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Showing papers on "Machining published in 1970"



Journal ArticleDOI
TL;DR: In this article, the use of the geometric programming technique was used to determine the cutting speed and feed level of a machining machine to yield the minimum production cost, and the method provided for simultaneous determination of the cost optimum values of speed, feed and allowed for the incorporation of restrictions on the allowable levels of the machining variables.
Abstract: SUMMARY This paper discusses the use of the geometric programming technique to determine the cutting speed and Teed which yield minimum production cost. The method provides for simultaneous determination of the cost optimum values of speed and feed and allows for the incorporation of restrictions on the allowable levels of the machining variables.

68 citations


Patent
29 Oct 1970
TL;DR: In this article, 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 by appropriate delivery of common form pallets loaded with the workpieces.
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.

67 citations


Journal ArticleDOI
01 Jun 1970
TL;DR: In this article, the results obtained from machining and conventional slow-speed compression tests are used to calculate the constants σ1 and n in the empirical stress/strain equation σ = σ 1/n in a range of strain-rates and temperatures for a low carbon, free machining steel.
Abstract: Results obtained from machining and conventional slow-speed compression tests are used to calculate the constants σ1 and n in the empirical stress/strain equation σ = σ1***enover a range of strain-rates (10-3to 2·8 times 104/s) and temperatures (room temperature to 200°C) for a low carbon, free machining steel. The results are consistent with those obtained for a similar material using high-speed tension tests. Some results showing the influence of higher temperatures (up to 800°C) on the flow stress are also obtained from the machining tests by considering the flow along the tool-chip interface. These results show a dynamic strain-ageing effect similar to that found in high-speed tension and compression tests on similar materials.

61 citations


Journal ArticleDOI
TL;DR: In this paper, the authors show that there is a good correlation between contact length and the thermal conductivity of the tool material and conclude that contact length is predominantly governed by the variation of the temperature field in the tool-chip contact zone.

59 citations



Journal ArticleDOI
TL;DR: In this article, the process of chip formation in copper and aluminum single crystals has been examined with a scanning electron microscope, and the morphology of the shear planes clearly illustrates that the actual deformation zone (layer or shear front) is an extremely thin and well-defined band of slip planes wherein the predominant deformation takes place.
Abstract: The process of chip formation in copper and aluminum single crystals has been examined with a scanning electron microscope. The morphology of the shear planes clearly illustrates that the actual deformation zone (layer or shear front) is an extremely thin and well-defined band of slip planes wherein the predominant deformation takes place. The appearance of the top or upper surface of the chip corresponds to the micro mechanisms operating during the process of machining.

47 citations


01 Jan 1970
TL;DR: In this article, the authors used regression equations to determine chip types and tool forces typical of loblolly pine earlywood and latewood machined orthogonally in three major directions.
Abstract: Specimens of earlywood and latewood o f Pinus taeda L . were excised so that length along the grain was 3 inches and thickness was 0.1 inch. These specimens were cut orthogonally-as with a carpenter’s plane-in the three major directions. Cutting velocity was 2 inches per minute. When cutt ing was in the planing (90-O) direction, thin chips, intermediate to high moisture content, rake angles of 5 and 15O favored formation of the Franz Type II chip and accompanying good surfaces. In the O-90 direction, a knife with 70’ rake angle cut the best veneer; wood cut saturated yielded the highest proportion of continuous veneer, although saturated earlywood developed some compression tearing. When cutting was across the grain (90-90 direction), McKenzie Type I chips were formed and the best surfaces were achieved with a knife having 45Orake angle cut t ing saturated wood; earlywood was more difficult to surface smoothly than latewood. For each cutting direction, regression equations were developed to state average cutting forces (normal and parallel) in terms of rake angle, depth of cut, specific gravity, and moisture content. Tool Forces and Chip Formation in Orthogonal Cutting of Loblolly Pine The objective of the study reported in this paper was to determine chip types and tool forces typical of loblolly pine earlywood and latewood machined orthogonally. Orthogonal cutting is the machining process in which the cutting edge is perpendicular to the relative motion of tool and workpiece. The surface generated is a plane parallel to the original work surface. A carpenter’s plane cuts orthogonally, as does a bandsaw. Rotary peeling of veneer approximates orthogonal cutting. A two-number notation used by McKenzie (1961) is useful in describing the machining situation (fig. 1).

