Tool Path

Modern CAD systems are essential in all phases of designing, evaluating and manufacturing mechanical parts. Efficient integration of CAE tools into modern CAD environments results in highly accurate procedures within a short time frame. In this work, a comparative study is presented, based on two novel hybrid methodologies for evaluating and optimising the reconstruction procedure for a 3D beam with an arbitrary cross-section. Both methodologies combine adaptive meshing techniques with quality tools (Taguchi method and response surface methodology), within the boundaries of a modern CAD system for the formation of the boundary element method (BEM) mathematical model. The application of such a methodology as an integrated CAD/CAE tool offers students and inexperienced engineers an excellent overview on the behaviour of structures in various loading and boundary conditions.

Sculptured surface machining is a material removal operation essentially adopted to manufacture complex products. Computing optimal tool paths with reference to ideally designed CAD models is indispensable to be able to suggest machining improvements in terms of high quality and productivity. The present paper proposes a new methodology based on a virus-evolutionary genetic algorithm for enhancing sculptured surface tool path planning through an automated selection of values for standard 5-axis end milling strategies' machining parameters to be decided upon in the context of a simulation-based; software-integrated, multi-objective optimization problem. The problem involves surface machining error as the first quality objective represented via the mean value of chordal deviations that tool path interpolation yields and effective radius of inclined tools that affects scallop. Machining time is the second quality objective entering the problem to assess productivity; whereas the number of cutter location points created for each tool path evaluation is also considered. Tool type, tool axis inclination angles as well as longitudinal and transversal steps are considered as the independent parameters in the case of 5-axis machining. Results obtained by conducting evaluation experiments and simulation tests accompanied by an actual machining process provided significant insight concerning the methodology's efficiency and ability of suggesting practically viable results.

Industrial parts with sculptured surfaces are typically, manufactured with the use of CNC machining technology and CAM software to generate surface tool paths. To assess tool paths computed for 3-and 5-axis machining, the machining error is evaluated in advance referring to the parameter controlling the linearization of high-order curves, as well as the scallop yielded as a function of radial cutting engagement parameter. The two parameters responsible for the machining error are modeled and corresponding cutter location data for tool paths are utilized to compare actual trajectories with theoretical curves on a sculptured surface (SS) assessing thus the deviation when virtual tools are employed to maintain low cost; whilst ensuring high precision cutting. This operation is supported by applying a flexible automation code capable of computing the tool path; extracting its CL data; importing them to the CAD part and finally projecting them onto the part's surface. For a given tolerance, heights from projected instances are computed for tool paths created by changing the parameters under a cutting strategy, towards the identification of the optimum tool path. To represent a global solution rough machining is also discussed prior to finish machining where the new proposals are mainly applied.

In today's business environment, the trend towards more product variety and customization is unbroken. Due to this development, the need of agile and reconfigurable production systems emerged to cope with various products and product families. To design and optimize production systems as well as to choose the optimal product matches, product analysis methods are needed. Indeed, most of the known methods aim to analyze a product or one product family on the physical level. Different product families, however, may differ largely in terms of the number and nature of components. This fact impedes an efficient comparison and choice of appropriate product family combinations for the production system. A new methodology is proposed to analyze existing products in view of their functional and physical architecture. The aim is to cluster these products in new assembly oriented product families for the optimization of existing assembly lines and the creation of future reconfigurable assembly systems. Based on Datum Flow Chain, the physical structure of the products is analyzed. Functional subassemblies are identified, and a functional analysis is performed. Moreover, a hybrid functional and physical architecture graph (HyFPAG) is the output which depicts the similarity between product families by providing design support to both, production system planners and product designers. An illustrative example of a nail-clipper is used to explain the proposed methodology. An industrial case study on two product families of steering columns of thyssenkrupp Presta France is then carried out to give a first industrial evaluation of the proposed approach.

Standard for Exchange of Product Model Data (STEP) is a Standard associated with representation of product data model to enable data communication between different Computer-aided Design (CAD), Computer-aided Manufacturing (CAM) and other engineering systems without any ambiguities and any possible data losses. The development of Open Architecture (PC-based) Numerical Control (OAPC-NC) Interpolator has enhanced the possibilities of data communication between the systems. A tool path data interface to OAPC-NC interpolator is proposed and developed; and a hierarchical-based algorithm is used to extract the tool path data from STEP-NC tool path file of a product model. The generated output of the interpolated data is computer simulated for 3D straight-line path to verify the validity of the interpolator input generated by the proposed interface.

