Development of a Cost Model for Vertical Milling Machines to Assess Impact of Lightweighting

Lightweighting is a design strategy to reduce energy consumption through the reduction of mass of a product. Lightweighting can be applied to machine tools to reduce the amount of energy consumed during the use phase. Thus, the energy cost of machine operation will be reduced. One might also hypothesize that since a lighter-weight machine tool requires less material to build, the cost to produce such a machine will be less. However, it may also be the case that lightweighting a machine tool increases its complexity, which will likely drive up the cost to manufacture the machine. To explore the cost drivers associated with building a machine tool, data on the features associated with a wide variety of vertical milling machine tools are collected. Then, empirical cost models are fit to this data. The results from the cost models show that the machine tool mass is a significant cost driver; other key drivers are the number of axes and spindle power. The models are used to predict the cost benefits of lightweighting in terms of mass, which are compared to potential increased manufacturing costs associated with complexities introduced due to lightweighting.

Wear Behavior of Ceramic-Metal Composites as Tool Material for FSW of Copper

Friction stir welding (FSW) is employed primarily for metals characterized by poor weldability at fusion welding: aluminium, magnesium, titanium and copper alloys as well as stainless steels. The focus of the study was on the feasibility of application of WC-based hardmetal 85WC-Co and TiC-based cermet 80TiC-NiMo as potential tool materials for FSW of copper. The single-pass welding trials of Cu sheets were performed using a vertical milling machine. For better understanding of interactions between the tool and workpiece at welding temperature EDS line scans across the interfaces tool-workpiece after welding as well as after diffusion tests were performed. It was concluded that both tested ceramic-metal composites did not failure during multiple plunges and during the total transverse welding distance of 10 m. Also, significant tool wear was not observed after such a welding distance. The possibility of producing visually defect-free welds using tools from WC- and TiC- based ceramic-metal composites was proved and also mutual diffusion of elements across the interface tool-workpiece was discussed.

Experimental Investigation of Friction stir Welding Using Hybrid Alloys : A Review

Friction stir welding is a solid state joining process which is used to join metals and alloys having low weldability .Study about the effect of FSW parameters like tool rpm, tool transverse speed and tool pin profile. A vertical milling head is used to produce FSW joints. In this study, solid state joining technology of friction stir welding (FSW) was carried out for Al and Mg butt joints and other dissimilar metals. This review article thoroughly highlights the influence of FSW working parameters on microstructure, mechanical properties. This effort not only sets eminent outcomes of the preceding research personnel but also proposes forthcoming guidelines for FSW of dissimilar metals.

Mapping positional accuracy for milling machine table

The article presents a technique for compiling a map of the positional accuracy of the table of a vertical milling machine when a vibration load of various frequencies is applied. A laboratory setup for creating forced oscillations of a cross table has been developed and manufactured. The reasons for the emergence of the highest deviations in specific areas of the working area of the machine tool are analyzed.

Research and improvement of methods of testing machines for geometric and kinematic accuracy

Purpose. To analyze and check for adequacy the known calculation formulas in determining the geometric and kinematic accuracy, statistical and dynamic rigidity and testing the machine for technological reliability. To carry out comparative calculations to simplify the methodology of complex tests of metal-cutting machines of the universal group. To select and improve the measuring equipment during the complex tests of the milling machine. Methodology. The research is based on the use of analytical methods for calculating the static rigidity coefficient, additional calculation of the measuring instrument design due to the gear ratio, the angle of rotation of the lever and the theoretical error of the displacement mechanism based on the known probability distribution theorem. Findings. The formulas of researches of the coefficient of static rigidity, the mechanism of the measuring device, the angle of rotation of the lever, the theoretical error of the mechanism of movement and the density of probability of distribution of the angle of the lever mechanism of the indicator of tangent type has been obtained. Originality. The research has been carried out and the parametric relationship between the static rigidity coefficient in the design of the spindle assembly of the vertical milling machine with the error of the calculations of the design, the departure of the spindle cone and the location between the supports has been established. The values and functional dependences of the amplitude of oscillations on the maximum allowable spindle speeds and feed rates at which the surface roughness of the workpiece reaches the specified geometric limits has been obtained. It is experimentally confirmed that the parameters of the system of pre-planned repairs are directly related to the reliability of the machine. The resource on the accuracy of the machine determines the need for overhaul, and the repair period depends on the service life of parts and elements of the machine. The actual service life should be a multiple of the repair period, as the restoration of the part is planned during the current repair. Practical value. The practical achievement of the obtained results is to confirm the adequacy of the known calculation formulas in determining the geometric and kinematic accuracy, statistical and dynamic rigidity and testing the machine for technological reliability. On the basis of the received analytical and settlement data was made the simplified complex technique of test of the metal-cutting machine during the: testing the machine at idle; testing of the machine when working under load; testing of the machine for geometric and kinematic accuracy; determination of statistical and dynamic rigidity; research of vibration-resistant vertical milling machine; testing of the machine for technological reliability.