CNC Machining Center Research Articles

The Analysis and Compensation Experiment of Linear Feed Axis Positioning Error Based on Matrix Operation

The positioning accuracy of the linear feed axis is a key factor affecting the machining accuracy of CNC machine tools. The generation process of the positioning error of the linear feed axis is expounded. The Z axis of the vertical linear feed axis of the machining center is the research object, the positioning error analytical matrix is established, and the positioning error calculation of the Z axis of the vertical linear feed axis is completed based on the principle of solving the inhomogeneous linear equation. The positioning error detection of the vertical linear feed axis Z axis of the CNC machining center is carried out. Based on the characteristics of the error detection data, an error compensation model is constructed. , the variance of the positioning error detection point after compensation is reduced to 1.562, which meets the needs of precision machining.

Application of PCA-LSTM algorithm in predicting component faults in CNC machining centers

Abstract In order to further explore the relationship between component failures and CNC machining center failures, a method of predicting component failures in advance was proposed to reduce the likelihood of machining center failures and improve CNC machining efficiency. In this paper, the principal component analysis method is used to optimize the Long short-term memory neural network to build a network model to study and predict the fault status of NC machining center components in work. The use of Principal Component Analysis (PCA) to extract the main features of machine tool faults can improve the speed of iterative training networks during the machining process and reduce the input dimension and prediction difficulty of LSTM. The extracted data is used as input for the LSTM network. The fault type is output. The comparison of diagnostic results between PCA-LSTM, LSTM, and BP neural networks shows that PCA-LSTM is a high-precision prediction model. The root mean square difference is reduced to 1.572. The predicted error results can effectively reflect the changes that occur in the machining center components with the occurrence of faults. It can be seen that it is feasible to use PCA-LSTM as a tool for predicting the faults of CNC machining center components.

Influence of HSS drill coatings on surface finish and cylindricity of AA6061/C/ZrO2 composite in CNC drilling operations under dry conditions

Abstract This study aims to evaluate the effect of HSS drill tool coatings, namely single-layer TiN, single-layer AlCrN, and double-layer AlTiN + TiSiXN (Durana), on the surface roughness and cylindricity of AA6061 (90 wt%)/C (5 wt%)/ZrO2 (5 wt%) hybrid composite material processed by the stir casting method. The fabricated sample was examined for the uniform particle distribution of reinforcements using Scanning Electron Microscope. The drilling operation was carried out on the fabricated in a CNC machining center by setting the spindle speeds of 800, 1200, and 1600 rpm, depths of cut of 0.5, 1, and 1.5 mm, and feeds of 50, 100, and 150 mm/rev. An orthogonal array (L27) designed by Taguchi’s method was used as the design of the experiment for the optimization of the best cutting parameters and coating. Surface roughness and cylindricity errors were determined for the 27 experimental runs. Field emission scanning electron microscopic (FESEM) examination and Energy Dispersive Spectroscopy (EDS) were used to analyze the surface integrity and elemental composition, respectively. The results revealed that Durana had a significant effect on the surface substrate with minimum surface roughness (Ra) of 1.666 μm and obtained the minimum cylindricity error for the parameters of depth of cut 0.5 mm, spindle speed of 1200 and feed of 100 mm rev−1.

Production scheduling decision-making technology for multiple CNC machining centers with constraints on serviceable time

Production scheduling decision-making technology for multiple CNC machining centers with constraints on serviceable time

Comparative Study of Conventional Machine Learning versus Deep Learning-Based Approaches for Tool Condition Assessments in Milling Processes

This evaluation of deep learning and traditional machine learning methods for tool state recognition in milling processes aims to automate furniture manufacturing. It compares the performance of long short-term memory (LSTM) networks, support vector machines (SVMs), and boosting ensemble decision trees, utilizing sensor data from a CNC machining center. These methods focus on the challenges and importance of feature selection, data preprocessing, and the application of tailored machine learning models to specific industrial tasks. Results show that SVM, with an accuracy of 96%, excels in handling high-dimensional data and robust feature extraction. In contrast, LSTM, which is appropriate for sequential data, is constrained by limited training data and the absence of pre-trained networks. Boosting ensemble decision trees also demonstrate efficacy in reducing model bias and variance. Conclusively, selecting an optimal machine learning strategy is crucial, depending on task complexity and data characteristics, highlighting the need for further research into domain-specific models to improve performance in industrial settings.

Influence of Machining Parameters on the Dimensional Accuracy of Drilled Holes in Engineering Plastics.

