CNC System Research Articles

DESIGN AND IMPLIMENTATION OF A MECHATRONIC SYSTEM NAMELY SEAT CHECK MODULE WITH APPLICATION TO CNC SYSTEM: A REVIEW

In this study an effective method has been developed to automate a process implemented in manufacturing industry "CNC system", it details the research and development of a mechatronic system to overcome one of the most difficult tasks in today's manufacturing industry which is to reduce number of rejected parts of NG parts. This problem mainly occurs when the metal workpiece is disturbed or not properly attached to the fixture and due to that small change in location, it gets improperly machined, which leads to part getting rejected. A gap inspection sensor is included in the design to confirm that the workpiece is properly seated on the fixture and all the components needed for module assembly are designed and tested on a VMC machine. As the gap check sensor uses the principle of back pressure sensing to monitor the gap or distance, the sensor is supplied with pneumatic pressure through a regulator to ensure stabilized input, and outlet of sensor is connected to the orifices on the fixture plate under clamping points, so when the job is placed properly there is no air leakage and the change in pressure will respond to sensor. The developed module gets linked to PLC and needed changes were also made in ladder logic program to incorporate the new module in machine running cycle. This developed architecture is flexible and can be used on many other machines and applications. Doing so automates the machine and prevents potential tool damage and material wastage. Keywords - Mechatronic System, Sensor, Automation, Back pressure Sensing, CNC Programming, PLC program (Ladder Logic), Precision manufacturing

Research on tool presetting and tool deviation in CNC lead screw grinding process

In CNC lead screw grinding, grinding allowance of screw groove is small. Tool deviation may lead to one side of the screw groove heavily grinded, while the other side of that not grinded or grinded not enough. Though the grinding wheel is right in the middle of the screw groove in the process of tool presetting for CNC lead screw grinding, tool deviation typically occurs in the subsequent grinding process. More specifically, the grinding wheel slightly deviates from the middle of the screw groove to the left or right of the screw groove.In this work, the cause of tool deviation is analyzed as follows: the mutual following error of Z-axis and A-axis due to the differences between the mechanical and electrical characteristics. A method and formulas to address the tool deviation are proposed: The coordinates of A-axis and Z-axis in the grinding process are measured and recorded by the CNC system; then, the value of tool deviation caused by the mutual following error of Z-axis and A-axis is calculated. As a result, the grinding start position and the grinding end position are adjusted according to the tool deviation in the subsequent grinding process, so as to address the tool deviation issue.

A spatial grid point compensation method for a one-translational two-rotational power head

Positioning accuracy is an important index used to indicate the accuracy of the moving parts in a machine tool under the control of CNC system. In order to improve positioning accuracy, error compensation is needed. Existing error compensation methods include model compensation and non-model compensation. However, due to the simplification of the error mapping model, some error parameters cannot be mapped to the model, so only part of the error parameters can be modified, and the compensation result is not ideal. In the present work, based on the thinking method of finite element, a non-model compensation method is used to compensate for the geometric error of a one-translational two-rotational (1T2R) power head (which is independently developed by Tianjin University). First, the pose error prediction model will be established, and the error of any point in the workspace can be predicted. The input correction method is then proposed to compensate for the pose error. Finally, both the proposed error prediction model and error compensation method are verified by simulation and experiment, and the results show that the proposed method can reduce the error of this 1T2R power head.

Local smoothing of the piecewise linear tool path in a CNC system for high-speed machining

The basic algorithms of trajectory smoothing in control systems of machine tools and industrial robots in the case of linear-piece trajectory assignment are considered. The method of local contour smoothing by cubic B-spline in three-axis interpolation, which together with the algorithm of quasi-optimal feed planning with jerk limiting allowed to signifi cantly increase the machining productivity, is discussed in detail. The insertion of splines takes into account userdefi ned geometric constraints and converts the original trajectory into a composite curve that has geometric continuity G2, providing continuity of accelerations for each link of the machine. The defi nition of geometric continuity G1 and G2 is discussed, and its effect on the quality of the machined surface.

Расчет температур при чистовом фрезеровании жаропрочного сплава марки ХН56ВМКЮ-ВД

