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Noise and Vibration

Noise and Vibration Laboratory, caters to the measurement of parameters like Force, Displacement, stress and strain in machine tools and components. The laboratory is equipped with qualified, trained and experienced Technical Staff and state of the art facility for measurement and analysis of various parameters such as Noise, Vibration, Force, Pressure, Strain, Torque, Speed, Temparature, etc
 
Noise and Vibration laboratory at CMTI :
 

  • Is capable of investigating ’one off’ problems from fundamentals and offer technology solutions
  • Equipped with qualified and trained man power in noise and vibration and instrumentation.
  • Equipped with measuring and analysis equipment which are configured on a case-to case basis in tune with the needs of the situation/problem being investigated.
  • Partnered and added value to the efforts of customers in enhancing their productivity, product quality and improving environmental conditions.
  • has design and development capability for modernizing testing equipment and systems
  • has trained customers in noise and vibration aspects

 

 
ACTIVITIES:
 
The Main areas of activity of the laboratory are:
 

  • Providing measurement and analysis assistance in NOISE & VIBRATION of machinery and environment at industrial sites and in-house
  • Problem investigation, analysis and mitigation - both immission and emission aspects of noise and vibration
  • Dynamic behaviour studies (Transfer Function (FRF), Compliance frequency and Dynamic stiffness measurements) , modal analysis of structures & machinery & Operation Deflection Shapes (ODS) Analysis.
  • Dynamic balancing of rotors:IN-SITU using portable equipment and on balancing machines -- special ultra precision balancing tasks
  • Assisting industries to adapt Predictive Maintenance practices through vibration monitoring.
  • Condition monitoring of machine tools, machines, transformers, circuit breakers, motors, control panels, furnaces etc., through Infrared Thermography.
  • Thermal Mapping, investigation and condition monitoring: Improving the machine design by experimentally evaluating heat zones, heat flow pattern, thermally induced stresses and in investigating the thermo elastic behaviour of machines, condition monitoring of machines, structures, Electrical Panels, etc….
  • Measurement of torque, force, pressure, strain, speed etc...,
  • Environmental Noise & Vibration assessment (ground vibration measurement and analysis)
  • Sound intensity analysis for sound power measurement, noise mapping, noise source identification and ranking
  • Calibration of noise/vibration transducers, instruments
  • Training and Consultancy in Noise and Vibration and Condition Monitoring

 

 
Noise and Vibration Infrastructure facilities ;
 
Table -1 and Table -2
 

 

Case studies

 

Case-1--  We can measure and evaluate very low levels of airborne and structure borne noise...

Case-2--  We can measure extremely low level and low frequency vibrations... 

Case-3--  We have undertaken ‘servicing of equipment’ even in cases where complete information was not                                                       available...have found innovative ways to handle obscure situations....

Case-4--  We can carry out Precision in-situ balancing of ultra precision spindles

Case-5--  We have assisted in product quality enhancement ....have actively contributed in technology upgradation                                             efforts of industries and institutions...

Case-6--  Noise & Vibration Analysis & Migration Of Motor Cycles

Case-7--  We have the comfort, the ergonomics and health aspects investigated with reference to noise and vibration norms.....

Case-8--  We have contributed to product quality enhancement even in already well established products in the market place......

Case-9--   We have investigated the big and the small alike.....

Case-10-- We have investigated the machine vibrations by modal analysis

Case-11-- Experimentation to study the chatter in micro end milling by measurement & analysis of Cutting Force and Vibration

Case-12-- Measurement of Damping Factor of Concrete Filled Fabricated Bed

Case-13-- Acoustic & Vibration analysis of tractor for mitigation of Noise.

Case 14-- Ground vibration measurement for assessing the vibration induced due to Metro Train Movement.

 

Table-1 List of transducers available in the laboratory

 

Transducers

Description

Accelerometers

  • High Sensitivity industrial accelerometers with different frequency ranges
  • Low ‘g’ accelerometer for measuring very low level and low frequency vibration measurement.

Accelerometers for measurement of Shocks

Microphones

Precision grade microphone of 1/4”, 1/2” and 1” size with suitable preamplifiers

Force transducers

  • Piezoelectric type for dynamic load/force measurement

 

Pressure transducers

Strain gage based and Piezoelectric pressure transducers for static and dynamic measurement respectively

Displacement pickups

LVDTs of various range, contact and non contact Displacement transducers for different situations

Torque transducers

Strain gage based torque transducers 5kg-m and 50kg-m capacity.