38 citations


Patent
C Guerci1, E Pagella1
02 Mar 1970
TL;DR: In this article, a tool holding device is described where the tool is slideably supported in the holder in order to enable a radial motion with respect to the axis of rotation of the holding device to be described.
Abstract: A tool holding device wherein the tool is slideably supported in the holder in order to enable a radial motion with respect to the axis of rotation of the holding device to be described. Control of the holder is effected by a control circuit which rapidly positions the tool for commencement of the machining operation and then controls the tool more slowly during the machining operation. A step motor is used as the motion source and is controlled directly by the control circuit.

29 citations


Journal ArticleDOI
TL;DR: In this article, a mass-spring-dampermedian system was used to determine how the vibration behavior during machining is affected by coupling between modes. But the authors focused on the effect on chatter-free machining performance of variations in the angle of setting of the boring head relative to the two planes of vibration, and applied the basic principles of the coupling mechanism over a wide range of conditions.
Abstract: The paper is concerned primarily with the stability of a slender boring bar which can be represented at the tool point by a simple two-degree-of-freedom, mass-spring-damper system. Its purpose is to determine how the vibration behaviour during machining is affected by coupling between modes.The stability behaviour is investigated for machining processes in which the cutting operation is of the regenerative type, when successive passes of the workpiece cause cuts to overlap. Account is taken of variations in certain system parameters, including the effect of workpiece speed, and results derived from practical cutting tests are described. Particular attention is paid to the effect on chatter-free machining performance of variations in the angle of setting of the boring head relative to the two planes of vibration.A theory is developed to apply the basic principles of the coupling mechanism over a wide range of conditions. Predicted changes in chatter characteristics are compared with experimental observatio...

29 citations


Patent
27 May 1970
TL;DR: In this article, thin film integrated circuits are formed by coating insulative substrates with conductive film and mounting them on the periphery of a rotating drum, where a switched laser machines the circuit pattern by vaporizing parts of the metal film of successive substrates.
Abstract: Thin film integrated circuits are formed by coating insulative substrates with conductive film and mounting them on the periphery of a rotating drum. As the drum rotates, a switched laser machines the circuit pattern by vaporizing parts of the metal film of successive substrates. Light from another laser is directed through a mask on the drum circumference and controls modulation of the machining laser.


01 May 1970
TL;DR: In this paper, the effect of machining conditions on the formation or avoidance of surface alterations is discussed in detail, and machining relationships and recommendations are given for chip removal operations, abrasive operations, as well as nonconventional operations, to minimize surface alterations.
Abstract: : As the strength level of High strength steels increases, fatigue and stress corrosion resistance exhibit a marked increase in sensitivity to surface conditions produced in machining. There are several significant surface alterations produced in machining which can seriously affect fatigue and stress corrosion resistance. These include untempered martensite, overtempered martensite, plastic deformation, cracks, tears, laps, burrs, spattered or redeposited metal, and residual stress. The effect of machining conditions on the formation or avoidance of these surface alterations is discussed in detail. Machining relationships and recommendations are given for chip removal operations, abrasive operations, as well as nonconventional operations, to minimize surface alterations. To maintain high surface integrity in milling, turning, drilling, etc. machining conditions are selected to provide long tool life. In addition, tools must be kept sharp, that is, tools must be changed frequently to minimize metallurgical alterations within the surface layer. In grinding, low wheel speeds, light down feeds, together with the use of highly active cutting oils are necessary to minimize surface alterations. Post-operative machining processes, such as heat treatment and shot peening are often needed to obtain desirable surface conditions. Rigid inspection techniques and often repair procedures are required to insure proper surface integrity. Particular attention is given to the problem of drilling and reaming holes with high surface integrity in high strength steels. (Author)

Patent
03 Mar 1970
TL;DR: In this article, the authors present an approach for electric discharge machining, which senses the commencement of each discharge across the gap between the electrode and workpiece and cuts off each discharge after a predetermined time interval.
Abstract: Apparatus used for electric discharge machining, which senses the commencement of each discharge across the gap between the electrode and workpiece and cuts off each discharge after a predetermined time interval.

