Showing papers on "Machining published in 1972"

Stress Distribution at the Interface Between Tool and Chip in Machining

Abstract: Stress distribution along a tool rake face were measured directly in the orthogonal machining of various metals. The method of measurement was based on the use of a composite tool which was divided into two parts parallel to a cutting edge in order to measure separately the force acting on one section of the tool. The stress distributions under actual cutting conditions were revealed, and the relationship between the nature of stress distribution and the mechanical properties of work material was clarified. It was ascertained that the nature of stress distribution was closely connected with the strain hardening index of work material and the frictional coefficient between tool and material.

Slip-Line Field Analysis for Orthogonal Machining Based upon Experimental Flow Fields:

Abstract: An experimental flow field for slow speed (0·5 in/min) orthogonal (plane strain) machining was analysed using slip-line field techniques. Although the experimental streamlines were not sufficiently...

Manufacturing processes using machine tools

Abstract: A system comprising a plurality of complementary numerically controlled machine tools in which different workpieces are each subjected to appropriate selected machining operations on selected machine tools in a selected order by appropriate delivery of common form pallets loaded with the workpieces. Transporters deliver pallets between the machine tools, a storage rack, and work-setting stations where workpieces, automatically delivered in bins from a bin store, are loaded on pallets. Tool magazines are delivered between a rack and the machine tools by transporter. Transport and machining operations are computer controlled, and monitors feed back signals indicative of location of pallets, tool magazines, and bins in the system.

Cooled turbine blade and its manufacture

Abstract: A turbine blade includes a hollow strut covered with a porous laminated material to provide a cooled blade portion and includes a supporting strut portion terminating in one or two bases for attachment to a turbine wheel. It also includes a blade platform bicast to the strut at the junction of the blade and supporting portions. The strut may be fabricated by casting or forging two parts, each defining one face of the strut, bonding these together at the leading edge of the airfoil, machining the leading edge portion, fitting the facing to the blade portion of the strut and bonding these together, then forming the blade portion to the desired airfoil contour and thereafter bicasting the platform onto the strut so as to cover the platform end of the blade facing.

Method for monitoring machining condition of machine tool

Abstract: In a machine tool having a work holder and a cutting tool which is brought into cutting engagement with a workpiece held on the work holder to machine the same, the reaction force on the cutting tool is detected in the form of three components, that is, a backing force component, a feeding force component and a main force component to obtain ratios of one component to the other two components The ratios are then compared with coresponding reference values which vary in accordance with the initial values of the ratios, so as to detect abnormal conditions of the cutting tool

Method of and apparatus for precision positioning of heavy workpieces

Abstract: At a loading station, a large heavy workpiece such as a turbine housing is anchored in a predetermined position on an underlying pallet which then is propelled and steered across the shop floor to a machining station while supported and floated vertically on a cushion of pressurized air. The pallet then is located accurately in all three dimensions in the machining station to enable precision machining of the workpiece while the latter is supported on the pallet.

Process and apparatus for machining by electro erosion

Abstract: A process and installation for machining by electro-erosion, comprising means for measuring the voltage between the electrode and the part to be machined during a discharge, and a device sensitive to the difference between the voltages corresponding to two distinct discharges, this device acting upon the electrical and/or the mechanical control of the installation.

Method of manufacturing bimetallic high-speed cutting tools

Abstract: A bimetallic high-speed cutting tool having a series of spaced teeth provided on one of its longitudinal edges is manufactured by providing each tooth at its forward top end with a cut-out portion on which a tip of super-hard material, molded before being sintered into a shape substantially equal to a desired final configuration, and having as cutting edges sharp square corners, is welded or brazed, so that the machining of said tip to said desired final configuration, after it has been welded or brazed to the tooth body is minimized, the super-hard materials constituting said tip being selected from those having such hardness and flexural strength as not to be affected by the heat applied thereto when the tip is welded or brazed firmly onto the tooth body.

Design and Performance of Reluctance Motors with Unlaminated Rotors

Abstract: The paper describes the design of reluctance motors having unlaminated rotors and gives test results for a range of motors which demonstrate the very satisfactory levels of performance which have been attained. Two types of design are described having, respectively, salient-pole rotors and rotors with flux barriers. The theoretical basis of their design is presented and is substantiated by the exprimental work. A particularly notable result is that good synchronising performance is obtained, without using embedded squirrel-cage windings, by incorporating either simple low-resistance sections in the rotor or by machining narrow axial slits in the rotor surface.

