NC Code Research Articles

Toolpath Planning and Simulation for Cutting Test of Non-Orthogonal Five-Axis Machine Tool

Owing to NAS 979 describes a cutting test for five-axis machine center with a universal spindle, several conditions for C-type machine tool have not been defined yet. This paper proposes a cutting test for a non-orthogonal swivel head and a rotary table type five-axis machine tool (C type) to evaluate its performance. The workpiece consists of 10 machining features. These features include the multi-axis simultaneous machining patterns and the positioning machining patterns. The flat end mill cutters are applied in each machining feature. Cutter location data for the test piece was generated using a commercial CAD/CAM system (UG) and converted to five-axis NC code using a postprocessor created in UG Post Builder. This UG postprocessor is verified through the developed postprocessor utilizing the modified D-H notation. It is also verified using VERICUT® solid cutting simulation software demonstrated the veracity of the generated five-axis NC code. The machining test is applicable for a variety of five-axis machine tool configurations.

Researches on the Measurement Rebuilding and Multi-Axis Flank Milling NC Machining of the Compressor Impeller

The ruled surface of impeller is widely used in the industry of automobile, shipbuilding, aerospace and aeronautics. Researches on the manufacture of blade possess general meaning. The importance of their performance in the certain field and the non-replace ability of their functions in the specified mechanical systems have resulted in that the technology of manufacturing and measurement for ruled surfaces has been a critical research project in the field of dimensional manufacturing and measurements. With the rapid development of the modern science and technology, complex ruled surfaces are employed more and more widely, but their tolerances become narrower and narrower. The common impeller surfaces represented by NURBS are given and then curve and surface interpolation algorithm represented by NURBS are presented. These provide theoretical foundation for NC machining programming of impeller surface. Principals of normal offset curve and inclined offset surface are used to simplify the model. The NC milling method of divide area is presented to raise machining efficiency and to improve quality of machined surface. The machining efficiency is important in line property of rule surface, flank milling rule surface with end-milling, improve surface quality and cutter efficiency. This paper presents a calculate method to generate five-axis flank milling NC code of divide area in the blade of compressor with Vericut simulating the five-axis flank milling NC code and measurement the result of processing that verification the precision of five-axis flank milling. This paper also simulates four-axis machining for comparing cutting efficiency between five-axis machining and four-axis machining and the status of both the great differences in processing efficiency.

Development and Research of Open CNC System Based on Motion Controller

A lab platform of Open Numerical Control System was designed to develop NC system based on PC and Motion Controller, a Master-Slave control system. The user interface application software was developed by C++ Builder and WINDOWS. It realized explanation and testing for bug function, data pretreatment function, NC code translation, NC simulation and execution, as well as motion controller function.

Research on Simulation of Virtual NC Lathe Machining Process

Virtual NC lathe machining simulation system is carried out with Visual C++ and Open Inventor software. The system possesses visible UI, interactive inputting workpiece and machining parameters, the integration of geometric simulation and physical simulation, all the simulation functions including real-time display machining process, tool moving, workpiece geometry shape change, the generation and movement of iron simulation, workpiece pressure shape change could be realized. Tool temperature analysis and stress & strain analysis are simulated in the cutting process by FEM. The simulation results show the high efficiency of the simulation algorithm, reasonable simulation results, lifelike. The practice and training could be replaced by the virtual one. The system is applied to verification of NC code, quality evaluation of machine operators, operators, CNC programming staff training and other functions.

Development of NC Wire Cutting Automatic Programming System Based on Component Technology

Based on analysis and research on the Wire cutting Electrical Discharge Machining process , developers could set up the whole system frame and each component mold ,as well as each component mold of function .At the same time ,developers researched the technique of Component Object Model , used the technique of Dynamic Link Library to realize the graphic input, used the technique of ActiveX to realize the code of Number Control imitation , established the whole database based on Access, successfully, realizing AutoCAD graphic input , taking the data processing and calculating the order of the cut, and then producing the postprocessing files, finally realizing all of NC code imitation .

Numerical Control for Multifunction Machining Based on Dual MCU

A new numerical control system (CNC) based on ARM9 and STC12C5410 is studied. The ARM9 core microprocessor and Samsung S3C2440A microprocessor, are the main operation cores. It treats the flowing tasks: response to keyboard inputting, display contents on LCD, interpretive the NC codes, output crude interpolations and so on. The secondary CPU, STC12C5410, as the assisting microprocessor is only to realize fine interpolation. The system can be connected an 8-inches display in order to display more information and it has an interface to a four-axis hand wheel. It has a communication interface and can receive CNC codes form other computer. The system can drive four step-servo motors or servo-actuators and realize turning, milling, grinding and combination machining, which making sure the system is a multifunction system.

