Opportunities for research on numerical control machining

1986 ◽  
Vol 29 (6) ◽  
pp. 515-522 ◽  
Author(s):  
David D. Grossman
Keyword(s):  
Numerical Control ◽  
Numerical Control Machining

Adaptive spiral tool path generation for computer numerical control machining using point cloud

2021 ◽  
pp. 095440622199007
Author(s):  
Mandeep Dhanda ◽  
Aman Kukreja ◽  
SS Pande
Keyword(s):  
Tool Path ◽  
Cnc Machining ◽  
Numerical Control ◽  
Numerical Control Machining ◽  
Form Errors ◽  
Spiral Tool Path ◽  
Novel Method ◽  
Mesh Grid ◽  
Cloud Of Points ◽  
Cam Software

This paper reports a novel method to generate adaptive spiral tool path for the CNC machining of complex sculptured surface represented in the form of cloud of points without the need for surface fitting. The algorithm initially uses uniform 2 D circular mesh-grid to compute the cutter location (CL) points by applying the tool inverse offset method (IOM). These CL points are refined adaptively till the surface form errors converge below the prescribed tolerance limits in both circumferential and radial directions. They are further refined to eliminate the redundancy in machining and generate optimum region wise tool path to minimize the tool lifts. The NC part programs generated by our algorithm were widely tested for different case studies using the commercial CNC simulator as well as by the actual machining trial. Finally, a comparative study was done between our developed system and the commercial CAM software. The results showed that our system is more efficient and robust in terms of the obtained surface quality, productivity, and memory requirement.

Numerical Control Machining of Scroll with Variable Thickness

2014 ◽  
Vol 490-491 ◽  
pp. 288-293
Author(s):  
Tao Liu ◽  
Xia Qin Wang ◽  
Jun Wu ◽  
Yong Wei Wang
Keyword(s):  
Variable Thickness ◽  
Processing Method ◽  
Numerical Control ◽  
Scroll Compressor ◽  
Numerical Control Machining ◽  
Cad Cam ◽  
Programming Process ◽  
Center Track ◽  
Fitting Error ◽  
Cam Software

With the development of scroll technology, the requirements of more efficient and more accurate processing method for scroll compressor parts become more urgent. This paper proposes a method to improve the machining effect of scroll compressor. The approach is based on 3-point arc approximation method which divides combined profile of scroll wrap into subparagraph arcs that can be interpolated on CNC System. This approach simplifies the programming process and improves the curve fitting effect. The results indicate that the fitting error is in the predetermined range, and the interpolation points of cutter center track are significantly less than those based on CAD/CAM software. The method presented in this paper is of significance to the NC machining of novel precise scroll profile.

Parallel acceleration/deceleration feedrate scheduling for computer numerical control machine tools based on bi-directional scanning technique

2017 ◽  
Vol 233 (3) ◽  
pp. 937-947 ◽  
Author(s):  
Jie Huang ◽  
Xu Du ◽  
Li-Min Zhu
Keyword(s):  
Computer Numerical Control ◽  
Numerical Control ◽  
Processing Unit ◽  
Numerical Control Machining ◽  
Computational Burden ◽  
Central Processing ◽  
Scanning Process ◽  
Scanning Technique ◽  
Feedrate Scheduling ◽  
Parallel Acceleration

The acceleration/deceleration feedrate scheduling is one of the most important techniques in computer numerical control systems. Along with this technique, the bi-directional scanning technique is always employed. The bi-directional scanning technique consists of a backward scanning process followed by a forward scanning process. The two scanning processes in the conventional methods are executed in a serial manner by scanning through all the scheduling blocks one by one. Consequently, the feedrate scheduling will suffer from a heavy computational burden when there are massive blocks to be scanned, which deteriorates its real-time performance for computer numerical control machining. To alleviate the computational burden, a parallel acceleration/deceleration feedrate scheduling approach is proposed in this article. With this method, the scheduling blocks are splitted into several scheduling units and the feedrate for each of them is scheduled simultaneously. The feasibility of the proposed approach is validated through the feedrate scheduling for two widely used butterfly and helix paths. For a constructed example of feedrate scheduling, a significant acceleration ratio about 3.7 on a personal computer with a quad-core central processing unit is achieved.

Application of Genetic Algorithm in Cutting Parameter Optimization

2014 ◽  
Vol 1082 ◽  
pp. 138-142
Author(s):  
Li Feng Zhu ◽  
Yan Zhang
Keyword(s):  
Genetic Algorithm ◽  
Mathematical Model ◽  
Parameter Optimization ◽  
Cutting Parameters ◽  
Parameters Optimization ◽  
Numerical Control ◽  
Numerical Control Machining ◽  
Factors Affecting ◽  
Cutting Parameter ◽  
Cutting Parameter Optimization

Process parameters optimization is an important problem in numerical control machining, through the analysis of various factors affecting the cutting effect in cutting process, a mathematical model of cutting parameter optimization in NC machining is established and the constraint conditions are also determined in the paper. The article puts forward using genetic algorithm to realize the optimization of mathematical model, and the optimization analysis results are verified in practical processing. The experimental results show that the optimized cutting parameters can satisfy machining requests and improve the cutting efficiency.

Dynamic Left Atrioventricular Phantom Test Bed Emulating Mitral Valve Motion

2020 ◽  
Vol 14 (3) ◽  
Author(s):  
Toufic Azar ◽  
Stewart McLennan ◽  
Michael Walsh ◽  
Jorge Angeles ◽  
Jozsef Kövecses ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Blood Flow ◽  
Polyvinyl Alcohol ◽  
Computer Aided Design ◽  
Human Heart ◽  
Numerical Control ◽  
Test Bed ◽  
Numerical Control Machining ◽  
Valve Motion ◽  
Test Beds

Abstract Novel catheter-based medical procedures targeting heart valve structures are currently under development. These techniques entail installing a prosthetic implant on valves inside a beating heart. The development of these approaches requires a simple and effective validation test bed. Current early process testing methods rely on both static and dynamically pressurized excised porcine hearts. The variability between excised-tissue mechanical properties poses problems of reproducibility. In addition, these test beds do not emulate annulus motion, which affects the implant installation. A reproducible phantom of the left atrioventricular chambers was developed. The system consists of a hydraulic constant flow arrangement and a polyvinyl alcohol phantom heart with material properties that mimic passive myocardium mechanical properties and annulus motion. The system was then used to emulate blood flow through an actual heart. The building process starts by obtaining an accurate computer-aided design (CAD) model of a human heart, from which, a mold is produced using a novel rapid-freezing prototyping method and computer numerical control machining. The phantom is then cast-out of polyvinyl alcohol (PVA), a hydrogel, whose mechanical properties are set by subjecting the phantom to freeze and thaw cycles. Subsequently, blood flow is emulated at a constant volumetric rate at the atrial pressure observed in a healthy adult human heart at rest. The annulus motion is implemented by suturing the outside of the phantom to a one-degree-of-freedom cam-follower mechanism reproducing valve motion. Such test beds could play a significant role in future development of medical devices.

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