Apparatus for the simultaneous machining of a material moving with relative motion with respect to the tools, in particular for cutting up a plate of glass

Abstract: Apparatus with several tools for the simultaneous machining of a material moving with relative motion with respect to the tools, said apparatus to be used in particular for cutting a glass plate to size and comprising a support table for supporting the material and a bridge extending over said table and carrying several tool carrier units displaceable in longitudinal direction by power drive. There is provided a drive means to drive a displacing means transversely to the direction of machining, the individual tool carrier units being connected through disengageable clutches with said displacing means at preset distances from one another.

Rake Face Action of Cutting Lubricants: An Analysis of, and Experiments on, the Machining of Iron Lubricated by Carbon Tetrachloride

Abstract: A number of suggestions are current concerning the rake face action of cutting lubricants; that they reduce the shear stress between chip and tool uniformly over the whole chip–tool contact area; t...

Cutting tool and method of making same

Abstract: A cutting tool of the type used in machining operations has a supporting substrate of metal-cemented carbide which was formed prior to being placed in a pressure chamber. The cutting edge of the tool is composed of diamond integral with the substrate which was grown on the substrate from nondiamond carbon by subjecting the preformed substrate with the carbon in contact therewith to pressures of about 45 kilobars in the pressure chamber at temperatures of 1,400*-1,600*C. The carbide-cementing metal is chosen from among cobalt, nickel and iron - all of which are catalyst metals for the formation of diamond. Under diamondstable thermodynamic pressure and temperature conditions, the nondiamond carbon is catalyzed by the cementing material to form diamond in predominantly a (111) crystallographic orientation plane to produce columnar grains perpendicular to the diamondcarbide interface.

Ion Machining of Diamond

Abstract: It is demonstrated that argon‐ion beams are effective in drilling holes in diamonds. Truncated conical holes were made with basal diameters as small as ∼0.375 mm and tapering to ∼0.05‐mm diameter at the top. Larger holes with diameters at the two surfaces of 1.45 and 2.26 mm were milled through a 1.58‐mm‐thick diamond. Milling rates of up to 2 μ/min were obtained. The inside surfaces of the holes are essentially polished, with adjacent regions appearing to be damage free. The technique also has the capability of milling holes of arbitrary shape and of finely polishing the inside surfaces.

Electrode for electro-erosion machining electrode

Abstract: Apparatus for and a method of electro erosion machining with increased stock removal rate with a fine finish is disclosed. The electro erosion machining apparatus disclosed includes an electrode having a plurality of separate portions insulated from each other and separately connected to a single source of pulsed electrical energy whereby the current from the source of pulsed electrical energy is divided among the separate electrode portions to provide a small current for each electrode. The method of the invention includes varying the current passed through each portion of the electrode, limiting the current through each portion of the electrode to a single direction and moving the electrode transversely of the direction of movement of the electrode toward a workpiece during electrical erosion machining to provide rapid total form machining.

Adjustment means for the tooling or machining angle in tooling or machining operations

Abstract: Adjustment means is provided for adjusting the tooling or machining angle, especially the boring angle of tooling devices. Said adjustment means is secured to the device proper and comprises a level carried by a lever which is pivoted between two discs having angular graduations on their rim portions for setting the angular position of the lever about a first axis. Also, the level is rotatably adjustable on the lever about a second axis extending perpendicular to the first axis, whereby the tooling angle can be accurately set relative to vertical and horizontal axes, that is, three-dimensionally.

Cutting Forces in Machining and Their Routine Measurement with Multi-Component Piezo-Electric Force Transducers

Abstract: Knowledge of actual cutting forces in machining is becoming of paramount importance to both designers and users of machine tools, because optimum machine performance, tool selection, tool life, cutting-edge geometry, combination of tool and material to be machined, accuracy and so on are closely related to the resulting cutting forces. Transducers and platforms for measuring forces in 1, 2 or 3 components and/or torques have been developed and are described here. Quartz is used as the piezo-electric transducer material because it provides extremely high rigidity and excellent dynamic response as well as minimal cross-talk between components. In contrast to other measuring systems, such platforms equal or exceed usual tool holders in terms of rigidity, thus permitting realistic, precise measurements. Practical aspects such as cross-talk between components, frequency response, measuring and recording techniques are discussed and the possibilities of adaptive control by directly mounting transducers into machine tools outlined.

