CAM System Research Articles

Application of Chairside CAD/CAM and Its Influencing Factors among Chinese Dental Practitioners: a Crosssectional Study.

To examine the increased use of chairside CAD/CAM among Chinese dental practitioners, and to explore the existing barriers influencing its further application and satisfaction levels. A semi-structured questionnaire was developed to gather respondents' demographic information, as well as their experiences and behaviours regarding the implementation of chairside CAD/CAM. A specialised web-based survey system and WeChat were used to display and distribute the final questionnaire. Then, the data were analysed with Chi-square tests and regression analyses to determine the effects of various demographic variables on chairside CAD/ CAM applications. A total of 1,969 questionnaire responses were included in the analyses. Chairside CAD/ CAM systems were used by 36.9% of participants, with a higher usage rate observed among prosthodontists (60.0%) and dental practitioners holding a PhD degree (57.7%). Chairside CAD/ CAM-fabricated prostheses were most commonly used in the posterior maxilla (83.3%) and mandible (86.0%), followed by the anterior maxilla and mandible (63.8% and 48.6%, respectively). Major barriers to further application included high initial investment, frequent updates of equipment and software programs, and a lack of expertise in chairside CAD/CAM usage. Most dental practitioners did not use chairside CAD/CAM systems. The application rate was significantly influenced by sex, location, educational background, department and type of healthcare facility. Chairside CAD/CAM users showed limited satisfaction with the aesthetic performance of the fabricated prostheses. To improve the popularity of chairside CAD/CAM systems, especially among dental practitioners lacking advanced academic degrees, it is highly advisable to optimise CAD software programs and offer comprehensive training opportunities.

A Comparative Evaluation of Marginal and Internal Fitness of Zirconia Monolithic Crown Fabricated with Different CAD\CAM Systems: (In Vitro Study)

The precision of computer-aided design/computer-aided manufacturing (CAD/CAM) systems is reliant upon their technical attributes and reliability in producing the designated restorations. The evaluation of this precision is primarily conducted through the examination of the marginal and internal fitness of said restorations. Consequently, the objective of this research endeavor was to analyze and compare the marginal and internal fitness of zirconia crowns fabricated using various CAD/CAM systems. The samples were categorized into four groups, each consisting of 10 samples, based on the specific CAD/CAM equipment employed for crown fabrication as follows: Group I fabricated using Sirona CAD\CAM milling machine, Group II fabricated using Dentium CAD\CAM machine, Group III fabricated using XTCERA CAD\CAM machine and Group IV fabricated using IMES-ICORE CAD\CAM machine. Tooth preparation done following the guidelines recommended by KATANA TM Zirconia (Kurary Noritake Dental Inc., Japan). To ensure standardization, one CAD/CAM program designed parameters was selected to be used for all CAD/CAM machines. Cement thickness was directly measured using sectioning technique to assess the crown's internal and marginal fitness. After performing sectioning, measurements were conducted using a digital microscope with a magnification of 230x. Eleven predetermined measuring locations were selected for each sample, representing four distinct areas: two marginal points, two chamfer points, four axial points, and three occlusal points. Results showed that none of four CAD\CAM machines tested was able to accurately reproduce the designed cement space parameter except Group I (Sirona) showed the closest results. As a conclusion, no CAD\CAM system is 100% accurate however, crowns fabricated using Sirona CAD\CAM milling machine showed the closest recordings to selected parameters among other CAD\CAM milling machines tested.

Multi-pillar piezoelectric stack harvests ocean wave energy with oscillating float buoy

Piezoelectric Energy Harvesting (PEH) has emerged as a promising alternative to traditional batteries for self-powered sensors. This paper proposed a multi-pillar piezoelectric stacks oscillating float wave energy harvesting device that utilizes a unique rack, pinion, and cam system to convert the heaving motion of the float into a unidirectional rotation. Subsequently, the cam actuates a linkage rod, driving multiple piezoelectric stack pillars to generate electrical energy. The innovative cam mechanism introduces frequency upconversion to improve the efficiency of power generation in conjunction with piezoelectricity. A theoretical methodology is also derived and validated with simulation and experimental model tests to characterize the output power. The results demonstrate that the system attains a peak output voltage of 32 V and a power output of 3.5 mW when utilizing 10 piezoelectric translation units connected in parallel. This achievement is facilitated by the oceanic force generated by wave motion, which exerts a force of 500 N over a wave period of 3 s. The sustainable energy solutions are developed for remote sensor applications in marine environments, offering potential advancements in the field of autonomous and self-powered sensing systems.

