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The paper is focused on the influence of the coolant pressure on the surface roughness of the workpiece when machining stainless steels. The components were machined on a STAR SR-32J dual spindle machining center and an external cooling unit HYTEK CHAV 160/150-AF-F-OL was used for cooling. Two stainless steel components were investigated, namely the gas control valve rod and the high-pressure control valve housing, which require low roughness Ra after machining (less than 0.375 and 0.25 micrometers respectively). The first component was tested at 8 different pressures in the range of 150 bar - 10 bar and the second component at 4 different pressures in the range of 120 bar - 10 bar. The roughness parameters were measured by the contact method using the MITUTOYO Surftest SJ-410 Roughness Tester and the Alicona InfiniteFocus optical microscope. Based on these sample input parameters, it was evaluated howmuch the pressure affects the surface quality or suggested its reduction due to the high cost of operation of the external high-pressure equipment.

The paper presents general aspects related to the influence of execution, assembly and functioning errors on the teeth profile modification from the spur gear in the front plane, in the case when the gear is fixed to the shaft in an asymmetrical position relative to the bearings. The numerical researches were done with FEM.

Craniofacial bone defects that produce morphological and functional disabilities can bring alteration of the quality of patient’s life. For this reason, the collaboration between the field of medicine with engineering, lead to the manufacture of custom implants from biocompatible materials. In the last years it was shown that Additive Manufacturing methods are very helpful to achieve customized medical implants. All the customized implants made of biocompatible materials have to be tested for mechanical properties, in order to have the optimal characteristics for the area were will be used. This paper presents the results for bending and compression tests for a biocompatible material, PA 2200. The samples were achieved using Selective Laser Sintering method and were obtained with different laser power, starting with 4 W. Maximum load, maximum stress, specific deformation and Young's modulus were analysed. The study showed that different mechanical properties can be obtained, depending on the laser power used. At bending tests, increasing values were obtained for the investigated parameters along with laser power increasing, but at compression tests a different trend was observed.

Worldwide, accidents are one of the main causes of illness in developed and undeveloped socio-economic countries. Additive Manufacturing (AM) technologies bring extremely useful and advantageous applications for the new neurosurgical procedures. Because the surgical insertion of devices for cervical disc replacement is very difficult, the development of new devices that can minimize these disadvantages, are needed. The aim of this paper was to improve the characteristics of an implant for cervical intervertebral disc replacement, a model based on an existing implant. A cervical cage designed for stabilization and arthrodesis between the cervical vertebrae was analyzed. A new design of a cage that have some improvements, useful for patient safety, as well as for facilitating the surgery was developed. The new proposed design was verified through Fine Element Analysis.

To manufacture metal parts with complex shapes through Investment Casting (IC) process using wax models, it is necessary to have a complete control over the entire process. A very important aspect is to know the shrinkage value of the wax models. If the master model has a very small scratch or imperfection, this will appear also on the metal part surface. The structure and the mechanical properties of the metal part can be influenced by material porosity which can appear during the casting process. A given set of parameters such as preheating temperature, casting temperature, turbo pressure applied to finish the casting and also the wall thickness contributes to obtain a good surface quality and to material density which influences the part functionality. The objective of this research is to understand the utility of Vacuum Casting (VC) technology comparing with other casting technologies regarding the part surfaces quality. [ABSTRACT FROM AUTHOR]