Critical factors in energy demand modelling for CNC milling and impact of toolpath strategy

Reducing energy demand in manufacture is an urgent challenge. This challenge is driven by higher consumer demand for manufactured products, increasing electricity and energy prices, volatility and uncertainty in energy supply and national policy. These factors, together with a need to reduce energy consumption derived carbon dioxide emissions, strategically call for energy efficient manufacturing. In manufacturing processes, especially mechanical machining, more than 90% of environmental impact arises from direct electrical energy demand in machine tools. At the machine tool level, the biggest share of the electrical energy associated with mechanical machining is required to bring the machine to a ready state and support non-cutting operations such as spindle torque requirements, auxiliary units and movements. These activities are controlled and related to machine commands such as NC codes. In this paper comprehensive information on energy intensity in machining process, including the influence of tool wear, was studied. Key energy states were identified to build up an energy demand for machining components. The paper defines the essential power constants for a database that can assist energy prediction for any available machines and workpiece materials. The assessment of alternative toolpaths identified major opportunities for energy demand reduction.

Modeling, identification and compensation for geometric errors of laser annealing table

In order to improve the process precision of an XY laser annealing table, a geometric error modeling, and an identification and compensation method were proposed. Based on multi-body system theory, a geometric error model for the laser annealing table was established. It supports the identification of 7 geometric errors affecting the annealing accuracy. An original identification method was presented to recognize these geometric errors. Positioning errors of 5 lines in the workspace were measured by a laser interferometer, and the 7 geometric errors were identified by the proposed algorithm. Finally, a software-based error compensation method was adopted, and a compensation mechanism was developed in a postprocessor based on LabVIEW. The identified geometric errors can be compensated by converting ideal NC codes to actual NC codes. A validation experiment has been conducted on the laser annealing table, and the results indicate that positioning errors of two validation lines decreased from ±37 μm and ±33 μm to ±5 μm and ±4.5 μm, respectively. The geometric error modeling, identification and compensation method presented in this work can be straightforwardly extended to any configurations of 2-dimensional worktable.

Direct Toolpath Generation Based on Graph Theory for Milling Roughing

The paper presents a tool path generation methodology for roughing operation based on the oriented graph theory. The cutting areas are identified using an original method that is based on a bicolor and binary map. The toolpath is generated using the searching Dijkstra algorithm inside a graph in order to find the single-source shortest path. The method was employed in order to be applied on ordered and/or unordered point clouds. The entire algorithm was implemented into a mathematic calculus solution which allows the import of point clouds and its processing until the final NC code is generated.

A micro cutter auto-alignment system with on-machine positioning error measurement and compensation methods

To perform an accurate micro machining process, accurate alignment of the micro cutter with respect to the local coordinate frame for machining is essential. Due to the fragility of the micro tool, traditional cutter alignment method used in industry is no longer proper for micro machining. Utilizing machine vision technology with 2 CCDs, a micro tool positioning error measurement and auto-compensation method and system were proposed. In the measurement method, Power Law Method was first used to enhance the image taken by a CCD. Canny Edge Method and image projection method were then used to identify the contours of the cutter and the workpiece from the image. Finally, the position errors of the cutter were determined through calculating the number of pixels between the cutter and the workpiece. The proposed error compensation system can automatically generate NC codes which will accurately re-locate the cutter based on the measured position errors. Experiments were conducted on a micro machine tool, and the results have shown that the y-dir. positioning error of the cutter was significantly improved from −0.025 mm to 0.001 mm, and the total machining error was reduced from −0.02 mm to −0.001 mm.

English

English

Development of the Virtual Designing and Manufacturing System Based on Microcomputer Platform

This article has introduced the composition of the engineering machinery virtual designing and manufacturing system which is based on the microcomputer platform, introduced the implementation plan of the system and the key technology such as the development of general machinery part CAD system, movement simulation, finite element analysis, NC code automatically programming, Visible CAPP system based on Solid Edge platform, the realization of network issue system and Solid Edge integration technology.

Verification of Manufacturing Accuracy of Mathematically Defined Shaped Surfaces on 3D CNC Milling Machine

Verification of programming of various control systems and production of mathematically defined shaped surfaces on 3D CNC milling machine is a challenging technological process. Appropriate design and optimization of tool path is essential for the production of high-quality surfaces with the required accuracy and roughness. This paper presents the design of shaped surfaces in various programming means in order to evaluate both the accuracy of the shape manufactured by the production machine and also by program created shapes for control systems of 3D milling machines. Based on the analysis of mathematically defined shaped surfaces to evaluate both accuracy of shape of 3D milling machine and also applied programs for the programming of the selected control system the shaped surface "Interface" was chosen. The advantage of mathematically described surface is a better way to evaluate the accuracy compare to surface modeled e.g. by Bezier ́s curves. Mathematically described surfaces enable us to optimize their shapes by available mathematical functions. Typical example the derivatives are, which make it possible to search extremes. Verification of the shaped surfaces accuracy according to created control programs was solved using the 3D Carl-Zeiss coordinate system and also HOLOS software. Verified programs for the NC machine programming were in CATIA V5, Pro/Engineer and EqCAM. The result is an optimally designed original EqCAM program for 3D CNC milling machine programming, which generates optimal NC codes and bypasses various built-in interpolations, and by precise control at every step it is possible to achieve maximum accuracy and quality of machined surface for each 3D CNC milling machine.

