3-axis CNC Machine Research Articles

STEP-NC compliant 3-axis CNC machine controller based on Field-Programmable Gate Arrays

ABSTRACT Manufacturing processes have gone through several transformations in history. Previously, G&M codes served as a common programming language for CNC machines. Codes of CNC machines contain the information related to the tools and trajectories. G&M codes are machine-specific and vendors must customize them for the tools installed on a particular machine. STEP-NC, described by ISO-14649, provides an alternative to G&M codes aiming at generic interoperability of CNC machine codes. STEP-NC includes information on both the trajectories and the tool’s specifications making it generic and machine-independent. STEP-NC is an emerging area and a gateway to intelligent machining targeting ‘design anywhere and develop anywhere’. Therefore, several researchers have developed software-based decoders and interpreters. They are difficult to implement on a serial pipelined processor limiting their use for real-time applications. This paper presents a Field Programmable Gate Array (FPGA)-based STEP-NC controller implemented and validated on a SPARTAN-3E kit. To the best of the author’s knowledge, this is the first FPGA-based implementation of STEP-NC. The main contribution of this work is a generic state-machine representation of the STEP-NC entities suitable for implementation on different FPGA platforms. The developed decoder was successfully tested and evaluated on a three-axis CNC machine for an example given in ISO-14649-11 for compliance.

Optimization of CNC milling parameters using the response surface method for aluminum 6061

The manufacturing sector is constantly seeking ways to optimize the machining process, specifically for 3-axis CNC machines. This study aims to identify the optimal parameter values that result in the lowest roughness and the highest process capability in 3-axis CNC milling. The roughness level (Ra) of the product is primarily influenced by factors such as feed rate, spindle speed, and depth of cut. Additionally, the reliability of the machining process was analyzed to evaluate its ability to consistently achieve low roughness values and to validate the process capability of the VH850L3 series 3-axis CNC milling machine. The suggested approach for this analysis was the RSM central composite design method, which involved conducting experiments under various input conditions. The results indicated that the feed rate had the most significant impact on roughness, followed by the spindle speed, while the depth of cut had no effect. The parameters that resulted in the lowest roughness response were a spindle speed of 2589.76 rpm, a depth of cut of 0.159 mm, and a feed rate of 247.731 mm/min. These parameter values were tested on a 3-axis CNC machine, and the resulting data exhibited variations. Data processing revealed that the machine still performed optimally in the machining process, as indicated by the value of . However, the milling process deviates from the standard target, as the response value shows significant variation with a Cpk value 1.

Reducing Cycle Time in the Manufacturing Process of Circular Pattern Interpolar Products (CPIP) Using Special Fixtures on a 3-Axis CNC Machine

This research focuses on the design of fixture aids to support the manufacturing process of Circular Pattern Interpolation Products (CPIP), such as disk brake components, flanges, turbine disk runners, and other plate components with circular feeding patterns in the 3-Axis CNC machining process. The objective of this study is to achieve more efficient CPIP production times on 3-Axis CNC machines. The research methodology employed a design and build approach, involving the design of fixture aids, fabrication, and testing during the production of turbine disk runners on a 3-Axis CNC machine. This was done by comparing the initial workpiece setup time and the workpiece clamping transfer time using CPIP production aids versus not using CPIP production aids. The results showed that the designed CPIP Fixture significantly reduced the CPIP manufacturing Cycle Time, with a reduction of 63.11% in the initial workpiece setup time and 83.55% during the clamping transfer process.

Intelligent feedrate optimization using a physics-based and data-driven digital twin

Intelligent manufacturing machines envisioned for the future must be able to autonomously select process parameters that maximize their speed while adhering to quality specifications. Accordingly, this paper proposes a framework and methodology for using a physics-based and data-driven digital twin of a feed drive to maximize feedrate while respecting kinematic and contour error limits. To correct for inaccuracies introduced by unmodeled dynamics and disturbances, the data-driven model is updated on-the-fly using sensor feedback. Experiments on a 3-axis CNC machine tool prototype are used to demonstrate up to 35% cycle time reduction without violating error tolerances compared to the status quo.