This paper explores the interaction between cutting parameters and the geometric accuracy of machined holes in a variety of engineering plastics, with the aim of improving manufacturing processes in the plastic processing industry. In the context of fast and precise manufacturing technology, the accuracy of drilled holes in polymers is of paramount importance, given their essential role in the assembly and functionality of finished parts. The objective of this research was to determine the influence of cutting speed and feed rate on the diameter and cylindricity of machined holes in six diverse types of plastics using a multilevel factorial design for analysis. The key message conveyed to the reader highlights that careful selection of cutting parameters is crucial to achieving high standards of accuracy and repeatability in plastic processing. The methodology involved structured experiments, looking at the effect of changing cutting parameters on a set of six polymer materials. A CNC machining center for drills and high-precision measuring machines were used to evaluate the diameter and cylindricity of the holes. The results of ANOVA statistical analysis showed a significant correlation between cutting parameters and hole sizes for some materials, while for others the relationship was less evident. The conclusions drawn highlight the importance of optimizing cutting speed and feed rate according to polymer type to maximize accuracy and minimize deviations from cylindricity. It was also observed that, under selected processing conditions, high- and medium-density polyurethane showed the best results in terms of accuracy and cylindricity, suggesting potential optimized directions for specific industrial applications.

Digital mapping of machine tool's volumetric and tracking errors left on the five axis tool paths

Five-axis contouring errors left on the parts contributed by feed drive servos, and intra- and inter-axis geometric errors are predicted along the five-axis tool paths. Quasi-static geometric errors are measured and modeled in the machine's workspace. Servo tracking errors of the three translational and two rotary drives are measured during machining or predicted from the CNC model. All errors are projected to the tooltip using a generalized screw theory-based forward kinematic model. The proposed model is validated experimentally on a CNC machining center for two test parts.

Health Monitoring System for CNC Machine

This paper introduces a novel Health Monitoring System (HMS) tailored for CNC machines, addressing the critical need for maintaining their optimal performance and preventing unexpected breakdowns in modern manufacturing settings. The system integrates various sensors and data acquisition methods to continuously monitor key parameters like temperature, vibration, and tool wear. By employing advanced data analytics and machine learning algorithms, the HMS can swiftly identify anomalies in real-time, facilitating proactive maintenance and minimizing operational downtime. Additionally, the system features a user- friendly interface for visualizing machine health status and creating predictive maintenance schedules. Experimental validation conducted on a CNC machining center validates the efficacy and reliability of the developed HMS in enhancing machine efficiency, prolonging equipment lifespan, and curbing maintenance expenses. In summary, this Health Monitoring System offers a robust solution for ensuring the seamless operation and longevity of CNC machines in modern manufacturing environments.

Design and optimization of high-precision servo control system in precision positioning technology

Abstract High-precision control technology, as a general technology in the field of manufacturing and assembly, is widely used in high-end manufacturing equipment such as chip packaging equipment and high-speed CNC machining centers. In this thesis, a permanent magnet synchronous motor is used as the actuator motor of a high-precision servo control system, and vector control strategy and sliding mode observer are adopted to study and realize the servo control of permanent magnet synchronous motor based on sliding mode observer. The current, speed, and position simulation experiments of the high-precision servo control method are also carried out to compare the positioning accuracy before and after the use of the servo control method and to study the performance of the method in precision positioning. The experiments prove the correctness and effectiveness of the SMO-based PMSM high-precision servo control method and the current response speed of the servo control in this paper is fast, and the speed and position estimation errors are maintained within 1.6 r/min and 0.15 rad in steady state condition, and within 20 r/min and 20 rad in the sudden-change condition, which is able to contribute to 11.91% and 19.30% of the machine’s X-axis and Y-axis positioning accuracy improvement. The SMO-based PMSM high-precision servo control method has high steady-state accuracy and immunity to disturbances and can be used for the precision positioning of machine systems.

