of MOTOMAN HP20 industrial robot. The measurements were performed to determine the statistical uncertainty of error measurement using the system applied. Analysed in tests was the robot's ability to recreate a circular outline through standard, complex and extended measurement of uncertainty measurement. The obtained results were served to perform rapid evaluation of robot inaccuracy. These uncertainties were based on the information included in the device calibration certificate (estimated with method B) but also on the basis of measurements and statistical data (estimated with method A). These components of the uncertainty budget take relatively small values (u c = 0.818 ÷ 4.130; U = 1.636 ÷ 8.260 for k = 2, which proves that a properly selected method was applied to the research task. The method of research and calculation precisely identified key uncertainties allowing for an objective assessment of the industrial robot errors carried out with Renishaw the kinematic telescopic bar.
The aim of the present article is the assessment of technical shear resistance (technological shear) of orthopedic screw made of titanium alloy Ti6Al4V, produced using incremental technology in the process of 3D printing process. The first part of the work presents incremental techniques in production engineering. The second part of the present work contains a specification of the 3D printing process of samples as well as the description of the used material. The fundamental part of the article is composed out of endurance tests for orthopaedic screws as well as the analysis of the obtained results and conclusions. The method of incremental production SLM using SLM 280 HL metal printer was used during the technological process. The resistance tests were performed using ZWICK/ROELL Z150 machines. Identical endurance trials were performed for monolithic bars made of titanium alloys (of bar core size ) made on a wire electric discharge machine Sodick SL600Q for comparative purposes. The obtained test results enabled comparative assessment of the value of shear resistance R t in the conditions of technological shear. According to the performed tests, the shear resistance R t of orthopaedic screws is nearly 33% lower than of monolithic bars of the same core size.
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