Research on virtual manufacturing models of a new type of taper ball-end milling cutter
Based on the analysis of the difficulties in design and manufacturing and cutting edge curves of many kinds of revolving milling cutters, a design method is presented in this paper for a new type of cutting-edge. The general differential equation is given so that the cutting-edge, the three-grooves and the grinding wheel to grind can be satisfied. The actual grooves and cutting-edges of virtual manufacturing are presented. The general feeding speeds of grinding wheel used in 2-axis NC machining of the cutter were deduced. The virtual simulation of the taper ball-end cutter is carried out. It has been proved that the traditional problems in designing and manufacturing are solved successfully in this way, simultaneously the process is much simple for it can be formed only in one time elementarily.
A Manufacturing Model of S-Shaped Ball-Nosed Milling Cutter and Error Analysis in Realisation in Industry
The paper first discusses the reasons for studying and manufacturing ball-nosed milling cutters with S-shaped cutting edges. Then, based on prior studies, and through introducing a helicoid, it presents a new manufacturing model used to grind the rake face and flank of the cutter. The amplitude of |Δs| machined via this model is much larger than that machined via other models. A special mechanism is also presented for grinding the flank of the cutter. Furthermore, to ensure the feasibility of manufacturing a ball-nosed milling cutter, error models are studied from four main aspects and interpreted in the text in detail. The mathematical formulae of the error models are presented, and a numerical example is also presented to illustrate the effectiveness of the proposed modelling procedure. The example includes the machining data and error scale of each main parameter. Those data indicate that the proposed model and grinding procedure are capable of producing the ball-nosed milling cutters with an accuracy conforming to the user-provided specific tolerance.
ROOM- AND HIGH-TEMPERATURE MAGNETIC PROPERTIES OF Sm(CobalFexCu0.088Zr0.025)7.5 (x=0.30) SINTERED MAGNETS
The effect of Fe content on room- and high-temperature magnetic properties of Sm(CobalFexCu0.088Zr0.025)7.5 (x=0-0.30) sintered magnets, prepared by the conventional powder metallurgy method, has been systematically studied. With increasing Fe content, the remanences BT and maximum energy products (BH)max at room temperature gradually increase and reach optimal values of 1.055 T with x=0.27 for BT, and 205 kJ/m3 with x=0.21 for (BH)max, respectively, and then drop sharply with further Fe increase. An excessive addition of Fe (x≥0.24) results in rapid deterioration of permanent magnetic properties due to the formation of a considerable amount of FeCo soft magnetic phase. It was found that the effect of Fe content on high temperature stability is huge. The lower the Fe content, the smaller the temperature coefficient of coercivity. When x=0.07, a temperature coefficient of coercivity of -0.14%/K (293-723 K) can be achieved, as compared with -0.23%/K for x=0.21. BT of 0.725 T, bHc of 517 kA/m, iHc of 764 kA/m, and (BH)max of 95 kJ/m3 at 723 K were obtained, and the B-H demagnetization curve remains a straight line.