A novel and adaptable forming method, known as Single Point Incremental Forming (SPIF), has emerged to meet the growing needs of the manufacturing industry. This technique is precious for producing innovative products from sheet metal, offering enhanced flexibility and precision in fabrication. The input parameters during the forming process play a crucial role in determining the final product's formability in terms of maximum formable depth (MFD) and surface quality in terms of average surface roughness (Ra). The present research aims to optimise the forming parameters for formability and surface quality during SPIF of material AZ31 magnesium alloy. In the present research, AZ31 is selected as the target material due to its widely recognized excellent strength-to-weight ratio, making it ideal for lightweight applications in the automotive, aerospace, and electronics industries. The experiments are accomplished based on the use of a Taguchi's design of experiments. The tool diameter (TD), tool rotational speed (TRS), tool feed rate (TFR), and incremental step depth (ISD) were chosen as variable parameters and, keeping other parameters constant for maximum formable depth and average surface roughness as response parameters. The best parameter settings were found, and the statistically significant parameters of the responses were examined using the Analysis of Variance (ANOVA). The results revealed that the maximum formable depth (23.5 mm), representing the material's formability, increases with larger tool diameters (10 mm and 12 mm), and higher tool rotational speeds (5000 rpm and 6000 rpm) but decreases with higher tool feed rates (500 mm/min and 600 mm/min). On the other hand, surface roughness improves (decreases) with higher tool rotational speeds, while it increases with larger tool diameters, higher tool feed rates and greater incremental step depths. Furthermore, the findings of a confirmation experiment using the optimal conditions showed a good agreement with the experimental observation. Additionally, linear regression models for predicting the maximum forming depth and average surface roughness were developed by applying the response surface methodology (RSM), which also had good agreement with experiments conducted on optimal parameters.

With the increased use of light-emitting diode technology, the design freedom of taillight shapes has improved, and the shape design of taillights has become a major design focus and breakthrough point for new energy vehicles. As traditional taillight shape design normally depends on the individual experience of designers who make considerable effort to capture design inspiration by manually searching for design references, taillight shape creative design in the field of computer-aided design is studied to assist designers' creative thinking and design efficiency. In this research, generative adversarial networks are applied to explore the creative generation mechanism of taillight shape designs. First, a dataset of high-quality vehicle taillight shape images is established, which combines safety and aesthetic taillight shape design rules and insights. Then, deep convolutional generative adversarial networks and progressive growing of generative adversarial networks are both introduced to train and construct the taillight shape generative design model, and the commonalities and differences between the two are further compared. Finally, the optimal creative generation design model of the taillight shape is constructed. This research provides a new idea for taillight shape design, and the constructed taillight shape creative generation design model is helpful in realizing efficient, diversified and innovative taillight shape design and provides designers with rapid and sustainable preliminary design proposals and creative inspiration support.

This paper gives a detailed explanation of the project, related to reverse engineering, which was conducted by the authors of this paper. The project was based on direct machining, which is done by generating efficient tool paths directly from point cloud data, stored in STL format. The primary objective was to achieve high efficiency in the machining of free-form surface geometries, having complex machining areas. Reverse engineering traditionally involves surface fitting. However, it has several drawbacks. To overcome these drawbacks, the concept of direct machining is used. This skips the surface fitting process and consists of three main steps: digitizing, tool path generation and machining. Therefore, an algorithm to generate tool paths for direct machining was developed. The algorithm works for three-axis milling, using a ball-end mill cutter. It includes dividing the surface into ranges and generating B-spline curves which are best fit curves within each range. These curves are the required tool paths. A few case studies have also been conducted using this algorithm.

Accuracy of machined components is one of the most critical considerations for any manufacturer. One of the challenging difficult areas is the machining of low-rigidity complex parts usually associated with industries such as aerospace. The paper reports on advanced error prediction and compensation strategy specifically focused on force-induced errors in machining of thin-wall structures. The machining error is predicted using a theoretical flexible force-deflection model and compensated for by optimising the tool path prior to machining. The error compensation scheme is simulated using NC verification tools and experimentally validated. The experimental results show that the overall error in the flexible milling can be captured and predicted with very high accuracy using the proposed flexible force-deflection model and a large percentage of it can be eliminated through the proposed error compensation scheme.

All information in this document has been obtained and presented in accordance with academic rules and ethical conduct. I also declare that, as required by these rules and conduct, I have fully cited and referenced all material and results that are not original to this work.