Book ChapterDOI
01 Jan 1970
TL;DR: In this paper, the fundamental relationship of system analysis of linear time invariant systems by means of the spectral density measurements are derived in detail, and a possibility is shown to estimate the statistical errors at any time.
Abstract: The special advantage of the system analysis by means of stochastic signals is that the record of signals for the dynamic compliance test is obtained under actual and therefore natural conditions. Often these stochastic machining signals (cutting forces and deformation of the machine) are sufficient to carry out the analysis. All machining conditions of the actual cutting process can be realized and this facility is very important if the influence of the single machining parameters is to be investigated. Until now, no procedure of analysis possessing the mentioned properties has been available. In this paper the fundamental relationships of system analysis of linear time invariant systems by means of the spectral density measurements are derived in detail. Hereby the statistical and systematical errors play a large part. But the knowledge of the behaviour of these errors allows the general application of this new system analysis. A possibility is shown to estimate the statistical errors at any time. In order to compensate the systematical error, a correction procedure is derived. Thus the necessary accuracy of the results is guaranteed. Some representative examples show clearly, that the influence of the machining conditions on the dynamic compliance behavior of the machine tool is very significant. The hitherto existing assumption, that the dynamic parameters of the machines measured during the standstill are equivalent to those of the working machines can lead to false conclusions. The illustrated examples demonstrate the high importance of the system analysis by means of spectral density measurement compared with the conventional deterministic procedures.

Patent
09 Feb 1970
TL;DR: In this paper, an automatic electrical discharge machining device, including a logic circuit and detecting units monitoring voltages and currents at different parts of the machining devices circuit, is presented, where the detecting units deliver their outputs to the logic circuit, for determining the short-circuit, large gap conductance, sustained arcing, and other detrimental conditions at the discharge gap.
Abstract: An automatic electrical discharge machining device, including a logic circuit and detecting units monitoring voltages and currents at different parts of the machining device circuit. The detecting units deliver their outputs to the logic circuit, for determining the short -circuit, large gap conductance, sustained arcing, and other detrimental conditions at the discharge gap, by suitably combining the outputs from the detecting units. Automatic control is made in response to the output from the logic circuit for regulating an electrode or various voltage pulses.

Patent
19 May 1970
TL;DR: In this paper, the deforming member is mounted in a holder which reciprocates and moves progressively with relation to the rotating article holder or with respect to the progressively moving article holder.
Abstract: The machining of the surfaces of articles for making grooves intended to retain liquid or gaseous media used for lubrication or as an interlayer to the devices for the realization of these methods, and to the articles machined by these methods. Most successfully the invention can be used in machining the surfaces of cylinder liners, pistons and the walls of the holes in the pistons for the piston pins in internal combustion engines and in machining sliding and rolling contact bearings, spinning machine rings, and gauge blocks. No less successfully this invention can be used for machining the reflectors of heating appliances, fountain pen caps, various vessels and articles of jewelry, because the network of grooves forms an attractive ornamental pattern. The method consists in forcing at least one spring-loaded spherical deforming member into the surface layer of the article. The machined surface of the article and the deforming member move at an angle to each other and the motion of at least one of them is either reciprocating or rotary. In the various forms of the device, the deforming member is mounted in a holder which reciprocates and moves progressively with relation to the rotating article holder or rotates with relation to the progressively moving article holder.

Patent
Lewis A Dever1
02 Jun 1970
TL;DR: In this article, an elongated workpiece is machined along its surfaces by relative longitudinal movement between the workpiece and a support for a pair of perpendicularly disposed cutting tools.
Abstract: An elongated workpiece, which is maintained under tension, is machined along its surfaces by relative longitudinal movement between the workpiece and a support for a pair of perpendicularly disposed cutting tools. A fixture, which is connected to the support for the cutting tools so that the fixture is always the same longitudinal distance from the cutting tools, has the elongated workpiece pass therethrough. The fixture has two reference surfaces, which are perpendicular to each other, against which two perpendicular surfaces of the workpiece are urged by pressure rollers in the fixture acting against workpiece surfaces, which are parallel to the surfaces of the workpiece engaging the reference surfaces.

