Feed Rate Determination Method for Tool Path Interpolation Considering Piecewise-Continued Machining Segments with Cornering Errors and Kinematic Constraints

2019 ◽  
pp. 354-360
Author(s):  
Syh-Shiuh Yeh
Keyword(s):  
Feed Rate ◽  
Tool Path ◽  
Determination Method ◽  
Kinematic Constraints

Development of CAM System for 3D Surface Machining With CNC Lathe (Tool Path Generation Considering Acceleration)

2014 ◽  
Author(s):  
Keigo Takasugi ◽  
Katsuhiro Nakagaki ◽  
Yoshitaka Morimoto ◽  
Yoshiyuki Kaneko
Keyword(s):  
Lead Time ◽  
Internal Combustion Engines ◽  
Tool Path ◽  
Tool Path Generation ◽  
Combustion Engines ◽  
Determination Method ◽  
Experimental Procedure ◽  
Surface Machining ◽  
Cnc Lathe ◽  
Lathe Tool

This study developed a method called non-axisymmetric curved surface turning (NACS-Turning) for a CNC lathe composed of a turning axis and two translation axes. The NACS-Turning method controls the three axes synchronously. This new machining method can reduce the lead time for non-circular shapes such as cam profiles or pistons for internal combustion engines. In our previous report, we presented an outline of a machining principle and a CAM system for NACS-Turning. However, at the same time, we found the problem that the X-axis slide exceeds the allowable acceleration. Therefore, it is preferable that the acceleration is verified during the cam application, and the tool path is generated within the allowable acceleration range. Therefore, this paper first describes the determination method of machinable conditions for NACS-Turning in the cam application. Next, based on the result, relationships between the acceleration of the X-axis slide and machining conditions are clarified. Finally, the experimental procedure showed that our proposed method does not exceed the allowable acceleration of the X-axis slide.

Micro Flat End Milling Simulation Model With Instantaneous Plowing Area Prediction

2016 ◽  
Vol 4 (2) ◽  
Author(s):  
Abdolreza Bayesteh ◽  
Junghyuk Ko ◽  
Martin Byung-Guk Jun
Keyword(s):  
Feed Rate ◽  
Tool Path ◽  
End Milling ◽  
Chip Thickness ◽  
Depth Of Cut ◽  
Uncut Chip Thickness ◽  
Chip Area ◽  
Edge Radius ◽  
Wide Range ◽  
Radial Depth

There is an increasing demand for product miniaturization and parts with features as low as few microns. Micromilling is one of the promising methods to fabricate miniature parts in a wide range of sectors including biomedical, electronic, and aerospace. Due to the large edge radius relative to uncut chip thickness, plowing is a dominant cutting mechanism in micromilling for low feed rates and has adverse effects on the surface quality, and thus, for a given tool path, it is important to be able to predict the amount of plowing. This paper presents a new method to calculate plowing volume for a given tool path in micromilling. For an incremental feed rate movement of a micro end mill along a given tool path, the uncut chip thickness at a given feed rate is determined, and based on the minimum chip thickness value compared to the uncut chip thickness, the areas of plowing and shearing are calculated. The workpiece is represented by a dual-Dexel model, and the simulation properties are initialized with real cutting parameters. During real-time simulation, the plowed volume is calculated using the algorithm developed. The simulated chip area results are qualitatively compared with measured resultant forces for verification of the model and using the model, effects of cutting conditions such as feed rate, edge radius, and radial depth of cut on the amount of shearing and plowing are investigated.

Characterizing the Effect of Cutting Condition, Tool Path, and Heat Treatment on Cutting Forces of Selective Laser Melting Spherical Component in Five-Axis Milling

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Amir Mahyar Khorasani ◽  
Ian Gibson ◽  
Moshe Goldberg ◽  
Guy Littlefair
Keyword(s):  
Heat Treatment ◽  
Production Process ◽  
Cutting Force ◽  
Feed Rate ◽  
Cutting Forces ◽  
Tool Path ◽  
Annealing Temperature ◽  
Spindle Speed ◽  
Cutting Condition ◽  
Scallop Height