Standard for Exchange of Product Model Data (STEP) is a Standard associated with representation of product data model to enable data communication between different Computer-aided Design (CAD), Computer-aided Manufacturing (CAM) and other engineering systems without any ambiguities and any possible data losses. The development of Open Architecture (PC-based) Numerical Control (OAPC-NC) Interpolator has enhanced the possibilities of data communication between the systems. A tool path data interface to OAPC-NC interpolator is proposed and developed; and a hierarchical-based algorithm is used to extract the tool path data from STEP-NC tool path file of a product model. The generated output of the interpolated data is computer simulated for 3D straight-line path to verify the validity of the interpolator input generated by the proposed interface.

Today, wooden products are widely spread in the industry of furniture, art boards, wooden dishes, etc. The traditional and manual manufacturing methods of producing these artefacts cannot compete with mechanized production methods, especially computer numerical control (CNC) machines. Therefore, using of these devices is always increasing. Nevertheless, one of the parameters that affect the production speed is the surface roughness, and the workshops have to spend a lot of time on polishing the products. For this reason, in the present research, the effect of machine parameters (feed speed, rotational speed and transverse step) and tool characteristics (diameter, number of cutting edge and type of cutting edge) on surface roughness of beech wood has been investigated. The outcomes demonstrated that cutting tools with two spiral cutting edges have a more favorable surface roughness than cutting tools with a straight cutting edge and one spiral cutting edge, and tools with a straight edge are not suitable for beech wood. It was also observed that by reducing the transverse step from 0.7D to 0.3D, a lower surface roughness is created. By reducing the tool diameter from 6 to 4 and 3 (mm), reducing the feed speed from 60 to 20 (mm/min) and increasing the rotational speed from 15000 to 25000 (rpm), the surface roughness of final product was improved, significantly.

In this work, the influence of the tool interpolation method on the HSC of free form surfaces with sharp edges is analyzed. The traditional linear interpolation was compared to polynomial interpolation by application of three different values of CAM tolerance. The results were analyzed in terms of machined surface roughness, contour dimensional form error measurements and dynamic behavior of the tool machine, through the real time acquisition of feed rate in x and z axes. It was shown that polynomial interpolation offers accuracy and surface quality gains if compared to linear interpolation, in the same cutting conditions. However the decision for applying both interpolation methods has to consider the CAM tolerance value in terms of lead-time reduction. By using of linear interpolations the programmer has to decide for opener CAM tolerances due to the NC program size and consequently the time to process the program. When the CAM programmer decides for applying polynomial interpolations the CAM tolerance must be closed as soon as possible due to more surface profile adjust to polynomial curve equation.

Abstract. In this work, the influence of the tool interpolation method on the HSC of free form surfaces with sharp edges is analyzed. The traditional linear interpolation was compared to polynomial interpolation by application of three different values of CAM tolerance. The results were analyzed in terms of machined surface roughness, contour dimensional form error measurements and dynamic behavior of the tool machine, through the real time acquisition of feed rate in x and z axes. It was shown that polynomial interpolation offers accuracy and surface quality gains if compared to linear interpolation, in the same cutting conditions. However the decision for applying both interpolation methods has to consider the CAM tolerance value in terms of lead-time reduction. By using of linear interpolations the programmer has to decide for opener CAM tolerances due to the NC program size and consequently the time to process the program. When the CAM programmer decides for applying polynomial ...

The toolpath optimisation has become the need of the hour due to fourth industrial revolution. The article presents an investigation on the toolpath optimisation for drilling process. Two novel algorithms have been introduced and implemented, namely Random Start of Shortest Distance Permutation (RSSDP) and First Point Start Shortest Distance Permutation (FPSSDP). The outcome has been compared with Shortest Distance Location (SDL) algorithm and Travelling Salesman Problem algorithm (TSP). MATLAB is used to implement the algorithms. Moreover, virtual simulation is carried out in CATIA V5 software. The results have shown significant reduction in the non-productive machining time.

The determination of the cutting-parameter values that cause increases in vibration values is important to minimize the errors that can occur. Thus, the first aim of this study was to investigate the optimum cutting-parameter values and tool-path strategies in ball-end milling of the EN X40CrMoV5-1 tool steel with three coated cutters using the Taguchi method. The parameters taken into consideration are the cutting speed, feed rate, step over and tool-path strategies. The second aim of the study, a model for the tool acceleration as a function of the cutting parameters, was obtained using the response-surface methodology (RSM). As a result, the most effective parameter within the selected cutting parameters and cutting strategies for both inclined surfaces and different coatings was the step over. In terms of tool coatings, the most deteriorating coating for the tool acceleration on both inclined surfaces was the TiC coating. In addition, the response-surface methodology is employed to predict the tool-vibration values depending on the cutting parameters and tool-path strategy. The model generated gives highly accurate results.

