CAM Software Research Articles

Research of CNC Automatic Programming Method Based on Process Database

In this paper, a method of NC process information extraction and import to template file based on Process Recording Files and database was proposed, which provides an effective way for NC process information sharing and reuse, and made positive effect on current situation in CNC manufacturers, such as: type of product is relative stable, process of CAM programming has lots of duplication, process parameters are dependent on programmers, the processing quality is instable and so on. The Process Recording Files are from mainstream heterogeneous CAM softwares, such as: PowerMILL, UG/CAM, which used to record CAM programming process, macro files from PowerMILL and UG/CAM are belongs to this kind of file.

Profile error compensation in high precision 3D micro-EDM milling

Together with the product miniaturization trend, manufacturing technologies to fabricate small size shapes are highly demanded for micro-mold and die industry. Among the versatile machining processes, micro-EDM milling is superior owing to its negligible cutting force. By using layer by layer removal strategy in association with CAM software for tool path generation, intricate 3D micro-shapes could be produced. However, there exist some systematic errors which affect the dimensional accuracy and the final form of obtained shapes. This study attempts to identify and analyze the error components of 3D micro-EDM milling process. It is found that aside from the inherent machining gap and the indispensible electrode wear, the corner radius of virtual electrode is also of prime importance in determining the machining accuracy. In this study, geometric models are presented to simulate its effects. It is detected that the profile error could be reduced by implementing the corner radius into virtual electrode model. For verification, typical 3D micro-shapes formed by the inclined planes and a partial sphere are fabricated with and without the new model for virtual electrode geometry.

Tool Path Generation for Five-Axis Controlled Machining with Consideration of Structural Interference

In the case of five-axis controlled machining, the machine components such as tables, spindles, and columns take various locations, so interference may occur among machine components. In commercial CAM software used five-axis controlled machining, however, structural interference is not considered. Output Cutter Location (CL) data may therefore cause structural interference. In this report, locations of the machine components where structural interference may occur are calculated and a tool path generation method considering the above-mentioned problem of interference is developed. The effectiveness of the devised technique was confirmed experimentally as a result of machining simulation.

NC code generation for laser assisted turn-mill of various type of clovers and square section members

Laser assisted turning (LAT) is one of the advanced machining technologies, which uses laser power to heat the surface of a workpiece before the material is removed. It has several advantages of low manufacturing costs, high productivity and high qualities to machine difficult-to-cut materials such as silicon nitride, mullite, zirconia and Ni. A large part of studies on LAT have been focused on a round bar. With increasing demands for high quality products and high performance engineering system, the researches on LAT for clover and square section members are necessary. But, these workpieces are impossible to be machined on conventional CNC lathe and to generate NC code with current CAM softwares. As a basic research for combining LAT with a tilting index table type 5-axis machining center, i.e. laser assisted turn-mill, a new method is suggested to generate NC code that can process various types of clover and square section members through development of C++ program.

Semantic Based Intelligent Resource Service Composition Technology

Intelligent resource includes the knowledge, hardware and software resources even workflow and human resource, etc. From the point of view of enterprise information management, the service composition is an essential element for companies’ informatization construction. Therefore, the paper describes a web service composition framework for semantically-annotated web service. Based on the state of art ontology technology, an OWL-S process model for the CAM software is established to describe resource service. Then a service discovery process which mainly consists of services’ property matching algorithm for words is set up. A backward chaining framework for service composition is employed to dynamically compose resource services finally.

The Study on the STEP-NC Program Generation for Milling Operations

STEP-NC is a new data model for data exchange between CAD / CAM and CNC, which provides rich information for CNC machine tools and tells CNC “what to do”rather than “how to do”, overcomes many shortcomings of the traditional G&M codes and has become a hot research issue now. How to efficiently and cost-effectively generate the STEP-NC program is a very crucial problem. Although some domestic scholars have done some research about STEP-NC program generation, most of them do second development base on ST-Developer software. The paper developed a STEP-NC program generation module by using the VC++6.0 and CAD / CAM software. The module can read AP203 file generated by CAD system, identify manufacturing features according to its geometry information and conduct process planning to generate STEP-NC file according to ISO14649 standard. This module has been proved effectively by an instance.

