Development of a hybrid dynamometer applied to the fourth axis of a vertical machine center
dynamometer, strain gauges, milling, wireless data transmission
In the context of multi-axis machining of mechanical components with free form geometries, the conventional configurations of the dynamometers (stationary and rotary) are not suitable for operating conditions. This fact occurs due to the mounting of stationary devices limits the workpiece geometry and size, while the assembly of rotating devices is affected by interference in the signal under the conditions of high-speed spindle rotation. In order to propose a solution to this conflicting situation, this research has the objective of developing a hybrid dynamometer, based on strain gauges, mounted in the fourth axis of a vertical machining center and able of measuring axial force and torque. To make this, steps such as conceptual design, engineering analyses, instrumentation, static calibration and dynamic properties evaluation are fundamental for manufacturing the device. In addition, the development of a wireless data transfer system must be performed. For this step, it is necessary to create a printed circuit for signal conditioning and amplification, a wireless transmission module and a data processing code aiming the mechanical loading analysis. The partial results showed that the conceptual design is appropriated to the dynamometer operating requirements to withstand loads of axial force up to 1 kN and torque 30 Nm, the manufacture of the sensing elements is in accordance to the tolerances established in design and the performed instrumentation shows correct to the application.