A multi-perspective dynamic feature concept in adaptive NC machining of complex freeform surfaces

Abstract

This paper presents a new concept of feature for freeform surface machining that defines the changes in feature status during real manufacturing situations which have not been sufficiently addressed by current international standards and previous research in feature technology. These changes are multi-perspective, including (i) changes in depth-of-cut: the geometry of a feature in the depth-ofcut direction changes during different machining operations such as roughing, semi-finishing and finishing; (ii) changes across the surface: a surface may be divided into different machining regions (effectively sub-features) for the selection of appropriate manufacturing methods for each region such as different cutting tools, parameters, set-ups or machine tools; and (iii) changes in resources or manufacturing capabilities may require the re-planning of depth-of-cuts, division of machining regions and manufacturing operations (machines, tools, set-ups and parameters). Adding the above dynamic information to the part information models in current CAD systems (which only represent the final state of parts) would significantly improve the accuracy, efficiency and timeliness of manufacturing planning and optimisation, especially for the integrated NC machining planning for complex freeform surfaces. Case study in an aircraft manufacturing company will be included in this paper.

Hole-making processes and their impacts on the microstructure and fatigue response of aircraft alloys

“…The emerging helical milling could be coupled with advanced automation/intelligent manufacturing technology [32][33][34] to minimize/eliminate the labor intensive and error-prone human operation. In addition, feature-based manufacturing parameter planning and optimization [35][36][37] could be considered in future aircraft holemaking processes to enhance accuracy, traceability and process control.…”

Review of Intelligence for Additive and Subtractive Manufacturing: Current Status and Future Prospects

“…This contrasts with the traditional process where modelling is conducted on the static feature of final geometry, which is assumed to be unchanged as the machining progresses. Hence, it is necessary for the representation of interim features corresponding to planned depth-of cuts, as illustrated in Figure 6 a [ 93 ]. In this respect, the dynamic feature concept is utilized for machining process optimization, as illustrated in Figure 6 b [ 94 ].…”

“… ( a ) Various depth-of-cuts in machining a freeform surface (reprinted with permission from [ 93 ]. Copyright 2015 Springer Nature).…”

Feature-based automatic NC programming for aero-engine casings

“…Li and colleagues 10,11 presented a high-level machining feature classification made up of general pocket, hole, profile and rib for aircraft structural parts to strengthen the connection between feature geometry and manufacturing knowledge. In their further work, 12,13 a multi-perspective dynamic feature is defined to facilitate freeform surfaces machining. Feature dynamics in the depth-of-cut, across the surface and in resources or manufacturing capabilities are defined in this feature concept to improve the accuracy, efficiency and timeliness of manufacturing planning and optimisation, especially for the integrated NC machining planning for complex freeform surfaces.…”