Rapid detection of glycosylated hemoglobin levels by a microchip liquid chromatography system in gradient elution mode

BackgroundThe determination of glycosylated hemoglobin (HbA1c) is crucial for diabetes diagnosis and can provide more substantial results than the simple measurement of glycemia. While there is a lack of simple methods for the determination of HbA1c using a point-of-care test (POCT) compared to glycemia measurement. In particular, high-performance liquid chromatography (HPLC) is considered the current gold standard for determining HbA1c levels. However, commercial HPLC systems usually have some sort of disadvantages such as bulky size, high-cost and need for qualified operators. Therefore, there is an urgent demand to develop a portable, and fast HbA1c detection system consuming fewer reagents. ResultsWe present a novel microchip that integrates a micromixer, passive injector, packed column and detection cell. The integrated microchip, in which all the microstructures were formed in the CNC machining center through micro-milling, is small in size (30 mm × 70 mm × 10 mm), and can withstand 1600 psi of liquid pressure. The integrated design is beneficial to reduce the band broadening caused by dead volume. Based on the microchip, a microchip liquid chromatography (LC) system was built and applied to the analysis of HbA1c. The separation conditions of HbA1c in blood calibrator samples were optimized using the microchip LC system. Samples containing four levels of HbA1c were completely separated within 2 min in optimal gradient conditions, with an inaccuracy (<3.2 %), a coefficient of variation (c.v. < 2.1 %) and a correlation coefficient (R2 = 0.993), indicating excellent separation efficiency and reproducibility. SignificanceThe POCT of HbA1c is critical for diabetes diagnosis. The microchip chromatography system was developed for HbA1c determination, which contains an integrated microchip and works under a gradient elution. It surpasses existing chip technology in terms of separation performance and detection speed, providing a competitive advantage for POCT of HbA1c. It is considered one important step for realizing efficient portable systems for timely and accurate diabetes diagnosis.

Identifikasi Aliran Energi Listrik pada Mesin CNC Machining Center

&lt;p&gt;&lt;em&gt;CNC machine tools have been widely used in the process and manufacturing industries, which have the potential to increase the intensity of electrical energy consumption so that energy efficiency is needed. Energy efficiency is a necessity for the sustainability of the process and manufacturing industrial sector which will be related to energy costs and environmental factors. In order to carry out energy efficiency, it is necessary to identify the consumption of electrical energy by tracing and mapping the electrical energy flow to the components in a CNC machining center machine, so opportunities for energy savings can be known. This research was conducted by collecting data by monitoring energy consumption in stand-by, setting and cutting machine conditions. Cutting tests are carried out to determine the energy consumption of each machine component that affects energy use. After that it can be seen the energy flow pattern by classifying the energy user components into primary and secondary components. Based on the analysis of electrical energy consumption data during the cutting process, it is known that the significat energy users are the spindle motor, the axis feed motor (X, Y, Z) and the coolant motor.&lt;/em&gt;&lt;/p&gt;

Design and comparison of a suitable dust separation technique during the machining process in a CNC machining center

Design and comparison of a suitable separation technique during the machining process in a CNC machining center. The paper deals with the issue of chip extraction from the milling process in a CNC machining center. The paper aimed to compare the particle size distribution of dust generated in the milling process of natural wood (beech, oak, and spruce) and MDF on a 5-axis CNC machining center. The particle size distribution was evaluated using sieve analysis of samples from the total weight of the captured dust. The results showed that the processing of natural wood is mainly characterized by the formation of coarse dust fractions (2 mm - 1 mm sieves), while the processing of MDF was associated with the formation of fine dust fractions with a size below 100 μm. Another of the objectives was to compare the separation values on the fractional separation curves of selected mechanical separators and filters with the size distribution of dust particles and to propose a suitable separation technique that meets the criteria of "best available technique" (BAT) in the processing of natural wood and MDF, as well as to point out the creation of and the production of harmful dust fractions, which arise mainly during the processing of MDF. We intended to assess whether the introduction of the given technology with the given material mix will also require modifications on the side of the extraction device.

Теоретическое исследование кривизны обработанной поверхности при косоугольном фрезеровании сборными фрезами

Introduction. The paper discusses the methods of processing large parts having curved convex surfaces with a rectilinear guide on multi-coordinate CNC machining centers using the touch method with a discrete motion of the tool feed along the profile of the part. It is shown that the main disadvantages of this method are lower productivity, which is due to the presence of discrete tool motions between cycles of its translation mode, where the value of discrete tool motion for a given processing accuracy depends on the curvature of the surface being processed. To improve processing performance, it is proposed to use prefabricated disc cutters equipped with replaceable polyhedral inserts (RPI) with rectilinear cutting edges. Its installation in the cutter body with non-zero angles of inclination of the main cutting edge, in combination with an additional rotation of the cutter, during processing, along the direction of the translational feed movement, allows you to obtain a concave surface and ensure a tighter fit of the producing surface of the tool and the machined surface of the part. The aim of the work is to reduce the error of approximation of the profile when it is processed using the touch method with discrete motion of prefabricated disc cutters along the profile and, consequently, to ensure workpiece the possibility of increasing the step of tool movement along the profile being formed to improve processing performance. Research methods: geometrical theory of designing metal-cutting tools. Results and discussion. The regularities established in the work made it possible to create a method for determining the angle of inclination of the main cutting edge of the RPI milling cutter and the angles of rotation of the milling cutter along the direction of translational feed movement during line-by-line processing of extended sections of parts with a curved profile on multi-coordinate CNC machines by turning the milling cutter to ensure the best fit of its producing surface to the surface being processed at the point of its contact, to reduce the approximation error processed profile and improve processing performance, due to the possibility of increasing the tool movement step.

