Computer numerical control

A strategy for adaptive control and energetic optimization of aerobic fermentors was implemented, with both air flow and agitation speed as manipulated variables. This strategy is separable in its components: control, optimization, estimation. We optimized parameter’s estimation (from the usual KLa correlation) using sinusoidal excitation of air flow and agitation speed. We have implemented parameter’s estimation trough recursive least squares algorithm with forgetting factor. We carried separate essays on control, optimization and estimation algorithms. We carried our essays using an original computational simulation environment, with noise and delay generating facilities for data sampling and filtering.

Our results show the convergence and robustness of the estimation algorithm used, improved with use of both forgetting factor and KLa dead-band facilities. Control algorithm used in our work compares favorably with PID using the integrated area criteria for deviation between oxygen molarity and critical molarity (set point). Optimization algorithm clearly reduces energetic consumption, respecting critical molarity. Integration of control, optimization and adaptive algorithms was implemented, but future work is needed for stability. Methods were defined and implemented for stability improvement. We have implemented data acquisition and computer manipulation of air flow and agitation speed for actual fermentors.

Parameter kecepatan putaran dan kecepatan potong mempengaruhi kekasaran permukaan dalam proses pembubutan. Tujuan Penelitian ini (1) Mengetahui tingkat kekasaran permukaan benda kerja menggunakan kecepatan putaran tetap (G97); (2) Mengetahui tingkat kekasaran permukaan benda kerja menggunakan kecepatan potong tetap (G96); dan (3) Mengetahui perbandingan tingkat kekasaran permukaan yang dihasilkan dari kedua parameter tersebut.
Metode penelitian ini adalah penelitian eksperimen, dengan melakukan proses pembubutan bertingkat pada spesimen Baja ST 37 di mesin NC PU 2A EMCOTURN 120. Jumlah spesimen sebanyak 6 spesimen, setiap spesimen dibubut bertingkat sebanyak 3 tingkat, setiap tingkat diuji sebanyak 3 titik kualitas permukaanya menggunakan “Surface Tester Mitutoyo SJ-201P”. Data hasil penelitian diolah menggunakan statistik deskriptif dengan mengambil nilai rata-rata dari kedua parameter.
Berdasarkan analisis data dari hasil pengukuran yang dilakukan, maka diperoleh harga rata-rata kekasaran permukaan dari ketiga spesimen menggunakan parameter kecepatan potong tetap yaitu 2,1492 μm masuk pada kelas N7, sedangkan saat menggunakan kecepatan putaran tetap rata-rata kekasaran permukaan dari ketiga spesimen yaitu 2,4125 μm masuk pada N8. Parameter kecepatan potong tetap (G96) lebih bagus dibandingkan kecepatan putaran tetap (G97) dalam proses pembubutan bertingkat pada mesin NC PU 2A.

This paper presents two cases of study where ergonomic evaluations were conducted in work stations related with the operation of Advanced Manufacturing Technology (AMT) equipment: Computer Numerical Control (CNC) Milling Machine and (CNC) Lathe. The Marley and Kumar (1996) Body Map format among 10 workers was conducted for pain in discomfort study and Hignett and Mc Atamney (2000) REBA method was used for ergonomic evaluation. Shoulders, middle back, hand and arm pain was identified. The evaluation results indicated a medium risk level for both work stations according to REBA. Recommendations for changes in equipment components and the work station are presented and it is found that models that would help identify and evaluate ergonomic aspects related with AMT equipment are desirable among decision makers, owners and users.

This paper describes an integrating hardware and software ensemble for the development of microcontroller-based computer numerical control system. The discuss is focused on design and implementation of the communication between the PC and a numerical control machine. Among topics covered are: the C#/.NET serial port programming, and further, how to create a Windows application for sending, trough a COM port, the Computer Aided Design/Manufacturing data needed by a numerical control machine. A PIC microcontroller-based communication hardware module was developed and tested.

Glass is an excellent material for use as a microfluidic chip substrate because it has great chemical and thermal stability. This work describes a flexible platform for the rapid prototyping of microfluidic chips fabricated from glass. A debris-free laser direct-writing technology that requires no photomask generation is developed. A 266 nm laser with a high repetition rate is employed in laser-induced backside wet etching (LIBWE) for glass machining. A microfluidic pattern is designed using computer drawing software and then automatically translated into computer numerical control motion so that the microtrench is directly fabricated on the glass chip. The overall machining speed can be increased by increasing the repetition rate to ∼6 kHz. Without a clean room facility or the highly corrosive acid, HF, the overall development time is within hours. Trenches with complex structures that are hard to fabricate by photolithography were easily produced by laser direct-writing. An integrated microreactor/concentrator is demonstrated. The crack-free and debris-free surface was characterized by SEM and a surface profiler. Various effective etching chemicals for the LIBWE process were investigated to understand the etching mechanism. The minimal laser power used for glass etching was approximately 20 mW for a 6 µm wide microtrench. Several new compounds have been demonstrated to be effective in ablation. The etch threshold is minimum and does not decrease further as the unit length absorbance increases above 8000 in acetone solution.

