Informatics Publishing Limited

K. T. Navya ¹, V. Shanmugaraj ¹, G. C. Mohan Kumar ², P. V. Shashikumar ³

Affiliations
1 National Institute of Technology, Karnataka, Surathkal, IN
2 Mechanical Dept., National Institute of Technology, Karnataka, Surathkal, IN
3 Central Manufacturing Technology Institute, Bengaluru, IN

Abstract

The proposed paper aims at designing a real time precision positioning control circuitry for a numerical control device used to control a machine tool with encoder type feedback. More particularly it is intended to design a digital compensating circuit for modifying a position control signal to effect a correction for repeatable linear errors such as the dimensional changes in the machine structure due to changes induced into the structure by operating temperature ranges. The error correction is performed by modifying encoder type position feedback signals supplied to the machine tool controller. This provides real time compensation for thermal errors in positioning of computer numerically controlled machine tools, coordinate measuring machines (CMMs), robots, assembly systems, and the like.

The error correction being accomplished by the Error Correction Circuit(ECC), which adds or subtracts a predetermined number of pulses to the pulses coming from a feedback device such as encoder to compensate for over shoot or under shoot of the machine tool respectively.

Keywords

Elongation of Ball Screw, Encoder Feedback Pulses, Pulse Addition and Subtraction, Thermally Induced Errors.

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Nitin K. Nandeshwar ¹, V. Shanmugaraj ², Vijay Desai ¹, P. V. Shashikumar ³

Affiliations
1 National Institute of Technology, Karnataka, Surathkal, IN
2 Central Manufacturing Technology Institute, Bengaluru, IN
3 Central Manufacturing Technology Institute, Bengaluru

Abstract

Among the factors affecting machine tool accuracy, thermally induced errors are considered to be significant. Thermal effect on machine tools is a well-recognized problem in an environment of increasing demand for product quality. Machine tool thermal distortion accounts for 75 percent of the total machining error. Thermal error models are derived based on the temperature variations data collected from the specified temperature sensors. As a result there has been a great deal of interest in techniques for reducing thermal errors. Error compensation technique is widely used to reduce the thermal errors. The performance of a thermal error compensation system typically depends on the accuracy and robustness of the thermal error model. The general practice is that temperature sensors are mounted at different locations on important elements of machine tool and temperature rise or fall is monitored at a constant interval of time. Based on the temperature measurements, the correction value to be given for each and every slide is computed. This correction value is used to either modify the tool offset table directly or passed on to the servo controller for further action. In the present work a fast and low cost thermal error measurement and compensation system developed and the simulation results are verified through experiments.

Keywords

Machine Tool, Real-Time, Temperature Measurement, Error Compensation, Embedded Controller.

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V. R. Raju ¹, C. K. Srinivasa ¹, A. R. Vinod ¹, M. Chellamalai ¹, P. V. Shashikumar ¹

Affiliations
1 Central Manufacturing Technology Institute, Tumkur Road, Bangalore, IN

Abstract

Electrical Discharge Machining (EDM) is one of the non-conventional machining processes used for machining of electrically conductive materials. Mechanism of material removal in EDM is based on conversion of electrical energy into thermal energy. In this paper, copper electrodes of diameter 0.1, 0.4 and 0.8 mm were used for machining holes on steel work-piece to a depth of 0.2 mm by micro-EDM process. Experiments were conducted at a capacitance of 0.001, 0.01, 0.1 and 0.4 μF with a gap voltage of 80 V and the electrode was rotated at 100 rpm during ED machining. Wear on the electrode; surface roughness and the size of the machined hole were measured. Capacitance had a profound influence on the material removal rate, volumetric wear ratio, spark gap and surface roughness of work-piece.

Keywords

EDM, Micro-Holes, Electrodes, Wear, Capacitance, Spark Gap.

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M. Girish Kumar ¹, Prakash Vinod ¹, P. V. Shashikumar ¹

Affiliations
1 Nano Manufacturing Technology Centre, Central Manufacturing Technology Institute, Bangalore, IN

Abstract

Nanotechnology deals with particles and system with dimensions of approximately 1 to 100 nanometers. The environment factors like ground vibration, temperature, humidity, acoustics, air velocity, Electro Magnetic Interference, Illumination and cleanliness will limit the performance of equipments used in nano manufacturing. Among all the environmental factors, ground vibration plays a major role in limiting the performance of the equipment. Some aspects of nanomanufacturing facilities like nanofabrication, nanometrology requires extremely stable environment with very stringent limits of ground vibration. This paper is focused on the study of vibrations induced by metro train movement. The study reveals that, the vibration induced by metro train is exceeding the limits as per the standard set by the National Institute of Standards and Technology (NIST).