Introduction. One of the most important tasks in cutting metals and alloys is the control of the temperature factor, since temperature is one of the limitations in determining cutting conditions. This approach makes it possible to determine rational (in some cases, optimal) milling modes. Experimental methods for determining the temperature are labor-consuming, costly and not always available. The labor-consuming nature lies in the need for constant adjustment of experimental equipment due to changing cutting conditions, electrical insulation of the tool and workpiece, the appearance of parasitic electrical micro-voltage (if we are talking about temperature measurement methods with thermocouples), constant calibration of instruments and selection of thermal radiation coefficients (if we are talking about non-contact measurement methods). In this regard, there is a need for a theoretical determination of temperatures during milling with minimal use of experimental data. The purpose of the work: to develop a method for theoretical calculation of temperature during milling (cutting) of nickel-based heat-resistant materials on the example of 56% Ni -Cr-W Mo-Co-Al alloy (56% Ni, 0.1% C, 10% Cr, 6.5% W, 6% Al, 6.5% Mo, 0.6% Si, 13 % Co, 1% Fe). Research methodology. To determine theoretically the cutting temperatures, a mathematical model is formed that takes into account the mechanical and thermophysical properties of the material being processed and its change depending on the temperature variations during milling, the geometry of the cutting tool and the features of the schematization of the milling process. The experimental part of the study is carried out on a console milling machine KFPE-250 with a CNC system Mayak-610. The 56% Ni -Cr-W Mo-Co-Al material is processed with a Seco JS513050D2C.0Z3-NXT cutter with different speeds and feeds. The temperature is measured using a Fluke Ti400 thermal imager. Results and discussion. A theoretical model for calculating the temperature (for the group of 77% Ni - Cr - Ti - Al - B, 66% Ni - Cr - Mo - W - Ti - Al, 73% Ni-Cr-Mo-Nb-Ti-Al and 56% Ni -Cr-W Mo-Co-Al alloys) during milling of heat-resistant nickel-based alloys is developed, which makes it possible to predict the temperature value at the face and flank of the tool when changing cutting conditions (speed, feed, depth, cutting tool geometry), as well as the cutting temperature. An analysis of the experimental and theoretically predicted values of the cutting temperature showed a satisfactory agreement between the corresponding values.

Modeling and Simulation of the NC Feed System based on MATLAB / Simulink

Feed servo system often adopts the CNC system with the digital controller as the core. In such a computer control system, it involves both continuous signal processing and digital signal processing.The numerical control machine tool feed sampling control system is a more complex electromechanical control system, and has nonlinear characteristics, the mathematical model established is a higher-order model, through the simplified transfer to the second-order system model, to facilitate computer simulation operation, so that the numerical control machine tool static performance and dynamic performance parameters to meet the design requirements.

Improving the Efficiency of Machine Grinding of Double Curvature Surfaces with a Profiled Flap Wheel

To obtain the desired shape of long panels and sheaths in the aircraft industry, the technology of shot peen forming with subsequent grinding with flap wheels is successfully used. To implement this technology, a special UDF-4 (shot peen forming equipment of the 4th version of modernization) device was designed and manufactured. The last version of this device is equipped with a CNC system and a revolver head with the 4-flap wheels for optimizing the grinding operation. The ability to select the desired flap wheel during the grinding process, depending on the curvature and width of panels or sheaths, has significantly expanded the technological capabilities of this equipment. During grinding with flap wheels of a rectilinear profile, to ensure uniform removal along the cross-section of the part’s curvilinear contour, it is necessary to carry out processing with overlapping previous passages. The need for overlapping passages significantly increases the processing time. At the same time, the calculation of the overlapping width during the changing curvature of the part’s profile is quite a difficult task. This paper presents analytical studies of the use of profiled flap wheels for grinding the part’s surface with a variable radius of transverse curvature, and also proposed the mathematical models for selecting the necessary profiled flap wheels depending on the curvature of the part’s processing surface.

A novel integration between service-oriented IoT-based monitoring with open architecture of CNC system monitoring

Smart factories are focusing on bridging the gap between physical and cyber-physical systems through software applications. This article proposed an efficient and sufficient data acquisition, storing and processing real-time monitoring information, response, and feedback in milling process monitoring. A methodology to enable integration between service-oriented IoT-based monitoring with interpreted information for open architecture CNC system was presented. The proposed system comprises four main layers: the perception layer, communication layer, application layer, and CNC machine. The developed system was validated through two case studies. First, the developed system successfully enabled data flow through the validation, from CNC machine back to CNC machine. Secondly, the reading of temperature, vibration, and electric current monitoring is higher for the worn cutting tool than the new cutting tool. Third, the percentage difference between new and worn cutting tools for temperature monitoring is up to 3.38%, and for vibration monitoring, it is up to 78.93%. Fourth, the electric current reading is proportional to cutting force as the reading of electric current on cutting insert is higher than reading before cutting tool insert with percentage differences more than 8.33% up to 20%. Based on the findings, it was summarized that the developed integrated monitoring system is feasible enough based on the performance and highly sensitive to any changes that occurred during the machining process, specifically on the cutting tool condition. In the future, this integrated monitoring system could be applied to other open CNC machine-based plug and play.