On modelling and analysis of voxel-based force prediction for a 3-axis CNC machining

ABSTRACT Determination of cutting forces is the main requirement for understanding the machining process and optimising its parameters for achieving higher productivity and surface finish. This paper presents an exploratory study and the development of a model to estimate cutting forces for a 3-axis CNC milling process using a voxel-based CAD model. The developed algorithm takes the NC code, workpiece/tool material properties, and the tool geometry data as inputs. The cutting tool engagement with the workpiece is computed using a discretized (voxelized) model. The calculated voxel engagement was finally used to calculate the cutting forces using the analytical method. The algorithm was implemented and tested for various case studies and the in-house experimental data for different types of end mill tools. Finally, the effect of variation in the size of the voxel and the number of flutes was studied. The model showed a good correlation and was found to be accurate (~80%) and robust.

Manufacturing System Design of a CNC Laser Engraver

This study aims to design manufacturing system of a CNC Laser Engraver Machine. The design starts from the laser module unit as input at the design stage of the 3-Axis CNC Machine to drive the laser. There are several important components in the production process of the CNC Laser Engraver machine, such as the Box Controller, the Laser Engraver Module unit, the Z-Axis unit, the X-Axis unit, and the Y-Axis unit. Bill of Material (BOM) design is very important to ensure the quantity and specification of materials, and the production of CNC Laser Engraver machines uses various types of production processes and ends with the assembly process. This CNC Laser Engraver machine was completed within 35 working hours, with a cost of Rp. 10,080,000,-.

On the milling strategy in machining curved surfaces based on minimum stress concentration by a 3-axis machining center

Three-axis computer numerical control machining centers are commonly used in machining due to their simple operations. When machining curved surfaces, the 3-axis CNC machining centers use interpolation line segment to fit the curved surfaces. The quality of the machined surface is affected by the length of the interpolation line segment. Sharp corners are formed at the junction of straight segments. The appearance of sharp corners will lead to increased stress concentration. To study the relationship between machined surface quality and interpolation straight line, this paper establishes the mathematical model of surface topography in ball-end milling multi-curved surfaces by a 3-axis milling center with considering the acceleration and deceleration controls. Based on the surface topography model, the stress concentration factor is analyzed in machining curved surfaces with different lengths of interpolation lines. The results show that the stress concentration factor decreases with the increase of the central angle when the length of interpolation lines and the radius of curvature are kept in constant, while decreases with the increase of the radius of curvature when the length of the interpolation lines and the central angle are held on. Moreover, the stress concentration factor increases as the length of the interpolation lines increases when the radius of curvature and the central angle are kept in constant. A method for selecting proper length of interpolation lines based on the stress concentration is proposed. In addition, the quality of the machined surfaces can be improved through the optimization of the tool path.

Design and Structure Analysis of a CNC Laser Engraver Machine

This study aims to design a CNC machine to perform the laser engraving process (called the CNC Laser Engraver Machine). The design stage starts from the laser module unit as an input at the design stage of the 3-Axis CNC Machine to drive the laser. The main geometry of the machine is designed referred to the laser position i.e. workspace and laser height with respect to the engraving table. Then the geometry of the Z-Axis unidirectional laser drive unit is determined to assist when adjusting the laser height of the engraving table. Then the geometry of the laser drive unit in the direction of X-Axis and Y-Axis is designed to move on the engraving area, and then the geometry of the engraving table is designed. After the design is complete, the design is validated by analyzing the structure of the machine based on the conditions and workload of the machine to obtain the appropriate dimensions and materials. The design and structure analysis of the CNC Laser Engraver Machine is carried out by using the CAD software. The design results of the CNC Laser Engraver Machine consist of 5 units i.e. Laser Engraver Module Unit, Z-Axis Unit, X-Axis Unit, Y-Axis Unit and Engraving Table Unit which are mounted with a bolt system. This CNC Laser Engraver machine designed has a workspace of 310 mm x 390 mm in the X-Y plane with the laser height in the Z-Axis direction can be adjusted 10 mm to 60 mm above the engraving table. The total dimensions of this CNC Laser Engraver Machine are 585 mm x 533 mm x 350 mm with a total weight about 22 kg.