AIl~tr~-t-A study of the effect of feed direction on five-axis tool paths generated using local surface properties for tool orientation and positioning is presented in this paper. The principal axis method for five-axis machining defines the placement of the cutting tool at a single point on the wotkpiece surface and assumes that a preferred feed direction will be maintained. This preferred direction may not represent a practical choice for tool path planning. In this work, numerical simulations are used to evaluate tool paths with different feed directions. Numerical simulations ate then verified experimentally by machining two example surfaces. The results show that both gouging and the effective cutter profile will dictate the optimal choice of feed direction.

This paper presents a numerical simulation of the incremental sheet metal forming (ISF) process, type single point incremental forming (SPIF). A finite element model (FEM) is developed by using the commercial FE code ABAQUS. An elasto-plastic constitutive model with quadratic yield criterion of Hill'48 and isotropic hardening behavior has been adopted during ISF operation. A user material subroutine (VUMAT) is used to implement this material behavior. Four strategies of tool path during the ISF of a piece having a square box final shape are presented. Results including thickness variation of sheet metal, forming force along Z-axis and the Hill'48 stress distribution for the four strategies are presented and compared at the aim to optimize the SPIF and to see which tool path strategy makes this process more effective with the consideration of the characteristics of specimen manufactured and its material properties.

In today's business environment, the trend towards more product variety and customization is unbroken. Due to this development, the need of agile and reconfigurable production systems emerged to cope with various products and product families. To design and optimize production systems as well as to choose the optimal product matches, product analysis methods are needed. Indeed, most of the known methods aim to analyze a product or one product family on the physical level. Different product families, however, may differ largely in terms of the number and nature of components. This fact impedes an efficient comparison and choice of appropriate product family combinations for the production system. A new methodology is proposed to analyze existing products in view of their functional and physical architecture. The aim is to cluster these products in new assembly oriented product families for the optimization of existing assembly lines and the creation of future reconfigurable assembly systems. Based on Datum Flow Chain, the physical structure of the products is analyzed. Functional subassemblies are identified, and a functional analysis is performed. Moreover, a hybrid functional and physical architecture graph (HyFPAG) is the output which depicts the similarity between product families by providing design support to both, production system planners and product designers. An illustrative example of a nail-clipper is used to explain the proposed methodology. An industrial case study on two product families of steering columns of thyssenkrupp Presta France is then carried out to give a first industrial evaluation of the proposed approach.

There are several practical methods to reduce machine tool vibrations that have negative effects especially on the quality of the machined surface. The most intricate vibration is the regenerative one originated in a delay effect of cutting processes. One group of the methods that may be successful in avoiding regenerative vibrations is the appropriate variation of the corresponding time delay. This study presents the stability analysis of milling processes in case of an especially intricate way of varying the delay in time: the radial depth of cut is varied in face milling resulting in a wavy tool path. The combination of the semidiscretization method and the implicit subspace iteration method is introduced to present an efficient way of calculating stability charts that provide conclusions regarding the use of this method in eliminating chatter.

Additive manufacturing (AM) has revolutionized the way industries manufacture and prototype products. A significant drawback that prevents 3D printing from being widely implemented in large-scale production is cycle time. This issue has been improved by allowing multiple collaborating printheads to print different parts of the same object simultaneously. However, little formal research has been done to support the aforementioned approach, and current implementations have room for improvement in terms of both makespan and mechanical properties. A new toolpath optimization methodology is proposed in this research to fill this need. The objectives are to create a collision-free infill toolpath for each printhead while maintaining the mechanical performance and geometric accuracy of the printed object. The methodology utilizes the combination of tabu search and novel collision detection and resolution algorithms, TS-CCR. The performance of the TS-CCR is analyzed and compared with the current industry standard.

Incremental sheet forming is an emerging process to manufacture sheet metal parts that is well adapted for small batch production or prototypes. The adjustment time is short, as it is sufficient to modify the tool motions to optimize the manufacturing process. Tool path generation therefore becomes a key topic linked to incremental sheet forming, and process characteristics ask for dedicated tool paths. Hence, this paper first discusses the impact of tool path types and other programming parameters on process implementation through an experimental campaign performed on a parallel kinematics machine tool. Then, a new approach to generate and control Intelligent CAM programmed tool paths is proposed. The major purpose of this innovative concept is to use process constraints for programming and controlling the tool path, which are adapted during the running of the CNC program according to real-time process data evaluation. Validation studies and an industrial implementation are finally presented to assess the efficiency of the proposed approach.

