In this paper, the influence of the input EDM parameters on the surface quality of tool steel 1.2713 has been modelled and optimised. Experimental studies were conducted with a design experiments (DOE) techniques. Based on the result of experimental investigation influence of EDM parameter: discharge current, time discharge and time interval on the roughness Ra and material removal rate were established using response surface methodology. Considering the properties of the EDM for the roughness Ra in the range between 1-2 µm with the maximum possible value of the MRR process optimization was conducted based on desirability technique.

This paper presents a new method of eccentric magnetic-abrasive finishing as applied to 316 stainless steel. The proposed solution is based on solid ferromagnetic abrasive grains (Fe-Si) held by an external magnetic field. A workpiece fixed in a holder with a certain eccentricity is inserted between the grains and the holder is rotated. The use of an additional eccentricity has a significant impact on the nature of the process, in particular, it increases the speed of the sample relative to the abrasive grains, makes it possible to use more abrasive grains, induces mixing abrasive grains, which can prolong their active life time. In this study, a three-factor, five-level design of experiment was conducted. The variable parameters were: machining time, eccentric value, and rotational speed. Samples in the form of rollers with a diameter of 3 mm were mounted in a special holder that allowed to obtain the assumed eccentricity. Based on the results obtained, regression equations were developed for selected roughness parameters Ra, Rz, Rq, Rt. The value of Ra roughness decreased from the initial value of 0.575 μm to a value below 0.1 μm (an 80% decrease) in 9.1 min. The results obtained provided the basis for further research in conducting eccentricity in magnetic-abrasive machining as an intensifying element of the process.

In this article, we present a numerical model of a magnetic abrasive finishing station, which was analyzed using the finite element method (FEM). The obtained results were compared with the real values measured on an experimental station of our own design. The prepared station had the option of adjusting the magnetic flux density inside the machining gap, the width of which could be changed from 10 to 30 mm. The maximum value of the magnetic flux density inside the air gap was 0.8 T. The real distribution of magnetic flux density in the finishing area was also analyzed. A design of experiment was carried out with the following variables: abrasive grain concentration, width of the machining gap, and process duration. The results are presented in the form of regression equations and characteristics for selected roughness parameters.

Physiotherapeutic procedures after surgical treatment of trochanteric fractures of femurs are a very important element of a postoperative management because they have a significant influence on the final result of physiotherapy. This is due to the nature of the fracture and the frequency of its occurrence. The aim of the work is, in particular, to determine the relationship between functional assessment scales in patients after trochanteric fractures treated surgically using extended statistical analysis including regression equations. Statistical analysis included a group of patients, which participated in a specialized programme of a post-operative procedure, called the ‘Individual’ Group. The matrix of research results, calculations of basic statistical measures, such as position, variability, interdependence, asymmetry and concentration were presented for this group. Regression equations representing the relationships between the considered variables, in particular concerning the applied scales and post-operative tests, were presented. Their purpose, mathematical interpretation, results of calculations and statistical tests were discussed. Attention was paid to the high correlation between the Parker and Mobility tests. The extended statistical analysis makes it possible to create an own system for assessing the treatment results of patients after trochanteric fractures are treated surgically.

Artykuł Pomiary płaskości na manualnych współrzędnościowych maszynach pomiarowych * | Mechanik Miesięcznik Naukowo-Techniczny