Keywords

Vibration, Rail, Nano Metrology, Nanotechnology, Nanomanufacturing.

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C. Rajesh Kumar ¹, V. Shanmugaraj ¹, Prakash Vinod ¹, P. V. Shashikumar ¹

Affiliations
1 Central Manufacturing Technology Institute, Bangalore, IN

Abstract

In Ultra precision machining best results are obtained with on-line monitoring and adaptive control of various process parameters during machining. For a reliable on-line process monitoring and error compensation system, it is necessary to have accurate sensor readings. However, sometimes sensors may become faulty and due to failure it gives erroneous or constant values throughout the process. The problem of sensor validation is therefore a critical part of effective process monitoring. The objective of this study is to develop a sensor fault detection module which will be useful for different error compensation /diagnostic techniques needed for the ultra precision machine. A procedure based on Principal Component Analysis (PCA) is developed, which enables to perform detection and identification of sensor failures. PCA is a data driven modelling that transforms a set of correlated variables into a smaller set of new variables (principal components) that are uncorrelated and retain most of the original information. This new index is proposed in order to detect simple and multiple faults affecting the process and diagnose abnormalities in the original system in a robust way. The PCA model maps the sensor variables into a lower dimensional space and tracks their behaviour using Hot teling T² and Q statistics.

Keywords

PCA, Scores, Faulty Sensor, HottelingT², Artificial Drifts, Q Statistics.

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S. Usha ¹, P. V. Shashikumar ¹, G. C. Mohan Kumar ², S. Srikantharao ²

Affiliations
1 Central Manufacturing Technology Institute, Tumkur Road, Bangalore, IN
2 NITK, Suratkal, Mangalore, IN

Abstract

Semiconductor device fabrication process is the most sophisticated and complex manufacturing process. Advances in the manufacturing processes has brought down the feature size of gate to as low as 22 nm. Hence there is a great demand for process control of feature dimension below the resolution limit of visible wavelength microscopy. Lot of research has been focused on increasing the resolution of the metrology tools. We have adopted a novel optical technique that shows nanoscale measurement sensitivity using conventional optical microscopes. Here through-focus images are acquired at different focus positions. These focused and defocused images are used to build an intensity map whose signature reflects the target pattern. This technique is used to identify relative nanoscale change in dimension between two targets by finding the change in the signature of the intensity map.

Keywords

Through Focus Imaging, Focus Metric, Through Focus Signature, CD Metrology, Nano Metrology, Diffraction Limit.

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Megha Agrawal ¹, G. V. Anusha ¹, N. Kusuma ¹, P. V. Shashikumar ¹

Affiliations
1 Central Manufacturing Technology Institute, Bangalore, IN

Abstract

The work presented in this paper involves design, analysis and simulation of micro fixed-fixed beam as a capacitive pressure sensor which is designed by using PolyMUMPs: Polysilicon Multi User MEMS Process. By applying a pressure on the top of fixed-fixed beam, the mechanical force pulls the beam down and increases the capacitance. The change in length of the beam influences the range of applied pressure while the effect of beam width on this is negligible. The PolyMUMPs was developed by MEMSCAP foundry focusing on the fabrication, reliability and cost effectiveness. This presented MEMS pressure sensor is capable of measuring pressure between 0.1MPa to 1.7 MPa which is useful in various field of applications.

Keywords

Polymumps, MEMS, Beam, Pressure Sensor.

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K. Niranjan Reddy ¹, N. Balashanmugam ¹, P. V. Shashikumar ¹

Affiliations
1 Central Manufacturing Technology Institute, Tumkur Road, Bangalore, IN

Abstract

With the objective of catering the R&D needs of machine tools and allied areas in focus, along with the basic infrastructure of the institute, various laboratories including metrology laboratory were setup in CMTI to support developmental activities and to assist prototype workshop. With the advancement of time, these laboratories started catering to the needs of industries throughout India. Over last 5 decades, CMTI had significantly contributed in Product development, Technology development, Training, Framing Standards, Development of Artefacts in Metrology field. CMTI has been a forerunner in all the above aspects in the country particularly in dimensional and surface metrology.

