Impact of Cutting Data on Cutting Forces, Surface Roughness, and Chip Type in Order to Improve the Tool Operation Reliability in Sintered Cobalt Turning.

The authors present the results of laboratory tests analysing the impact of selected cutting data and tool geometry on surface quality, chip type and cutting forces in the process of orthogonal turning of sintered cobalt. The selected cutting data are cutting speed and feed rate. During the experiments, the cutting speed was varied in the range of vc = 50-200 m/min and the feed rate in the range of f = 0.077-0.173 mm/rev. In order to measure and acquire cutting force values, a measuring setup was assembled. It consisted of a Kistler 2825A-02 piezoelectric dynamometer with a single-position tool holder, a Kistler 5070 signal amplifier and a PC with DynoWare software (Version 2825A, Kistler Group, Winterthur, Switzerland)). The measured surface quality parameters were Ra and Rz. The components of the cutting forces obtained in the experiment varied depending on the feed rate and cutting speed. The obtained test results will make it possible to determine the optimal parameters for machining and tool geometry in order to reduce the machine operating time and increase the life of the cutting insert during the turning of sintered cobalt, which will contribute to sustainable technology.

Optimization of Titanium Alloy Drilling to Minimize the Secondary Burr after Deburring Process.

The formation of burrs on the edges of machined surfaces is one of the inherent problems during machining. The burrs are formed both on the tool entry surface and exit surfaces. The paper proposes a modification of the drill involving an additional cutting insert located in the shank part. This innovative solution allowed the drill and deburring insert to be integrated, enabling both processes to be performed within one machining operation. The impact of the selected insert geometry and deburring process parameters on the size of burrs was determined during the experimental studies. Using the proposed deburring process for the Ti6Al4V titanium alloy, with appropriately chosen tool geometry and cutting parameters, reduces the secondary burr height by more than 90% compared to the original value.

A Comparative Study on the Structure and Quality of SLM and Cast AISI 316L Samples Subjected to WEDM Processing.

Additive manufacturing technologies are increasingly used in the production of semi-finished workpieces intended for further processing. This entails the need to investigate the machinability and final properties of such products. Comparative research on wire electrical discharge machining (WEDM) processes performed with two kinds of AISI 316L stainless steel workpieces is presented in this paper. The first workpiece was made by selective laser melting (SLM), while the second one was casting. Both working materials were cut with current values ranging from 8 to 72 amps. A comparison of roughness, structure and chemical composition of machined surfaces was performed between the two kinds of specimens. For the SLM sample, parameters of the cutting process that provide relatively low surface roughness (Ra ≤ 10 µm) with the simultaneous maximization of the process efficiency were determined. It was found that in the case of applying high current values (72 amp.), more favorable properties of the treated surface were obtained for the SLM sample than for the cast one.

Investigation and Optimization of the SLM and WEDM Processes' Parameters for the AlSi10Mg-Sintered Part.

Presented study concerns the issue of processing the AlSi10Mg aluminum alloy with a use of WEDM technology. Two types of samples tested during the experiment were previously produced in SLM and in casting processes. The aim of the research was to determine the dependence of the input parameters of SLM (laser scanning speed) and WEDM (current amplitude) processes on the performance of the WEDM process as well as on the roughness of the cut surfaces. The experiment was carried out on a specially prepared test stand, and the results' analysis was carried out using the ANOVA (analysis of variance). A strong influence of the WEDM current on the process speed and on the Ra and Rz roughness parameters of the produced samples was found. The effect of SLM laser scanning speed was not so strong, but it tended to be uniform. On the other hand, the influence of the tested parameters on the WEDM process energy turned out to be insignificant and irregular. It was also found that for the WEDM process a sample made in SLM technology with relatively high laser scanning speed may be a better choice than the cast one. A case study was carried out to optimize the parameters of the tested processes.

Drilling Burr Minimization by Changing Drill Geometry.

This article presents an attempt to solve the problem of the formation of burrs and drilling caps in the process of drilling in difficult-to-cut materials, specifically in the titanium alloy Ti-6Al-4V. In order to eliminate these phenomena, a chamfer of specific length and angle was made on FANAR drill's margin. Taguchi and ANOVA methods were used to plan and analyze the experiment aimed at determining the optimal geometry of the modified drill. Chamfer with a length of 2 mm and an angle of 10° was selected. In the next stage of research, the values of cutting forces and burr heights obtained during drilling with the original and modified drill were compared for three different feed rate values. It turned out that the introduced changes significantly reduced both the axial cutting force (22-23%) and the height of burrs (10-22%) and caused the complete elimination of the presence of drilling caps. Additionally, a positive correlation between the cutting force and the burr size was found.