Tachometer Probes

  • Measures speed up to 1,00,000 rpm

Low “G” Ultra low noise Accelerometers

  • Low ‘g’ , High Sensitivity, measuring very low frequency, low level vibrations

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Table-2 List of instruments  available in the laboratory

 

Instruments and Accessories

Description

Pre amplifiers and signal conditioners

  • Charge Amplifiers for accelerometers microphone pre-amplifiers
  • Delta Tron Conditioning Amplifiers for ICP accelerometers
  • Tuneable and band-pass filters

Precision Voltmeters for true rms measurements

Precision Sound Level Meters with 1/1 and 1/3 octave filters

  • Precision Integrating Sound Level meters Type-0 and Type-1 as per IEC

 

2 - Ch. FFT analysers/ Multi Channel PC Based FFT analyzer

  • Portable analyser for Vibration, noise measurement and analysis, order tracking, sound intensity measurement.

 

Data collector/ Vibration analyser/ Field Balancer

  • For noise and vibration measurement, Route Base Data Collection, Analysis and in-situ dynamic balancing of rotors

Signal generators

  • For various types of signal and waveform generation and arbitrary wave form generator

Electrodynamic shakers

  • Used to excite the structures in vibration test and also used for accelerometer calibration. Max. pay load 10kgs

Calibration equipment

For calibration of transducers and instruments used in noise and vibration measurement (Example: Accelerometers, preamplifiers, microphones and sound level meters.

Sound Intensity Analysers

PC based Sound intensity measurement & Analysis system for Noise source Identification and ranking, Noise level contour mapping and sound power measurement

Non Contact Laser Vibrometer

Portable Non-Contact Precision vibration measurement from a distance up to 30 meters for special applications

Dynamic Balancing Machines

  • For Dynamic Balancing of various types of rotors

DAT Recorders

 

  • Portable, Battery operated 8 Ch DAT recorder for recording dynamic signals in field and laboratory

Digital Storage Oscilloscope

  • Portable, Battery operated  2 Channel storage oscilloscope -100mhz

Carrier Frequency Amplifiers

  • Max. 6 channels - Used in strain gage based measurements

Machinery Health Analyser/

ODS and Modal Analysis

  • CSI 2130A2 with Machinery health manager, Advanced vibration analysis, Advanced cross channel analysis, ODS (Operation Deflection shape) & Modal analysis softwares

Multi Channel Vibration and Mode Shape Analyser

  • Portable, Battery operated 8 Channel with advanced noise and vibration analysis software like FFT, Waterfall, Octave, Order Tracking, Modal Analysis Software, Data Recording, Multi Analysis software.

Infrared Thermography System

  • Portable, Battery Operated used in improving the machine design by experimentally evaluating heat zones, heat flow pattern and thermally induced stresses. The system should help in investigating the thermo elastic behaviour of machines. 

Condition monitoring of machine tools, machines, transformers, circuit breakers, motors, control panels, furnaces etc.,

Portable Hand Held Calibration Exciter

  • Portable Handheld accelerometer calibration exciter for field calibration check of transducers

Tachometer Probes

  • High Speed Measurement used with Noise and Vibration Analysers. Output signal can be recorded.

AE Measurement and Analysis System

  • Occurrence of crack, location of defects and Tool Condition Monitoring.

Multi-Component Force Dynamometer- MiniDyn 9256C1

 

  • Measurement of three orthogonal components of cutting forces in ultra precision machining such as Diamond turning, machining of hard & brittle material and high speed machining, etc. 

 

Low “G” Ultra low noise Accelerometers

  • Wilcoxon Low ‘g’ , High Sensitivity Accelerometer for  measuring very low frequency, low level vibrations

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Glimpse of challenging tasks executed:

 

Case-1-- We can measure and evaluate very low levels of airborne and structure borne noise...

 

VERY LOW NOISE LEVEL MEASUREMENT AND EVALUATION

 

Task: Measurement of very Low level Power Transformer Noise and sound power estimation as per IEC-551-1987 standard:

 

Transformer detail: 800KVA step-down transformer (11kV/433V)

 

Order of noise level:  typically 38 dBA

 

As the difference between background noise level and combined noise level (background noise+ transformer noise when energised) was very less (< 3 dB) the measurement of noise level of transformer alone was difficult.

