Published report discusses development of two-component force dynamometer which is used for dynamic measurement of machining forces in cutting and thrust directions. Resulting data suggest that faster metal-cutting machines may be developed that have reduced vibrations

Sutherland, I. A.

English

NASA Technical Reports Server

Thrust
Gat
September 1974
	 B74-10148 
NASA TECH BRIEF 
Marshall Space Flight Center
	
1 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Dynamometer for Measuring Machining Forces in Two

Perpendicular Directions 
Cutting
Gauge 
Schematic of Basic Dynamometer 
The speed of present metal-cutting machines is 
limited by self-excited vibration. This vibration, com-
monly known as chatter, occurs at high cutting speeds 
because of a dynamic interaction between the metal 
workpiece and the machine tool structure. It causes 
increased tool wear, dimensional inaccuracies, poor 
surface finish, and can be extremely noisy. 
A report has been published which discusses the 
development of a two-component force dynamometer. 
The dynamometer is to be used for the dynamic 
measurement of the machining forces in the cutting and 
thrust directions. From the resulting data, faster metal. 
This document was prepared under the Sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
cutting machines may be developed that have reduced 
vibrations. 
The dynamometer structure is a part of the basic 
tool control system as shown in the illustration. The 
dynamometer itself includes a mounting structure, a 
toolholder, and a set of gauges. The horizontally 
positioned strain gauges are used for measuring the 
thrust force, and the vertically positioned gauges are for 
measuring the cutting force. The toolholder is used for 
supporting the workpiece perpendicularly to the turning 
axis of the machine tool.
(continued overleaf) 
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19740000148 2020-03-17T14:06:10+00:00Z
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The dynamometer is vibrated in the thrust direction 
by an electromagnetic vibrator. This simulates the thrust 
vibrations encountered in the actual machining process. 
The vibration signals are provided by a sinusoidal 
oscillator. The oscillator signals are summed with the 
velocity and displacement signals from the dynamometer. 
They are then amplified and fed to the electro-
magnetic vibrator. This feedback arrangement provides 
a stable vibrational force to the dynamometer.
Notes: 
1. The developed dynamometer may be of interest to 
manufacturers of high-speed machine cutting tools. 
2. Requests for further information may be directed to: 
Technology Utilization Officer 
Marshall Space Flight Center 
Code ATOI 
Marshall Space Flight Center, Alabama 35812 
Reference: B74-10148 
Patent status: 
NASA has decided not to apply for a patent. 
Source: I. A. Sutherland 
Marshall Space Flight Center

(MFS-22899)
S 
. 
B74-10148	 Category O6,07,08	 0


Dynamometer for measuring machining forces in two perpendicular directions

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