Process planning for Floor machining of 2½D pockets based on a morphed spiral tool path pattern

This work proposes a process planning for machining of a Floor which is the most prominent elemental machining feature in a 2½D pocket. Traditionally, the process planning of 2½D pocket machining is posed as stand-alone problem involving either tool selection, tool path generation or machining parameter selection, resulting in sub-optimal plans. For this reason, the tool path generation and feed selection is proposed to be integrated with an objective of minimizing machining time under realistic cutting force constraints for given pocket geometry and cutting tool. A morphed spiral tool path consisting of G1 continuous biarc and arc spline is proposed as a possible tool path generation strategy with the capability of handling islands in pocket geometry. Proposed tool path enables a constant feed rate and consistent cutting force during machining in typical commercial CNC machine tool. The constant feed selection is based on the tool path and cutting tool geometries as well as dynamic characteristics of mechanical structure of the machine tool to ensure optimal machining performance. The proposed tool path strategy is compared with those generated by commercial CAM software. The calculated tool path length and measured dry machining time show considerable advantage of the proposed tool path. For optimal machining parameter selection, the feed per tooth is iteratively optimized with a pre-calibrated cutting force model, under a cutting force constraint to avoid tool rupture. The optimization result shows around 32% and 40% potential improvement in productivity with one and two feed rate strategies respectively.

Transepithelial photorefractive keratectomy mode using SCHWIND-ESIRIS excimer laser: initial clinical results.

To evaluate postoperative pain, uncorrected visual acuity (UCVA), and cornea haze value after transepithelial photorefractive keratectomy (T-PRK) performed with aspherical ablation profile using SCHWIND ESIRIS excimer laser. Retrospective case series. Fifty-nice eyes (32 patients) with myopia associated with or without astigmatism underwent phototherapeutic keratectomy (PTK) followed by photorefractive keratectomy (PRK) which performed by Optimized Refractive Keratecomy (ORK)-CAM software based on aspherical ablation profile using SCHWIND ESIRIS excimer laser. Postoperative pain scale was measured on a questionnaire through five levels. Haze was graded by five grades, and UCVA, manifest refraction spherical equivalent (MRSE) were analyzed. Mean pain level was (1.37±0.613) (range: 1 to 3), the mean time picking out the soft contact lens was (6.22±1.73) days, at 3 months, UCVA was 1.0 for 40 eyes (67.8%), 0.5 for all eyes (100.0%). The UCVA was significantly less than the preoperative best spectacle corrected visual acuity (BSCVA) (t=-2.84, P=0.006), haze value was (0.27±0.25), no patients had a haze grade up to 2. Mean MRSE was (0.76±0.96) diopter(D) by 3 months. The outcomes from this study show that using the SCHWIND ESIRIS aspherical ablation profile for transepithelial PRK has a good visual result. The primary advantage is related to a spherical ablation profile, automatically considers the ablation volume of the stroma and the accurate and smooth removal of the epithelium with PTK. Additional studies are needed to determine long-term outcomes.

Topological model for machining of parts with complex shapes

Complex shapes are widely used to design products in several industries such as aeronautics, automotive and domestic appliances. Several variations of their curvatures and orientations generate difficulties during their manufacturing or the machining of dies used in moulding, injection and forging. Analysis of several parts highlights two levels of difficulties between three types of shapes: prismatic parts with simple geometrical shapes, aeronautic structure parts composed of several shallow pockets and forging dies composed of several deep cavities which often contain protrusions. This paper mainly concerns High Speed Machining (HSM) of these dies which represent the highest complexity level because of the shapes’ geometry and their topology. Five axes HSM is generally required for such complex shaped parts but 3 axes machining can be sufficient for dies. Evolutions in HSM CAM software and machine tools lead to an important increase in time for machining preparation. Analysis stages of the CAD model particularly induce this time increase which is required for a wise choice of cutting tools and machining strategies. Assistance modules for prismatic parts machining features identification in CAD models are widely implemented in CAM software. In spite of the last CAM evolutions, these kinds of CAM modules are undeveloped for aeronautical structure parts and forging dies. Development of new CAM modules for the extraction of relevant machining areas as well as the definition of the topological relations between these areas must make it possible for the machining assistant to reduce the machining preparation time. In this paper, a model developed for the description of complex shape parts topology is presented. It is based on machining areas extracted for the construction of geometrical features starting from CAD models of the parts. As topology is described in order to assist machining assistant during machining process generation, the difficulties associated with tasks he carried out are analyzed at first. The topological model presented after is based on the basic geometrical features extracted. Topological relations which represent the framework of the model are defined between the basic geometrical features which are gathered afterwards in macro-features. Approach used for the identification of these macro-features is also presented in this paper. Detailed application on the construction of the topological model of forging dies is presented in the last part of the paper.