Development of new integrated CNC system for ISO 6983 data interface model

Development of new integrated CNC system for ISO 6983 data interface model

Application of artificial intelligence technology in CNC system

Application of artificial intelligence technology in CNC system

ЕКСПЕРИМЕНТАЛЬНІ ДОСЛІДЖЕННЯ ШЛІФУВАННЯ ТОРЦІВ РОЛИКІВ ПІДШИПНИКІВ НА МОДЕРНІЗОВАНОМУ ДВОСТОРОННЬОМУ ТОРЦЕШЛІФУВАЛЬНОМУ ВЕРСТАТІ 3342АДО

Rolling bearing rollers are very important components of rolling bearings, the end surfaces of which are processed in mass and serial production on two-sided end grinding machines. They must be manufactured in accordance with the require-ments of GOST 25255-82 "Rolling bearings. Rollers cylindrical long. Technical conditions" made of bearing steel ShKh 15 according to GOST 801-78. The end surfaces of the rollers of rolling bearings are subject to high requirements for the accuracy of dimensions, shape and quality of the end surfaces while ensuring high processing productivity. Therefore, it is very important to find new reserves of the process.The analysis of research and publications showed the importance of the thermal effect and rotation of the workpieces in the processing zone during double-sided face grinding on the productivity, accuracy and quality of the processed end surfaces. This becomes even more important when grinding with crossed axes of wheelsand workpieces, since a special profile adjust-ment of the wheel is carried out, which makes it possible to obtain an area for removing the rough allowance and a calibration area on the surface of the wheel. At the same time, the entire allowance is cut inthe area adjacent to the calibration area. The calibration area at the entrance of the parts to the processing area does not participate in cutting the allowance, has high stability and forms the final accuracy of the end surfaces at the exit.The purposeof the article is to conduct experimental studies of the temperature on the ends of the machined bearing rollers along the processing coordinate and the rotation of the machined rollers in the closed zone between two grinding wheels along the processing coordinate on a modernized end-grinding machine 3342 ADO.The work proposed for the first time a new way of adjusting grinding wheels on a two-sided face grinding machine 3342 ADO, which made it possible to obtain a calibration area of grinding wheels of the correct geometric shape (without concavity). For this, the system of straightening of the basic face grinding machine 3342 ADO was modernized, which ensured the syn-chronization of the movements of the product feeding disc with the diamond pencil located on it for straightening the calibration area and the movement along the axis of the headstock of the rotating grinding wheel. All movements were controlled by the CNC system with a specially developed control program.

Orientation smoothing in multi-axis additive manufacturing

In multi-axis processes, such as material extrusion like Fused Filament Fabrication (FFF), the orientation of the tool relatively to the workspace is usually set by the CAM software to an angle that is locally constant relative to the manufacturing surface. However, in the case of large curvature gradients or small curvature radius of the surface or the path, this method leads to significant variations of the tool orientation. These variation require large compensating movements of the axes to maintain the desired deposition tool orientation along the path. Kinematic constraints such as acceleration or jerk limits can lead to a reduction of the path velocity or noticeable positioning errors along the movement, as well as unwante vibrations, which means poor process conditions and defects in the parts. The paper presents a post path planning algorithm that allows smooth in of the tool orientation to avoid jerky compensation motion of the CNC system by varying the orientation within a defined tolerance. This tolerance depends on the deposition process, and is determined experimentally for a FFF process. The proposed methodology was successfully validated b the manufacturing of two sample parts using a robotic additive manufacturing cell.

Investigation of the Required Discreteness of Interpolation Movement Parameters in Cyber-physical Systems

Improving the accuracy, reliability, and performance of cyber-physical systems such as high-speed machining, laser cutting, welding and cladding etc. is one of the most pressing challenges in modern industry. CNC system carries out data processing and significantly affect on accuracy of operation such equipment. The paper considers the problem of controlled axes motion differential characteristics data processing in the internal representation of the discrete space of the CNC system. Equations for determining the required discreteness of the differential characteristics position and resolution, such as the speed, acceleration, and jerk are proposed. For the most widely used CNC equipment specific discreteness and resolution values have been determined.

Vehicle Cruise Braking Distance Calibration based on Embedded CNC System

Most of the vehicle cruise braking calibration algorithms only calibrate the distance, ignoring that the driver cannot control the vehicle braking in time under fatigue conditions. Therefore, an embedded CNC system is added to the vehicle cruise braking distance calibration algorithm to control the vehicle speed and prevent the vehicle from rear-end collisions. At this time, the CNC system uses incremental control to control the vehicle cruise braking. The reaction time model and braking distance calculation model under control increment are established. At the same time, air resistance and rolling resistance of cruise braking distance parameters are calculated. Cruise braking distance calibration is completed by integrating the two models, CNC system control increment, air resistance and rolling resistance parameters. The experimental analysis shows that the calibration error of the algorithm is within ±30cm and the calibration accuracy is high, which meets the practical application standard of cruise braking.