This paper presents a novel method to generate three-axis CNC tool paths for machining freeform surfaces based on a preferred feed direction field. This research was initiated from a fluid dynamics behavior that the energy loss can be reduced when the streamlines of fluid and the small grooves on a surface are in the same directions. In this research, the fluid streamlines above the surface are defined by a collection of vectors. These vectors are regularized into a grid of vectors, and these regularized vectors are further projected onto the tangent planes of a grid of points on the surface to create the preferred feed direction field. Based on the parametric model of the surface, the vectors on the tangent planes of the surface are mapped into vectors in the parametric domain. A scalar function is constructed such that the isolines of this scalar function and the preferred feed direction vectors in the parametric domain are in the same directions. A group of isolines of the scalar function are identified and these isolines are mapped back onto the 3-D surface as the created tool paths considering the tolerance requirement. The developed method has been applied to generate the tool paths for machining surfaces of a compressor blade.

The most evident characteristics of body components used in automotive industries are two overall dimensions with much higher values compared to a third one, as well as the relatively uniform apportion of functional elements on the surface of the workpiece. During the inspection process, these characteristics determine the active measuring element to pass greater distances between the measuring areas, in comparison to the distances required for the effective measurement. Heuristic and approximate methods for measuring path optimization have the advantage of finding a solution making fewer operations, and the found solution differs from the optimal solution with no more than 2-3%. In the present paper, optimization algorithms based on the matrix relaxation method and nearest neighbor method were imagined and applied. These algorithms have served as a basis for developing a software. This software allows the optimization of the measurement path for car body parts which characterized by areas where the inspection is carried out, relatively uniformly apportioned over the surface of the workpiece.

Recently, incremental sheet metal forming (ISMF) process as one of the new methods in rapid prototyping collection has been considered by researchers. This process is based on a defined path in CNC controller and applies a spherical-head tool that supplies the required pressure for sheet metal forming. Despite affirmation of process ability in forming symmetric geometries, some of its aspects such as: high cost in die design and its manufacturing, high cost in using NC machine tools and time consuming forming processare its constraints. Hereupon, a new method for incremental sheet metal forming on turning machine has been presented. This process uses a spherical-head tool in tool-holder turret, forming sheet metal in symmetric geometries in shortest possible time without requiring a die. With a view to increasing sheet formability, two types of forming strategies were designed and implemented. Finally, the best forming strategy based on final forming depth and effective strain calcu...

In computer-aided manufacturing systems a number of methods have been published for milling path generation considering different geometric requirements and conditions determined by specific environments. In this paper we propose a method for the computation of the moving direction of the cutting tool in 3-axis milling considering the local features of the surface. Our method combines two geometric approaches. Computations are presented on analytical surfaces and on triangle meshes.

This paper presents a numerical simulation of the incremental sheet metal forming (ISF) process, type single point incremental forming (SPIF). A finite element model (FEM) is developed by using the commercial FE code ABAQUS. An elasto-plastic constitutive model with quadratic yield criterion of Hill'48 and isotropic hardening behavior has been adopted during ISF operation. A user material subroutine (VUMAT) is used to implement this material behavior. Four strategies of tool path during the ISF of a piece having a square box final shape are presented. Results including thickness variation of sheet metal, forming force along Z-axis and the Hill'48 stress distribution for the four strategies are presented and compared at the aim to optimize the SPIF and to see which tool path strategy makes this process more effective with the consideration of the characteristics of specimen manufactured and its material properties.

Single-point incremental forming (SPIF) is a flexible technology that can form a wide range of sheet metal products without the need for using punch and die sets. As a relatively cheap and die-less process, this technology is preferable for small and medium customised production. However, the SPIF technology has drawbacks, such as the geometrical inaccuracy and the thickness uniformity of the shaped part. This research aims to optimise the formed part geometric accuracy and reduce the processing time of a two-stage forming strategy of SPIF. Finite element analysis (FEA) was initially used and validated using experimental literature data. Furthermore, the design of experiments (DoE) statistical approach was used to optimise the proposed two-stage SPIF technique. The mass scaling technique was applied during the finite element analysis to minimise the computational time. The results showed that the step size during forming stage two significantly affected the geometrical accuracy of t...