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Prakash Vinod ¹, M. Girish Kumar ¹, P. V. Shashikumar ¹

Affiliations
1 Nano Manufacturing Technology Centre, CMTI, Bangalore, IN

Abstract

Nanometrology deals with measurements and analysis of dimensions of approximately 1 to 100 nanometres as well as measurement of force, electrical, magnetic and optical properties and to correlate the measured size with properties. Some aspects of this work require extremely stable environments. Very stringent limits are often required on environmental vibration and noise, temperature, EMC, Illumination and Clean Room requirements. The environmental requirements of Nanometrology from the perspective of designing of an advanced Nanometrology laboratory are studied and reviewed in this paper. A desirable environment at a site may be adversely affected by ground vibration from a variety of sources such as road traffic, metro train movements, utility plants and the construction. The environment inside the lab is also affected by temperature fluctuation, humidity, acoustics disturbances, air velocity, EMC, Illumination and cleanliness. All these factors affect the nano level measurements. This paper addresses various environmental conditions, its potential effect on nano level measurements and environmental conditions to be maintained for a nano metrology laboratory.

Keywords

Ground Vibration, Nano Metrology, Noise, Temperature, Humidity, Metro Train, EMI/EMC, Airflow, Cleanroom, Vibration Isolation.

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A. Murugan ¹, R. Ramesh ², P. V. Shashikumar ³

Affiliations
1 Ultra Precision Engineering Department, Central Manufacturing Technology Institute, Tumkur Road, Bangalore, IN
2 Laboratory of Molecular Imaging, Department of Biomedical Science, CHA University, 605-21 Yoeksam 1-dong, Gangnam-gu, seoul-135-081, KR
3 Central Manufacturing Technology Institute, Tumkur Road, Bangalore, IN

Abstract

In the report presents on a multi-color fluorescent and water soluble carbon nanoparticle (CNPs) were fabricated by a facile one-step hydrothermal method by using L-Ascorbic Acid as a carbon source. Height distribution of Atomic Force Microscope (AFM) image revels CNPs are monodisperse having average size of 5.0 nm with narrow distribution. Raman analysis shows, as synthesized CNPs having sp² hybridization of carbon having graphite crystalline structure. The CNPs could emit bright and colorful photoluminescence (PL) which covering the entire visible to Near Infrared (NIR) spectral range. Moreover, these particles also had excellent up conversion fluorescent properties over the range.

Keywords

Nanoparticles, Carbon, Multi-Color Fluorescence, Hydrothermal Method, Carbonization.

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A. R. Vinod ¹, C. K. Srinivasa ¹, R. Keshavamurthy ¹, P. V. Shashikumar ¹

Affiliations
1 Central Manufacturing Technology Institute, Tumkur Road, Bangalore, IN

Abstract

Direct Metal Deposition (DMD) is an additive manufacturing process for fabrication of metal parts directly from CAD model using high power lasers as heat source. In this paper, bronze nickel material was deposited on steel substrate by DMD process. Laser power was varied from 100 to 300 W in steps of 50. Laser scan speed, powder flow rate, nozzle stand-off and step-over were maintained at 165 mm/min, 1.2 g/min, 10 mm and 0.15 mm respectively. Laser power had a significant influence on the quality of joint between bronze nickel and steel.

Keywords

Additive Manufacturing, DMD, Laser, Dissimilar Materials.

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Prakash Vinod ¹, J. Ramachandra Kiran ¹, M. Girish Kumar ¹, P. V. Shashikumar ¹

Affiliations
1 Micro Engineering and Nano Technology Dept, Central Manufacturing Technology Institute, Bangalore, IN

Abstract

Nanometrology deals with measurements and analysis of dimensions of approximately 1 to 100 nanometres. Some aspects of this work require extremely stable environments. Very stringent limits are often required on environmental vibration and noise, temperature, EMC, Illumination and Clean Room requirements. The environmental requirements of Nanometrology from the perspective of designing of an advanced Nanometrology laboratory are studied and reviewed in this paper. A desirable environment at a site may be adversely affected by ground vibration from a variety of sources such as vehicle traffic, rail, utility plants and the construction. The environment inside the lab may be also affected by temperature fluctuation, humidity, acoustics disturbances, air velocity, EMC, Illumination and cleanliness. All these factors affect the nano level measurements. This paper addresses various environmental conditions to be maintained for establishment of a nano metrology laboratory and its potential impact on nano level measurements.

Keywords

Nano Metrology, Vibration, Noise, Temperature, Humidity, Traffic, Rail.