Voxel-Based Adaptive Toolpath Planning using GPU for Freeform Surface Machining

Abstract Today freeform surfaces are widely used on products in automobile, aerospace, and die/molds industries, which are generally manufactured using multi-axis CNC machines. Frequent changes in the design of products necessitate creation of CNC part programs which need fast and accurate toolpath generation methods. Traditional toolpath generation methods involve complex computations and are unable to consider multiple surface patches together. The voxel-based CAD model provides the ability to represent the multi-patch surfaces in a discretized manner which can be processed using an advanced parallel computing framework for accurate tool path planning. This paper presents a new method to generate an adaptive Iso-planar toolpath for a 3-axis CNC machine using the voxel-based part model. The algorithm is designed to work on a Graphics Processing Unit (GPU) that allows parallel processing for faster toolpath generation. The proposed approach consists of two main steps, an algorithm to generate gouge free cutter location points from the voxel-based CAD model and an algorithm to find out sidestep and forward step from those cutter location points to create the final CNC tool path. A new image-processing technique has been proposed to identify gouge by detecting the shadow surface voxels and their intersection with the cutting tool. The developed system was extensively tested and compared with the various reported toolpath planning strategies for machining complex freeform surface parts. The results show that the developed method is computationally efficient, robust, and accurate in generating adaptive planar toolpath.

Development of CNC Milling Machine for Small Scale Industry

The development of small-scale industry (SME) has increased the demand of small-scale CNC machines since the implementation of machine in production of small-scale product shown a profitable economic value. The use of machines in the fabrication of small part has been proven to increase product production efficiency as well as reduce product costs. This is able to increase the business profits of small companies and push the business development to a higher level. The main purpose of this paper is to discuss the development of 3-axis CNC machines using integration between microcontroller as main controller and spindle drill. The main application of this built machine is to cut and carve low-hard materials such as wood and acrylic material. The design product to be fabricate is sent to the microcontroller through a serial communication system. The microcontroller will control the movement of the spindle drill according to the point coordinates to perform the desired engraving or cutting according to the desired design. Three tests to determine the quality of product production are carry out. The tests are surface section, circular test and axial perpendicular test which can determine the accuracy of cutting geometry such as position, straight, roll, tone, evaporate and perpendicular to the work section under certain tool grooves and feed rate. The results of tests carried out on the products produced by the 3-axis CNC machine developed showed that this machine has a cutting and engraving accuracy of 98.5% and a depth accuracy of 100% for wood and archival materials. This machine is suitable for carving 2D and 3D objects with a maximum size of 30 cm x 30 cm.

Mechanisms of a 3-axis CNC machine design and experiment

CNC technology has become a requirement in the industrial world without complying with educational, pedagogical and private ratings. Manufacturers of this type of machine are trying to conform with the marketing requirements in terms of quality, price and quantity, so the CNC machine can meet the requirements and has acquired a leading position. The study and design of the three-axis CNC machine are based on the Fusion 360 software for the design and PROTEUS software for simulation to perfect our device.

Generative design case study of a CNC machined nose landing gear for an unmanned aerial vehicle

Generative design is a design method inspired by nature’s evolution, pushing the limits of the industry to new design solutions. Using minimum input requirements, the resulting designs can be structurally adequate, weight-optimised and almost production-ready. The main purpose of this paper is to present the different approaches of the standard engineering design and the generative design methods. This is achieved through the case study of a nose landing gear for a prototype tactical unmanned aerial vehicle, intended for low volume production. The first part of the paper outlines the conceptual design of the nose landing gear. Subsequently, during the preliminary phase, the stress distribution along the different parts is calculated, based on the classic Strength of Materials theory and therefore a design solution is produced. In the second part, a generative design study is carried out with a commercially available tool, based on the conceptual parameters previously chosen. Both concepts are studied with industry-standard finite element analysis tools in order to validate, from a theoretical standpoint, the strength requirements according to the STANAG 4671 regulation. The final structure will be manufactured with 3-axis CNC machining, while providing about 36% weight reduction without compromising the structural functionality.