The Application of Additive Composites Technologies for Clamping and Manipulation Devices in the Production Process.

Additive technologies have been widely adopted in various industries. The choice of additive technology and material directly affects the functionality of the manufactured components. The development of materials with better mechanical properties has led to a growing interest in replacing traditional metal components with those manufactured using additive technologies. The application of Onyx as a material comes into consideration, which contains short carbon fibers to increase the mechanical properties. This study aims to experimentally verify the viability of substituting metal gripping elements with nylon and composite materials. The design of the jaws was customized to meet the requirements of a three-jaw chuck of a CNC machining center. The evaluation process involved monitoring the functionality and deformation effects on the clamped PTFE polymer material. When the metal jaws were applied, significant deformation of the clamped material occurred, which varied with the clamping pressure. This deformation was evidenced by the formation of spreading cracks on the clamped material and permanent shape changes in the tested material. Conversely, nylon and composite jaws manufactured using additive technology demonstrated functionality across all tested clamping pressures, without causing permanent deformation of the clamped material, unlike the traditional metal jaws. The results of this study confirm the applicability of the Onyx material and provide practical evidence of the potential for reducing deformation caused by clamping mechanisms.

Використання систем автоматизованого проектування для підвищення точності механічної обробки

The subject of the study is methods and means of determining the influence of the trajectory of the tool on the foreground of the volume of complex parts. The aim is to improve the quality and accuracy of the production of composite profile parts after machining at CNC machining centers, by using the optimal machining strategy. Task: to analyze existing methods of processing complex profile parts at CNC processing centers and justify the choice of the optimal strategy for the side of the surface of the part. The methods used are: methods of controlling the accuracy of processing complex surfaces, graphical methods of forming the trajectory of the tool, and mechanical methods of measuring geometric dimensions. The results obtained are as follows. To achieve this goal, an analysis of existing methods and strategies for processing surfaces of a complex profile was carried out and the existing experience in the development of control programs was adapted using automated methods with the application of CAD/CAM systems. As a result, SolidWorks was chosen as the primary modeling tool for creating a part with a complex profile. The tool path is created using the SolidCAM CAM system, which supports various strategies for processing such elements. Using the developed control programs based on the methods of linear trajectory, bitmap trajectory, spiral trajectory, and waterline trajectory, experimental analysis of the influence of the tool trajectory on the accuracy of processing surfaces located at different angles to the processing axis was carried out. Deviations of geometrical dimensions of parts obtained in re-treatment by programs formed using different methods from the real values of model characteristics are evaluated. Conclusions. Based on the analysis of the strategies for processing parts of a complex profile, the optimal trajectories of the tool are determined for parts with surfaces such as at a low angle, at a high angle, radius surface, and joints between surfaces. The results of experimental studies in further shaping of folding parts when they are prepared on CNC machine with the choice of the optimal trajectory of the movement of the tool. The choice of the optimal trajectory of the processing of parts allows to increase the accuracy of the processing in finishing operations.

Chip grain size from the process of machining steamed and unsteamed alder wood on a cnc machining center and assessment of separation results

The paper discusses the particle size of the chips formed in the process of machining unsteamed and steamed alder wood on a CNC machining center. From the granulometric analysis of the chips, it follows that the average share of the coarse fraction of the chips created from unsteamed alder wood is 66.0% and steamed alder wood is 62.9%. The representation of medium-coarse fractions of alder wood with dimensions of 1.0-0.125 μm in unsteamed wood is 29.5% and steamed by 32.7%. Dust fractions with dimensions below 125 μm in unsteamed alder wood account for 4.5% and in steamed alder wood 4.4%. Chips of non-steamed or steamed alder wood with dimensions below 32 μm were not measured, so it can be concluded that no respirable dust particles with dimensions below &lt; 10 μm are formed. Changes in the physical and mechanical properties of steamed alder wood are manifested by a decrease in the coarse fraction above 2 mm and an increase in the fraction of chips 0.125 to 2000 μm. For the separation of chips, both unsteamed and steamed alder wood, from the transport air, fabric filters and filter fabric Finet PES 4 are suitable, the separation limit of which is smaller than the size of the smallest chips formed in the milling process: aMO = 7 m &lt;&lt;&lt; amin = 32 m.