In this work we present how Augmented Reality (AR) can be used to create an intimate integration of process data with the workspace of an industrial CNC (computer numerical control) machine. AR allows us to combine interactive computer graphics with real objects in a physical environment -in this case, the workspace of an industrial lathe. ASTOR is an autostereoscopic optical see-through spatial AR system, which provides real-time 3D visual feedback without the need for user-worn equipment, such as head-mounted displays or sensors for tracking. The use of a transparent holographic optical element, overlaid onto the safety glass, allows the system to simultaneously provide bright imagery and clear visibility of the tool and workpiece. The system makes it possible to enhance visibility of occluded tools as well as to visualize real-time data from the process in the 3D space. The graphics are geometrically registered with the workspace and provide an intuitive representation of the process, amplifying the user's understanding and simplifying machine operation.

Nickel-based alloy is difficult-to-machine because of its low thermal diffusive property and high strength at higher temperature. The machinability of nickel- based Hastelloy C-276 in turning operations has been carried out using different types of inserts under dry conditions on a computer numerical control (CNC) turning machine at different stages of cutting speed. The effects of cutting speed on surface roughness have been investigated. This study explores the types of wear caused by the effect of cutting speed on coated and uncoated carbide inserts. In addition, the effect of burr formation is investigated. The chip burr is found to have different shapes at lower speeds. Triangles and squares have been noticed for both coated and uncoated tips as well. The conclusion from this study is that the transition from thick continuous chip to wider discontinuous chip is caused by different types of inserts. The chip burr has a significant effect on tool damage starting in the line of depth-of-cut. For the coated insert tips, the burr disappears when the speed increases to above 150 m/min with the improvement of surface roughness; increasing the speed above the same limit for uncoated insert tips increases the chip burr size. The results of this study showed that the surface finish of nickel-based alloy is highly affected by the insert type with respect to cutting speed changes and its effect on chip burr formation and tool failure.

This study presents a new suction-type, pneumatically driven microfluidic device for liquid delivery and mixing. The three major components, including two symmetrical, normally closed micro-valves and a sample transport/mixing unit, are integrated in this device. Liquid samples can be transported by the suction-type sample transport/mixing unit, which comprised a circular air chamber and a fluidic reservoir. Experimental results show that volume flow rates ranging from 50 to 300 μl/min can be precisely controlled during the sample transportation processes. Moreover, the transport/mixing unit can also be used as a micro-mixer to generate efficient mixing between two reaction chambers by regulating the time-phased deformation of the polydimethylsiloxane (PDMS) membranes. A mixing efficiency as high as 98.4% can be achieved within 5 s utilizing this prototype pneumatic microfluidic device. Consequently, the development of this new suction-type, pneumatic microfluidic device can be a promising tool for further biological applications and for chemical analysis when integrated into a micro-total analysis system (μ-TAS) device.

Conventional programming of Numerically Controlled machine tools is normally based on ISO 6983. In conventional CNC machining, a part is designed using a CAD system, and that is read into a CAM system. The standard assumes information flow is from CAD to the shop floor, and doesn't enable feedback of experience from the shop-floor to the designer. In this paper, we introduce STEP-NC, a STEPcompliant data interface for Numerical Control that aims to overcome the problems of ISO 6983 and take advantage of advances in computing and controllers. The new STEP-compliant programming interface is based on an object-oriented data model to ensure that information remains in its context and is not reduced to primitive instructions such as G-Codes.

The evolution of semiconductor manufacturing was very much driven by precision control demands in the United States military but because of its complementary and enabler properties it is increasingly diffusing into the manufacture and use of many different products and processes. It is therefore very common to find semiconductor chips driving central panel control systems in the manufacture of steel

Parametric interpolation has many advantages over linear interpolation in machining curves. Real time parametric interpolation research so far has addressed achieving a uniform feed rate, confined chord errors and jerk limited trajectory planning. However, simultaneous consideration of confined chord errors that respect the acceleration and deceleration capabilities of the machine has not been attempted. In this paper, the offline detection of feed rate sensitive corners is proposed. The velocity profile in these zones is planned so that chord errors are satisfied while simultaneously accommodating the machine's acceleration and deceleration limits. Outside the zone of the feed rate sensitive corners, the feed rate is planned using the Taylor approximation. Simulation results indicate that the offline detection of feed rate sensitive corners improves parametric interpolation. For real time interpolation, the parametric curve information can be augmented with the detected feed rate sensitive corners that are stored in 2 £ 2 matrices. q