The article presents the results of machining materials in hardened state. In the paper, different trochoidal tool paths are compared with each other and with the conventional milling. The results of measurements show the relationship between tool path, roughness and waviness of grooves wall. The paper also presents pictures of grooves which were made. These results provide comparative material useful in the choice of the best milling strategy to the cutting process.

Nowadays the trend of using monolithic parts on aerospace industry has suffered a considerable increase due to the benefits they provide. However, their complex shape and the low machinability of the materials used to manufacture them make their manufacturing by conventional methods difficult or even impossible. Electro discharge machining is an alternative to manufacture this kind of parts. Existing solutions do not offer a generic method that guarantees the smoothness of the erosion path, independently of the workpiece geometry and "user-dependent" features. With the aim to solve the problem, a new objective function has been proposed and a hybrid optimization method (Genetic Algorithmþ Trust Region Reflective method) has been implemented. Results obtained by a single variable problem show that the proposed objective function generates a smooth path regardless of machined shape and available degrees of freedom. Therefore, the implemented optimization method combines a low computational cost together with the obtaining of the largest possible electrode. The optimized algorithm has been applied to an industrial case-study, the erosion of a shrouded blisk, to check its adequacy. The lack of instabilities during the erosion of the part proves the best performance of the developed work.

Recent technological advances in the field of Additive Manufacturing (AM) and the increasing need in Regenerative Medicine (RM) for devices that better and better mimic native tissues architecture are showing limitations in the current scaffolds fabrication techniques. A switch from the typical layer-by-layer approach is needed to achieve precise control on fibers orientation and pores dimension and morphology. In this work a new AM apparatus, the RAVEN (Robot-Assisted Volumetric ExtrusioN) system, is presented. RAVEN is based on a 7-DOF robotic arm and an FDM extruder and allows for volumetric extrusion of polymeric filaments. The development process, namely the robotic motion optimization, the optimization towards small-scale trajectories, the custom-made hardware/software interfaces, and the different printing capabilities are hereby presented. The successful results are promising towards future advanced applications such as in vivo bioprinting, in which the ability of the robot to change its configuration while printing will be crucial.

In this paper, we present our research dealing with the choice of the reference of compensation with respect to a given tolerance and the compensation tool trajectory in the milling process. The general purpose of our research is to compensate the tool deflection that occurs during the milling process. We consider it under two aspects : surface prediction generated by the tool deflection and surface prediction generated by the contact points between the cutting tool flute and the workpiece. These two aspects imply two different approaches to carry out the compensation method , called miTTOT method, which can generate a new tool trajectory. In order to compare these two approaches, we present some practical examples.

This paper presents a new efficient and robust tool-path generation methods for clean-up machining by employing a curve-based approach. The clean-up machining to be discussed in this paper are pencil-cut and fillet-cut for a polyhedral model of the STL form with a ball-end mill. The pencil-cut and fillet-cut paths are obtained from the curve-based scanning tool paths on the xz, yz, and xy planes. The scanning tool path has exact sharp-concave points and bi-contact vectors, both of which are very useful to detect 'pencil-points', trace the pencil-cut path, and generate the filletcut path. In the paper, some illustrative examples are provided, and the characteristics of the proposed method are discussed.

This paper presents a new efficient and robust tool-path generation methods for clean-up machining by employing a curve-based approach. The clean-up machining to be discussed in this paper are pencil-cut and fillet-cut for a polyhedral model of the STL form with a ball-end mill. The pencil-cut and fillet-cut paths are obtained from the curve-based scanning tool paths on the xz, yz, and xy planes. The scanning tool path has exact sharp-concave points and bi-contact vectors, both of which are very useful to detect 'pencil-points', trace the pencil-cut path, and generate the filletcut path. In the paper, some illustrative examples are provided, and the characteristics of the proposed method are discussed.

Most of CAD/CAM systems lack fully-automated process planning capabilities and depend on semi-automatic capabilities that necessitate the traditional selection of tools and cutting parameters. This paper attempts to determine proper combinations of cutting tools through the generation of tool paths and optimisation of machining parameters using an example of the CNC milling process. Several machining simulations with different combinations of tool sizes were performed using MasterCAM software. Based on these simulations, substantial variations in tool paths were observed for different tool combinations and as such the optimum tool combination could only be obtained arbitrarily. The tool paths derived from machining simulations were used to optimise machining parameters, that is, cutting speed, feed rate and depth of cut with the objective of minimising production time. In this case, an optimisation model was developed as a nonlinear programming problem and solved using extended LINGO nonlinear software. The results show that the subjectivity when selecting cutting tools can be avoided when appropriate tools are chosen alongside with the generation of a tool path within a CAD/CAM system using optimised machining parameters. As a consequence, CNC machine tools could be effectively utilised and the productivity significantly improved at shorter production time and cost.

