DESIGN OF A COMPUTER-AIDED GEAR MANUFACTURING TOOL – RACK-SHAPED CUTTER

In this work, the calculation of Maag gear shaper cutter parameters is performed for spur gears with helical teeth in three variants – straight-tooth tool with machine offset, helical-tooth tool without machine offset and helical-tooth tool with machine offset. It is therefore a prerequisite that the manufactured involute gearing has helical teeth for each variant. The created CAD program is universal and can be used for construction in other combinations as well. The tool clamping angles on the tool holder, the cutting geometry of the cutter and the characteristic of the gearing are introduced into the calculation. The output of the work will be then calculated individual parameters of the Maag shaping cutter in the tooling system, necessary for its construction. The calculation are performed in program T-Flex CAD and the summary output is graphical 2D/3D representation of the rack-shaped cutter in its base, normal and side planes, always in a different design based on the change of the tool input data and gearing characteristic. The analysis of the tool´s involute profile was solved by vector calculus and matrices and by rotating the tool in the chosen coordinate systems. The specific calculation of the tool parameters will be solved using goniometric functions.

Processing of quasi-equidistant surfaces with the detection of the dependence of the roughness parameters on the tool pitch in the cam system

This article discusses the basic principles of generating a tool path when processing quasi-equidistant surfaces. The review and analysis of the origin of the automation of technological preparation of production in the world is carried out. The concept of integrated automated production is revealed. Considered are the leading enterprises that were among the first to introduce computer-aided design systems. The article discusses technologies for processing complex surfaces with the maximum removal of the metal layer from the work piece, with the maximum approximation to the given shape. The types of complex spherical surfaces have been identified, the processing of which is a complex technological process that requires a high level of qualifications of a specialist and expensive equipment. Before the introduction of automated machine control, such types of complex surfaces were almost impossible to process, the geometry was only close to the real one. Here we consider a modern CAM-system, which is a complex software package. Over the past decade, several generations of CAM systems have changed. When forming the tool path, it is possible to use the functions of their viewing and editing. In most cases, the system automatically generates the tool path based on the cutting geometry and machining parameters. The authors proposed a method for creating a machining path in the NX CAM environment. In this work, the optimal trajectory of the tool movement is determined, the cutting pattern is selected for processing quasi-equidistant surfaces, the cutting modes, the cutting tool, and the overlap step between passes are determined.

Determination of the Bucket Wheel Drive Power by Computer Modeling Based on Specific Energy Consumption and Cutting Geometry

Starting from the general principles of material cutting, with applicability to coal and overburden excavation using bucket wheel excavators (BWEs), this paper proposes another method for calculating the drive power of the bucket wheel excavator by computer modeling. This approach required two steps. In the first step, the volume of the excavated material for one slewing movement of the boom and for a particular excavation geometry was determined, and the slewing time in the open pit coal mine was measured. In the second one, the values of the specific energy (SE) consumption for cutting were determined by laboratory tests on samples of material taken from the open pit mine. The proposed method allows for the estimation of the load of the bucket wheel drive motor by taking into account only the specific energy necessary for the cutting of the material, the excavated volume during one slewing, and the time required to excavate this volume, and not the wear coefficients of the teeth or bucket edge. This method is important for establishing the correlation between the height of the excavated slice and the slewing speed of the boom in order to optimize the drive power of the bucket wheel and thus improve energy efficiency, increase the performance of excavators, and reduce operating costs.

ANALYZING THE PERFORMANCE OF CIRCLE SEGMENT END MILL WITH PCD INSERTS WITH LASER-MACHINED INTEGRAL CHIPBREAKER WHEN DRY MILLING OF ADDITIVE MANUFACTURED TI-6AL-4V TITANIUM ALLOY

Components with generally shaped surfaces requiring higher surface quality and dimensional accuracy are, in most cases, machined. Specifically, milling technology is involved very often, which can be supplemented by finishing operations. Besides standard ball-nose end mills, circle segment end mills are modern type of cutter that has begun to be used with the development of advanced computer aided machining software, that allows to work with these shaped tools. In this research, comparing the performance of these two modern shaped end mills was investigated. One tool was a commercially available coated solid carbide circle segment end mill. A second prototype end mill with the same profile but different geometry was made with a PCD insert, that additionally had a chipbreaker produced by laser technology. Machining was carried out on the workpiece material the Ti-6Al-4V that was manufactured by additive manufacturing (AM) technology – selective laser melting (SLM). The titanium complex parts are generally used in the transport industries and medicine. Milling tests were performed under dry cutting conditions. The evaluation was based on the force load, the roughness of the machined surface and tool wear. The higher total forces were measured by the tool with a PCD insert, because a different tool geometry was used, despite the use of integral chipbreaker, which allows a partial change of the cutting geometry of the insert. The geometry of end mills with brazed insert is limited by the production process.