Selection of a workpiece clamping system for computer-aided subtractive manufacturing of geometrically complex medical models

Abstract Physical models of anatomical structures can be made using Additive Manufacturing (AM) or Subtractive Manufacturing (SM). The advantage of subtractive techniques over additive ones is the possibility of maintaining the homogeneity and consistency of the processed material, which is extremely important in the case of medical devices. Currently, a geometrically complex medical model can be made even on a simple, 3-axis CNC machine tool. However, often the semi-finished product must be machined in at least two clamping configurations. The aim of the work is to present the method of fixing a workpiece in the process of subtractive production of geometrically complex medical objects on the example of skull bone prostheses. The paper discusses the use of two clamping systems for machining such models. It presents the process of subtractive production of bone prostheses models fitted to the defect of the skull bone with the use of the proposed methods of fixing the workpiece. The result of the work are two models of the skull bone prosthesis. A more complex model was analysed in terms of the accuracy of geometry reproduction. The research confirmed the usefulness of the proposed clamping systems for the preparation of medical models of geometrically complex anatomical structures.

Voice Controlled Mini CNC Plotter

The (CNC) stands for Computer Numerical Control.It is an advanced technology that has automated many manufacturing applications concerning parts machining as well as other applications. This work presents the implementation of a low-cost desktop size 3-axis CNC machine. It has been built from free software and cheap components. It is able for light duty cutting, painting, carving, and drawing. The control system of the machine consists of a PC and a microcontroller running Grbl software, which is an open source free program. The PC has the task of loading files written in a special programming language for CNCs, which is called G-code. It sends the lines of this file to the microcontroller, which parses the code, interpolates the motion commands, and drives the stepper motors of the machine. The system is built and tested experimentally to prove its operation, robustness, and accuracy. Also this paper presents techniques for speech-to-text and speech-to-speech automatic summarization based on speech unit extraction and concatenation. For the latter case, sentences, words, and between-filler units are investigated as units to be extracted from original speech. These methods are applied to the summarization of unrestricted-domain spontaneous presentations and evaluated by objective and subjective measures. It was confirmed that proposed methods are effective in spontaneous speech summarization.

Optimization of CNC technology in the manufacturing process of an artistic product

The work analyses the optimisation of the manufacturing process of an artistic wooden product (mirror frame) with a 3-axis CNC machine. The 3D model was first made in ArtCAM, from where the STL file was later uploaded to SolidWorks. The parameters for the HSR (high-speed roughing), and HSM (high-speed machining) operations were determined in SolidCAM. The findings show that a combination of operations from HSR and HSM are the best choice, considering the shape of the model and the capabilities of the machine, as the best ratio between the quality of the surface and the time needed for the operation is provided by these. Operations differ with regard to the tool path and parameters that can be adjusted. The operations were compared and the best results are achieved when the HSR operations “Contour Roughing” and then “Rest Roughing” are used and when the HSM operation “3D Constant Step Over” is used, where the machining time amounted 4 hours and 1 minute. Finally the G code was made for our product.

RETRACTED] A Study on the Effect of Tool-Path Strategy When Machining a Saddle-Free Surface in 3-Axis CNC Machine

==========================================================Available online: 31 December 2020This article has been retracted by International Journal on Advanced Science, Engineering and Information Technology Editorial team, following clear correspondence and confirmation with authors.The paper is retracted from 29 November 2021.==========================================================The development of the CNC machine and its advantages led to the constantly developing fields for this system, which are CAD (Computer-Aided Design) and CAM (Computer-Aided Manufacturing). However, surface issues were rarely mentioned in these studies, but mainly on tool path calculations or cutting modes. Reasonable selection of cutting tools, optimal tooling strategy for surfaces, and cutting mode parameters impact productivity and form quality of details containing complex surfaces. This study evaluates free surface based on Gaussian curvature and mean curvature, thereby providing a suitable instrument selection for the evaluated free surface areas. In this paper, the authors analyze and select tools and tool paths when machining freedom faces on 3-axis CNC machines to satisfy surface shaping accuracy requirements and reduce machining time related to the traditional freedom-face machining method. Before doing experimental research, the authors designed experimental samples on CATIA V5R20, simulating the machining process to verify the theoretical calculation. Empirical models for machining on 3-axis CNC milling machines were built and measured the parameters on 3-coordinate measuring machines to evaluate the effect of tool selection and tool paths in the machining of freedom surface areas. Experimental results show that the tool path when machining freedom surfaces dramatically affects the quality of freedom surface shaping. Moreover, the experimental results also show that when processing saddle-face samples, the one direction tooling path should be selected.

