Yasuo Kondo

Reversibility and disassembly time of part connection

Abstract The reversibility and disassembly time of part connections were experimentally examined through the actual disassembly work of some spent industrial products. The disassembly time for connections depends on the joining method, joining direction, length of product life and chemical and physical deformation. The strongest relation was observed between the joining method and disassembly time. The male–female joint (socket joint) and snap fitting had a relatively short disassembly time of

A discussion on the resource circulation strategy of the refrigerator

Abstract In order to discuss the optimal resource circulation strategy of refrigerators, actual resource recovery experiments and a life-cycle simulation were carried out. The combined processing of disassembly and shredding had the most high recovery rate, more than 80 wt.% of a refrigerator, while the disassembly can recover only 30 wt.% of components as a re-usable component. An alternative strategy, the elongation of life span, had a good performance in improving the resource circulation characteristics. The two-life scenario can decrease the environmental load by twice that of the conventional recycling scenario. However, the elongation of life span does not become a successful resource circulation strategy until the old refrigerator was up-graded to a low-energy consumption type after one life-span running.

A design for recycling technique for optimizing resource circulation characteristics of products

A design for recycling technique was developed for evaluating the disassembly and resource. circulation characteristics from the design data on CAD software. The product component tree, disassembly curve, reduction characteristics map and resource circulation index showed a good performance for evaluating the disassembly and resource circulation characteristics. An advanced product design support tool was also originated for improving the disassembly and. resource circulation characteristics. The case study on a notepad-type PC showed that the depletion of parts number by material unification had a better effect on improving the disassembly and resource circulation characteristics of the notepad-type PC than the parts number depletion by integration of UNIT components.

Effect of cutting force control on cutting characteristics of CFRP in diamond saw cutting

We examined the relation between the cutting force and the cutting characteristics of CFRP in diamond saw cutting. When a larger cutting force was applied, the cutting had been propagated with a mixed mechanism of the cutting by cutting edges and the cleaving of carbon fiber by shear force. While a good cutting surface was formed in the case of cutting with less than 23 N of cutting force. In this condition, the cutting had been propagated only by the cutting with cutting edges.

A Dynamic Observation Concept to Keep Water-Soluble Coolant in Normal Condition for Long Time

We propose a dynamic observation concept to pretend aged degradation of water-soluble coolant. The first-hand observation of coolants by a CCD microscope is extremely useful for monitoring the drastic appearance change. The appearance changes of coolant also could be monitored by combining the reflectance changes from the Red, Green and Blue LED lights. The physical process of absorbing light is occurred only at the specific wavelength in the water-soluble coolants. The absorbance at the specific wavelength would become a reliable indicator to predict the controlled condition of water-soluble coolant. Setting up these sensing systems to the machine tools make it possible to observe the coolant dynamically and on real time.

Study on Precision Polishing Using Gelatin Stone

A gelatin stone having a new polishing mechanism that can polish a free-form surface is proposed in this study. The gelatin based stone can easily control the hardness and the melting point by changing the density, the cooling condition and the kinds of additives. The main conclusions obtained in this study are as follows. The proposed gelatin stone can polish the surface of various materials. The high density of gelatin is suited for a gelatin stone. Surface roughness improves as the polishing time gets longer. Polishing by gelatin stone needs a high-speed relative motion.

Study on Metabolic System for Water-soluble Coolant (1st Report)

A bio-chemical treatment system was developed to reutilize the spent water-soluble coolant as a diluent of renewal coolant. The bio-chemical treatment using oil-decomposing microorganisms and a biological activated carbon filtration method showed a high recovery rate of water resource from an emulsion-type coolant. The water-soluble coolant can form the uniform micelle colloid in the recovered water and showed no quality change during the nine months standing at ambient temperature. The processing cost, around 35 yen/L, was equal to or less than current disposal cost. No difference was shown in the chisel and flank wear of machine tool after 100 holes drilling between the water-soluble coolants diluted with recovered water and service water. These facts indicated that the proposed treatment system must be an effective way to reutilize the water-soluble coolant as the diluent of renewal coolant.