This study aimed at developing an application and comparison of performance between the two main incremental sheet forming (ISF) variants, single-point incremental forming (SPIF) and two-point incremental forming (TPIF), on a scaled prototype of a biopsy micro forceps (BMF). Experimental tests were carried out initially with the SPIF setup. Rupture of specimens and low accuracy of them due to bending of the material led to the more complicated TPIF variant. Prior to the physical support tool construction, FEM simulations allowed validating the precision gains. After several adjustments to the tool-path in the new configuration, the BMF was successfully manufactured by TPIF on AA1050-H24 and AISI 304 05 mm thick. Therefore, the presented results demonstrate the feasibility to use ISF for the rapid prototyping of sheet metal medical devices.

During the micromachining of hardened materials, the low stiffness of the milling tool results in an increased tool deflection which has a great influence on the shape and dimensional accuracy of the machined components. In order to compensate these deflections, an optimization method is presented in this paper. Based on measured form errors of the machined workpieces, the NC programs are optimized iteratively to reduce the shape deviations. To verify this method, experimental investigations were carried out by milling pockets in hardened steel. The results show a significant reduction of the tool deflection after the optimization.

M. Emin Tamer, Omer Music, İzzet Özdemir, Besim Baranog̃lu, Ali Sakin and İsmail Durgun 1 Metal Forming Center of Excellence, Atilim University, Ankara-Turkey, Email: etamer@atilim.edu.tr 2 Dept. of Manufacturing Engng., Atilim University, Ankara-Turkey, Email: omusic@atilim.edu.tr, iozdemir@atilim.edu.tr, bbaranoglu@atilim.edu.tr 3 R&D Prototype manufacturing Dept., TOFAS Turkish Automobile Factories Co., Email: ali.sakin@tofas.com.tr, ismail.durgun@tofas.com.tr

El sector del mueble a nivel mundial, por naturaleza es, una industria que ocupa un alto porcentaje de trabajo manual. Los países más industrializados han conseguido sustituir el trabajo humano por máquinas sumamente sofisticadas; esto por el alto costo del mismo. En México, por el contrario, debido a que el nivel de los salarios es aún bajo, es rentable no equiparse con tecnología y dar empleo a más gente. Lamentablemente el mercado actual exige volúmenes de producción y estándares de calidad en este tipo de productos que la mano del hombre no puede conseguir. La industria y productos de madera se han caracterizado por su alto dinamismo, el cual se muestra en la Tabla 1.1, Año Valor total

Gear is mechanical component mounted on the shaft to transmit the power from one shaft to another. Gear is mostly manufactured by using the hobbing process. In hobbing process the tooth are cut on the gear blank with the help of the indexed hobs. The hobbing process the gear blank and the hob are rotated with each other simultaneously with certain speed. The rotating movement of the hob and the blank creates the cuts and forms the tooth on the gear blank. In the process of the gear hobbing the rotating speed of the hob and rotating speed of the gear blank plays an important role in teeth cutting operation and the formation of the teeth on the gear blank. The rotating speed of the hob also determines the tool life of the hob. As the hob rotates with high speed the wear occurs in the hob due to variation of the cutting force with respect to the cutting speed. This paper will conclude how the variation of the cutting speed of the hob and gear blank affects the cutting of tooth on the g...

