Key Engineering Materials Vols. 304-305

Abstract: The paper describes the heavy abrasive belt grinding technology and the conventional machining method to reduce thickness of connecting rod head, analyses the technique difficulties with the latter, brings forward a reasonable new method which can reduce thickness by heavy abrasive belt grinding, expatiates on the grinding result with the grinder which is designed by this method, finally summarizes and prospects to this new method.

Abstract: In this paper, a snagging parallel machine with 3-DOF is presented. It has the dominate merit in layout, structure, controlling manner and an attribute of large working space and easy real-time control. The machine tool achieves the anticipating effect and satisfies the need of the snagging operation.

Abstract: Good balancing is very important to improve the moving performance of grinding machine. General balancing technology of grinders was analyzed. The structure features of a new type of hybrid CNC grinding machine were introduced. The necessity of obtaining good balance of the hybrid grinder was demonstrated. Based on simulation and calculation of the distribution law of potential energy over the grinder, a solution for obtaining partial balance of the machine was worked out. An optimal parameter value of the designed balance unit was reached through optimization calculation with optimal balancing effect as target function. The max actuating force of balanced machine accounts for only 13.7% of the force of un-balanced. The balancing unit is of features of simple structure and good balancing effect.

Abstract: Based on the shortcoming and deficiency of deep hole machining, a grinding wheel spindle with squeeze film damper—SFD is design based on squeeze film damped theory. The motion differential equation of SFD grinding wheel spindle is constituted according to D’ Ale mbert principle，and a lot of simulated research has been carried out about the locus of grinding wheel spindle affect by SFD. Founded on the simulated result, the SFD grinding wheel spindle of internal grinder have designed, and the grinding experiments have been performed. Experimental result indicate that the rationality of design for SFD can make the vibration of the grinding wheel spindle reduce 25% , and make machining precision of hole improve 20% , make work efficiency of the grinder raise 15%.

Abstract: According to the definitions of the CIRP Unification Document, The locus equations of the rotating center and the average rotating center are deduced, and then, the parameter equations of the rotating axis and the average rotating axis are obtained. All of above verify the definition of the rotating axis of the CIRP Unification Document in theory, and it is also proved clearly that the rotating axis and the average rotating axis are sole.

Abstract: In this paper, the characters of the 5-axes NC grinding machine for the drill point MK6335 are introduced. The attributes of Ni Zhifu drill (Chinese multi-facet drill-CMFD) are stressed. The sharpening key technology for the Ni Zhifu drill point in this grinding machine is stated. By using the grinding machine and the key technology, the CMFD can be ground accurately. After ground, the geometric angle error of the drill point is less than 1 degree.

Abstract: Hydraulic grinding saw is a kind of important equipment broadly used in billet precise cutting in metallurgical industry. In order to improve productivity significantly, control feeding speed reasonably, at the same time to compensate the variation of driving torque caused by the change of contacting area between grinding wheel and slab, thus to obtain the optimized match between the feed of the grinding wheel and the driving motor, the application of hydraulic servo system in the control of the feeding speed of grinding wheel is discussed in this thesis. This article introduces the principle of hydraulic grinding saw, brings out the project of constant power PID control based on the relationship between driving torque and motor current. The transfer function of the hydraulic servo system, the optimized PID controller is also worked out. According to the result of simulation analysis, the controlling factors can be well obtained.

Abstract: Crooked shaft grinder is the key machining equipment of engine Crooked shaft, as the principal axis system of grinder head failure occasionally, it influences the cutting precision greatly. So it has significance to research on failure diagnosis method for engine crooked shaft grinding equipment. The method, which diagnoses the causes and degree of failure, based on fuzzy logic and recognition theory is presented for the principal axis system of crooked shaft grinder. The mathematics model of fuzzy recognition and the conditional distribution function of fuzzy relationship between failure and symptom are given and the method of determining the function is simple and practicable. The method that is got through fuzzy reasoning and fuzzy recognition can be used not only to diagnose failure cause but also to determine failure level. The vibratory diagnosis for the principal axis system of crooked shaft grinder shows that it possessed a good rationality as well as availability.

Abstract: By applying NC system with three axes ganged function to M1432 universal cylindrical grinding machine, a NC grinding machine with two moving axes and one circumrotating axis ganged function is designed and developed. Besides two moving axes ganged function, this machine has a special function of driving the form wheel dresser to circumrotate around the Y axis. Ordinary grinding machine with two axes ganged function can’t machine complicated parts such as seaming roll with steep gradient groove. But a grinding machine with this special unction can do this by precisely dressing the form wheel with various aspheric curves. With the set-in PLC function of NUM1020 NC system and the correlative parameters to be respectively setup, the new machine can be used to machine some complicated parts such as seaming roll. The system receives machining process codes which is pretreated by computer firstly and dresses the form wheel in DNC mode, then machines parts with the form wheel later.

Abstract: Focus on the accuracy problem in machining process of SK21 NC cam grinder, the precision-machining restriction condition equation and the calculation method of precision NC instruction are deduced. The reversible calculation model from NC instruction to the cam’s outline is given and a software package of error compensation is developed. Many error parameters which include the abrasion of the grinding wheel, load distortion of the grinding wheel axis, rotation precision of the cam axis and movement precision of the worktable are measured through experiments. The finally grinding experiments results show that the cam’s machining accuracy can be improved more than 50% by the error compensation method in this paper.