Property and Recyclability Change of Corrosion-Inhibition-Improved Amine-Free Water-Soluble Cutting Fluid with Repeated Recycling

Cutting fluid is commonly used during metal cutting process for cooling and lubrication. Fluid types are generally classified into mineral or fatty oils and water miscible oils. In Japan, the former is called water-insoluble coolants, and the latter is called water-soluble coolants. Water-insoluble coolants are specified as dangerous material by the Japanese law due to its flammability. Therefore, the water-insoluble coolants are not appropriate for unmanned operation of machine tools. Therefore, the usage rate of water-soluble coolants is increasing. Water soluble coolants are diluted with a water by several ten times. The waste management of the water-soluble coolant become important for environment-conscious green manufacturing. We have been developing a recycling system for water-soluble coolants. In the recycle system, water is extracted from the waste coolant and the water is then reutilized as a diluent of a new coolant. We have developed various types of chemical or bio-chemical water recovery methods for recycling systems. We found a commercially available amine-free water-soluble coolant is suitable for the recycling system. The processing time, processing cost, and the biochemical and chemical oxygen demand of the extracted water are improved by the amine-free water soluble coolant compared with a conventional amine-containing coolant. However, its corrosion inhibition performance was poor in general machining applications. Our cooperative company developed a prototype of a corrosion-inhibition-improved amine-free water-soluble cutting coolant. The prototype coolant showed a good stability and cooling and lubricating performances, and its recyclability was as good as that of conventional amine-free coolants. In this study, we focused on repeated recycling of the prototype coolant. We repeatedly applied the water recycling process to the recycled coolant. The recyclability of the prototype coolant was not affected by repeated recycling; however, process residues increased with the number of recycles, and a deterioration was noticed in the corrosion-inhibition performance of the coolant diluted with recycled water.

Fundamental Characteristics of Grooving Aiming at Reduction of Kerf Loss Using an Ultrafine Wire Tool

Thinning of silicon wafers and reduction of kerf loss can minimize the manufacturing costs of semiconductor products. Currently, the volume of kerf loss is about the same as the volume of the wafer itself. Therefore, we study slicing techniques for silicon wafers that result in reduced kerf loss by using an ultrafine wire tool and fine abrasive grains. As a first step, grooving characteristics using an ultrafine tungsten wire tool and fine abrasive grains are investigated in this paper. A borosilicate glass is used as the work material. The main conclusions are as follows: Precision machining using ultrafine wire tool is possible and the kerf loss decreases because the groove width decreases. However, a larger diameter of the wire tool results in a deeper groove. A faster relative speed produces a shorter wire tool lifetime, but a deeper groove. To supply enough abrasive grains to the machined portion, it is necessary to use abrasive grains having a suitable particle size for the specific diameter of the ultrafine wire tool.

Feature Extraction from Sensor Data Streams for Optimizing Grinding Condition

A visualization method for time-series sensing data was designed to optimize grinding condition. The fluctuation pattern of time-series data streams can be visualized as a white and black pattern by utilizing the spindle power change rate average. The designed visualization method was applied to a condition monitoring in lapping operation. The relation between the fallout abrasive grain content and lapping behaviour was experimentally examined. In the lapping with grinding fluid containing no fallout abrasive, the spindle power decreased in a monotone manner with lapping time, while in the lapping with fallout abrasive, the spindle power decreased with lapping time up to 20s of lapping and then tended to converge on a constant value. The spindle power change rate average displayed as a white and black pattern reproduced the changes of spindle power very well. The appearance probability of white or black pattern has a strong relation with the fallout abrasive content and the designed data processing scheme could make possible to predict the grinding fluid condition from the easy-handling grinding test.