Automation of determining the compliance of domestic stainless steels with ISO classification material codes

For domestic stainless steels, criteria are developed for compliance with M group of processed materials according to the international ISO classification. An algorithm is proposed for determining codes according to the Coromant classification for stainless steels based on the grade of material, chemical composition, hardness and method of obtaining of the workpiece. The algorithm is implemented as part of an integrated CAM system for the KOMPAS-3D platform and is intended for use in calculation of cutting modes with imported carbide tools. Keywords:material, cutting mode, SANDVIK, KOMPAS-3D, CAM system, CNC schekin@inbox.ru, mayorovam@mail.ru

APPLICATIONS OF CAD/CAM TECHNOLOGY IN DENTISTRY

Digital dentistry has been introduced for over 40 years, but their overspread use has become available in the last two decades, after year 2000. First to introduce it in dentistry was a dentist, but the widespread of the digital dentistry was carried out mostly by dental technicians. In Romania, digital dentistry had become available with state funding projects for the dental field. Objective The aim of the study was a broader assessment of the use of CAD/CAM systems in dental practices and dental technology laboratories. Materials and method. The study consisted in a survey based on a questionnaire, distributed in electronic form, applied to two branches of dentistry, respectively, for dentists and dental technicians. The study was attended by dentists and dental technicians, from the urban environment. Results were analyzed using statistical methods with Microsoft Excel. Results. The results of the present study showed a high degree of knowledge regarding CAD/CAM technology, as most of the participants were aware of the introduction and use of digital technology in dentistry. Majority of dental technicians have introduced and have worked with CAD_CAM systems, comparative with dentists, which only a third part worked usually with these technologies. Conclusions. Even though digital dentistry is a modern technology with advantages, there are still some concerns from dentists and technicians about the quality and costs of CAD/CAM restorations.

Design and implementation of an innovative canned cycle for variable pitch thread cutting on CNC milling machines

This paper presents the development of a new canned cycle for CNC milling machines capable of cutting threads with variable pitch, addressing a significant limitation in modern CNC systems. While existing CNC milling machines provide canned cycles for thread cutting, they lack the capability to program variable pitch, necessitating reliance on CAM systems. In response, the proposed canned cycle offers increased flexibility, quicker setup times, and reduced dependence on CAM systems. The cycle accommodates both internal and external threads, supports left-hand or right-hand threading, and incorporates a user-friendly control panel for easy programming. To validate its efficiency, the canned cycle is implemented using a G-code parametric algorithm, and a series of simulation tests are conducted. The results demonstrate the viability and advantages of the new CNC milling feature in cutting threads with variable pitch, opening up possibilities for various mechanical applications.

Intuitive toolpath planning in computer-aided manufacturing systems using artificial intelligence in a virtual reality environment

CAM systems are widely used in many key industries and are essential for many machining processes such as 5-axis milling. For toolpath planning, state-of-the-art CAM systems require the user to enter many abstract parameters, making these systems difficult to use. This paper presents a more intuitive approach to toolpath planning. The approach uses convolutional neural networks to interpret user gestures in a virtual reality environment and predicts the values of the aforementioned parameters. The results show that many of these parameters can be extracted from user gestures with high accuracy, which can be used to greatly simplify toolpath planning.

Research on Space Cam Automation Design and Manufacturing Scheme Based on CAD and CAM Systems

Research on Space Cam Automation Design and Manufacturing Scheme Based on CAD and CAM Systems

Тимчасові незнімні ортопедичні конструкції виготовлені із використанням CAD/CAM системи методом фрезерування, як альтернатива постійним на тривалий термін

