Tatsuya Furuki

Monitoring Method of Process Temperature and Vibration of Rotating Machining Tool with a Wireless Communication Holder System

We developed a wireless communication holder system to monitor the process temperature and vibration of a rotating machining tool. This report presents an estimation of the process temperature in end-milling and the chatter vibration when boring with it. The thermocouple is set in the end-mill tool to measure the process temperature, and the MEMS accelerometer is set in the boring tool to measure the chatter vibration. We also present an investigation of the end-mill temperature observed using infrared thermography and the vibration of the spindle using a traditional accelerometer. The proposed holder system was found to be effective to estimate the process monitoring of the rotating machining tools.

Estimation of Unsteady and Steady Polishing Force in Magnetic Abrasive Finishing Using a Permanent Magnet End-Mill Tool

Stable finishing is considered difficult to achieve using conventional magnetic abrasive because of its unstable polishing characteristics. In this paper, three different shapes of iron particles are used to produce a magnetic brush to improve stability. The unsteady and steady polishing force produced under the magnetic field of an end-mill type tool is discussed. We also develop prototype equipment combining a high speed camera with a force sensor to analyse micro-changes in the magnetic brush while machining. The relationship between the unsteady or steady polishing force and the polishing capability of the magnetic brush is explored in an attempt to construct a model for predicting polishing forces.

Investigation of cBN Electroplated End-Mill Shape for CFRP Machining

Currently, carbon fiber reinforced plastics (CFRP) are being increasingly adopted in various fields. Thus, machining CFRP with high accuracy and high efficiency is required. In addition, machining stack materials composed of CFRP and titanium alloys is required. Therefore, in this study, a novel end-mill electroplated with a cubic boron nitride (cBN) abrasive, which has high thermal resistance, is proposed. In order to evaluate the influence of the base metal shape of the proposed end-mill on the machining process, several cBN-electroplated end-mills with different rake angles or chamfers were fabricated and used to cut CFRP. In addition, in order to evaluate the abrasive shape, a blocky abrasive was also electroplated on the end-mill. The results indicate that the negative rake angle is useful to restrain the progression of tool wear. However, in order to obtain the element of cutting and grinding, it is required that the rake angle should be positive. Moreover, the reasonable width of chamfer is effective for restraining the increase in CFRP temperature. Further, a sharp shaped abrasive can more effectively generate a CFRP with a sharp edge compared with a blocky shape abrasive.

Elucidation of polishing mechanism used in magnetic polishing brush

In recent times, there has been growing demand for environmentally friendly methods for finishing freeform surfaces (e.g., molding-die surfaces). This demand has generated interest in the development of a new polishing technology that uses less abrasive slurry and employs magnetic abrasive finishing. However, it is well known that the traditional magnetic polishing method is unstable and produces insufficient surface smoothness. In the present paper, we discuss the reasons causing instability in conventional magnetic polishing. We systematically investigate the magnetic pressure distribution characteristics and measure the pressure distribution of the magnetic brush during machining. Furthermore, we propose a new magnetic brush that uses steel balls (steel-ball brush) and abrasive slurry and compare this brush with a brush that uses iron powder paste (employed in the traditional magnetic polishing method). Finally, we present the processing mechanism of the proposed brush for polishing a flat surface on a three-axis machining center.

Fabrication of Electroplated CBN End-Mill for High-Efficiency Face Milling of Carbon Fiber Reinforced Plastic

Carbon fiber reinforced plastic (CFRP) was developed in the 1960s. Since then, it has been used in various fields. Accordingly, the number of studies related to machining of CFRP has been increasing (e.g. cutting, laser processing, or abrasive water jet machining). However, these studies have been focusing on the trimming of surplus portions or drilling. In addition, the degradation of mechanical properties due to the heat induced during machining has not been sufficiently considered. Furthermore, another issue is the cost involved, such as tool and equipment costs. This makes several of these proposed methods tremendously expensive. Therefore, in this study, electroplated end-mills with electrodeposited cBN or diamond grains of different grit sizes (the mesh size are #600, #1000, #1500 and #2000) are fabricated. As a result, the cost of the electroplated tool will decrease by 2/3 compared to general diamond-coated tools. Moreover, the flat cutting of CFRP is often carried out with these fabricated tools and with general diamond-coated tools. In cases where the fabricated tools are used, the machined CFRP products are burr-free or nap-free. Additionally, the induced CFRP temperature during cutting decreases compared to the case of diamond-coated tools. From these results, the optimum grit size was determined to be #1000. On the other hand, end-mills with deposited cBN or diamond grains, fixed on the tip of the fabricated tool, occasionally dropped out after a few paths. Therefore, efforts are presented to improve the tool tip shape and minimize its grain dropout rate. Based on such improved characteristics, the electrodeposited end-mill is expected to be able to machine CFRP more effectively.Copyright

Satiny and Continuous-Curvature Corrugated Surface Generation by Integrating End-Milling Processes and Magnetic Polishing with a Machining Center

It is difficult to hand down magic-mirror fabrication technology, which has an extremely small satiny and continuous-curvature corrugated surface, due to downsizing of veteran engineers or even their successors. Therefore, the purpose of this study is to digitalize the magic-mirror fabrication technology using a CNC technology. A mirror finishing method is thus proposed that integrates ball end-milling and magnetic polishing it on the machining center. In addition, the workpiece is end-milled from the rear. Generation of the magic-mirror surface is also carried out.