Working Hours Calculation for CNC Milling Machining Center

Working hours is a important link in product costing, it is also an important component of enterprise process management and Lean Production. The relationship of NC code and working hour was studied. As the corresponding mathematical models were established. It is more scientific, rationalization and precise for the CNC Milling Machining hours. An actual case was given.

Chatter Prediction Based on NC Physical Simulation in Machining Ti6Al4V Thin-Walled Components

Chatter has been a problem in CNC machining process especially during machining thin-walled components with low stiffness. For accurately predicting chatter stability in machining Ti6Al4V thin-walled components, this paper establishes a chatter prediction method considering of cutting parameters and tool path. The fast chatter prediction method for thin-walled components is based on physical simulation software. Cutting parameters and tool path is achieved through the chatter stability lobes test and finite element simulation. Machining process is simulated by the physical simulation software using generated NC code. This proposed method transforms the NC physical simulation toward the practical methodology for the stability prediction over the multi-pocket structure milling.

Development Research of the End Mills Grinding Programming System Based on MATLAB

Using MATLAB for development tools,we has developed a set of end mills CNC grinding programming system by analysis the end mills grinding craft ,research on cutter location trajectory calculation and post-processing technology. Meanwhile, build a five-axis tool grinder grinding simulation processing by VERICUT(a kind of CNC machining simulation software), through the edge grinding simulation , we confirm the cutter location trajectory and the NC code is errorless.

A MODIFIED Z-MAP COMPUTATIONAL INTERPOLATION ALGORITHM FOR SURFACE MACHINING SIMULATION

The Z-Map algorithm is one of the most simplistic methods for NC code simulation in obtaining the machined working surface information; therefore, it is often being applied in NC simulation. In this paper, a modified Z-Map computational algorithm was proposed to calculate mesh position and Z coordinates of tool scanning surface according to tool path and initial tool scanning boundary in reducing the long computation time. The proposed algorithm not only can be used to derive straight line and arc machining tool path, but also can be adopted for helical and spline curves. There is no need to simplify the non-linear curves beforehand. The method proposed in this paper provides a feasible reference for decision about the reliability and suitability of each machining step.

Automatic NC Programming for Chamfering Addendum of Spiral Bevel Gear Based on UG/Open

A chamfering algorithm was put forward to achieve automatic NC programming for chamfering addendum of spiral bevel gears and a NC programming module was developed based on UG/Open through secondary development. Furthermore, a practical example was used to demonstrate the automatic NC code generation process for chamfering addendum according to the preset chamfer surface and its permissible error.

An approach towards the integration of CAD/CAM/CAI through STEP file using feature extraction for cylindrical parts

Rapid product development and cost reduction are the critical issues for organisations in this globalisation era. To succeed in a competitive environment, manufacturing industries should integrate the elements of a manufacturing system with the help of information flow. In this environment, computer-aided design (CAD), computer-aided manufacturing (CAM) and computer-aided inspection (CAI) play a vital role and these should be integrated for high-quality production with minimum lead time. However, in real-time manufacturing, there is a lack of smooth information flow between these systems. Hence, it is proposed that the use of CAD exchange files provides automatic transmission of data between these systems leading to a successful integration of CAD/CAM/CAI. In this work, an attempt was made to integrate CAD, CAM and CAI by way of a feature extraction process using the STEP file. Using the feature information, NC codes were generated for a CNC machine to manufacture the desired parts. The feature information is also useful as reference data for controlling the quality of manufactured parts by comparing with the data measured by machine vision system and coordinate measuring machine. In this paper, the concept of integration is explained with the demonstration of a cylindrical component.

The Methodologies of Automatically Analyzing the Similarity of Processes Based on Features Abstracted From NC Codes

It is difficult to draw the similarity correlation degree of the process features from NC codes since the NC codes do not represent the process features directly. This research works at the methodologies of automatically analyzing the similarity of process based on features abstracted from NC codes to improve the group efficiency. Employing the NC codes' advantages of the clear and stable structure, good readability, taking the similarity principles as the theoretical foundation, this research regards the NC codes as similar systems to study on the problem of automation for similarity correlation comparison of process features. A detailed and concrete case study demonstrates the specific steps of the process features modeling and similarity comparison of the NC codes. The calculation and comparison shows the effectiveness of the method, which provides the foundation for group automation.