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S. Sathiyamurthy ¹, A. Syed Abu Thaheer ², U. Natarajan ², P. V. Shashikumar ³, M. Chellamalai ³

Affiliations
1 A C College of Engg. and Technology, Karaikudi, IN
2 Dept. of Mechanical Engineering, A C College of Engg. and Technology, Karaikudi, IN
3 Central Manufacturing Technology Institute, Tumkur Road, Bangalore, IN

Abstract

In this paper, the influence of micro-EDM-drilling process variables on surface roughness using an integrated multi-process micro machining machine (IMMM) is presented. The machining parameters considered are feed rate, capacitance & voltage and response parameter is surface roughness. Experiments are designed as per full factorial design using Design of experiments. Response surface methodology approach is used for modeling the surface roughness and finding out the optimal values of drilling parameters. The influence of each drilling parameter in micro-EDM process is characterized and the optimum value of parameters is determined. The interaction effects of parameters on surface roughness are discussed and the mathematical model and optimized parameters are validated for micro-EDM-drilling process.

Keywords

Surface Roughness, Full Factorial Design, Response Surface Methodology Micro-EDM.

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N. Balashanmugam ¹, P. V. Shashikumar ¹

Affiliations
1 Micro Engg. and Nano Technology Division, Central Manufacturing Technology Institute, Tumkur Road, Bangalore-560022, IN

Abstract

Miracles are indeed happening around the world with the wide and continuously expanding applications of Laser. Pulsed lasers show its supremacy over continuous wave lasers in micro machining. Solution seems to be available to machine any material in nano metric range with laser. New lasing materials available in the present day are aiding this objective. Ultra short pulse lasers generate curiosity in the field of micro machining as its application area is rapidly increasing.

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M. Girish Kumar ¹, Prakash Vinod ¹, P. V. Shashikumar ¹

Affiliations
1 MNT Dept., CMTI, Bangalore, IN

Abstract

Unbalance in rotating machinery is a common source of vibration in many applications and has a strong impact on the performance, accuracy of product and life of the rotating system. Generally, the dynamic balancing of rotors are carried out with the help of FFT Analyzer with expensive balancing software. Most of the commercially available balancing programs are not flexible, requires input like exact location o f the trial mass with respect to reference mark and do notallow intervention in between balancing procedure and in case of any mistake, the entire procedure need to be repeated. There are other methods for dynamic balancing like graphical method and trial and error method is cumbersome and prone to errors. This paper gives details on the development of an analytical method for dynamic balancing, which can be used with normal FFT Analyzer (with amplitude and Phase information). This method is inexpensive, easy to use, flexible and requires less time. This method provides correction mass and its angle with respect to the trial mass position. The developed analytical method has been validated by graphical method, experimental data and practical cases.

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A. Raghunatha ¹, P. V. Shashikumar ¹

Affiliations
1 Micro Engineering and Nano Technology Dept., Central Manufacturing Technology Institute, Tumkur Road, Bangalore, IN

Abstract

Geometric Dimensioning and Tolerancing (GD&T) is an international and exact language that enables the designers to "say what they mean" on a drawing. It consists of a well-defined set of symbols, rules, definitions, and conventions that can be used to describe the size, form, and orientation and location tolerances of part features. It is a precise language & must be used precisely. Reference datums are critical & symbols must be used in precise order. Many errors can occur when inexperienced designers try out GD&T. This article Is intended to stress the need for gaining more knowledge in the area of GD&T. Many technical personnel and managers in particular are finding difficult to understand and use the drawing coming across their desks. Perhaps they need to know more about the various aspects of the GD&T representations used in the engineering drawings such as fundamental dimensioning rules, basic tolerancing concepts, geometric tolerancing symbols, definitions and representations, positional tolerancing, reference datum, definition and usage of material condition modifiers, etc.

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A. Raghunatha ¹, A. V. Srinivasa Rao ¹, P. V. Shashikumar ¹

Affiliations
1 Central Manufacturing Technology Institute, Bangalore, IN

Abstract

Surface topography and profile play very important role in the performance of components in some high precision applications. Only when advanced technology is coupled with proper measuring and environment conditions nanometric level measurements are possible. Sometimes even improper selection of probes, measuring speed and other parameters, setting of component for measurement, measuring environment, etc could lead to erroneous results. In depth evaluation of these aspects using advanced machines and methods is very crucial for proper analysis of the behaviour of the components under different conditions.

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