Boron Doped Diamond for Real-Time Wireless Cutting Temperature Monitoring of Diamond Coated Carbide Tools.

Sérgio Pratas,Miguel A Neto,António J S Fernandes,Daniel Figueiredo,Rui F Silva,Eduardo L Silva,Cristina M Fernandes

doi:10.3390/ma14237334

Abstract

Among the unique opportunities and developments that are currently being triggered by the fourth industrial revolution, developments in cutting tools have been following the trend of an ever more holistic control of manufacturing processes. Sustainable manufacturing is at the forefront of tools development, encompassing environmental, economic, and technological goals. The integrated use of sensors, data processing, and smart algorithms for fast optimization or real time adjustment of cutting processes can lead to a significant impact on productivity and energy uptake, as well as less usage of cutting fluids. Diamond is the material of choice for machining of non-ferrous alloys, composites, and ultrahard materials. While the extreme hardness, thermal conductivity, and wear resistance of CVD diamond coatings are well-known, these also exhibit highly auspicious sensing properties through doping with boron and other elements. The present study focuses on the thermal response of boron-doped diamond (BDD) coatings. BDD coatings have been shown to have a negative temperature coefficient (NTC). Several approaches have been adopted for monitoring cutting temperature, including thin film thermocouples and infrared thermography. Although these are good solutions, they can be costly and become impractical for certain finishing cutting operations, tool geometries such as rotary tools, as well as during material removal in intricate spaces. In the scope of this study, diamond/WC-Co substrates were coated with BDD by hot filament chemical vapor deposition (HFCVD). Scanning electron microscopy, Raman spectroscopy, and the van der Pauw method were used for morphological, structural, and electrical characterization, respectively. The thermal response of the thin diamond thermistors was characterized in the temperature interval of 20–400 °C. Compared to state-of-the-art temperature monitoring solutions, this is a one-step approach that improves the wear properties and heat dissipation of carbide tools while providing real-time and in-situ temperature monitoring.

Highlights

Nowadays, three main factors drive the need to increase productivity in metalmachining companies: (i) the development of special alloys with tight machining requirements, (ii) the increase in global market competition fueled by cheap labor costs in emerging economies, and (iii) the rise of additive manufacturing
chemical vapour deposition (CVD) DiamondlaMyeorrepdhsotlrougcyture is related to the intrinsic properties of diamond and the requirements
Boron doped diamond-based thermistors were fabricated by hot filament chemical vapor deposition (HFCVD) and used for temperature monitoring during the face milling of an Inconel 718 workpiece with a diamond coated carbide end mill

Summary

Introduction

Three main factors drive the need to increase productivity in metalmachining companies: (i) the development of special alloys with tight machining requirements, (ii) the increase in global market competition fueled by cheap labor costs in emerging economies, and (iii) the rise of additive manufacturing. Considering that in an automotive shop tool costs represent only 3% of the total manufacturing cost, there is a great potential to increase productivity by using advanced tools that allow higher cutting speeds and/or feed rates [1]. An increase in productivity can be achieved by optimization of the cutting cycle, with the objectives of improving tool life and the minimization of downtime. Heat generation during machining occurs in three main zones [2]. The primary shear zone generates maximum heating due to plastic deformation of the metal. In the secondary shear zone, heat originates from friction between the tool and the moving chip. At the tertiary deformation zone, heat is mainly produced due to the work required to overcome friction between the flank face and the machined surface [2]

Methods

Results

Conclusion