High pressure rotary coupling

Abstract: This invention relates generally to the field of high-pressure fluid transmission, and has to do particularly with apparatus which enables high-pressure fluid to be transmitted through rotatable joints, as required, for example, to enable highpressure fluid jets to be maneuvered for machining or cutting.

Electrical discharge machining pulse control method and apparatus

Abstract: A system for controlling machining pulse on-off time to limit gap power in response to a short or an open circuit machining gap condition in electrical machining systems wherein a multivibrator applies a preset on-off time at an electronic switch between the power supply and the gap. The condition detected at the gap in the form of an electrical signal is delivered via a delay network to a control circuit adapted to shunt one of the impedances of the resistance-capacitance network of the multivibrator.

Polarity reversal system for electrical discharge machining apparatus

Abstract: A control system is provided with an electronic switch control network for maintaining a constant polarity gap output signal from a single or multiple electrode gap system independently of whether the electrical power conducting leads from the power source are connected to one or the other of the EDM gap elements. In a multiple gap setup, provision is made for independently changing polarity of the gap elements in the different gaps. The gap output signal which is ordinarily representative of gap voltage is then utilized in other associated EDM circuits such as for an example power feed control networks and machining pulse cut-off control networks to regulate their operation.

Tool-Life Equations and Machining Economics

Abstract: Since F. W. Taylor first expressed the life of cutting tools in a mathematical form, several workers have proposed alternative equations. The important equations used in the past are reviewed and their validity discussed. The effects of tool-life criteria and machining conditions are considered, and the feasibility of incorporating the various equations into economic machining analyses are discussed.

Control method and apparatus for a machine in particular for a grinding machine

Abstract: A method and apparatus for improving the speed of operation of a machine tool wherein a given dimension of a workpiece being machined is continuously measured, the signal representing the measured dimension being supplied to the machine tool control apparatus; this measured value is also compared with a preset reference value representing the given dimension at a time prior to completion of machining; the current machining speed is also calculated from the measured dimension. When the measured value of the dimension equals the reference value, the measuring means is moved out of engagement with the workpiece and the amount of machining is thereafter calculated on the basis of the last machining speed calculated just prior to the disengagement of the measuring means; the calculated machine amount is then compared with the reference value and the difference therebetween is supplied to the machine tool control apparatus.

The use of a cutting force spectrum for tool wear compensation during turning

Abstract: The variations of tangential cutting force during finish turning of AISI–1045 and AISI–4130 steel have been measured for depth of cut from 0.001 to 0.008 in. Changes in tool geometry, such as the reduction of rake face areas as a wear criterion, have been obtained and the consequent modifications of the depth of cut on the workpiece were related to the cutting force spectrum. This relationship between machining variables has been incorporated into a control algorithm and the flow chart suggesting numerically controlled turning with corrections for tool wear is presented here.

Method and apparatus for cutting thermoplastic coated members

Abstract: Burr-free fast cutting or machining of workpieces with thermoplastic layers bonded to harder backing members. Both the thermoplastic and its backing member are contacted by a high speed tool, and the thermoplastic layer is trimmed before the produced heat softens or melts the thermoplastic at the trim location. A high speed tool is used which is capable of operating upon the harder member. Offset from the workpiece contacting portion of the high speed tool, one or more trimming teeth trim the thermoplastic layer at intervals inwardly of the machined workpiece area where the thermoplastic is yet to be heated significantly and softened. The high speed tool may be a multitooth rotary cutter blade supporting a single offset tooth.

Machine for multiple grinding of semiconductor

Abstract: A machine for multiple grinding blanks of crystalline structure in the production of semiconductors. It accomplishes the cutting-off, grinding and polishing operations. The machine comprises a turn table on which there are mounted carriages with blanks. Around the table there are mounted grinding heads. The process of machining blanks is carried out continuously by way of successive steps of grinding and polishing the ends of blanks and then cutting-off the latter.

Replaceable tip shear proof punch

Abstract: A shear proof punch with heel aligning structure formed as a part of the punch tip retainer but without difficult machining tolerances.

Numerical control for machining complex surfaces

Abstract: The art of machining complex, doubly curved surfaces has been advanced by experimental extensions to the Automatic Programmed Tool Language (APT) and its numerical control program. Described are mathematical programming procedures and language extensions for directing the cutting path of a machine tool over a ship's propeller, which serves as an example. Illustrative of an area for future development is the possible extension of interactively designed surfaces - using graphic displays - to interface with an APT processor.