Patent
09 Jan 1970
TL;DR: In this paper, a circuit for providing machining pulse off-time control responsive to gap short-circuit condition and gap open circuit condition is presented. But, the machining on-time is maintained constant and is substantially the same as before the occurrence of either gap short circuit or open circuit conditions.
Abstract: A circuit for providing machining pulse off-time control responsive to gap short circuit condition and responsive to gap open circuit condition. During the aforesaid short circuit condition, machining current is reduced by increasing machining pulse off-time. However, the pulse on-time is maintained constant and is substantially the same as before the occurrence of either gap short circuit or open circuit condition.

Patent
09 Mar 1970
TL;DR: In this paper, a machine for CUTting a web of textiles into individual RECTANGULAR Sheets with rounded corns is described, and the machine operates autonomously to provide the SEVERAL FUNCTIONS and may be adjusted to adaptively to CUT Rectangular Sheets of varying lengths and width.
Abstract: A MACHINE FOR CUTTING A CONTINUOUS WEB OF TEXTILE MATERIAL INTO INDIVIDUAL RECTANGULAR SHEETS HAVING ROUNDED CORNERS. THE MACHINE CONTINUOUSLY CUTS BANDS OF MATERIAL FROM EACH SIDE OF THE WEB AS IT TRAVELS AND INTERMITTENTLY MAKES TRANSVERSE CUTS ACROSS THE WEB TO FORM SHEETS OF PROPER LENGTH. A DIE CUTTING DEVICE CUTS ROUNDED CORNERS ON THE SHEETS. THE MACHINE OPERATES AUTOMATICALLY TO PROVIDE THE SEVERAL FUNCTIONS AND MAY BE ADJUSTED TO CUT RECTANGULAR SHEETS OF VARIOUS LENGTHS AND WIDTHS.

Patent
03 Nov 1970
TL;DR: A turntable for fastening workpieces during machining in which the work table holding the workpiece can be lifted above the bed and be turned and moved with relation to a gas or liquid cushion is described in this article.
Abstract: A turntable for fastening workpieces during machining in which the work table holding the workpiece can be lifted above the bed and be turned and moved with relation thereto on a gas or liquid cushion.

Patent
10 Aug 1970
TL;DR: In this article, a sizing device is used to measure the diameter of a workpiece during a grinding operation, and a grinding resistance control means is provided for detecting the grinding resistance applied on the grinding wheel.
Abstract: A grinding machine operative for controlling the feeding speed of a wheel slide to obtain high machining accuracy and efficiency, incorporating a sizing device for constantly measuring the diameter of a workpiece during a grinding operation thereon and directs feed control means to change the feed speed of the wheel slide. A grinding resistance control means is provided for detecting the grinding resistance applied on the grinding wheel and supplies the feed control means with the detected grinding resistance in a rough grinding stage at a predetermined value. For the final grinding operation, the axis of a wheel spindle carrying the grinding wheel is shifted to obtain a required diameter of the workpiece.

Journal ArticleDOI
TL;DR: The application of ion beam techniques to surface machining and the surface properties of glass is discussed in this paper, with a brief review of the relevant theory, and some experimental results.

Patent
R Hague1, E Hantman1, H Laucks1, Alfred J Mastropole1, G Loos1, M Marsicano1 
29 Apr 1970
TL;DR: In this article, a tool changer is disclosed for automatically removing a working tool after having been used from the spindle of a machine tool such as a vertical milling machine, transferring the used working tool to a rack which stores a plurality of working tools, picking up from the rack another working tool for the next machining operation, and operatively mounting such new working tool on a spindle.
Abstract: A tool changer is disclosed for automatically removing a working tool after having been used from the spindle of a machine tool such as a vertical milling machine, transferring the used working tool to a rack which stores a plurality of working tools, picking up from the rack another working tool for the next machining operation, transferring such new working tool to the spindle, and operatively mounting such new working tool on the spindle

Proceedings ArticleDOI
24 May 1970
TL;DR: A wide variety of surface alterations can be produced by conventional machining as well as by a variety of electrically and chemically assisted metal removal methods as discussed by the authors, and the effect of variables in milling and grinding will be reviewed.
Abstract: Metal removal processes disturb or alter the surface layer creating characteristics which may be quite different from those of the base metal. A wide variety of surface alterations can be produced by conventional machining as well as by a variety of electrically and chemically assisted metal removal methods. The effect of variables in milling and grinding will be reviewed. Photomicrographs illustrating surface alterations produced in martensitic steels, titanium and nickel alloys will be presented, as well as microhardness data illustrating the types of hardness changes found in these surfaces. Data on residual stresses produced in some of these materials as a function of machining variables will also be presented. The fatigue characteristics of these alloys, as affected by conventional metal removal process variables, are summarized and explained. It can be concluded that the method of machining and the variables chosen for a particular machining method are significant in relation to the mechanical performance of finished parts. Machining methods must, therefore, be carefully evaluated in their relation to the performance of highly stressed components which are subjected to a variety of hostile environments.Copyright © 1970 by ASME

