Before occurrence of self-excited chatter, initial resonance has to be grown in turning. In this study, despite external forced vibration, we explain occurrence and growth of SDoF tool oscillation from the trajectory of the tool nose contacting with wavy cylindrical workpiece. By regarding the deviation of the workpiece as a simple sinusoidal function and local contact of the tool with finite radius, we showed the trajectory excites the oscillator under high-order harmonic resonance conditions. The amplitude of the resonance is affected from local contact radius against that of workpiece. From damping effect these resonance conditions are expanded. The growth of the initial resonance would cause either forced or self-excited chatters in afterwards. The occurrence of chatter during wear and the existence of ultra-precision machining are explained from these properties.

Since cutting force acts on feed drive and spindle drive systems as force disturbance, feed speed and spindle speed are changed. As the results, cutting force is changed because the depth of cut and cutting speed are changed due to the feed and spindle speed changes. In this study, a coupled simulation method, which considers the dynamic behaviors between feed and spindle drive systems and the cutting force, is developed. Simulation results are compared with the experimental results, and it is confirmed that the vibration of the feed and spindle drive systems due to the cutting force can be simulated by the proposed method. It is also confirmed that the cutting force influenced by the vibrations can be expressed.

Instantaneous cutting force model is widely used for the cutting force prediction for end milling operation. However this model is required to prepare 6 parameters called cutting coefficients which can be determined from experimentally measured cutting forces. In this study, a new end-milling force prediction method based on oblique cutting model is proposed. This method can predict cutting force using only the experimentally predetermined shear angle instead of 6 cutting coefficients required for a conventional instantaneous cutting force model. This method is easier to apply for practical cutting force prediction, because it is easier to predetermine shear angle than 6 cutting coefficients.

The ball end mill is used as a tool for cutting the metal mold. The demand for the precise machining of the ball end milling is increasing. Previous studies clarified that machining error have the correlation with geometrical interference quantity calculated by the geometric analysis of ball end milling at any tool position. The purpose of this study is to propose a method of calculating tthe machining error estimation index for the complex shape machning, and some experimental results are shown.

Helical milling has recently been applied to machining of large diameter holes in the airplane manufacturing. In the helical milling, a rotating end mill is fed helically to finish the holes in a rotation radius around the center of the hole at a revolution rate. The paper presents a model to simulate the cutting force in the helical milling. The chip flow model in milling is modeled with piling up the orthogonal cuttings in the planes containing the cutting velocities and the chip flow velocities, where the chip flow direction is determined to minimize the cutting energy. The cutting force model is validated in the peripheral cutting tests. Then, the cutting force is simulated in a helical milling. The cutting force changes with revolution of the end mill in the penetration, the steady and the exit processes.

In order to improve milling performance of difficult-to-cut materials, a unique milling cutter with SPRT (Self-Propelled-Rotary-Tool) was developed. Use of slide bearings enables a compact SPRT mechanism, while influence of bearing friction becomes not negligible. To attain self-revolution of a circular insert regardless of the bearing friction, the cutter geometry was optimized. Through face milling experiments of Inconel 718, superior tool wear resistance was verified as compared to the conventional milling without insert rotation. Analytical result of the measured cutting forces also indicated interesting phenomena in SPRT milling.

Insert milling tools are used for processing cost reduction in hard metal cutting. However, tool life will be shorter because insert tools have tip runout caused by machining error of cutter body and insert tip casting problem. In this paper, we have developed a control method for longer tool life by adjusting feed rate for each tip runout and by reducing cutting speed temporarily. The experimental results described here show how this method effectively improves tool life in machining difficult-to-cut materials.

This research clarified the effects of solid lubricating sheet for reduction of burr generation and lowering of cutting temperature through examining of drilling in titanium alloy for aircraft. Titanium alloy is difficult to drilling. Moreover worker cannot use plenty of lubricating oil in drilling. So drills are exchanged frequently even if the cost increases. In this study, the temperature of work pieces made of Ti-6Al-4V were measured by thermo camera while drilling. As the results, a height of back burr increases rapidly around 350～400°C and more. Moreover, in specific range, the solid lubricating sheet can be decreased height of back burr and lowering of cutting temperature compared to without it.

In this paper, we examined the effect of drill surface texturing with solid lubricating sheets on exit burr in drilling process of work pieces made of Ti-6Al-4V. As a result, drill with rough textured rake face shows high burr of Ti-6Al-4V in exit. On the other hand, drill with rough textured flank shows low burr height only if drilling with solid lubricating sheet. Moreover, the specific texturing by wire electric discharge machining causes decrease of burr height.

3 flutes twist drills have recently been used to metal cutting in terms of accuracy of drilled holes. The paper discusses the cutting processes of 2 and 3 flutes drills in drilling of uniaxial carbon fiber reinforced plastic (CFRP). The cutting force depends on the relative angle of the cutting direction with respect to the fiber orientation of workpiece. The changes in the cutting forces with the cutter rotation are analyzed in the cutting force measurement and the cutting simulation based on a force model, where the orthogonal cutting data for the simulation changes with the relative angle of the cutting direction to the fiber orientation. The averages and the periodical amplitudes in the cutting forces are discussed for drilling of 2 and 3 flutes tools. Large cyclic changes in thrust and torque appear in drilling with 2 flutes drill. X and Y components, in contrast, change periodically in drilling with 3 flutes drill.

In this study presents the drilling on CFRP continuous 40 hole which is material thickness of 8 mm using drill tool was seven types of different coating and tool form by WC drill of tool diameter of 6 mm. We evaluated the relationship between the tool material and the cutting temperature was measuring with a thermocouple and an infrared thermometer. As the result, the cutting temperature has begun to rise due to the number of holes increases regardless of the difference of the tool shape and coating. After 40 hole drilling has reached about 120°C. In the case of diamond coating tool is low cutting temperature. Cutting chips affect in the cutting-temperature increase.