Tool Path Generation for Linear Cutting Using Step File (ISO 10303) Data Structure

The ISO 10303 also known as the Standard for the Exchanged Product data (STEP) that describes how to represent and exchange the product manufacturing information. STEP’s data structure incorporates three-dimensional data of product design elements and manufacturing details which allows users to access 3D product model/information via different CAD applications. These product data model if exploited fully can be used in CAD/CAM and CNC system to perform machining simulation or physical machining operation. The paper describes the interface system development of tool path generation for linear cut using STEP file as input file. The system must be capable of identifying, extracting, processing the geometric data from STEP file and generate tool path according to G-code ISO 6983. A machined block sample with straight slot profile is designed from a 3D CAD modeler and saved in the STEP file format. This file was then upload into the Interface system to auto generate a G-code. The simulation and physical machining using 3-axis CNC milling as to validate the output.

Method for assessing the thermophysical properties of the contact pair ‘tool – steel workpiece’

To The analysis of methods for evaluating the properties of contact pairs “hard -alloy coated tool-steel billet” is carried out in order to use them to increase the reliability of the choice of turning modes in the generations of CNC systems equipped with technological intelligence. It is proposed to use the value of the thermo-emf of the test pass as an indirect indicator of the properties of contact pairs composed of a coated carbide tool and a processed steel billet. Models for calculating the cutting speed based on a given tool durability period of a coated carbide tool and predicting the actual cutting tool durability period for given processing conditions are proposed by introducing into their structure an additional informative value about the properties of each contact pair - the thermo-EMF of the test pass. The conducted resistance tests of various carbide plates during the processing of P-group steels showed sufficient reliability of the proposed dependences.

Development and Implementation of a Mini CNC Milling Machine

Abstract The development of mechanical processing machines with integrated CNC systems allows the manufacturing industry to produce complex products quickly with high quality. CNC has become a main course for mechanical students in technical and vocational universities. CNC machine training is required to enhance student’s skills to learning in design and manufacturing technology. However, the cost to buy a CNC machine is not cheap. In a developing country like Vietnam, along with the limited budget of most universities, this is an obstacle for students to have the opportunity to use CNC machines. To help students have a teaching aid in learning, improve practice capacity. The article proposes an alternative to design and manufacture a simple, inexpensive milling machine with all the required functions. The CAD models design of the machine model structure were done using Solidwork and NX software. Most of the machine’s parts are manufactured and assembled in the Faculty of Engineering Mechanics and Automation laboratory of Engineering and Technology, Vietnam National University Hanoi. The study’s main objective is to propose a process for designing and manufacturing a mini vertical 3-axis CNC milling machine with low cost but full features similar to an industrial CNC machine. The machine model introduced in the article can be used as a teaching aid, improving practical capacity for students of machine building

Pipe Welding Machine Modernization

There are the results of pipelines rolled joints welding machine modernization. The machine is designed using a welding rotator, linear electric drives, stepper motors, CNC system. The machine is controlled by a CNC system according to ISO 6983-1: 2009. The machine consists of: stepping rotary device, welding torch stepping device, controlled TIG welding power source, controlled welding wire feeder, welding current control system, workpiece rotation control system and welding torch. The welding torch movement trajectory controlling software has been created. It allows to weld by any type of welding torch recommended movements. The modernizing machine allows welding the pipelines rolled joints in automatic mode both in one pass and in multi-pass. The machine can be used for industrial pipeline elements welding, for welding modes testing, for studying the effect of welding modes on the quality of pipeline welds. The results can be adapted for sheet structures welding using the standard commands of the ISO 6983-1: 2009 standard. The results can be adapted to industrial welding robots control. The welding machine can be used for MIG / MAG welding and surfacing.

Enhanced feedrate scheduling algorithm for CNC system with acceleration look-ahead and sin2 acceleration profile

Enhanced feedrate scheduling algorithm for CNC system with acceleration look-ahead and sin2 acceleration profile

The Improvement Method of the Auxiliary Tool Holder of the Inner Diameter Tool of the CNC Lathe in the Internet Era

Regarding how to make better use of the system functions of the CNC machine tool after the transformation and reduce the cost, this paper studies the vertical data lathe system device to demonstrate that the auxiliary tool holder of the inner diameter tool is controlled by the CNC system and the axis control. Through the fusion of NC and PLC to operate the tool change, develop the tool change and tool change PLC program. Test the function of the tool post, and the experiment proves that the tool change of the machine tool is safe, accurate, and has fewer failures. The control standard of the servo tool post is realized, and the resources of the numerical control system are better adopted, and the cost of the transformation is saved on the basis of reducing the hardware devices.