The industry of machine tools keeps a constant progress that responds to the most demanding market requirements, such as production-time decreasing and zero-defect manufacturing. As part of this progress, sensors and monitoring instruments have been integrated on machine tools, improving computer numerical control (CNC) and monitoring during the manufacturing process. The vibrations are one of the most significant variables to be monitored on machine tools since they directly affect the end piece finishing, tool life expectancy, general machine-tool condition, current consumption, etc. Time domain, fast Fourier transform (FFT), and discrete wavelet transform (DWT) are techniques often used for vibration analysis, because they are computationally efficient for online implementation; unfortunately, it is difficult to find an instrument for vibration analysis that allows individually applying the time, FFT, and DWT techniques, and their fusion. Moreover, the lack of instruments with characteristics such as open architecture, low cost, parallel processing, and continuous online monitoring is remarkable. The contribution of this work consists of developing a vibration-analysis instrument based on the time, FFT, DWT, and DWT-FFT fusion techniques. The instrument is implemented into a low-cost field-programmable gate array with proprietary hardware signal-processing cores in parallel for achieving real-time and continuous online analysis. Experimentation is done to show the proposed methodology efficiency and the developed-instrument versatility, focusing on industrial control applications for CNC machine tools.

The application of '41 technologies using modem computers and controllers is seen as a way forward to produce higher quality components more efficiently with smaller batch sizes and more frequent changeovers. Users continue to demand better accuracy, surface integrity, and shorter cycle times with reduced operator intervention and increased flexibility. This paper reviews research into the use of intelligent control and optimisation techniques in grinding and propose the incorporation of intelligent techniques into computer numerical controls (CNCs). Two main trends are evidenced in the development of AI technologies in grinding: desktop systems to assist tool and parameter selection and self-optimising systems integrated within the machine controller. It is predicted that future developments will favour increasing incorporation of intelligence into CNC. The development of modular systems which are sufficiently robust to plan. supervise and control abrasive processes requires ongoing research and development. Ke.ywords: Grinding; Artificial intelligence: CNC 0166-3615/96/$15.00 Copyright 0 1996 Elsevier Science B.V. All rights reserved. PII SOl66-3615(96)00036-X 46 W.B. Rowe et al. / Computers in Industry 31 (1996) 45-60 creasingly CNC is presented as an intelligent con-Grinder Grinding Dressing Wheels Diagnosis Control Year Billatos [ 1.21 Brown [3] Chen [4] Dornfeld [5] Du l61 Inasaki [7,8] Inoue [9] Junkar [lO,ll] Koenig [12,13] Liao [14] Malkin [15-171 Midha [18-211 Mori [22-241 Nagasaka [25] Nakajima [26] Paul [27] Roberts [28] Rowe [29-361 Sathyanarayanan [37] Tanaka [38] Tonshoff [39-421 Trtnal [43] Ueda [44] Venk [45-471 Walter [48] Wobker [49] Yoneda [50,5 l] Zhao I52,53] Screw FL

In this work we present how Augmented Reality (AR) can be used to create an intimate integration of process data with the workspace of an industrial CNC (computer numerical control) machine. AR allows us to combine interactive computer graphics with real objects in a physical environment - in this case, the workspace of an industrial lathe. ASTOR is an autostereoscopic

The purpose of this research is to investigate the relative importance of spindle speed, system dynamics, and cutting conditions on the accuracy of surface location in computer numerical-control (CNC) finish machining operations. The relationship between the spindle speed, the most flexible modes of the machine/cutting tool system and the final part dimensions is rather complex. The underlying theory, based on the situation of forced vibrations, is outlined. It is shown that the critical factor is the ratio of the tooth passing frequency to the system most flexible mode and corresponding natural frequency. Simple analytical calculations are carried out to illustrate the overcut/undercut surface error phenomenon. A simple simulation for end milling operations is also described which calculates the force on the cutter, the resulting cutter deflection, and the final error of surface. A comparison between the simulated and experimental results is presented. From experimental data, it shown that a change in surface location (and part dimension) of up to 50 m is seen for a set of given conditions (i.e., cutter, material, chip load) simply by changing spindle speeds. Furthermore, it is seen that certain spindle speeds produce surfaces with no error introduced by the machining process.

