The objective of this thesis is to design and manufacture a three dimensional dynamometer for drilling and milling, and to present the design method.
Forces are measured by octagonal half rings on which strain gages are attached. Half rings are used instead of full rings to increase sensitivity.
The material of half rings is SCM-4, heat treated to Rc 35 hardness. Top and bottom plates are manufactured of mild steel.
In order to obtain maximum output, full bridges are used. Wiring arrangement is designed so that either three dimensional forces can be measured or thrust and torque can be measured.
Natural frequencies were analyzed and compared with the design values for the dynamometer.
From 0.3-300 kg three dimensional forces and 50-50,000 kg-mm torque can be measured by this dynamometer.
Dead weights were used for calibration and it had good linearity.
Measured natural frequencies were much lower than design values based on simple theory, which neglects rotational effects at support and effective mass of the beam. When these effects are included in analysis, agreement with measured values in quite good.
Two cutting experiments, one for milling and another for drilling, were set up to demonstrate the use of the dynamometer.
