Method for optimum calculus of machining parameters according to tool trajectories type based on milling process simulation

Virtualni obradni sustavi mogu biti od koristi u izradi proizvoda za koje nije potrebno fizičko ispitivanja u radionici. Kao rezultat, može doći do smanjenja vremena i troška izrade dijela. U radu se opisuje utjecaj putanje alata na devijaciju površinske geometrije kod završne obrade kosih površina. Cilj rada je optimizirati postupak glodanja uzimajući u obzir strategiju glodanja. Istraživanje je usmjereno na završnu obradu kuglaste glave jer je poznato da kod ravnog glodanja brzina glodanja u sredini glodala iznosi vc= 0 m/min. U skladu s tim, na hrapavost površine utječe činjenica da u tom području dolazi do postupka trenja a ne narezivanja. Simulirano je šest vrsta putanje alata i procijenjena je površinska devijacija.Virtual manufacturing systems can provide useful means for products to be manufactured without the need of physical testing on the shop floor. As a result, the time and cost of part production can be decreased. The paper presents the influence of tool path trajectory on surface deviation geometry when finishing inclined surfaces. The aim of the study is to optimize the milling process taking into account the milling strategy. The research was focused on ball end finishing because it is well known that in plain cutting, in the centre of the flat mill the cutting speed is vc = 0 m/min. According to that, the surface roughness is influenced by the fact that in this area a friction process occurs and not a cutting process. Six types of tool trajectories were simulated and surface deviation was evaluated

EDUCATIONAL 5 AXIS ROBOT CONTROLLER OPTIMIZATION USING ARM HARDWARE INSTRUCTIONS

This paper presents a programming method of a Raspberry Pi controller for a 5-axis articulated arm robot. The goal is optimization of direct kinematics calculations, based on the universal approach for direct kinematics method. Matrix multiplication is implemented using ARM hardware instructions. The main advantage of this method is lower computation time, which means faster robot response time. Programmability of the robot is done by means of a custom-made instruction set, called RASM

Surface quality and machining time optimization based on feedrate correction function of tool trajectories types

Danas svaki CAM program nudi različite strategije putanje alata za glodanje geometrije slobodnih oblika. Svaka završna operacija glodanja usmjerena je kvaliteti površine. Ipak, korisnici CAM-a moraju znati kako odabrati putanju alata u skladu sa složenošću geometrije, geometrijom alata i njegovim dodirom s obrađivanom površinom. Na kvalitetu površine te vrijeme obrade djeluje i putanja alata. Rezultati ovog istraživanja usmjereni su određivanju faktora korekcije parametara rezanja na osnovu vrste putanje alata. U svrhu provjere eksperimentalnog faktora korekcije, izračunate su optimalne brzine posmaka za svaki tip putanje na temelju kvalitete površine i analize vremena obrade za kose površine. Završni postupci obrade načinjeni su alatom za glodanje s kuglastom glavom.Today, any CAM software offers some different tool trajectories strategies for milling free form geometries. In any finishing milling operation the most important objective is the surface quality. However, the CAM users must have the know-how to choose the tool trajectories according to geometry complexity, cutting tool geometry and its contact on the machined surface. The quality of the surface and machining time is influenced also by tool trajectories. Research results presented in this paper are focused on determination of a correction factor for cutting parameters based on tool trajectories type. To validate experimental correction factor, optimum feed rates are calculated for each type of trajectories based on surface quality and machining time analysis for inclined surfaces. The finishing procedures are made with a ball end milling tool

Research Regarding the Increase of Durability of Flexible Die Made from 50CrMo4 Used in the Typographic Industry

A large amount of packaging used mainly in the food industry is obtained by technologies that involve the use of machines such as those that cut with flexible die. The durability of the flexible die is a very important aspect and in this regard the purpose of the research was to identify technologies for its development. Thus, the research considered the analysis of the durability of the knives made of 50CrMo4 steel considering hard chrome-plating treatment, as well as laser hardening of the knives. For the analysis of the durability of the tools, two technological parameters were considered, namely the moment of the tightening force, which had values in the range of 50 Nm–110 Nm, and the die cutting speed, which was adjusted to values in the range of 50–60 m/min. For the analysis of the durability of the flexible die, the wear of the tools was taken into account, as well as the maximum length of the die cut material

ROUGHNESS ESTIMATION OF A MILLED SURFACE BY USING NEURAL NETWORK BASED ON MINIMUM NUMBER OF EXPERIMENTAL MEASUREMENTS

Artificial Neural Network is a powerful tool for prediction of parameter values, which presents a set of low input data, especially in terms of reducing costs and time for making measurements. The prediction of surface roughness according to the different tool trajectories of the finishing phase in milling process can be achieved both by unifying the results and by dividing the set of data into multi-classes. The paper presents, for the roughness parameter, how a set of low number of input data obtained by measurement is used for prediction as well as data set extension. The experimental tests were made for machining an aluminum 7075 part with plane surfaces at constant angle. The milling process was made without cooling

Reconditioning by Welding of Prosthesis Obtained through Additive Manufacturing

Biocompatible titanium alloys are increasingly being used to make custom medical implants using additive manufacturing processes. This paper considered the welding reconditioning of a titanium-alloy customized additive manufactured hip implant with several manufacturing defects. The personalized implants are made starting from a Computer-Aided Design (CAD) model as a direct result from the medical imaging investigations of the areas of interest. Then the customized implant is fabricated using an additive manufacturing process (in this case Powder Bed Fusion—Direct Metal Laser Sintering—DMLS). The analysis of the chemical composition values as well as the values of the mechanical properties of the samples obtained via DMLS additive manufacturing process, revealed that such a manufacturing process can be successfully used to make customized surgical implants. The mechanical properties values of the DMLS samples are approximately equal to those specified by the manufacturer of the titanium powder used for sintering. On average, the tensile strength was found to be 24.75% higher, while yield strength 22.7% higher than the values provided in the standard for surgical implants applications. In case the additive manufacturing process produces products with defects one might want to try and recover the implant due to costs and time constraints. The Tungsten Inert Gas (TIG) welding reconditioning process with ERTi-5 Ti64 rod for welding titanium alloys with a content of 6% aluminum and 4% vanadium filler material was used to restore the geometric characteristics as well as the functional properties of a custom hip medical prosthesis. After welding depositing successive layers of materials, the surfaces of the prosthesis were machined to restore the functional properties according to the characteristics of the original 3D model. A 3D scan was used to compare the geometrical characteristics between the original part and reconditioned one. Deviations were less than 1 mm and were acceptable from the medical point of view