— Average Surface Roughness (R a) is one of the most frequently used texture parameters to define the quality of turned components. The roughness values of a turned surface much depends on cutting parameters such as cutting speed, feed rate and depth of cut. Optimization of these parameters is very important in relation to surface roughness as they reveal the best suitable conditions for the turning operation. In this project, a correlative study of machining parameters and the surface roughness for ferrous (stainless steel 304) and non–ferrous alloy (Aluminium) material is carried out. Response Surface Methodology (RSM) and Analysis of Variance (ANOVA) techniques are employed in this analysis to explain the influence of different cutting parameters on surface roughness values. The combination of optimum experimental parameters can be found by machining these ferrous and non-ferrous materials in CNC turning center and finding the least surface roughness parameters. ANOVA analysis, integrated with Design Expert software, is used to determine effective ratios of the parameters and subsequently the relationships between input parameters and their responses relationship are established. The minimum surface roughness results in reference to spindle rpm, feed rate, and depth of cut are determined and estimation of the optimal surface roughness values (Ra) for least surface roughness are the results obtained in the study. In case of stainless steel 304, optimal values of cutting speed, feed and depth of cut against the least surface roughness value of 1.33 microns are found to be 220 m. min-1 , 0.2 mm. rev-1 and 0.3 mm respectively. In case of Aluminium, optimal values of cutting speed, feed and depth of cut against the least surface roughness value of 2.8 microns are 200 m. min-1 , 0.2 mm. rev-1 and 1.15 mm respectively. These results reaffirm that RSM and ANOVA techniques are useful and efficient in achieving optimal set of machining parameters for select ferrous and non-ferrous materials in correlating the surface finish values.

CNC feature-based programming with STEP-NC standard extends the collaborative model of manufacturing data exchange all along the numerical data chain. This paper considers the mutations related to this approach from the manufacturing system level to the industrial enterprise as a whole. The eXtended Manufacturing Integrated System concept is introduced to fill in the gap of the current manufacturing data exchange bottleneck. It is composed of eXtended CAD and eXtended CNC systems to link the CAD model to the real machined part through the Manufacturing Information Pipeline. The contributions associated with these concepts are demonstrated through a validation platform implemented on industrial CNC manufacturing equipments.

Early detection of pathogens is crucial for the effective surveillance of diseases. Many efforts have been made to explore methods which can detect these pathogens within a short period of time without requiring a tedious protocol. However, these developed methods have disadvantages such as they are relatively time-consuming or require specialized laboratory facilities. In this work, we have developed an integrated microfluidic system for rapid and automatic detection of viruses by direct analysis from fresh Phalaenopsis orchid leaves. The entire protocol, including ribonucleic acid (RNA) purification, reverse transcription loop-mediated-isothermal-amplification (RT-LAMP) and optical detection by measuring changes in turbidity was performed on a single chip. This is the first time that an integrated microfluidic system for the detection of viruses infecting the Phalaenopsis orchid has been demonstrated. The sensitivity of the developed system was also explored in this study to validate its performance.

It is a fact that virtual training has been a scope of interest for vocational training for a very long time. However, it needs more time to be more common in all specific training fields. This paper presents the development of a Virtual Training Centre (VTC) to promote and reinforce Vocational Training in Computer Numerical Control (CNC) Machines. "Virtual Training Centre for CNC" is a multilateral LdV project and of high importance in terms of virtual teaching and learning in vocational education and training. This virtual training environment is based on a common curriculum developed by the project partners. Since it is an interactive training tool, accessibility is the most important advantage over other training tools in VET.

The current standard programming of machine centers is still the (ISO 6983-1) standard, known as G-code, which was developed in the 1950s. This language contains low-level information performing the movement of the tool in the machining process, making it difficult for the operator to take decisions in machining. For this reason, the (ISO 6983-1) standard currently limits significantly the flexibility and interoperability part manufacturing. Given this scenario, in the 1990s a new data model for manufacturing processes was proposed to extend the STEP standard (ISO 10303-1), called STEP-NC (ISO 14649-1 standard), which was developed as a result of numerous projects by companies and universities. In this paper we describe the development and validation of software and hardware that allows the user to command a CNC gantry milling machine so that it will machine parts using the STEP-NC standard (ISO 14649-11). STEP-NC is based on the concept of workingsteps, machining features and machining operations, among other entities described by the standard (ISO 14649-1). The STEP-NC Controller software was developed using the Java programming language, which enabled the creation of a control interface for the CNC milling machining process. Programming compliant with the RS-274 standard (G and M codes) generated by the open source software GRBL (software and control movements on machines) was used to program the Arduino MEGA2560 microcontroller in the C programming language. G-code programming was removed from GRBL in order to make room for use of the STEP-NC standard (ISO 14649-1), thus allowing the physical file p21 (a part of the STEP standard) to be interpreted and sent to the axes of the CNC milling machine. A direct connection is established between the STEP-NC Controller and a board with 8 relays to allow the CNC milling machine to work selectively (either with G and M code or STEP-NC). Remote operation of the machine via the Internet was also implemented, allowing the sending of a p21 file via web, and the machining process can be monitored via webcam.

