End Mill Tool Research Articles

Geometrical Study on Machining Mechanism at Center of Ball-Nosed End Mill.

This paper presents a geometric analysis of an undeformed chip thickness at the top of tool in ball-nosed end milling. It has been firstly pointed out backward near the center of tool that is irregular interference between the flank and the workpiece. So backward occurs a non contact part on the cutting edge. Secondly a condition of backward has been clarified. An area of backward in a ball-nosed end mill is shaped circle that exists beside the center of tool axis. Thirdly a method of avoidance from backward has been brought up. Then its influence for surface roughness is verified by a few experiments.

A Feature-Based Approach to Automated Design of Multi-Piece Sacrificial Molds

This paper describes a feature-based algorithm for automated design of multi-piece sacrificial molds. Our mold design algorithm consists of the following three steps. First, the desired gross mold shape is created based on the feature-based description of the part geometry. Second, if the desired gross mold shape is not machinable as a single component, then the gross mold shape is decomposed into simpler geometric components to make sure that each component is machinable using 3-axis CNC machining. The decomposition is performed to ensure that each component is accessible to end-milling tools, and decomposed components can be assembled together to form the gross mold shape. Finally, assembly features are added to mold components to eliminate unnecessary degrees of freedom from the final mold assembly to facilitate molding.

205 加工面への影響を考慮した5軸制御ボールエンドミル加工のための工具経路生成法(OS4 生産システムとCAD/CAM)

This paper deals with the development of CAD/CAM system for getting a good machined surface. In case of inclination machining using the ball end mill tools, various change of the tool attitude can be carried out. Thus inclination machining is used in order to avoid machining in a tool tip. We searched a difference of surface appearance and surface roughness in terms of the tool attitude. However it is difficult to keep a tool attitude when a tool interference is considered in case of the form for which 5-axis control machining is needed. This research aims at development of the CAD/CAM system in order to create the tool path for good machined surface.The tool path is created in consideration with the machined surface quality of different tool attitudes. Using deviced method, cutting start point, tool feed direction and tool attitude can be determined automatically.

断続切削における工具逃げ面温度 高速エンドミル加工に関する研究 １

The temperature of cutting tool in high speed endmilling is measured using a two-color pyrometer with an optical fiber. This pyrometer has a flat response for the square-wave signal up to approximately 400kHz, which is enough speed to measure the temperature of an endmilling cutter passing at a cutting speed of 628m/min. The influence of cutting speed v and feed per tooth f on the cutting temperature at the flank face of the cemented carbide insert is investigated. The heating and cooling characteristics of the cutting tool during an intermittent cutting cycle are also examined. In dry cutting of carbon steel, the cutting tool temperature θα rises rapidly with the increase of cutting speed and θα reaches approximately 770°C at v=628m/min. The feed per tooth, however, has less effect on cutting tool temperature. The temperature change during an intermittent cutting process is about 150°C when v=471.2m/min and f=0.047mm/tooth. The temperature distribution along the contact edge between a tool and workpiece is almost uniform although those at tool tip and boundary region are somewhat higher.

高硬度金属材料の高速エンドミル加工に関する研究 （第２報） 工具形状が切削抵抗，切れ刃温度および工具損耗に及ぼす影響

The newly developed cutting force and temperature measuring system with high response speed and fine resolution can monitor cutting process as well as tool wear during high-speed endmilling of hard materials. The system enables us to precisely determine a transient cutting force and temperature action which is generated by each cutting edge of an endmill tools with various rake angles and helix angles. It is found that the cutting force and temperature in high-speed endmilling are sensitive to the helix angle rake angle and tool wearing process. When the helix angle and rake angle are 60 degrees and - 15 degrees respectively, the cutting force and the flank wear of each cutting egde generated is smaller than those for other angles of helix and rake.

ゴムの高速フライス加工に関する研究 (第1報)

In this research, a method for the precision machining of soft rubber (50IRHD hardness), which is difficult by conventional grinding, has been proposed. In view of the unique behavior of various kinds of rubber when subjected to machining, i.e., strong effects of their dynamic properties, the authors have considered that rubber can be successfully machined with good precision by means of tools having a large positive rake angle and using high-speed intermittent cutting. More specifically, the authors assumed that high-precision machining of soft rubber could be realized using the high-speed milling method. As a first step of the study, the authors have carried out high speed milling of various types of soft rubber with end mill tools. As a result, the authors have found that the higher the cutting speed or the larger the rake angle of a tool, the higher the precision, the lower the surface roughness and the better the flatness of workpieces, thus proving that this high-speed milling can be used as a new method for the precision machining of rubber.

高硬度金属材料の高速エンドミル加工に関する研究 (第1報)

This paper describes a newly developed cutting force and temperature measuring device with high response speed and fine resolution. It can monitor cutting process as well as tool wear during high-speed endmilling of hard steel materials. The device enables precise determination of the transient cutting force and temperature which are generated by each cutting edge of an endmill tool rotated at a speed of 20000 rpm. It is found that the cutting force and cutting edge temperature in high-speed milling are affected markedly by the cutting speed and tool wear. The cutting force and cutting edge temperature proportionally increase with increasing cutting speed.