A force model is presented to analyze cutting processes in drillings with cutter runouts. In the simulation, three dimensional chip flow in drilling is modelled by piling up the orthogonal cuttings in the planes containing the cutting and the chip flow directions. The cutting model in the chip flow, therefore, is made using the orthogonal cutting data in the coordinate system including the direction of the cutting velocity. The cutter runout, then, is considered by the rotating coordinate system. The cutting simulation is performed in drilling of titanium alloy based on the force model presented. First, the force model is validated in comparison of the simulation with the measured cutting force. Then, the cutting force is predicted in drilling with the cutter runout. The cutting forces loaded on the edges are compared each other.

Series of drilling tests of PCB have been carried out to investigate the shape of chips produced and the chips evacuation behavior out of drilling hole at the drilling rotational speed of from 20×103min-1 to 160×103min-1. With an increase in the drilling rotational speed, the chips evacuation out of drilling hole is very well, the chips of GFRP are short and small pieces and both of maximum cutting torque and average cutting torque are decreasing. On the other hand, the chips evacuation behavior out of drilling hole is worse because of increasing coefficient of between surface of drill flute and chip with an increase in the drilling rotational speed, and both of maximum cutting torque and average cutting torque are increasing. The chips of GFRP grow long and large pieces after adhering one chip to another chip when the drill flutes are full with chips.

In this paper, the failure mechanism of a multilayered CVD-diamond coated tool in sintered WC-Co cutting is discussed. In most cases, thick diamond coating is suddenly peeled off only at the rake face in early stage of cutting. This sudden peel-off creates a sharp edge and then excellent cutting ability is given to the cutting tool. Therefore, failure behavior after this peel-off is actually worthy to investigate. Simple model for coating failure progression, which is based on interlaminar fracture, is proposed. From cutting experiments for different types of sintered WC-Co, the model can approximately represent failure behavior of the multilayered CVD diamond coating after large peel-off at the rake face.

Generally, high-speed cutting can improve productivity of manufacturing, while it often causes severe tool wear. In this study, the effect of finished surface property was investigated.As the result it was found that finished surface roughness was improved and the tool wear was decreased with Binder-less cBN tool. Furthermore, effect of chanfer angle on surface quality was investigated in this study.

Conventionally, the evaluation of wear in the cutting tools have been focused mainly on the rake and flank face, but there is little research that paid attention to the cutting edge of the tools. Therefore, by extracting its complicated features, a valid technique for evaluating this matters has not been established. That is why this research is carried out to focus on the cutting edge of the tool which involve a quantitative evaluation of its complexity due to the change of this edge line by the fractal dimension. As a result in the 3-dimensional cylindrical turning using this method, tendency that the fractal dimension of the nose corner part of the cutting edge approaches 1.08, and the fractal dimension of the straight part approaches 1.12 when the tool reaches its end life are obtained.

Additive manufacturing processes, which can fabricate complicated shapes from 3D-CAD data, have become a popular approach to making prototypes, machine parts, and die tools. However, selective laser sintering (SLS) and selective laser melting (SLM) techniques, which have become mainstream, are expensive. Furthermore, the built efficiency (i.e., the amount of laminated material volume per unit time), is not high. Therefore, we propose a wire and arc-based additive manufacturing process that is inexpensive and has a built efficiency ten times higher than SLS and SLM. With this process, the surface roughness of fabricated objects is several hundred μm or more; therefore a finishing process is unnecessary. In this paper, a cooperative system for wire and arc-based additive manufacturing and machining was developed, and the effectiveness of the system was demonstrated. First, a three-dimensional fabricated object was measured by SfM (structure from motion), and measurement accuracy was investigated. Then the original workpiece design was modified, and the amount of material removed on the finish cutting was optimized. As a result, the fabricated objects did not contain a large amount of material to be removed by finish cutting.

This paper discusses the relationship between hardness of the nitride diffusion layer and the cutting characteristics of the orthogonal cutting. We verified the effectiveness of cutting resistance by using the hardness equivalent to the depth of cut and cutting edge shape. The cutting experiments were conducted using a CBN tool and the shaper machine. In the method, Piezoelectric dynamometers is adopted to the cutting forces. As a result, it was found that cutting resistance was dependent on the hardness of depth of cut. In the indentation hardness test, the nitride workpiece is hard and brittle. Produced as a brittle fracture the chip. Edge shape thrust force is increased, the compression force at the shear plane is increased. The cutting characteristics results are shown in this paper.

Whirling has been applied to manufacturing of worm and ball screws for motion controls. The whirling cut, in which the tool and the workpiece rotate simultaneously with an eccentricity between the centers of the workpiece and the tool rotations, has advantages over the general threading in terms of the tool life, the surface finish and the chips control. Whirling has been used for only machining of the screws so far. However, whirling mechanism is expected to machine the several complicated part shapes with control of the ratio of the spindle speed of tool to that of workpiece. This paper presented a surface texturing to fabricate the controlled geometrical structures on the cylinder surfaces in the whirling with 3 cutting tools. The machining tests were conducted to verify the presented texturing manner.

Dry hobbing is a useful method in order to reduction of production costs of gears, and to reduction of pollutions. However, the dry hobbing tends to increase the cutting temperature and to reduce the life of tool. To solve these problems, we have produced a new hobbing method called a vibration hobbing. The vibration hobbing can reduce the cutting temperature, however, this property is only qualitatively confirmed. In this study, we measure the temperature of chips during the vibration hobbing by radiation thermometer. As a result, we show that the temperature of chips of the vibration hobbing decrease about 6-15% in comparison with the conventional dry hobbing, quantitatively.