This paper documents part of a research program which has been under way at the CIM Centre at Swinburne University of Technology since 1989. The purpose of the research program was to develop an open-architecture machine tool control system and then to see how that system could be used to change the distribution of traditional manufacturing design, planning and control functions. This paper examines one part of that research program and focuses on a methodology which could prove to be useful in the machine tool selection, cutter selection and cutter path generation phases of process planning for cutting operations on workpieces in computer-controlled machine tools.

A number of unique challenges arise in fabricating and assembling complex mechanisms at the meso-scale (hundreds of microns to centimetres). In general, for a complex multi-part mechanism at this length scale, no single machining technique can produce all the necessary parts-or often even a single individual part. Towards developing a comprehensive set of 'best practices' for combining multiple precision micromachining operations at the meso-scale, we present a case study on fabricating and assembling an endoscopic capsule robot. Existing passive imaging capsules have proven exceptionally useful in the diagnosis of the gastrointestinal tract, and robotic capsules promise to enhance their diagnostic capabilities and enable non-invasive treatment delivery. In this case study, we describe the fabrication of a robotic capsule (2.6 cm 3 in volume) containing a complex mechanism consisting of 72 components, each of which requires a variety of meso-or even micro-scale features. We describe the manufacturing processes used to produce these components and features (combinations of high precision, multiply refixtured computer numerical control processes, sink and wire electro discharge machining , laser cutting, etc). These results contribute to the emerging framework of best practices in meso-scale design and manufacture, illustrating ways to effectively combine several processes to produce a complex meso-scale device. Figure 4. The two faces of one of the caps. The two cylindrical protrusions, that are the reference surfaces, are 3.85 mm in diameter and the inter-axis spacing is 6.8 mm.

Each year, billions of dollars are spent by U.S. manufacturers to acquire hard and soft manufacturing technologies. Hard technologies are bundle of equipment, computer hardware and software such as computer numerical control, computer-aided manufacturing, robots, etc. In contrast, soft technologies are manufacturing techniques and know-how such as just-in-time, total quality management, statistical quality control, etc.-hardware is not essential to their successful use but can enhance their scope and effectiveness.

The majority of state-of-the-art speech recognition systems make use of system combination. The combination approaches adopted have traditionally been tuned to minimising Word Error Rates (WERs). In recent years there has been growing interest in taking the output from speech recognition systems in one language and translating it into another. This paper investigates the use of cross-site combination approaches in terms of both WER and impact on translation performance. In addition the stages involved in modifying the output from a Speech-to-Text (STT) system to be suitable for translation are described. Two source languages, Mandarin and Arabic, are recognised and then translated using a phrase-based statistical machine translation system into English. Performance of individual systems and cross-site combination using cross-adaptation and ROVER are given. Results show that the best STT combination scheme in terms of WER is not necessarily the most appropriate when translating speech.

Although efforts in this field are significant around the world, real prognostics systems are still scarce in industry. Indeed, it is hard to provide efficient approaches that are able to handle with the inherent uncertainty of prognostics and nobody is able to a priori ensure that an accurate prognostic model can be built. As for an example of remaining problems, consider datadriven prognostics approaches: how to ensure that a model will be able to face with inputs variation with respect to those ones that have been learned, how to ensure that a learned-model will face with unknown data, how to ensure convergence of algorithms, etc. In other words, robustness, reliability and applicability of a prognostic approach are still open areas. Following that, the aim of this paper is to address these challenges by proposing a new neural network (structure and algorithm) that enhances reliability of RUL estimates while improving applicability of the approach. Robustness, reliability and applicability aspects are first discussed and defined according to literature. On this basis, a new connexionist system is proposed for prognostics: the Improved-Extreme Learning machine (Imp-ELM). This neural network, based on complex activation functions, enables to reduce the influence of human choices and initial parameterization, while improving accuracy of estimates and speeding the learning phase. The whole proposition is illustrated by performing tests on a real industrial case of cutting tools from a Computer Numerical Control (CNC) machine. This is achieved by predicting tool condition (wear) in terms of remaining cuts successfully made. Thorough comparisons with adaptive neuro fuzzy inference system (ANFIS) and existing ELM algorithm are also given. Results show improved robustness, reliability and applicability performances.