Additive manufacturing (AM), partly due to its compatibility with computer-aided design (CAD) and fabrication of intricate shapes, is an emerging production process. Postprocessing, such as machining, is particularly necessary for metal AM due to the lack of surface quality for as-built parts being a problem when using as a production process. In this paper, a predictive model for cutting forces has been developed by using artificial neural networks (ANNs). The effect of tool path and cutting condition, including cutting speed, feed rate, machining allowance, and scallop height, on the generated force during machining of spherical components such as prosthetic acetabular shell was investigated. Also, different annealing processes like stress relieving, mill annealing and β annealing have been carried out on the samples to better understand the effect of brittleness, strength, and hardness on machining. The results of this study showed that ANN can accurately apply to model cutting force when using ball nose cutters. Scallop height has the highest impact on cutting forces followed by spindle speed, finishing allowance, heat treatment/annealing temperature, tool path, and feed rate. The results illustrate that using linear tool path and increasing annealing temperature can result in lower cutting force. Higher cutting force was observed with greater scallop height and feed rate while for higher finishing allowance, cutting forces decreased. For spindle speed, the trend of cutting force was increasing up to a critical point and then decreasing due to thermal softening.

Virtual Five-Axis Flank Milling of Jet Engine Impellers—Part II: Feed Rate Optimization of Five-Axis Flank Milling

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
W. B. Ferry ◽  
Y. Altintas
Keyword(s):  
Feed Rate ◽  
Tool Path ◽  
Fixed Time ◽  
Flank Milling ◽  
Tool Deflection ◽  
Jet Engine ◽  
Root Finding ◽  
Five Axis ◽  
Feed Rate Optimization ◽  
Chip Load

This paper presents process optimization for the five-axis flank milling of jet engine impellers based on the mechanics model explained in Part I. The process is optimized by varying the feed automatically as the tool-workpiece engagements, i.e., the process, vary along the tool path. The feed is adjusted by limiting feed-dependent peak outputs to a set of user-defined constraints. The constraints are the tool shank bending stress, tool deflection, maximum chip load (to avoid edge chipping), and the torque limit of the machine. The linear and angular feeds of the tool are optimized by two different methods—a multiconstraint based virtual adaptive control of the process and a nonlinear root-finding algorithm. The five-axis milling process is simulated in a virtual environment, and the resulting process outputs are stored at each position along the tool path. The process is recursively fitted to a first-order process with a time-varying gain and a fixed time constant, and a simple proportional-integral controller is adaptively tuned to operate the machine at threshold levels by manipulating the feed rate. As an alternative to the virtual adaptive process control, the feed rate is optimized by a nonlinear root-finding algorithm. The virtual cutting process is modeled as a black box function of feed and the optimum feed is solved for iteratively, respecting tool stress, tool deflection, torque, and chip load constraints. Both methods are shown to produce almost identical optimized feed rate profiles for the roughing tool path discussed in Paper I. The new feed rate profiles are shown to considerably reduce the cycle time of the impeller while avoiding process faults that may damage the part or the machine.

Quintic Spline Interpolation With Minimal Feed Fluctuation

2005 ◽  
Vol 127 (2) ◽  
pp. 339-349 ◽  
Author(s):  
Kaan Erkorkmaz ◽  
Yusuf Altintas
Keyword(s):  
Real Time ◽  
Feed Rate ◽  
Tool Path ◽  
Interpolation Method ◽  
Spline Interpolation ◽  
Tracking Error ◽  
Arc Length ◽  
Quintic Spline ◽  
Rate Profile ◽  
Spline Parameter

This paper presents a parameterization and an interpolation method for quintic splines, which result in a smooth and consistent feed rate profile. The discrepancy between the spline parameter and the actual arc length leads to undesirable feed fluctuations and discontinuity, which elicit themselves as high frequency acceleration and jerk harmonics, causing unwanted structural vibrations and excessive tracking error. Two different approaches are presented that alleviate this problem. The first approach is based on modifying the spline tool path so that it is optimally parameterized with respect to its arc length, which allows it to be accurately interpolated in real-time with minimal complexity. The second approach is based on scheduling the spline parameter to accurately yield the desired arc displacement (hence feed rate), either by approximation of the relationship between the arc length and the spline parameter with a feed correction polynomial, or by solving the spline parameter iteratively in real-time at each interpolation step. This approach is particularly suited for predetermined spline tool paths, which are not arc-length parameterized and cannot be modified. The proposed methods have been compared to approximately arc-length C3 quintic spline parameterization (Wang, F.-C., Wright, P. K., Barsky, B. A., and Yang, D. C. H., 1999, “Approximately Arc-Length Parameterized C3 Quintic Interpolatory Splines,” ASME J. Mech. Des, 121, No. 3., pp. 430–439) and first- and second-order Taylor series interpolation techniques (Huang, J.-T., and Yang, D. C. H., 1992, “Precision Command Generation for Computer Controlled Machines,” Precision Machining: Technology and Machine Development and Improvement, ASME-PED 58, pp. 89–104; Lin, R.-S. 2000, “Real-Time Surface Interpolator for 3-D Parametric Surface Machining on 3-Axis Machine Tools,” Intl. J. Mach. Tools Manuf., 40, No.10, pp. 1513–1526) in terms of feed rate consistency, computational efficiency, and experimental contouring accuracy.

