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In order to improve machining efficiency and quality of aero-engine blisks, a novel multi-spindle 5-axis machine tool is developed under the inspiration of the blisk structure. The proposed machine contains 8 spindles, which are arranged radially along the blisk and simultaneously participate in machining. The actuator of the machine contains three rotation axes and two translation axes, which can realize 5-axis CNC machining. Based on the unified kinematics model, the mechanism is analyzed in terms of forward and inverse kinematics, singularity, and flexible workspace. Meanwhile, the structural parameters of the machine are optimized according to the flexibility index to improve the kinematic performance of the mechanism. Theoretical and experimental results show that the machine tool has a more compact structure, fewer moving axes, and better kinematics performance, compared with the traditional multi-spindle modular machine tool. Therefore, the machine has significant advantages in processing efficiency and has great application potential in large batch machining of the blisk. [ABSTRACT FROM AUTHOR]

Blade is the core component of aero-engine, and its manufacturing capability improvement has always been the focus of aviation manufacturing industry. With the high-efficiency machining of multi-spindle machine tool, this paper proposes a synchronous polishing method based on the cluster grouping of actual blade profile. Firstly, the multi-spindle machining system, flexible polishing with determined path, and synchronous polishing process cycle are analyzed in detail. Secondly, the allowable difference within group is determined by the relationship of polishing compression and surface roughness/removal. Then, the distribution of grouping mark points is determined by the profile differences of sampled blades. Thirdly, the consistency of each two blade profiles is expressed as the vector difference of measurement data, and the grouping result can be established with the Ray-Turi index. Finally, a typical blade is used to demonstrate the effectiveness and efficiency. After multi-spindle synchronous polishing, the average synchronous polishing cycle time is 3.14 times less than single-spindle machine tool, the profile error and its difference are less than 0.0685 mm and 0.048 mm, the surface roughness can satisfy Ra ≤ 0.4 μ m , which can meet the design requirement of aero-engine blade. [ABSTRACT FROM AUTHOR]

The aero-engine blade is typically a thin-walled part with poor rigidity and a complex structure. This causes aero-engine blades to be susceptible to flutter and deformation during the machining processing, leading to the dimensional and positional accuracy outside the stipulated tolerance values. With the aim of improving the machining precision of the blades, the conventional blade processing methods were analysed in this study. Based on the analysis, a novel deformation control method named reverse segment machining method was proposed. Additionally, a stress-free auxiliary fixture was designed to improve the stiffness of thin-walled parts. Finally, an experiment was conducted to study the effectiveness of the developed reverse segment method and the stress-free auxiliary fixture in comparison to the forward machining methods. The results show that they can significantly improve machining precision. [ABSTRACT FROM AUTHOR]

Contact calculation is of great importance in predicting the material removal (MR) of flexible grinding process (FGP). The contact is mostly considered approximately constant in the existing MR models, while the situations that contact varies a lot after FGP are ignored. Therefore, a novel model is proposed in this paper to take those situations into consideration. Firstly, the nonconstant-contact situation is introduced. Then, an equivalent method is developed to convert the nonconstant-contact grinding process into the accumulation of several quasi-constant-contact grinding processes. Based on the equivalent method, a MR model is established, and the procedure to obtain the model parameters by the finite element analysis (FEA) is introduced. In the end, the equivalent method and the MR model are tested by a series experiments of different process parameters. Results show that the proposed MR model can predict the material removal effectively for the nonconstant-contact situations. [ABSTRACT FROM AUTHOR]

The sculptured surface has been widely used in aerospace and machinery manufacturing industries. CNC machining of sculptured surfaces is an important research area, and computation efficiency improvements are considered critical topics in this field. This paper presents a highly efficient method to generate smooth tool paths by establishing a mathematical model to describe the relationship between the relative curvature of sculptured surface and the machining strip width in five-axis machining. The method is improved from the middle-point error control method (MPECM) and the feasible tool position surface method (FTPSM), by changing the objective from the complete optimization for each drive point to the drive points' interpolation. The drive point with the narrowest machining strip width and some sample points is selected to interpolate the remaining points. Both theoretical analysis and test examples show the correctness of the proposed method. Under the same condition, compared with the MPECM and the FTPSM, the computing time of the new method decreases to 10% at least. Besides, the fluctuation of the tool path is reduced. The machining examples verified the superiority of the proposed method. [ABSTRACT FROM AUTHOR]