This article examines the measurement uncertainty in terms of the incident angle, the object colour and the measurement distance for a Computer Numerical Control (CNC) laser-scanning process. It describes a new method for predicting the measurement uncertainty that simultaneously considers all three parameters. A set of measurements with different values for these parameters was made in order to describe the measurement uncertainty for the whole measuring range of the laser-scanning device. The final result of this research is an equation model that allows an accurate prediction of the measurement uncertainty within the investigated measurement field while the results of the extrapolated measurement field give an accuracy of the prediction that is better than 15%. In general, the model can also be useful as a measuring guideline for any other laser-triangulation measuring device, although the values would need to be adapted to each particular device. The, thus, obtained equation model could then be implemented into automatic inspection/control lines or used for self-adaptive measuring CNC paths to perform measurements in the optimal measuring range for a particular surface.

We investigate in this paper a numerical method to control the temperature of an induction heating process through electric current parameters such as frequency and current voltage imposed to the terminals of the inductor. We seek a sinusoidal voltage function whose amplitude varies in time. For this, we use a two-dimensional induction heating model that involves a phase transition in which the magnetic field has only one nonvanishing component. The procedure can be extended to more sophisticated models without major modification of the optimal control problem. We present a numerical control algorithm and discuss numerical experiments that prove the efficiency of the procedure.

It is a fact that virtual training has been a scope of interest for vocational training for a very long time. However, it needs more time to be more common in all specific training fields. Focusing on Computer Numerical Control (CNC) Training, new developments in the CNC machinery produce a continuous demand on enhancing the programming and technical capabilities of the involved personnel. Training on CNC should follow similar developments and in particular in their programming capabilities, automation they offer and their technical capabilities. Based on these main objectives a Virtual Training Center (VTC) for CNC has been developed and it is presented in this paper. The VTC is the main result of a multilateral Leonardo Da Vinci project witch aims to promote and reinforce Vocational Training in CNC Machines.

Parameter kecepatan putaran dan kecepatan potong mempengaruhi kekasaran permukaan dalam proses pembubutan. Tujuan Penelitian ini mengetahui perbandingan tingkat kekasaran permukaan yang dihasilkan dari parameter kecepatan putaran tetap dan kecepatan potong tetap. Metode penelitian ini adalah penelitian eksperimen, dengan melakukan proses pembubutan bertingkat pada spesimen baja ST 37 di mesin NC PU 2A EMCOTURN 120. Jumlah spesimen sebanyak 6 spesimen, setiap spesimen dibubut bertingkat sebanyak 3 tingkat, setiap satu tingkat diuji sebanyak 3 titik kualitas permukaanya menggunakan “Surface Tester Mitutoyo SJ-201P”. Hasil penelitian dianalisis menggunakan statistik deskriptif dengan mengambil nilai rata-rata dari kedua parameter. Berdasarkan analisis data dari hasil penelitian yang dilakukan, kekasaran permukaan yang dihasilkan menggunakan kecepatan potong tetap (G96) lebih baik dibandingkan kecepatan putaran tetap (G97). Kecepatan potong tetap lebih stabil saat melakukan pemotongan dalam pembubutan bertingkat.

This paperwork deals with a low-cost actuation solution, based upon induction motors, which was seldom used in the motion control systems, especially for the machine tools feed drives. A simulation approach, based upon a mathematical model of the induction motor, for tuning the controllers of the systems is presented. Experimental researches developed upon a two axes motion control system, both axes being driven by alternating current asynchronous motors were also performed in order to test the proposed strategies. The asynchronous motors, used as actuation devices were equipped with incremental rotary encoders and controlled by vector frequency inverters and DSP motion control cards were used for position control.

This paperwork deals with a low-cost actuation solution, based upon induction motors, which was seldom used in the motion control systems, especially for the machine tools feed drives. A simulation approach, based upon a mathematical model of the induction motor, for tuning the controllers of the systems is presented. Experimental researches developed upon a two axes motion control system, both axes being driven by alternating current asynchronous motors were also performed in order to test the proposed strategies. The asynchronous motors, used as actuation devices were equipped with incremental rotary encoders and controlled by vector frequency inverters and DSP motion control cards were used for position control.

The problem illustrated in this paper is a special type of scheduling problem found in a re-entrant flow shop where two of its processes has high tendency of exhibiting bottleneck characteristics. The processes scheduling resembles a four machine permutation re-entrant flow shop with the process routing ofMl,M2,M3,M4,M3,M4 where Ml and M4 have high tendency of being the dominant machines. Due to the re-entrant and permutation nature of the process routing, the actual bottlenecks were identified as Ml and combinations of M4+M3+M4. Two makespan algorithms using absolute bottleneck analysis were developed for the identified bottleneck categories. Each algorithm was only valid under several conditions identified as absolute bottleneck conditions. Using these conditions, a constructive heuristic was then developed to solve for near-optimal scheduling sequence. The heuristic performance was evaluated for small, medium and large job numbers using random data. For small job numbers, the heuristic results were compared with the optimum makespan generated from complete enumeration. For medium and large job numbers, the heuristic performance is measured by comparing its makespan with the one generated by the NEH. At strong Ml and M4+M3+M4 dominance level, this heuristic shows slightly better makespan performance compared to the NEH for problems with large job numbers. For smaller job numbers, NEH shows its superiority.

