NON-CONTACT VIBRATION MONITORING FOR HIGH-SPEED MACHINE TOOLS

Authors:M. Klein

J. EichenbergerT. Delio

Machining Technology, 2005

Joel Shepherd

M.E. 482Oct 04, 2010

(High Speed Cutting)

References M Klein, J Eichenberger, & T Delio. (2005, October). Noncontact Vibration

Monitoring for High-Speed Machine Tools. Machining Technology, 16(4), 1-5.  Retrieved October 4, 2010, from ABI/INFORM Trade & Industry. 

Dane J.H., Topp G.C, co-editors 2002. "Methods of Soil Analysis Part 4-Physical Methods." Soil Science Society of America, Inc. Madison, Wisconsin.

Czarnomski N.M., Moore G.W., Pypker T.G., Licata J. 2005. "Precision and accuracy of three alternative instruments for measuring soil water content in two forest soils of the Pacific Northwest".Canadian Journal of Forest Research 35, 8, pg. 1867.

Russell, John (1848). "On certain effects produced on sound by the rapid motion of the observer". Report of the Eighteen Meeting of the British Association for the Advancement of Science (John Murray, London in 1849) 18 (7): 37–38. Retrieved 2008-07-08.

http://www.efunda.com/designstandards/sensors/laser_doppler/laser_doppler_flow_theory.cfm

http://www.fvfowler.com/d-200.html http://www.freepatentsonline.com/5638824.pdf www.wikipedia.org

Introduction

The purpose of this paper is to introduce a new method(s) to measure vibrations and chatter in a tool during static and dynamic uses. The tests to control these adverse effects will drastically improve high speed machining characteristics.

Why Important? The Harmful Effects of Vibration/Chatter

Suggestions?? Surface Finish Reduction Limit Dimensional Accuracy Increase Tool Wear Create High Noise Levels Reduced Tool Life

http://http://www.youtube.com/watch?v=NP4sDX87JE8&feature=related

Current Control Solutions

Increasing the tool stiffness

Reducing the cutting depth

Reducing machine speed

Current Methods to Monitor

Vibration/Chatter

Strain Gauges/Accelerometers

Uses an impulse hammer and then detects the resulting vibrations via an accelerometer or strain gauges near the tip of the tool.

Impulse Hammer is calculated at the simulated force during the cutting process.

Problems: Can only measure static vibrational

characteristics – no dynamic measurements. Accelerometers are too large and bulky

Other Methods

Acoustic Pickup Devices (Microphones Fiber-Optic Displacement Sensors Capacitance Probes Inductive Probes Laser Doppler Effect

Requirements for Monitors

1. Provide High Vibration Measurement Accuracy

2. Be insensitive to the machining environment

3. Be both used for characterization prior to the operation as well as during the milling process

4. Induce minimal loading5. Be compact and low-cost

Solution: Active Vibration Monitor

Created by Lasson Technologies Inc. It is a noncontact sensor for vibration

testing, monitoring and control related to high-speed machining.

It can monitor vibrations on the cutting tool as well as the work piece and the spindle.

The sensor is also small and easily reconfigured to change to specific positions being monitored.

How?

Results

Results

Application

It is very valuable Improves:

Surface Finish Dimensional Accuracy Tool Wear Reduction Noise Reduction Higher Throughput Reduced Scrap

Review

1. Provide High Vibration Measurement Accuracy

2. Be insensitive to the machining environment

3. Be both used for characterization prior to the operation as well as during the milling process

4. Induce minimal loading5. Be compact and low-cost

Originally designed for Ultrasonic tests-Tests babies for apnea (sounds an alarm if their breathing stops)

Other Practical Uses

Piezoelectric elements are also used in the detection and generation of sonar waves.

Power monitoring in high power applications (e.g. medical treatment, sonochemistry and industrial processing).

Piezoelectric microbalances are used as very sensitive chemical and biological sensors.

Piezos are sometimes used in strain gauges. Piezoelectric transducers are used in electric drum pads to

detect the impact of the drummer's sticks. Automotive engine management systems

use piezoelectric transducers to detect detonation by sampling the vibrations of the engine block and also to detect the precise moment of fuel injection (needle lift sensors).

Ultrasonic piezo sensors are used in the detection of acoustic emissions in acoustic emission testing.

Future Fields of Study

Sensors can be integrated into new and existing machines for in-process diagnostics and feedback control

Sensors for off line dynamic tool characterization and process optimization

All technology fields will be affected that want to measure small vibrations in small compact systems.