Reduction of geometry-based errors in five-axis machining through enhanced 5D interpolation

Geometry-based errors constitute a special category of CAM-originated machining inaccuracies that significantly influence the precision of five-axis surface machining operations. Geometry-based errors reflect the inability of the cutter to accurately trace a prescribed 3D tool path in five-axis machining. Their magnitude constitutes an overlapped effect of the adopted interpolation scheme, cutter, and surface geometries, as well as kinematics of the five-axis machine tool, assumed free of errors by the CAM software. Although the presence of these errors is inherent in the current configuration of five-axis computer numerically controlled machining systems, little efforts were made so far towards their reduction. In this regard, the present study has investigated the magnitude of geometry-based errors as generated by various 5D interpolation schemes. These enhanced interpolation functions were determined by enforcing better approximations of the ideal machine control coordinate (MCC) trajectory as calculated in five-axis machine tool’s joint space. By comparing the geometry-based errors generated by the enhanced 5D interpolation schemes with linear interpolation baseline, it was found that significant error reductions will be obtained when synchronized 5D quadratic functions are used to approximate the ideal MCC curve in joint space. Moreover, the parametric synchronization between rotational and translational machine tool motions represents an essential requirement for limitation of the amount of geometry-based errors.

Study regarding complex shapes manufacturing using CAM

In the case of complex cavities shapes, manufacture using classical methods proved to be a very difficult process. Classical methods imply splitting the part in many leveling planes, the distance between them being given by the depth of the cut and the feeding rate. The purpose of this paper is to present how cavities are made using CAM softwares, mainly SolidCAM and how fast this method is in comparison with the classical one. A mold cavity of a complex shape is presented as the example of this aspect. The cavity of the mold was made using 3 axes machine tool equipped with Heidenhain CNC control.

Digital Photonic Production of Micro Structures in Glass by In-Volume Selective Laser-Induced Etching using a High Speed Micro Scanner

Digital photonic production of 3D microfluidic devices and assembled micro mechanics inside fused silica glass is carried out using ISLE directly from digital CAD data. To exploit the potential productivity of new high average power fs-lasers >150 W a modular high speed scanning system has been developed. Acousto-optical beam deflection, galvo-scanners and translation stages are controlled by CAM software. Using a lens with 10 mm focal length a focus radius of 1 μm is scanned with a velocity of 12 m/s on 400 μm track radius enabling the up-scaling of the ISLE- process using fs-laser radiation with up to 30 W.

Realistic Machine Simulation with Virtual Reality

Today highly complex components are manufactured on NC-controlled machine tools. The NC programs, controlling these machines, are usually automatically generated by CAM software. This automatic processing is often erroneous. The VR-based realistic machine simulation, presented in this paper, extends the usual content of a machine simulation, like material removal and collision detection, by various new aspects. The coupling of a real NC unit allows the recognition and elimination of all process- as well as controller-caused errors. The integration of the multi-body simulation enables the consideration of inertia, machine rigidity and milling cutter deflection.

Offline Force Control and Feedrate Scheduling for Complex Free Form Surfaces in 5-Axis Milling

An enhanced Force model based Feedrate Scheduling (FFS) technique for rough cutting of parts with complex free form surfaces in 5-axis machining is presented. In order to estimate the cutting forces in complex 5-axis machining an enhanced solid modeler kernel based model is developed to find the complicated engagement between cutter and workpiece for each cutter location. In this paper, cutter-workpiece engagement model is presented using the commercial Parasolid solid modeler kernel, and then cutting forces are estimated based on the developed model. In this approach, the resultant cutting forces are kept constant on a user defined threshold. The feedrate will be adjusted to keep the resultant cutting forces constant all along the tool path. Therefore, it is shown that this approach allows decreasing the cycling time drastically. The scheduled feedrate in each cutter location is carried out in NC blocks using an off-line postprocessor that can be used in commercial CAM software. Eventually, the proposed FFS technique is experimentally tested on rough machining of an impeller with free form surfaces and force validations are presented in this article.

B16 産業用ロボットを用いた研磨作業の自動化 : 切削用NCデータを利用したロボットプログラムの作製(OS4 生産システムとCAD・CAM(2))

Recently, processes in manufacturing industry have been automated increasingly using various automatic machines. However, automation of polishing process is difficult due to demands for skills and sense of human. Then, our laboratory has been aiming at fully automation of polishing process using an industrial robot. In the previous study, original CAM system was developed to realize the automation of polishing process. However, CAM system's flexibility and versatility is insufficient because it only copes with the surface machined with scan milling path. If it enables to generate more various paths, many type of polishing will be possible. This study aims to generate various polishing paths by using the NC data that is output from the commercial CAM software. In addition, we have devised the method to automatically generate robot programs with consideration of tool location to avoid sudden change in movement of industrial robot.

