Methods of power consumption reduction in metal cutting machines

W artykule przedstawiono potrzebę oszczędności energii w przemyśle, ze względu na koszty i ochronę środowiska. Wyznaczono obszary występowania strat energii w obrabiarkach i systemach wytwórczych. Ponadto omówiono możliwości wpływania na redukcję zużycia energii. Opisano sposoby zmiany struktury obrabiarek, redukcję ruchomych mas w obrabiarkach oraz tzw. „dematerializację".Necessity of energy consumption reduction in the industry is presentee this paper. An area of machine tools' and production systems' energy we is determined and opportunities for its reduction are discussed. Methods machine tool structural change, movable mass reduction and so called materialisation are described

Numerical model of fricional damper for glas – making robot lance

The need to design a friction damper for glass-making robots arose because of the excessive vibrations, which occur in the course of their work. The robots are commonly used in the manufacture of glassware. The vibrations adversely affect the work of ball gatherers, which results in a large number of defects in the finished glass products. As a result of the vibrations molten glass may become unevenly distributed on the ball's surface and as the material flows down the ball into the mould the thermal conditions of its solidification may change. It is proposed to damp the vibrations by means of a prototype friction damper mounted directly on the ball gatherer lance. The glass-making robot lance with the friction damper was modelled. The vibrations of the glass-making robot lance tip under static load and impact excitation were measured during simulations. Also the relative displacements of the damper rings in the course of the excitations were measured. Moreover, the dependence between the preload force and the system's damping decrement was determined. The main aim was to select proper operating parameters for the proposed structure in order to obtain maximum system damping

Comparison of Methods for Adjusting and Controlling the Preload of Angular-Contact Bearings

The effect of preload on the operating conditions of angular-contact bearings is described. The interdependences occurring during mutual displacements of bearing rings at different bearing contact angles are discussed. The criteria of the classification into low-speed and high-speed angular-contact bearings are presented. Selected methods of preloading angular-contact bearings are compared and discussed. Their advantages and disadvantages with regard to the active control and adjustment of the bearing system during its operation are presented. The structure of a developed test stand with a spindle assembly is described. Preliminary measurements of the behaviour of the spindle assembly during operation are reported. Conclusions are drawn and the direction for further research is indicated

Finite Element Modelling of burr formation in metal cutting

The paper presents a two-dimensional FEM model of burr formation in metal cutting. Abaqus/Explicit software was used for the build of the model. The workpiece geometry, the tool and the cutting parameters were modelled. Physical properties and the method of deformation and fracture of the workpiece material is described using Johnson Cook's constitutive law and the ductile damage criterion. The simulation of the edge formation process during orthogonal cutting was carried out for different depths of cut and cutting speeds. The results of these simulations allowed the verification of the FEM model. The components of the resultant cutting force measured during the actual cutting process with the values of these forces determined based on FEM simulation of this process were compared. The geometry of burrs formed during the actual and simulated the edge forming process was assessed. The analysis showed that the FEM model built enabled a correct prediction of the shape of the workpiece edge and the estimation of geometric features of the edge

Modelling of a glass gatherer robot arm with a frictional damper

A numerical model of a friction damper used for damping vibration in glass gatherer robots was described. The damper with a lance was modelled using finite elements. Primary natural frequency of the system was determined. Numerical calculations were performed to determine the best operating parameters of the damper for excitations using a impulse of a force. Results of the damping decrement calculations for the friction damper model with a constant coefficient of friction and for the model, in which the coefficient of friction varied depending on the sliding velocity and the normal pressure occurring at the contact surfaces of the damper’s friction rings, were presented. Based on numerical simulations, the values of relative displacements between the damper’s friction rings were also determined