Patent
20 Feb 1970
TL;DR: A sleeve actuated hydraulic chuck for accurately locating internal work pieces or tool elements for machining, grinding, gauging or other operations is described in this article, where the chuck is substantially symmetric for vibrationless operation at high speeds.
Abstract: A sleeve actuated hydraulic chuck for accurately locating internal work pieces or tool elements for machining, grinding, gauging or other operations. The chuck is substantially symmetric for vibrationless operation at high speeds.

Patent
08 Jun 1970
TL;DR: In this paper, the capacity of a centrifugal compressor having an overhung rotor with a plurality of separate stage impellers is changed by machining the free curved edge of each impeller blade by an equal amount of machining along the entire curved edge length from the radially extending axial flow edge to the axially extending radial flow edge.
Abstract: The capacity of a centrifugal compressor having an overhung rotor with a plurality of separate stage impellers is changed by machining the free curved edge of each impeller blade by an equal amount for each impeller along the entire curved edge length from the radially extending axial flow edge to the axially extending radial flow edge. Additional separate shrouds are provided that differ in diameter from the shrouds supplied with the impellers before machining by an amount equal to the diametric change occurring during machining. Further, separate annular diffusers are provided, with each diffuser having integral blades with free terminal edges lying in a common plane perpendicular to the axis of rotation and engaging the adjacent shroud, so that these radially extending diffuser blade edges may be machined by an amount equal to the axial component of machining on the corresponding impeller blades.

Patent
24 Feb 1970
TL;DR: In this article, a laminated, relatively massive metal member requiring a minimum of finish machining is made by cutting a number of thin metal laminae in the shape of the final member.
Abstract: A laminated, relatively massive metal member requiring a minimum of finish machining is made by cutting a number of thin metal laminae in the shape of the final member. The laminae are stacked into the shape of the member, and held therein by suitable restraining means. The laminae stack is then diffusion bonded together at an elevated temperature and pressure in a nonoxidizing environment.

Patent
12 Oct 1970
TL;DR: In this paper, a method and apparatus for dissipating heat generated during the machining and processing of metals or other materials is described, which includes directing toward the work piece and/or cutting tool a needle-like or sharp tooth-shaped probe that is connected to a high voltage direct current potential, and electrically insulating the workpiece and cutting tool from the machine.
Abstract: A method and apparatus for dissipating heat generated during the machining and processing of metals or other materials which includes directing toward the workpiece and/or cutting tool a needle-like or sharp tooth-shaped probe that is connected to a high voltage direct current potential, and electrically insulating the workpiece and cutting tool from the machine

Journal ArticleDOI
TL;DR: In this paper, a bending model that estimates the effects of thermal distortion using knowledge of the position of the temperature gradient is derived, and the performance of the bending model is compared with a finite element analysis model and a model that has no knowledge of temperature gradients.
Abstract: Heat sources internal and external to a machme tool cause temperature gradients to arise due to resistance to heat flow in and around the machine tool and workpiece This causes linear expansion and distortion of the structural elements from which the machine tool is constructed The connectivity of the structural elements sets the effect of the expansion and distortion on the relative positions of the tool and workpiece, leading to thermal errors on the workpiece Measurement on a wide range of machine tools confirms that temperature gradients are significant in their effect on machining accuracy and that they move and change shape during the machining process An analysis of machine tool structures and connectivity shows that both the position and magnitude of temperature gradients is important in its effect upon the relative movement of the tool and workpiece A bending model that estimates the effects of thermal distortion using knowledge of the position of the temperature gradient is derived The performance of the bending model is compared with a finite element analysis model and a model that has no knowledge of the position of temperature gradients Results obtained from a vertical machining centre show that knowledge of the position and magnitude of temperature gradients is an essential part of predicting thermal distortion accurately