Manufacturing technologies have enjoyed fast growing during the last several decades, more versatile and advanced machine platforms are available. On the software front, however, a lot is left to be desire.

For the traditional five-axis point milling, as the demand for high speed and high accuracy of complex machined parts arising, the tool orientation planning in 5-axis machining is drawing more attention. For complicated shaped components, it is particularly hard to balance between the required collision avoidance constraint and the desired smooth change of tool orientation. In this study, a reference plane based method is proposed to calculate tool accessible ranges of the CL points along a given tool path, which ensures collision free throughout the machining process while...[ Read more ]

Manufacturing technologies have enjoyed fast growing during the last several decades, more versatile and advanced machine platforms are available. On the software front, however, a lot is left to be desire.

For the traditional five-axis point milling, as the demand for high speed and high accuracy of complex machined parts arising, the tool orientation planning in 5-axis machining is drawing more attention. For complicated shaped components, it is particularly hard to balance between the required collision avoidance constraint and the desired smooth change of tool orientation. In this study, a reference plane based method is proposed to calculate tool accessible ranges of the CL points along a given tool path, which ensures collision free throughout the machining process while providing linear boundary conditions for the ensuing tool orientation optimization. The tool orientations are optimized in terms of the smoothness of tool motion in part coordinate system and smoothness of machine’s rotational axes’ motion, using the combination of greedy based algorithm and SQP.

A novel tool path generation & optimization scheme for five-axis flank milling of an arbitrary twisted ruled surface is presented. A two-stage optimization method is proposed to deal with the high dimensions of the flank milling tool path planning problem while covering a large searching area for each tool position at the same time. A multi-objective optimization algorithm – NSGA-2 – is applied to generate a set of trade-off solutions that form a curve in the solution space with detailed trade-off information between different objectives, such as overcut vs. undercut, maximal undercut vs. overall undercut, machining error vs. smoothness, etc., so that the user is better informed in making the final decision on critical machining parameters such as the size of the tool.

With the development of new hybrid machining platform that incorporates both additive manufacturing and five-axis machining modules, it is conceivable that complex models that are previously impossible to manufacture with solely one of the two methods can now be produced. In order to successfully manufacture a complex structure, the additive and the subtractive process need to work alternatingly: to roughly stack a layer of material of certain height and then accurately machine it to the desired shape. Multiple alternations are needed to eventually produce a complex model. The planning of the build-up height in each alternation plays a crucial role in the overall process: a large build-up height may increase the chance that the partially constructed obstacle will block the cutter from accessing the in-process part; conversely, frequent alternations will degrade the overall efficiency and produce an inferior surface finish with dense marks. In order to find a perfect balance, a metric called “machinability” is proposed to evaluate the subtractive machining feasibility. An efficient algorithm for calculating the machinability under the dynamic obstacle growing environment is then developed accordingly. Based on that, an efficient and deterministic top-down sequential maximization algorithm is presented that strives to minimize the number of alternations while at the same time ensuring a smooth tool path for each subtractive operation.

Ample computer simulation examples and real cutting experiments are given to illustrate the effectiveness of the proposed methodologies.