Relevance. Prevalence of partial loss of teeth in the population of Ukraine is from 62.3% to 84.5%. The war in Ukraine significantly affected the provision of timely and high-quality dental care. However, the restoration of the destroyed crown part of the tooth and the integrity of the tooth rows must take place in a timely manner, as it leads to the development of secondary deformations of the dental and jaw system. One of the options for solving the problem of timely orthopedic treatment, in these conditions, can be the use of temporary fixed orthopedic structures made using the CAD/CAM system by the milling method. The aim is to investigate the possibility of using non-removable temporary orthopedic structures made using the CAD/ CAM system by the milling method and cements for their temporary fixation for a period exceeding that established by the general protocols of orthopedic treatment and declared by the manufacturer. Materials and methods. The study was conducted in the period from September 2022 to April 2024 at the Department of Orthopedic Stomatology of the National Medical University named after O.O. Bogomolets For the study, 60 patients aged 25-59 years were selected, with the destruction of the crown part of the tooth, which required replacement with a fixed orthopedic structure and included dentition defects of various lengths. All supporting elements were divided into groups, depending on the cement used for fixation: Group I – Freegenol (GC, Japan), Group II – Provicol (Voco, Germany), Group III – RelyX Temp NE (3M ESPE, Germany), IV group – Temp-Bond NE (KERR, USA). Re-examinations of patients were carried out in periods from two weeks to six months. Results. Depending on the selected cement for temporary fixation of a non-removable orthopedic structure, the percentage of decementing of temporary single crowns, in terms of two weeks to six months, was from 2.22% to 32.65%, structures with support on two elements from 5.55% to 52.94% and based on three elements from 7.14% to 77.78%. A direct relationship was established between the appearance of mobility of the temporary fixed orthopedic structure, the sensitivity of the vital tooth and bleeding gums in all groups of subjects. Conclusions. Temporary non-removable orthopedic structures made using the CAD/CAM system by the milling method, depending on the selected cement for temporary fixation, can be used to restore the crown part of the tooth and included defects of the dentition for a period that exceeds that established by the general protocols of orthopedic treatment and declared by the manufacturer. Key words: temporary non-removable orthopedic structures, CAD/CAM systems, milling, cements for temporary fixation.

Integrating Cloud Computing, Bayesian Optimization, and Neural-Additive Modeling for Enhanced CAM Systems in 5-Axis Milling

This publication introduces the development and application of an advanced CAD/CAM/CAE system that leverages the computational capabilities of an edge-cloud infrastructure. The developed system consists of containerized technology models for various complex process planning simulation tasks in 5-axis-milling, such as toolpath calculation, cutter-workpiece-engagement, uncut chip geometry or cutting force simulations. Moreover, a Bayesian optimization (BO) algorithm is coupled with the system enabling multi-objective optimizations of the considered machining operations by varying predefined CAM-parameters. The result of the optimization consists of a set of Pareto-efficient solutions. Each solution realizes a different tradeoff between the technological objectives of the process planner. Since mastering the complexity of the design space is a major challenge in today’s CAM programming workflow, a Neural-Additive Model (NAM) is coupled with the system improving guided search through the configuration/result space. This reduces the convergence time to an optimal CAM parameter set. The coupling of the cloud computing, multi-objective optimization and artificial intelligence method with a CAM-kernel is demonstrated based on the process design of 5-axis milling operations for a blade-integrated disk (blisk).

Evaluation of Non-Planar Tool Interaction in Milling of Shaped Surfaces Using a Copy Milling Cutter

When milling complex parts or curved surfaces, we encounter several problems that must be addressed in the production process. Various factors affect the quality and accuracy of production. The main objective of this paper was to analyse the size of the effective tool diameter when machining a shaped surface concerning the selected position, namely at the perpendicular position of the tool. At the same time, the distribution of the engagement area on the tool surface was evaluated by extracting the area content and volume data at the point of contact. This study highlights the importance of the choice of finishing strategy in a CAM system. The results showed that the tool engagement size corresponded to the extracted data describing the area and volume for each tool position with regards to the curvature of the surface. The negative deviations obtained by the scanning method were due to machining near the tool centre, which was affected by the changing effective tool diameter.