Monitoring and control of machining systems has been shown to dramatically improve operation productivity and part quality; however, very little attention has been given to the coordination of multiple complex machining modules. The current practice is to design the module coordination and to debug the resulting computer code in an ad hoc manner. In this paper, the concept of supervisory machining control, in the context of machining module regulation, is presented. The structure of, and elements contained in, a supervisory controller are detailed, and a systematic design procedure for constructing these controllers is presented. The design procedure is utilized to construct a supervisory machining controller which is experimentally implemented in a face milling operation.

Computer Numerically Controlled (CNC) laser cutting machines are capable of producing high-quality precise parts. However, as cutting speeds is increased, in order to achieve higher productivity, the accuracy of the parts is affected. In order to improve the contouring accuracy of these machines, a simple straight-forward joint simulation and experimental strategy is proposed. The position controllers within the feed drives are considered the key factor in improving the dynamic behavior and consequently the contouring accuracy of a CNC laser cutting machine at the shop floor level.

Computer Numerically Controlled (CNC) laser cutting machines are capable of producing high-quality precise parts. However, as cutting speeds is increased, in order to achieve higher productivity, the accuracy of the parts is affected. In order to improve the contouring accuracy of these machines, a simple straight-forward joint simulation and experimental strategy is proposed. The position controllers within the feed drives are considered the key factor in improving the dynamic behavior and consequently the contouring accuracy of a CNC laser cutting machine at the shop floor level.

While simulation has been successful in tying design and process planning into an iterative loop, machining has traditionally been a downstream terminus of the manufacturing cycle. Simulation of machining has proven difficult due to the highly dynamic and nonlinear nature of the material removal process. Consequently, actual machining must be performed to determine the suitability of designs and process plans. The nature of the programming interface to machine tools has been an obstacle to information flow in both directions. Toward the machine tool, useful design and process information is reduced to primitive tool path motion statements. From the machine tool, no automatic data paths exist, so machinists must translate results into recommendations for design or process changes manually. The advent of STEP (ISO 10303) data for numerical control, or STEP-NC, promises to rectify these problems by providing full product and process data to the machine tool controller at run time and an automatic path back to these upstream activities using technologies such as XML. This paper describes STEP-NC and early experiences that show how these benefits can be achieved.

This paper introduces an adaptive fuzzy logic controller (AFLC) for precision contour machining which adjusts both input and output membership functions simultaneously. The parameters of the proposed controller are self-tuned in real-time according to a continuous measurement of the performance of the controller itself and estimated disturbance values. The adjustment of the membership functions are restricted within a stable range derived from a stability analysis. The proposed controller as well as a conventional fuzzy logic controller and a PID controller were simulated and implemented on a 3-axis milling machine in contour milling. Both the simulations and experiments show that the AFLC can provide superior performance in terms of contour tracking accuracy compared with the other two controllers particularly in machine tool systems where friction is a serious problem in the feed drives.

It is a fact that virtual training has been a scope of interest for vocational training for a very long time. However, it needs more time to be more common in all specific training fields. This paper presents the development of a Virtual Training Centre (VTC) to promote and reinforce Vocational Training in Computer Numerical Control (CNC) Machines. "Virtual Training Centre for CNC" is a multilateral LdV project and of high importance in terms of virtual teaching and learning in vocational education and training. This virtual training environment is based on a common curriculum developed by the project partners. Since it is an interactive training tool, accessibility is the most important advantage over other training tools in VET.

Purpose -The purpose of this paper is to study the effect of the height and diameter of the dies as well as work-piece dimensions, on stresses and strains on dies in the forging process. This helps in developing a better understanding of the effect of process parameters. As a result, the manufacturing task could be accomplished with minimal number of trials. Design/methodology/approach -After determining the most influencing parameters on the forging process, the mechanical part is drawn, size of initial billet and shape of punch and die are also determined to build a finite-element model to represent the process. Several outputs are taken as an indication for die wear and process performance. Finally, a computer numerical control (CNC) code to manufacture the selected die is generated. Findings -It was found that when the die diameter increases, the effective stress decreases. On other hand, it was found that the work required to finish the forging process is highly affected by the dimensions of work-piece. Therefore, it is possible to save power if work-piece dimensions are adjusted. Originality/value -This paper was meant to be a universal step or guide in developing a computer aided design/computer aided manufacturing (CAD/CAM) system to design, simulate, and manufacture molds for the forging process using a statistical method.