 

This was due to differentiating the background noise from transformer noise whose levels were of the same order;

 

The problem was sorted by obtaining 1/3 octave spectra of background noise and combined noise.  As the transformer noise was mainly at 50 Hz and its harmonics the measurements were validated by spectral contents at these frequencies.

 

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Case-2 -- We can measure extremely low level and low frequency vibrations...

 

EXTREMELY LOW LEVEL AND LOW FREQUENCY VIBRATION MEASUREMENT AND EVALUATION

 

Task: Measurement of very low frequency and low amplitude ground vibrations:

 

These measurements were made with the help of Low ‘g’ accelerometers (B&K type 8306) having sensitivities of the order 1V/g.  The orders of vibrations were 10-3 g between 0.5 Hz to 10 Hz.

 

Such measurements were required for estimation of ground vibrations in machine shops and rooms which houses precision measuring equipment such as CMM, Form testers etc., and to suitably select isolation systems or special foundations. Such low frequency vibrations will affect the quality of the components manufactured from precision machines and quality of the measurement results from precision measuring equipment.   CMTI also used this type of measurements to identify the best location within the campus for its PRECISION ENGINEERING CENTRE.

 

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Case-3-- We have undertaken ‘servicing of equipment’ even in cases where complete information was not available...have found innovative ways to handle obscure situations....

 

SERVICING, ASSEMBLY, ALIGNMENT AND IN-SITU BALANCING of PRECISION AIR BEARING SPINDLES used in page fax machines in news paper industry.

 

Earlier the damaged spindles were being sent back to the manufacturer (to USA) for service and repair.  This involved both time and cost.  The serviced spindles with polygon mirror required realignment and balancing for vibration free operation to obtain clarity transmission of pictures and text. 

 

CMTI’s assembly and testing group under took the servicing and assembly of air bearing and Noise and vibration laboratory carried out the alignment and Balancing the spindle and polygon mirror.  

 

Air bearing spindle of pagefax machine

 

The vibration levels of the air spindles due to unbalance were brought down to the extent of 0.01 micrometers.

 

This service is offered to many News paper Industries such as  INDIAN EXPRESS, MALAYALA MANORAMA, TIMES OF INDIA, DECCAN HERALD etc.

 

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Case-4-- We can carry out Precision in-situ balancing of ultra precision spindles

PRECISION IN-SITU BALANCING OF SPINDLE OF ULTRA PRECISION DIAMOND TURNING MACHINE

 

Ultra Precision Turning Machine to obtain mirror finish using diamond turning tool

 

In-situ balancing of spindle with vacuum chuck running on aerostatic bearings of diamond turning machine (Ultra precision machine, First of its kind in India) was carried out to bring down vibration level down to few nano-meters level.

 

 

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Case5. -- We have assisted in product quality enhancement ....have actively contributed in technology upgradation efforts of industries and institutions...

 

A) NOISE SOURCE IDENTIFICATION AND RANKING OF TWO WHEELER

Noise source ranking by sound Intensity Technique

Task: Identification and ranking of different noise sources of a Two-Wheeler.

 

Customer: TVS-SUZUKI Ltd., Hosur.

Technique: Measurement of SOUND INTENSITY over a surface of a complex and multiple noise sources. 

Result: The investigation led to redesign of transmission element assembly features.

 

 

B) NOISE SOURCE IDENTIFICATION AND RANKING OF CIGARETTE MAKING M/C

Noise source ranking by sound Intensity Technique

Task: Identification and ranking of different noise sources of a Cigarette Making Machine

Customer: ITC Ltd., Bengaluru

Technique: Measurement of SOUND INTENSITY over a surface of a complex and multiple noise sources. 

Result: The investigation has helped in controlling Noise emitted by the machine.

 

C) NOISE SOURCE IDENTIFICATION AND RANKING OF TRACTORS

 

Noise source ranking by sound Intensity Technique

Task: Identification and ranking of different noise sources of Tractor

Customer: Eicher Tractors., Bhopal

Technique: Measurement of SOUND INTENSITY over a surface of a complex and multiple noise sources. 

Result: The investigation led to redesign of engine and transmission element assembly features. Predominant noise source components in the tractor are identified and ranked to help in product development to reduce the noise level further in order to meet the Environmental Norms.