هلاقم تاعلاطا هدیکچ لماک یشهوژپ هلاقم :تفایرد 19 دادرخ 1395 :شریذپ 06 دادرم 1395 :تیاس رد هئارا 21 رویرهش 1395 نیشام فلاخ رب هاگتسد نیا .تسا رادروخرب يدازآ هجرد شش زا يزاوم يراتخاس ندوب اراد اب داپازگه هاگتسد ییلااب یکلااچ یتنس ياهرازبا یم نآ زا يدازآ هجرد شش نیا هب هجوت اب .دراد دازآ لکش اب حوطس .دومن هدافتسا دازآ لکش اب حوطس يراکنیشام يارب ناوت حوطس هلمج زا یم زورما تعنص رد دربراکرپ بلاق و اضف اوه ،يزاس وردوخ عیانص رد حوطس نیا زا .دنشاب یم هدافتسا روفو هب يزاس دربراک نیا هب هجوت اب .ددرگ زور نیشام ،نوزفا نیشام رد .تسا هدش عقاو نارگشهوژپ هجوت دروم رایسب زین حوطس نیا يراک رد هروحم جنپ زرف ياهرازبا ياهراک هنیمز نیا حب و تسا هتفرگ رارق یسررب دروم داپازگه هاگتسد زا هدافتسا اب دازآ لکش اب حوطس يراکنیشام هلاقم نیا رد .تسا هتفریذپ تروص یناوارف ث نیشام زیم ناونع هب داپازگه هاگتسد زا هدافتسا يریذپ ناکما دییات نآ یلصا حن ادتبا .تسا نآ کمک هب يراکنیشام و رازبا حوطس نیا یباینایم هو لومرف کمک هب دازآ لکش اب حوطس تاعلاطا جارختسا همادا رد .تسا هدش هدروآ هاگتسد يزاوم راتخاس هب هجوت اب هدش هداد حیض...

We consider a new algorithm designed for five-axis milling to minimize the kinematics error near the stationary points of the machined surface. Given the tool orientations, the algorithm optimizes the required rotations on the set of the solutions of the corresponding inverse kinematics equations. We solve the problem by means of the shortest path scheme based on minimization of the kinematics error. We present an application of the proposed algorithm to tool-path planning and demonstrate the efficiency of the proposed scheme verified by practical machining.

This paper presents a new tool-path-generating methodology for five-axis machining of 3D curves that are projected from 2D planes onto free-form part surfaces. In our approach, the scanning for mapping is planned directly on parameter domain. The DXF pattern was scaled to parametric dimension and transferred to parametric domain, and thus, all entity coordinates were transferred from X,Y to (u,v). By using a B-spline surface equation algorithm, the projected curves were obtained on a free-form surface for tool path generation. 2D pattern models were delineated with the DXF format; 3D free-form surfaces were delineated with the STEP-AP214 format and the "B_Spline_-surface_with_knots" entity was used to define the free-form B-spline surface geometry. Windows® based software written in Borland® Delphi has been developed according to the presented algorithm. Cutter contact (CC) data and surface normals for CC points were obtained with this software. The obtained CC data and surface normal data were transferred to cutter location (CL) data and the tool path verification is obtained by simulation successfully.

A spiral tool-path generation method with constant scallop height for the sheet metal CNC incremental forming was proposed based on triangular mesh model. On the basis of the curvatures estimation of triangular mesh model, the calculation method of spiral tool-path interval with constant scallop height was discussed. Moreover, the algorithms for generation of spiral drive path using the polygon boundary of the triangular mesh model undersurface and the method of spiral paths propagation according to the spiral drive path were also presented. The case study shows that the proposed method can automatically generate smooth and continuous spiral tool path with constant scallop height according to the given scallop height and tool radius; in addition, the simulation model is nearly identical to the test model. The developed software system runs steadily and reliably.

In this research tool path is generated for high speed machining of aluminium alloy.High Speed Machining (HSM) is a powerful machining method that combines high feed rates with high spindle speeds, specific tools and specific tool motion. This practice can be effective for machining intricate core and cavity geometries in mold machining, and for quickly machining large, complex aircraft structural components out of solid blocks of aluminium. The milling operation employed in the research is pocket milling. Pocket milling is a major machining process carried out in aerospace industry. They are mainly employed in isogrid panels of heat shields used in launching vehicles. The conventional sharp cornered tool path limits the feed rate of high speed machine. So a new smooth tool path is generated using mathematical method along with the help of Matlab software. For comparison of conventional strategy with the generated smooth tool path, two different pockets are machined namely each usin...

Single point incremental forming (SPIF) is a new innovative and feasible solution for the rapid prototyping and the manufacturing of small batch sheet parts. The process is carried out at room temperature and requires a CNC machining centre, a spherical headed tool and a simple support to fix the sheet being formed. In incremental Sheet Metal Forming the blank is incrementally deformed in to a desirable shape by hemispherical or ball nose tool traveling along a prescribed path. Due to the various advantages including the reduced production cost and time of prototypes, improved formability, easy modification of part design etc. the ISF is being popular as a new innovative forming technology. In the present study experiments were conducted to analyze the deformation mechanism of commercial aluminum alloy. Beside this analysis result of the effect of forming angle, step size, tool diameter on formability and wall thickness distribution are presented.