A generic mechanistic approach for simulating multi axis machining of complex sculptured surfaces is presented. A generalized approach is developed for representing an arbitrary cutting edge design, and the local surface topology of a complex sculptured surface. A NURBS curve is used to represent the cutting edge profile. This approach offers the advantages of representing an arbitrary cutting edge design in a generic way, as well as providing standardized techniques for manipulating the location and orientation of the cutting edge. The local surface topology of the part is defined as those surfaces generated by previous tool paths in the vicinity of the current tool position. The local surface topology of the part is represented without using a computationally expensive CAD system. A systematic prediction technique is then developed to determine the instantaneous tool/part interaction during machining. The methodology employed here determines cutting edge in-cut segments by determining the intersection between the NURBS curve representation of the cutting edge and the defined local surface topology. These in-cut segments are then utilized as integration limits for a comprehensive force modeling methodology. A systematic model calibration procedure that incorporates the effects of varying cutting edge geometry, cutting speeds, and feed rates is developed. Experimental results are presented for the calibration procedure. Model verification tests were conducted with these cutting force coefficients. These tests demonstrate that the predicted forces are within 5% of experimentally measured forces.

An enhanced approach for dynamic mechanistic modeling for multi-axis machining is developed. The dynamic process simulation methodology is presented as a continuous solution for complex sculptured surface machining. The methodology is formulated to include the instantaneous deflection of the tool, and the tool deflection history over the entire tool path. The continuous dynamic process simulation methodology is compared with both static and dynamic simulation methodologies based on control points. The comparison is for linear cuts with constant and variable tool/workpiece immersion. This comparison shows that the modeling methodologies based on control points only offer a piece-wise continous representation of the static and dynamic cutting force and tool deflection over a given tool path. The accuracy of the cutting force prediction and the calculation of tool deflection using methodologies based on control points degrades for variable tool/workpiece immersion. The continous dynamic simulation methodology demonstrates a good representation of the static and dynamic cutting force and tool deflection for variable tool/workpiece immersion. The continous dynamic process simulation methodology is demonstrated for a complex sculptured surface machining operation. The rough machining operation for an airfoil-like surface is presented. The simulation results demonstrate how the continuous dynamic process simulation methodology is capable of predicting the cutting force and tool deflection for variable tool/workpiece immersions that occur during complex sculptured surface machining operations.

The generic simulation approach for multi-axis machining has been demonstrated as a process optimization tool. Feed scheduling was used to demonstrate the process optimization for multi-axis machining. A feed scheduling methodology for multi-axis machining was developed. The feed scheduling methodology was formulated based on maximum chipload and maximum force constraints. A case study for process optimization of machining an airfoil-like surface was used for demonstration. Based on the predicted instantaneous chip load and/or a specified force constraint, feed rate scheduling was utilized to increase metal removal rate. The feed rate scheduling implementation results in a 30% reduction in machining time for the airfoil-like surface without any sacrifice in the surface quality or part geometry.

The machine tool feed drive performance capabilities were integrated with the feed scheduling methodology. Two strategies were developed. The first strategy guaranteed that the scheduled feed rates were attainable within the machine Acc/Dec time constant, Ttotal. The second strategy optimized the use of the feed drive capabilities while tracking the changes in cutting geometry along the tool path. A comparative study was performed for feed scheduling based on control points, Acc/Dec time constant, and optimized strategy. Both simulated and experimental results were given for each feed scheduling strategy. The criteria for comparison were the production savings, the machining integrity, and the machining safety. The optimized feed scheduling strategy was the unique strategy that improves simultaneously the production saving while guaranteeing the machining integrity.

The concept and implementation of an Internet-based facility for multi-axis milling process simulation and optimization was presented. The facility integrates the generic simulation approach for multi-axis machining, and state of the art multimedia and Internet technologies. The Internet-based facility for multi-axis milling process simulation and optimization provides a formalized system for designing and proofing machining processes. Process develoment can occur iteratively, without the need for lengthy and/or expensive process trials. Implementing these development tools using internet technologies has several advantages. It allows all of the development tools to be in a centralized location, allowing for quick and reliable upgrade paths. Internet accessibility also gives quick and easy access to these development tools to users around the world.