In-situ characterization method for tool ultrasonic vibration in rotary ultrasonic machining based on radiated acoustic pressure

In order to be used in the CNC machining center, one rotary ultrasonic machining (RUM) system needs to adapt to various cutting tools. Corresponding ultrasonic vibration units are often designed to work in a local resonant state rather than a full resonant state due to the diversity and complexity of tool shapes. Since the frequency at which the vibration of various cutting tools reaches the maximum is probably different, it is necessary and important to in-situ determine the working frequency of cutting tools in RUM. The key to determining working frequency is to characterize the tool vibration. Although the existing optical and electrical methods have been widely used for tool vibration characterization in some scenarios, they still have obvious limitations when applied to in-situ characterization in RUM systems. In this context, an in-situ characterization method for the tool ultrasonic vibration based on radiated acoustic pressure is presented in the paper. Firstly, characteristics of acoustic pressure distributions radiated from typical cutting tools in RUM are comprehensively studied based on analytical analysis, numerical simulation, and experimental measurement. Secondly, based on the relationship between the acoustic pressure and tool vibration, the measurement strategy and corresponding in-situ measurement system for acoustic pressure are developed to characterize the tool vibration in RUM. Finally, a series of experiments are conducted by using the measurement system, including determining the working frequency of cutting tools and quantitatively describing the vibration amplitude in RUM. It is shown that the proposed method is efficient and cost-effective for the in-situ characterization of the ultrasonic vibration of various cutting tools in RUM, especially for complexly shaped tools working in a local resonant state.

Advisability-Selected Parameters of Woodworking with a CNC Machine as a Tool for Adaptive Control of the Cutting Process

The operation of CNC machining centers, despite their technological progress, can still be affected by undesirable events associated with the technological parameters of their operation. The minimization of these risks can be achieved via their adaptive control in the process of operation. Several input parameters for adaptive control are still the subject of research. The work aimed to find out the influence of the change in feed speed, revolutions, and radial depth of cut on the noise and temperature of the tool during the milling of wood-based composite material particleboard. At the same time, it was evaluated whether it is possible to use the measured values of these parameters in the future in the process of an adaptive control of the CNC machine with the minimization of their negative influence. The methods of measuring these parameters were chosen based on valid legislation and previous research. The results of the research show that all parameters influence both the noise and temperature of the tool, while the rate of the radial depth of cut has the greatest influence on the increase in temperature, and the noise is most affected by the revolutions. The effect of temperature during woodworking can also be characterized in terms of the potential long-term wear of the cutting tool. The setting of optimization algorithms of monitored parameters in the adaptive control of the CNC machining center will be the subject of further research.

Reduction in the Volumetric Wear of a Ball Polishing Tool Using Ultrasonic-Vibration-Assisted Polishing Process

Ultraprecision freeform polishing using a bonnet or a felt ball mounted on a polishing head plays an important role in the mold and lens production industries. The volumetric wear of a bonnet or a felt polishing ball is still a problem to be solved. The objective of this study was to develop an ultrasonic-vibration-assisted ball polishing process on a CNC machining center to improve the surface roughness of a STAVAX mold steel and to reduce the volumetric wear of the polishing ball. The optimal combination of the ultrasonic-vibration-assisted ball polishing parameters for a plane surface was determined by conducting the Taguchi L18 matrix experiments, ANOVA analysis, and verification experiments. The surface roughness of the polished specimens was improved from the burnished surface roughness of Ra 0.122 μm to Ra 0.022 μm. In applying the optimal plane surface ball burnishing and vibration-assisted spherical polishing parameters sequentially to a fine-milled and burnished aspherical lens surface carrier on a five-axis machining center, the surface roughness of Ra 0.014 μm was obtainable. The improvement in the volumetric wear of the polishing ball was about 62% using the vibration-assisted polishing process compared with the nonvibrated polishing process.

Seven facts about machining centers

Milling, turning and drilling are used to transform a metal block into a complex shape. Automated CNC machining centers are frequently used for this kind of workpiece processing. But what are they actually?