Digitalization of Radial Piston Pumps through Internal Mechanically Actuated Designs

Digital hydraulics is a technology gaining perceptible growth in fluid power research. The advantages of digital fluid power systems can be realized through improved system efficiencies, energy savings, increased productivity, and system performance compared to traditional fluid power systems. Conventional check valve pumps use differential pressures to deliver pressurized flow to the system. Digital fluid power pumps enable conventional check valve pumps to achieve variable displacements by enhancing the controllability of the inlet and outlet valves through digital hydraulic technologies and techniques. The benefit of this technology is the use of positive sealing check valves with lower leakage losses compared to typical variable displacement pumps, increasing the unit’s overall efficiency. The primary focus of prior digital pump/motor research has been on digital actuation using electronic solenoids to actuate or latch the valves. While these electrical systems provide a platform for digital hydraulic techniques, they come with a cost: added energy sources, advanced controls, and expensive data acquisition systems. Research has also shown that minor valve timing inconsistencies can limit the potential energy savings of digital pumps in electrically actuated systems. A system configuration that promotes the advantages of digital hydraulics while mitigating the disadvantages associated with electrical systems is mechanically actuated systems. This work discusses variable cams and their advantages/disadvantages in digital radial piston pump/motor technologies. The significance of this work is the investigation of the digitalization of radial piston pumps through mechanically actuated valving systems, which has yet to be implemented in prior research. This paper evaluates various design concepts for commercializing digital radial piston pumps using mechanically actuated cams. A two-quadrant pump and a four-quadrant pump/motor design are simulated to assess their potential efficiency across the bandwidth of their displacement. The results show that the two systems can achieve relatively high efficiencies across their displacement bandwidth but show room for further improvement by optimizing these systems. This study is the first step in designing an integrated mechanically actuated variable cam system in digital radial piston pumps.

Energetic and structural insights behind calcium induced conformational transition in calmodulin.

Calmodulin (CaM) is a key signaling protein that triggers several cellular and physiological processes inside the cell. Upon binding with calcium ion, CaM undergoes large scale conformational transition from a closed state to an open state that facilitates its interaction with various target protein and regulates their activity. This work explores the origin of the energetic and structural variation of the wild type and mutated CaM and explores the molecular origin for the structural differences between them. We first calculated the sequential calcium binding energy to CaM using the PDLD/S-LRA/β approach. This study shows a very good correlation with experimental calcium binding energies. Next we calculated the calcium binding energies to the wild type CaM and several mutated CaM systems which were reported experimentally. On the structural aspect, it has been reported experimentally that certain mutation (Q41L-K75I) in calcium bound CaM leads to complete conformational transition from an open to a closed state. By using equilibrium molecular dynamics simulation, free energy calculation and contact frequency map analysis, we have shown that the formation of a cluster of long-range hydrophobic contacts, initiated by the Q41L-K75I CaM variant is the driving force behind its closing motion. This study unravels the energetics and structural aspects behind calcium ion induced conformational changes in wild type CaM and its variant.

Effectiveness of Active Confinement Techniques with Steel Ribbons: Masonry Buildings

Abstract In the present paper, we analyzed the main advantages of the active confinement techniques with a particular focus on the CAM system, which is an Italian reinforcement technique with pre-tensioned stainless-steel ribbons. Italian seismic codes classify the CAM system as belonging to the strengthening category of “horizontal and vertical ties”. Therefore, we compared the CAM system to the reinforcement techniques with horizontal and vertical ties in order to understand the actual similarities and possible differences between them. Moreover, we offered a deep analysis of the main critical issues of the CAM system, distinguishing between geometrical and mechanical weak-points. In particular, we analyzed the strengthening mechanism of the CAM system, still poorly understood, by performing a static analysis in the Mohr/Coulomb plane. Finally, we provided suggestions for future developments.

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.

An integrated trajectory smoothing method for lines and arcs mixed toolpath based on motion overlapping strategy

Smoothing the discretized toolpaths generated by CAM systems is vital for CNC options in improving the quality of machined surfaces. One discretized toolpath from CAM is commonly represented in the form of a series of linear and arc segments. The linear segment smoothing method has been extensively investigated. However, for linear and arc joint segments, which are in the form of G01 and G02/03 mixing modes, efficient smoothing strategies are still lacking. In this study, an integrated toolpath smoothing method based on motion overlapping strategy is proposed to improve the continuities of the mixture of G01 and G02/03 codes. To satisfy the requests of the kinematic limitations and high efficiency, heuristic algorithms are used to seek optimum kinematic parameters. Meanwhile, we also introduce a variable jerk-limited feedrate profile in the motion overlapping strategy to further reduce the machining time. Simulations on various toolpaths are performed to validate the effectiveness of the proposed method compared with the classical FIR and B-spline methods. The machining experiment executed on a 3-axis machine tool with a real-time CNC system also demonstrates the applicability of the proposed method.