Method for Feed-Rate Optimization Based on S Curve Acceleration and Deceleration Control of Piecewise Tool Path

2012 ◽  
Vol 542-543 ◽  
pp. 551-554
Author(s):  
Xiao Bing Chen ◽  
Wen He Liao
Keyword(s):  
Feed Rate ◽  
Tool Path ◽  
Complex Surface ◽  
Experimental Result ◽  
Threshold Method ◽  
Lower Efficiency ◽  
Acceleration And Deceleration ◽  
S Curve ◽  
Rate Optimization ◽  
Feed Rate Optimization

Aiming at the problem of lower efficiency of complex surface machining with constant feed-rate, a method for feed-rate optimization based on S curve acceleration and deceleration control of piecewise tool path is researched. With constraints of kinematic characters of machine tool and geometric characters of tool path, tool path segments are obtained by curvature threshold method, and feed-rates are planned in these segments, then feed-rate transition of adjacent segments is processed by the method of S curve acceleration and deceleration control. Experimental result indicates that the proposed method is feasible and effective.

Minimum Time Trajectory Planning Along Specified Tool Path With Consideration of Cutting Force Constraint and Feed Drive Dynamics

Manufacturing ◽  
2002 ◽  
Author(s):  
Nejah Tounsi ◽  
Trevor E. Bailey ◽  
Mohamed A. Elbestawi
Keyword(s):  
Cutting Force ◽  
Feed Rate ◽  
Tool Path ◽  
End Milling ◽  
Low Frequency ◽  
Minimum Time ◽  
Force Model ◽  
Modeling And Analysis ◽  
Feed Drive ◽  
Drive Dynamics

This paper proposes an Optimized Feed Scheduling Strategy (OFSS). This strategy integrates the feed drive dynamics with the minimum-time trajectory planing to achieve the desired feed rate at the appropriate tool position along specified tool path. It optimizes the use of the feed drive capabilities and provides good tracking of the cutting geometry variations. The feed scheduling is applied to maintain near-constant cutting force magnitude. An integrated geometric and mechanistic force model is used to estimate the in-cut geometry and the cutting force. A methodology based on time series modeling and analysis is proposed to identify the low frequency feed drive dynamics. The resulting model is applied as an acceleration/deceleration processor (Acc/Dec) to relate the actual feed rate to the commanded feed rate specified in the G-Code file. The effectiveness of the OFSS is analyzed using ball end milling operations. Its performance in terms of productivity and machining safety is assessed based on comparison with other feed scheduling techniques where the trajectory planing does not consider the feed drive dynamics.

Improvement of Surface Flatness in Face Milling by Varying the Tool Cutting Depth and Feed Rate

2009 ◽  
Author(s):  
Bruce L. Tai ◽  
David A. Stephenson ◽  
Albert J. Shih
Keyword(s):  
Feed Rate ◽  
Tool Path ◽  
Face Milling ◽  
Mirror Image ◽  
Cutting Depth ◽  
Surface Flatness ◽  
Local Compliance ◽  
Automatic Tool ◽  
Tool Cutting ◽  
Cutting Path

This paper explores two approaches to improve the flatness of face milled surfaces by modifying the tool cutting depth and feed rate based on the 3D holographic laser measurement. The tool cutting depth compensation method generates a cutting path which is the mirror image of the measured error profile to reduce the flatness errors. Issues of back-cutting and the interference due to cutter size limit the range of applicability of this approach. The feed rate is varied to match the axial force on the cutter with the local compliance of the workpiece to further improve the surface flatness. Using a flat plate workpiece and 50.8 mm diameter face milling cutter, the surface flatness can be reduced from around 15 μm without compensation to lower than 10 μm by varying tool cutting depth. Modification of feed rate further reduces the flatness errors from 10 μm to 6 μm. Automatic tool path compensation based on holographic feedback is also discussed.

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