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Smart Tool Holder 3.0

An A2DP stereo Bluetooth transmitter is dissected and integrated into an endmilling tool holder to transmit a signal from a sensor-amplifier system. The amplifier consists of dual AD623 instrumentation amplifiers and their supporting hardware. Both the transmitter and amplifier circuit are powered from a common source aboard the tool holder. The system is designed to power and sample a variety of dynamic sensors including electret condensers, strain gages, and accelerometers. The tool holder can simultaneously sample two sensors from a sensor integrated tool. These sensors reside inside of the endmill tooling and interface via an electrical connector within the tool holder. The compliance of the tool and tool holder are not impacted by the sensing system. A tool integrated with a torque strain bridge is demonstrated.

Smart Tool Holder with Interchangable Smart Tooling

The Smart Tool Holder is a robust real-time sensor interface system that can provide tool tip sensor data for process condition monitoring during metal cutting. Condition monitoring includes tool wear, runout, and system stability evaluation. The objective scope of the smart tool holder is to enable accurate determination of NC metal cutting system dynamics so cutting forces and, ultimately, part quality can be estimated in-process. To solve this problem, a wireless sensor system has been developed for noninvasive integration into commercial cutting tool holders. This wireless sensor system combines existing robust hardware technologies in a novel application. Electret based accelerometers are used as the sensors. The system is plug and play with modern PC hardware.

Testing a Four Insert Facemilling Smart Tool

The Smart Tool Holder is a robust real-time sensor interface system that can provide tool tip sensor data for process condition monitoring during metal cutting. Condition monitoring includes tool wear, runout, and system stability evaluation. The objective scope of the smart tool holder is to enable accurate determination of NC metal cutting system dynamics so cutting forces and, ultimately, part quality can be estimated in-process. To solve this problem, a wireless sensor system has been developed for noninvasive integration into commercial cutting tool holders. This wireless sensor system combines existing robust hardware technologies in a novel application. Electret based accelerometers are used as the sensors. The system is plug and play with modern PC hardware.

Chatter Prediction with a Smart Tool Holder

The Smart Tool Holder is a robust real-time sensor interface system that can provide tool tip sensor data for process condition monitoring during metal cutting. Condition monitoring includes tool wear, runout, and system stability evaluation. The objective scope of the smart tool holder is to enable accurate determination of NC metal cutting system dynamics so cutting forces and, ultimately, part quality can be estimated in-process. To solve this problem, a wireless sensor system has been developed for noninvasive integration into commercial cutting tool holders. This wireless sensor system combines existing robust hardware technologies in a novel application. Electret based accelerometers are used as the sensors. The system is plug and play with modern PC hardware.

Design and Fabrication of a Smart Tool Holder

The Smart Tool Holder is a robust real-time sensor interface system that can provide tool tip sensor data for process condition monitoring during metal cutting. Condition monitoring includes tool wear, runout, and system stability evaluation. The objective scope of the smart tool holder is to enable accurate determination of NC metal cutting system dynamics so cutting forces and, ultimately, part quality can be estimated in-process. To solve this problem, a wireless sensor system has been developed for noninvasive integration into commercial cutting tool holders. This wireless sensor system combines existing robust hardware technologies in a novel application. Electret based accelerometers are used as the sensors. The system is plug and play with modern PC hardware.

Fabricating an Electret Based Accelerometer

The objective of this work is to present an inexpensive alternative to traditional accelerometer and DAQ components for machine condition monitoring. This work explores the feasibility of using a PC sound card for high bandwidth data acquisition from an epoxy-sealed electret condenser. This sensor's frequency response will be contrasted against that of a commercial piezoelectric accelerometer amplified and sampled by a traditional DAQ system. The frequency response of the sealed electret accelerometer is shown to be a linear function of acceleration input magnitude. As a result, the electret accelerometer is capable of replicating the response of the piezoelectric system through calibration and a mapping transfer function.

Testing an Electret Based Accelerometer

Developing a low cost accelerometer is an important step towards creating a 'smart' tool holder for condition monitoring in an end mill system. In this work, an inexpensive accelerometer is fabricated from an electret condenser and shown capable of capturing high bandwidth machining data. Data acquisition for this sensor is conducted with a generic PC sound card.

Microprocessor Controlled Impulse Response Hammer

Using an HC11 microcontroller, an electromechanical system is designed for repeatable impulse response testing using a PCB impact hammer and charge amplifier. The system performs the following functions:

  1. 8 bit (256 level) control of hammer impact magnitude through solenoid control
  2. Impact 'sufficiency analysis' to determine whether the hammer properly impacted the DUT
  3. Programmable repetition cycles (control over how many sequential impact tests to perform for repeatability)
  4. LED display of system status including test cycle number and cycle status (indicates when a test is 'bad' due to insufficient impact magnitude)

This hammer control system achieves the goals of impact repeatability, fulfills a magnitude sufficiency analysis, and tracks successful impact cycle completion until the desired number of impacts is reached.