An Investigation of the High-Frequency Ultrasonic Vibration-Assisted Cutting of Steel Optical Moulds

Ultrasonic vibration-assisted cutting (UVAC) has been regarded as a promising technology to machine difficult-to-machine materials such as tungsten carbide, optical glass, and hardened steel in order to achieve superfinished surfaces. To increase vibration stability to achieve optical surface quality of a workpiece, a high-frequency ultrasonic vibration-assisted cutting system with a vibration frequency of about 104 kHz is used to machine spherical optical steel moulds. A series of experiments are conducted to investigate the effect of machining parameters on the surface roughness of the workpiece including nominal cutting speed, feed rate, tool nose radius, vibration amplitude, and cutting geometry. This research takes into account the effects of the constantly changing contact point on the tool edge with the workpiece induced by the cutting geometry when machining a spherical steel mould. The surface morphology and surface roughness at different regions on the machined mould, with slope degrees (SDs) of 0°, 5°, 10°, and 15°, were measured and analysed. The experimental results show that the arithmetic roughness Sa of the workpiece increases gradually with increasing slope degree. By using optimised cutting parameters, a constant surface roughness Sa of 3 nm to 4 nm at different slope degrees was achieved by the applied high-frequency UVAC technique. This study provides guidance for ultra-precision machining of steel moulds with great variation in slope degree in the pursuit of optical quality on the whole surface.

Analysis & Optimization of Parameters During EDM of Aluminium Metal Matrix Composite

In now days Aluminium Metal Matrix Composite (AMMC) has become one of the most favorite material for automotive, aerospace, shipyard etc. industry because of their outstanding properties such as high wear and corrosive resistance, remarkable hardness and toughness, low density, light weight etc. But because of the complexity of the cutting geometry and mechanical properties of work materials the use of convectional machining process becomes limited. Such difficulties are easily sort-out by using electric discharge non convectional machining process (EDM) because in this case material removal takes place by thermal erosion process. The present research work highlight the effect of process parameter on output response during the EDM of Aluminium7075- Boron carbide-Graphite (Al/B4C/Gr) metal matrix composite (MMC). Taguchi technique is used for design of experiments. Fitness and adequacy of the experimentation has tested through the analysis of variance (ANOVA).

Proximate composition and kinectics drying of sweet pine nuts compared to typical nuts of Araucaria angustifolia

ABSTRACT: The objective of this research was to determine the proximate composition and kinetics drying of sweet pine nuts compared to typical pine nuts of Araucaria angustifolia. This study is based on the proximate components, color, and duration of pine nuts drying of both types, and the influence of temperature and cutting geometry on the dehydration process. Sweet pine nuts had lower calorific value and carbohydrate content, but higher lipid, dietary fiber, protein, and ash contents when compared to typical pine nuts. Color of sweet pine nuts is light pink whereas the typical pine nut is yellowish-white. Sweet pine nuts were also softer. Drying kinetics of the seeds fit well into the logistic and Thompson models. To accelerate drying rates, we recommend slicing pine nuts into thin cross-sections and drying them at temperatures of 60 °C for typical pine nuts and 70 °C for sweet pine nuts.

Effect of Geometrical Parameter Cutting Edge on the Toroidal Forming Surface of a Solid End Mill

Solid end mill with a toroidal forming section are the most productive solutions in the field of processing difficult-to-process materials. The process of forming the cutting geometry of such cutters is performed on grinding machines with CNC with the use of abrasive grinding wheels. The formation of the cutting edge on the toroidal section is carried out by discrete movements of the working bodies of the machine in accordance with the control program. The disadvantage of the stepper drive used in CNC machines is the limited discreteness of the described trajectory resulted in the loss of accuracy when forming radius, arc, spherical and toroidal sections. Loss of accuracy in the formation of elements of the working geometry of a solid end mill can negatively affect the tool life, and the structural strength of the joints of the transition of working surfaces. The study is aimed at identifying the necessary and sufficient number of points that describe the spatial shape of the cutting edge with acceptable loss of accuracy.

An experimental study on shear bands in sand using the orthogonal cutting setup

We study the evolution of shear bands in granular media subjected to very large deformations using the orthogonal cutting geometry. We perform our cutting experiments on Cauvery Delta sand with d50 of 0.45mm. We also capture images of the cutting process which allows us to perform a PIV analysis to determine the deformation in material around the cutting tool. In our experiments we observe that the dynamic angle of repose of the pile that forms in-front of the tool as cutting progresses, approaches the critical state friction angle of the material. We observe a flow bifurcation around the tool as the material begins to slip along planes which are oriented at an angle of π/4 – θ/2, θ being the dynamic angle of repose, to the cutting direction. This leads to formation of shear bands/velocity jumps which contain around 14 particles. A measurement of dilation angle within the shear bands indicate that material is in a critical state of deformation.

A novel method of blade-inclined ultrasonic cutting Nomex honeycomb core with straight blade

Ultrasonic cutting with a straight blade is an advanced cutting method for Nomex honeycomb core. However, crushing has generally been observed on the machining surface of the honeycomb core in ultrasonic cutting (UC). In this paper, aiming at avoiding crushing, a new blade-inclined ultrasonic cutting (BIUC) method is proposed to decrease the geometric interference between the cutting tool and the honeycomb cores. The cutting geometry systems of UC and BIUC with a straight blade are systematically established to study the effect of cutting geometry on the machining quality. The crushing degrees caused by the major flank under different tool orientations in UC and BIUC are analyzed. The causes of crushing during the machining of the honeycomb core were revealed from aspects of machining quality, cutting force and geometric interference between the major flank and the material. Experiments on quantitive analysis of crushing and cutting forces verify that the BIUC method is able to avoid crushing by controlling the cutting angle. This paper provides a new method for solving the crushing problem in machining honeycomb core with the straight blade.