Study on High-Speed Milling of Hard Materials. 1st Report. Development of Cutting Force Measuring Device with High Response and Resolution and Monitoring of Cutting Process.

In this paper we describe a newly developed cutting force measuring device with high response speed and fine resolution. It can monitor cutting process as well as tool wear during high-speed endmilling of hard steel materials. The device enables precise determination of an transient cutting force which is generated by each cutting edge of an endmill tool rotated at a speed of 20000 rpm. It is found that the cutting force and its waveform in high-speed milling are affected markedly by the cutting parameters and tool wear. The cutting force proportionally increases with increasing cutting speed. When the cutting speed exceeds a certain speed, the cutting edges rapidly wear out, also the increasing rate of cutting force changes quickly.

Study on High-speed Milling of Hard Materials. 2nd Report. Effect of Tool Helix Angle on Cutting Force and Tool Wear.

In this paper we describe a newly developed cutting force measuring system with high response speed and fine resolution. It can monitor the cutting process using various tools as well as the tool wearing process during high-speed endmilling of hard steel materials. The system enables us to precisely determine a transient cutting force action which is generated by each cutting edge of various helix angled endmill tools rotated at speeds of 40000 rpm. It is found that the cutting force and its waveform in high speed endmilling are sensitive to by the helix angle and tool wearing process. When the helix angle is 45 degrees, the cutting force and the flank wear of each cutting edge generated is smaller than those for angles of 15 and 30 degrees.

拡張Ｚ‐ｍａｐモデルによるＣＡＭシステムの開発 オフセット画生成法の一提案

This paper presents a new generating method of an offset surface on which a milling tool path moves. It consists of three steps; 1. A workpiece and an end-milling tool are represented by 2.5 dimensional lattice space model, enhanced Z-map model. 2. The calculation of a center position of the tool is done through the detection of a nominal cutting point in the geometric simulation. Namely the sum of a height of the workpiece at a lattice point of the XY domain and that of the tool at the same point in scanned at all over the lattice point of the covering area of the tool. This successive locus of the tool center coincides with an offset surface. 3. If a geometric machining error due to a tool path generation is estimated to be over a tolerance, lattice pitches of the XY domain are binary subdivided hierarchically. Then Step 2 is carried out based on the new lattice pitch till the satisfaction of tolerance requirements. Through the comparative simulation with the inverse offset method, the proposed method performed the improvement of processing time and a small memory size. The conclusions are briefly mentioned too.

遺伝的アルゴリズムによる最適工具群の選択

This paper presents a new method of optimal selection of cutting tools in a geometric cutting simulation. Firstly an area to be cut by an end-milling tool is calculated according to each different tool. The shape of the workpiece is represented in a hierarchical lattice space model, Enhanced Z-map model. Secondly a tool set prepared is coded as a binary bit string, i. e. gene. Each bit corresponds with a certain tool and 1 indicates its use and 0 is not. Thirdly a fundamental Genetic Algorithm consisting of selection, crossover and mutation is applied based on the index which takes account of total cutting time, uncut area, the number of tools used etc. Here it is assumed that the selected tools would be used in descent order of diameter and it would cut its corresponding area as entirely as possible. Some simulations are illustrated and the conclusions are briefly mentioned too.

A method of NC gear cutting with a simply shaped tool. (3rd Report, Worm wheel cutting with an end mill).

The so-called fly tool method of cutting hourglass shaped worm wheels offers an economical production of large-size worm gears. This method however, gives us only an approximate tooth surface of the wheel. The previous reports introduced the numerical control (NC) technique to the fly tool method for making a tool which is able to trace the wheel surface. The fly tool method demands high responsibility of the NC servo to obtain a high cutting speed. To prevent the speed problem, this report discusses two methods of end milling : (1) the end mill tool is driven as the tool of the fly tool method, and (2) the tool is fed in the orthogonal three directions. The tooth profile errors of wheels cut with these two methods are investigated. Compared to the latter method, the first method gives a higher precision of profile, but it is difficult to realize the motion of the tool. A bronze wheel is cut for a trial with the latter method, and the tooth bearing pattern is checked. A method of tooth surface modification is proposed.

A method of NC gear cutting with a simply shaped tool. (2nd Report, Worm wheel cutting with a fly tool).

The so-called fly tool method of cutting hourglass shaped worm wheels offers an economical production of large-size worm gears. This method however, gives us only an approximate tooth surface of the wheel. The previous reports introduced the numerical control (NC) technique to the fly tool method for making a tool which is able to trace the wheel surface. The fly tool method demands high responsibility of the NC servo to obtain a high cutting speed. To prevent the speed problem, this report discusses two methods of end milling : (1) the end mill tool is driven as the tool of the fly tool method, and (2) the tool is fed in the orthogonal three directions. The tooth profile errors of wheels cut with these two methods are investigated. Compared to the latter method, the first method gives a higher precision of profile, but it is difficult to realize the motion of the tool. A bronze wheel is cut for a trial with the latter method, and the tooth bearing pattern is checked. A method of tooth surface modification is proposed.