VDAC

We introduce carvable volume decomposition for efficient 3-axis CNC machining of 3D freeform objects, where our goal is to develop a fully automatic method to jointly optimize setup and path planning. We formulate our joint optimization as a volume decomposition problem which prioritizes minimizing the number of setup directions while striving for a minimum number of continuously carvable volumes, where a 3D volume is continuously carvable, or simply carvable, if it can be carved with the machine cutter traversing a single continuous path. Geometrically, carvability combines visibility and monotonicity and presents a new shape property which had not been studied before. Given a target 3D shape and the initial material block, our algorithm first finds the minimum number of carving directions by solving a set cover problem. Specifically, we analyze cutter accessibility and select the carving directions based on an assessment of how likely they would lead to a small carvable volume decomposition. Next, to obtain a minimum decomposition based on the selected carving directions efficiently, we narrow down the solution search by focusing on a special kind of points in the residual volume, single access or SA points, which are points that can be accessed from one and only one of the selected carving directions. Candidate carvable volumes are grown starting from the SA points. Finally, we devise an energy term to evaluate the carvable volumes and their combinations, leading to the final decomposition. We demonstrate the performance of our decomposition algorithm on a variety of 2D and 3D examples and evaluate it against the ground truth, where possible, and solutions provided by human experts. Physically machined models are produced where each carvable volume is continuously carved following a connected Fermat spiral toolpath.

Configuring of 3-axis vertical CNC Machine for Rapid Prototyping with two Translatory and one Rotary Axes

This paper describes the configuration of a 3-axis vertical CNC machine tool for rapid prototyping with one rotary and two translational axes. The machine works in a polar-cylindrical coordinate system. The structure of the machine is C’OXZ. The virtual machine model is configured in the PTC Creo software environment. After configuring the virtual machine, the simulation of the CLFbased was performed in the mentioned software environments, and then the verification according to the G-code program in the Vericut software environment was performed. Programming and control of the configured prototype machine are realized in the LinuxCNC software environment, which is based on the PC platform. Also, in this paper, digital twin of machine realized in a python software environment is shown. The presented results show the proper functioning of the whole system.

Automatic minimal partitioning method guaranteeing machining efficiency of free-form surfaces using a toroidal tool

Toolpath planning to machine free-form surfaces on a 3-axis CNC machine remains a complex issue. Research work has proven the relative effectiveness of toroidal tools in material removal rates as compared with spherical tools. However, this efficiency has only been confirmed and maximised for a specific feed direction, i.e. the one with the steepest slope. Since the optimal direction for the use of toroidal tools varies on the surface to be machined, more recent works have proposed surface partitioning methods where the surface to be machined is divided into zones, each machined in an optimal direction. The planning of machining toolpaths for free-form surfaces nowadays involves choosing the number of zones when cutting the surface to be machined: too coarse a partitioning will not guarantee the efficiency of using a toroidal tool, while too fine a partitioning will lead to increased travel times between the zones and frequent changes in direction, impairing productivity. The present article therefore proposes a minimum partitioning method for free-form surfaces guaranteeing the efficiency of a toroidal tool. A first section recalls the state of the art in the matter and the issues involved. The next section introduces the parameters needed to define a strategy. In the third section, an efficiency coefficient to quantify the benefits of using a toroidal tool is introduced. The fourth section describes a surface cutting strategy to ensure the efficiency of the tool at any point machined. The fifth section is dedicated to validating the results on machined and simulated parts in different configurations. Analysis of the results confirms the benefits of this new method.

Tool path generation for a car rear door die: UMO versus rest milling tool paths

Tool path generation for sculptured surfaces that contain many concave and convex features involves gouging and undercut problems. Past research has paid little attention to tool path generation for hard materials, which require careful and precise planning. In this paper, a comparison is made between traditional unit machining operation (UMO) and rest milling-based tool paths for the various machining steps (roughing, semi-finishing and finishing) of a car’s rear door, designed by NURBS surfaces. The experimental work involves the machining of two dies in a 3-axis CNC machine. Each die comprises two parts: punch (convex) and die (concave). Various tool path patterns (contour, zig-zag, zig, concentric zig-zag) are generated and compared via NX8 software. The results show a great saving of time and less tool consumption by using a rest milling technique over UMO techniques.