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First photometric study of three eclipsing binary star systems: V495 Aur, V589 Aur and V478 Cam

The light curve solutions and orbital period analysis of V495 Aur, V589 Aur and V478 Cam eclipsing binary star systems are presented for the first time in this study. Transiting Exoplanet Survey Satellite (TESS) observations were used as observational data. From the light curve solutions, it was concluded that all three systems are semi-detached binary star systems in which the secondary components fill their Roche lobes. The absolute parameters of the systems were also estimated. Accordingly, the photometric mass ratios of V495 Aur, V589 Aur and V478 Cam are found to be 0.251±0.035, 0.254±0.038 and 0.078±0.010, respectively. Upward parabolic change was observed in the O-C diagrams of all the systems considered. As a result of parabolic changes, we concluded that the orbital periods of the V495 Aur, V589 Aur and V478 Cam systems increased secularly with a rate of 0.050±0.010 s/year, 0.018±0.004 s/year and 0.070±0.015 s/year, respectively. The increases in orbital periods are explained by the dominant mass transfer mechanism from the secondary components to the primary components. In addition, the mass transfer rates between components and the rates of mass lost from the systems were estimated.

COMPARISON OF FINISHING MILLING STRATEGIES USING TOPOGRAPHY OF THE MACHINED SURFACE

The plastics processing and injection molding industry is known for the fact that the future molded part contains a variety of geometric shapes and, in some cases, free surfaces. To produce these shapes, knowledge of CAM systems is required to enable the programmer to select the necessary milling strategies designed to achieve the best possible quality and dimensional accuracy. However, it is equally necessary to understand and appreciate the effect of each strategy and which strategy is best suited for a given type of surface. The paper compares finishing milling strategies by evaluating the topography of the machined surface. The material was AlCu4Mg aluminium alloy, where Constant-Z and Spiral strategy – circle-type finishing strategies were selected for the production process. Surface topography analysis was evaluated and compared at three different heights of the produced part with respect to the tool contact with the machined surface, which showed a variation in toolpaths and therefore also in the quality of machining. The surface topography results demonstrated the Constant Z strategy to be the more suitable strategy for producing the shaped surface, which achieved uniform toolpaths over the whole height of the part.

Optimization of product processing modes in modeling and programming of machining on machine tools with program control

Purpose. To solve a scientific and technical problem related to the technological support of high-performance machining of a cast iron part by optimizing and controlling its machinability with a hard-alloy tool on multi-axis CNC machines using CAD-CAM systems. The methods. The methodological basis of the work is a systematic approach and analysis of the study of the object of research, based on the use of: numerical and graphical-analytical research methods in order to establish a systematic relationship between turning parameters and the properties of the material being processed, tool geometry and its stability, parameters of cutting modes with the corresponding indication in the control program for the CNC machine. Findings. Numerical research results have been obtained for a scientifically based approach to solving the technical problem of high-performance turning of cast iron parts on multi-axis machining centers, which contains a set of adjusted methods and algorithms for predicting their machinability with ensuring the reliability of hard alloy cutting tools. The results obtained were compared with known works related to the study of machining processes of various grades of steels, alloys, and cast irons, the assessment of the reliability of cutting tools, the accuracy and roughness of the machined surface, and the results of measurements of cutting force parameters. The maximum relative error of the calculations did not exceed 6-8%. The originality. Establishment of a complete and systematic connection of machining parameters with the properties of the processed material, tool geometry and design and technological factors of the part for the calculation of an optimized automated production technology. In the mathematical and statistical processing of experimental data, which made it possible for the first time to obtain complex dependencies in a form convenient for calculation and analysis, which give a clear picture of the effect of each parameter of the turning process on its energy and time indicators when compiling a rational technology for machining a part of complex geometric shape in a CAM system. Practical implementation. It consists in selecting and justifying the optimal geometric parameters of cutting tools and equipment, establishing the nature of the influence of the conditions of turning cast iron on the main process parameters - machining time and operating parameters depending on the hardness of the part material and tool material. Practical recommendations are given on the optimal use of CAD-CAM systems, adjustment of process results and operating parameters to obtain optimal results at the stage of production preparation.