Parametric multi-axis tool path planning for CNC machining: the case of spur gears

Four and five axis machining strategies are difficult to standardise in the general case. General purpose CAM systems are an important tool allowing the experienced machinist to experiment with machining strategies and assess quality of the resulting tool paths. However, in the case of machine elements, such as gears, shape definition by parametric equations is most inviting for development of fit-for-purpose machining strategies and corresponding parametric tool paths without the use of CAM software. Such an approach is materialised in this paper for spur gears, drawing on discretisation of involute and trochoidal curves constituting the tooth profile, so as to satisfy scallop height constraints. The roughing stage is performed with a flat end mill, implementing slot milling along a meander type tool path. The finishing stage is performed with a bull-nose end mill, implementing peripheral milling circumferentially around the full gear profile. The algorithms were tested on a three-axis machining centre equipped with an additional 4th rotary axis to manufacture a plastic spur gear.

New computer vision based Snakes and Ladders algorithm for the safe trajectory of two axis CNC machines

Multi-axis machine production process optimization, automation and intelligence are the key codes of today’s scientific community. Rapid decision and intelligence are becoming more important for precise and safe virtual and real production. Multi-axis CNC production is a high speed machining process that demands less human intervention and high intelligence, to deal with any uncomfortable situation regarding collisions. Current CAM softwares as well as CNC machines are able to detect collisions but are unable to avoid these collisions automatically. This paper aims to make the CAD-CAM/CNC multi-axis safe trajectory generation process optimal, intelligent and automatic, using vision based image processing by the Snakes and Ladders game analogy. Applying the Snakes and Ladders analogy on machine virtual scene (trajectory preparation) and real scene (during production) images gives promising methodology for safe and efficient trajectory generation while avoiding collisions named Snakes and Ladders Analogy for Production Trajectory (SLAPT). Our Rectangular Enveloped Safe and Efficient Trajectory (RESET) algorithm, based on the same principle of the SLAPT methodology is also discussed in this paper. Results include some applications of algorithms on virtual and real machine scene images for the safe and optimized trajectory of tools. This paper focuses on intelligence and optimization of 2D non-functional transversal trajectories of 2-axis machines for production and preparation processes as an initial effort towards the complex safe trajectory generation process (mill-turn).

Machining Process Analysis and Parametric Programming of Parts with Complex Surfaces

Take the complex three-dimensional (3D) surfaces which consist of all kinds of curves, such as cosine, parabolic and elliptic as examples, the processing is analyzed to determine the reasonable feed routes. The method of parameter programming provided by SINUMERIK 802D system is applied to choose reasonable machining parameters. Using these parameters for NC programming, not only the roughing and finishing machining with different processing requirements can be met, but also the programming solutions are optimized and the NC program is briefer than that generated by CAM software. Furthermore, human-computer interaction can be achieved by means of assignment to the parameters.

Research on the Digital Design and Manufacture Technology in the Manufacturing of Titanium Alloy Cranial Prosthesis

It is a new design and manufacturing method which forming medical image data processing technology and multi-point forming technology for titanium alloy cranial prosthesis digital design and manufacturing. First, the head of the CT data of patients according to medical image segmentation approach to the skull and scalp, brain image segmentation boundaries, using registration method to segment the skull CT image registration, and application of 3D visualization technology in patients with skull reconstruction of the mathematical model. Then on this basis, the use of thin-plate spline interpolation in accordance with the health side of the skull surface extension of the transition to be a mathematical model of the skull prosthesis. Finally, the mathematical model of the skull prosthesis passed to the multi-point forming CAD / CAM software system, so that multi-point forming the basic body to adjust the upper and lower press out the skull prosthesis forming surface, and processing the required titanium alloy cranial prosthesis. The technical solution of the skull repair system prepared in the presence of low precision machining, production costs are high, long cycle and so on, while improving the prosthesis fit and the precision of the edge defects.

Engineering Design of A Gang Drilling Machine Equipped with Jig and Fixtures to Make A Prototype Machine in Birdcage Production

This paper is dealing with the engineering design of a gang drilling machine with jig & fixtures to make a prototype machine. This effort has been done in order to solve the problem which aroused in small business enterprises producing birdcages. The problem was how to minimize the production time in making a lot of holes that have same distance and straightness. Hopefully, the prototype machine can help the small business enterprises to increase their production rate.The design engineering process has been carried out by variant approximation on dowel pin modular fixtures in order to simplify fixtures design. CAD CAM software has also been used as fixtures synthesized method including geometric analysis and three dimensional fixtures assembling. The resulting prototype machine can be well operated and based on the running test, it can be concluded that the greater the motor rotation the greater the power needed. As for teak wood, at 250 rpm motor rotation the power needed is 26.5 watt, and at 400 rpm the motor needs power of 43.6 watt while at 600 rpm the motor needs power of 600 watt. The power consumption is also depends on the type of material, the better the mechanical properties of the materials, the higher the power consumption. For cast iron, the 400 rpm motor rotation needs power as high as 569.7 watt. This prototype of gang drilling machine needs power of 350 watt to make five holes on teak wood while ordinary drilling machine needs total power of 1350 watt.