The industry of machine tools keeps a constant progress that responds to the most demanding market requirements, such as production-time decreasing and zero-defect manufacturing. As part of this progress, sensors and monitoring instruments have been integrated on machine tools, improving computer numerical control (CNC) and monitoring during the manufacturing process. The vibrations are one of the most significant variables to be monitored on machine tools since they directly affect the end piece finishing, tool life expectancy, general machine-tool condition, current consumption, etc. Time domain, fast Fourier transform (FFT), and discrete wavelet transform (DWT) are techniques often used for vibration analysis, because they are computationally efficient for online implementation; unfortunately, it is difficult to find an instrument for vibration analysis that allows individually applying the time, FFT, and DWT techniques, and their fusion. Moreover, the lack of instruments with characteristics such as open architecture, low cost, parallel processing, and continuous online monitoring is remarkable. The contribution of this work consists of developing a vibration-analysis instrument based on the time, FFT, DWT, and DWT-FFT fusion techniques. The instrument is implemented into a low-cost field-programmable gate array with proprietary hardware signal-processing cores in parallel for achieving real-time and continuous online analysis. Experimentation is done to show the proposed methodology efficiency and the developed-instrument versatility, focusing on industrial control applications for CNC machine tools.

This paper presents an effective patient-specific approach for prediction of failure initiation and growth in human vertebra using the general framework of the quantitative computed tomography (QCT)-based finite element method (FEM). The studies were carried out on 13 vertebrae (lumbar and thoracic), excised from 3 cadavers with the average age of 42 years old. Initially, 4 samples were QCT scanned and the images were directly converted into voxel-based 3D finite element models for linear and nonlinear analyses. The equivalent plastic strains obtained from the nonlinear analyses were used to predict the occurrence of local failures and development of the failure patterns. In the linear analyses, the strain energy density measure was used to identify the critical elements and predict the failure patterns. Subsequently, the samples were destructively tested in uniaxial compression and the experimental load–displacement diagrams were obtained. The plain radiographic images of the tested samples were also examined for observation of the failure patterns. In continuation, the presence of osteolytic defects in vertebrae was simulated by creation of artificial cavities within 9 remaining samples using a computer numerical control (CNC) milling machine. The same protocol was followed for scanning, modeling, and destructive testing of these samples. A strong correlation was found between the predicted and measured strengths. Finally, a typical vertebroplasty treatment was simulated by injection of low-viscosity bone cement within 3 compressed samples. The failure patterns and the associated load levels for these samples were also predicted using the QCT voxel-based FEM.

In the experiment, 24 samples of data has been tested in real machining by using uncoated, TiAlN coated, and SN TR coated cutting tools of titanium alloy (Ti-6Al-4v). The fuzzy rule-based model is developed using MATLAB fuzzy logic toolbox. Rule-based reasoning and fuzzy logic are used to develop a model to predict the surface roughness value of end milling process. The process parameters considered in this study are cutting speed, feed rate, and radial rake angle, each has five linguistic values. Nine linguistic values and twenty four IF-THEN rules are created for model development. Predicted result of the uncoated, TiAlN coated, and SN TR coated has been compared to the experimental results, and it gave a good agreement with the correlation 0.9842, 0.9378 and 0.9845, respectively. The differences of the uncoated, TiAlN coated, and SN TR coated between experimental results and predicted results have been proven with estimation error value 0.00025, 0.0015 and 0.0008, respectively. It was found that by applying SN TR coated cutting tools with the recommended combination of linguistic values might gave best surface roughness values.

This paper presents a real time simulation for virtual end milling process. A virtual end milling process was simulated and the flank wear graphs of the cutting tools can be visualized during the machining process. The prototype of the 3D virtual environment which is based on the standalone concept has been developed using AutoCAD 2002, VRML Out, VRML Pad, JavaScript and Java. AutoCAD 2002 was used to model the 3D objects and then the models were transformed into VRML format using VRML Out. Java, JavaScript and VRML were used to develop the animation of end milling process simulation and machining parameters simulation such as the flank wear on cutting tools. The simulation for the geometrical modeling of end milling process and analytical modeling of machining parameters was developed based on real data from some experiments using Computer Numerical Control (CNC) milling machine. The experiment for this study is divided into two categories, 100% full engagement milling and 15% engagement down milling with two different types of feed rate, 0.02 mm/rev and 0.04 mm/rev. This application can simulate the virtual end milling process and real time graph of flank wear (mm) against cutting time (min) on tool cutter simultaneously. The user can also analyze parameters that influenced the machining process such as cutting speed, feed rate of worktable or types of engagement against the flank wear on cutting tools and the tool life of cutting tools used.