 

 

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Case-6--NOISE & VIBRATION ANALYSIS & MITIGATION OF MOTOR CYCLES

Technique:   Noise and Vibration Analysis of Motor Cycles by Time Event Analysis, FFT Analysis, 1/3 octave analysis, Order Tracking & waterfall Analysis, Transfer Function Analysis of Motor Cycle Elements to identify the resonant frequencies. All these techniques are used simultaneously to identify improvement areas in the motor cycle.

 

Results: - We identified major improvement points for reduction of noise emitted from the engine for the customer. In the first instance engine noise level was brought down by 8 dBA

Customer: Royal Enfield Motors, Chennai.

 

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Case-7-- We have the comfort, the ergonomics and health aspects investigated with reference to noise and vibration norms.....

OPERATOR COMFORT EVALUATION IN AN EARTH MOVING EQUIPMENT:

Task: Measurement of seat vibration, noise at operator position and pass-by noise as per ISO and SAE standards respectively.

Result: - Improved design of seat isolators effected with a better understanding of the customer perception in respect of conflicting requirements arising for vibration isolation and damping during dumping operation and vehicle movement on plain ground.

 

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Case-8--We have contributed to product quality enhancement even in already well established products in the market place......

 

NOISE SOURCE RANKING AND NOISE CONTROL OF NAIL MAKING MACHINE:

Task: Ranking of various noise sources and control of noise by active and passive methods.

Technique:  Source ranking by Sound pressure level measurement with progressive assembly and Noise control by quality improvement of components and redesigning the machine guard for better noise insulation

Results: - We identified about 20 improvement points for the customer to deal with. In the first instance noise level was brought down by 5.5 dB.

Customer: National Wire Products, Rajkot

Noise Measurement/analysis of Nail Making Machine.

 

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Case 9-- We have investigated the big and the small alike.....

 

BALANCING OF 1000MW REACTOR COOLANT PUMP MOTORS USED IN NUCLEAR POWER PLANTS:

Task: In-situ Dynamic balancing of rotor of 1000MW reactor coolant pump motor, speed 3000 rpm

Results:- Vibration levels brought down to 0.001mm peak  - typically 100% reduction in vibration levels achieved. (More than 6 motors investigated)

Customer: NGEF, Bengaluru.

 

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Case 10-- We have investigated the machine vibrations by modal analysis

Vibration analysis by operational deflection shape of WIRE PAIRING MACHINE

Customer: M/s Garware Wall Ropes Ltd.., Pune

Results: Improved and light cradle system and better isolators resulting in better strand quality and reduced machine outage/interruptions.

 

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Case-11-- Experimentation to study the chatter in micro end milling by measurement & analysis of Cutting Force and Vibration

 

Customer: M/s IIT, Madras.

Results: This work has been carried out in association with M/s IIT, Madras in order to provide instrumentation and infrastructure to assist the research work. Improved and light cradle system and better isolators resulting in better strand quality and reduced machine outage/interruptions.

 

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Case-12-- Measurement of Damping Factor of Concrete Filled Fabricated Bed

 

Customer: M/s Aeromech Pvt. Ltd., Bengaluru.

Results: Damping factor of the concrete filled fabricated bed is better than the fabricated bed.

 

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Case-13- Acoustic & Vibration analysis of tractor for mitigation of Noise.

Customer: M/s Eicher Tractors Ltd., Bhopal.

Results: We identified major improvement points for reduction of vibration and noise emitted from the tractor for the customer.

 

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Case 14-- Ground vibration measurement for assessing the vibration induced due to Metro Train Movement.

 

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Customer: CMTI.

Results: This is a research work undertaken by NV Lab to assess the ground vibration induced due to Metro Train Movement and its impact on Nano Technology Laboratories.

 

CALIBRATION SERVICES:
 
CALIBRATION OF NOISE AND VIBRATION INSTRUMENTS AND TRANSDUCERS with traceability to International Standards.
 

  • Primary calibration of accelerometers and microphones by reciprocity technique
  • Secondary calibration (comparison method) of accelerometers
  • Calibration of sound level meters, vibration meters and FFT analysers.

 

 
SATISFIED AND EVER INCREASING CUSTOMER BASE
 
Noise and vibration laboratory has served a wide spectrum of industries ranging from Automobile to machine tool to Paper to Newspaper industries.
 

Contact: Girish Kumar, Sc-C
E-mail : girishkumar.cmti@nic.in

 



by Dr. Radut.