Showing papers on "Machining published in 1971"

A Theory of Machining of Fiber-Reinforced Materials

Abstract: A theory of the machining of fiber-reinforced materials is pre sented. The analysis is restricted to plane deformations of incom pressible composites reinforced by strong parallel fibers. Complete deformation and stress fields, as well as estimates of the forces re quired to maintain continuous machining, are derived. The results apply to both elastic and plastic stress responses.

Ion-Beam Techniques for Device Fabrication

Abstract: Sputtering of solid surfaces by low-energy ion beams can remove materials at a rate useful for machining purposes; the system can be called an ion-milling machine. Milling of solid materials, with minimum change to adjacent materials, is possible by this method. The first part of the paper discusses the parameters involved in ion interactions with solid surfaces. Six different ion-milling techniques and ion sources are next described. Finally, practical procedures obtained with some current problems are given.

Connecting rod manufacturing

Abstract: High quality connecting rods and similar machine components comprised of an assembly of two clamped together parts are manufactured from tough heat treated high carbon steel, or the like, according to a manufacturing method of reduced cost. Essentially all machining of the component is conducted on an integral piece prior to its being divided into the two separate parts by fracturing along a frangible zone effected by electron beam bombardment. The resulting irregular mating surfaces of the respective parts have substantial resistance to relative sliding upon clamping of the parts together.

Group technology and manufacturing systems for small and medium quantity production

Abstract: Group technology, a manufacturing concept for small and medium quantity production, is receiving more and more interest from the machine-building industry all over the world. A prerequisite for the implementation is the grouping of parts, which are similar with respect to manufacturing. As an aid to this a classification system based on a form description is introduced. For the machining of this similar parts several manufacturing concepts according to the complexity of the parts have been developed, e.g. machining centres, flow lines and automats. Two case studios are presented. One is the layout of an unlinked flow line, the other one is the utilization of a machining centre. With the introduction of group technology in a firm, the design and work-planning departments can take advantage. Some hints are given with respect to that possibility.

Electric discharge machining device

Abstract: An electrical discharge machining device comprising a plurality of detectors for detecting currents and voltages at different parts of the device and generating detection signals in response to the detection, a logic circuit for determining different machining conditions of the device by logical combination of the detection signals so as to generate different discerning signals corresponding to the different machining conditions, and a control means for controlling the machining device based on relative frequency ratios of different discerning signals Said relative ratios may be determined by using integrating circuits

A Structural Investigation of the Laser Machining of Thin Bismuth Films

Abstract: An experimental investigation of laser matching of thin films of Bi deposited on Mylar substrates has been carried out. Both He–Ne and argon acousto‐optical intracavity modulation systems were used to effect the machining. Scanning and transmission electron microscopy were employed to determine the structural changes caused by machining. It was found that the formation of holes several microns in diameter by laser beams requires melting and probably the initiation of evaporation in the center of the illuminated region. Liquid‐phase material is then transported from the center resulting in the formation of machined holes bounded by thicker rim structures. Only a few percent of the material removed needs to be in the vapor phase to achieve the maximum spot diameter for a given pulse energy. It was also found that for short optical pulses (≤ 50 nsec), which require lower machining energies to create a machined spot of a given size than with longer pulses, the substrates are undamaged.

Laser Machining with a Holographic Lens

Abstract: A holographic lens is used in conjunction with a pulsed ruby laser for machining single and multiple spots on a 0.12-μm thin film of tantalum deposited on glass. Spot sizes as small as 14 μm have been obtained with hologram diffraction efficiencies as great as 30%. Imaging of two spots separated by 3.18 mm has resulted in the simultaneous machining of two 30-μm spots having equal intensity and spot shape. The resolution that has been obtained with the high powered laser and the observed durability of the dichromated gelatin holograms for very high energy densities are encouraging and suggest a number of possible applications.

Method of performing sequential non-mechanical and mechanical machining operations along a common centerline

Abstract: The disclosure relates to a method of drilling holes in difficulty machinable material wherein non-mechanical means, such as a laser or an electron beam, is used to drill a first undersize hole which is characterized by a surrounding recast area followed by a mechanical reaming operation to remove the recast area and produce a finished bore in the material which then reveals no metallurgical alteration.

Computer optimization of multi-pass turning

Abstract: The results of optimization of multi-pass turning using a computer programme are described. By graphical presentation, the variations in cutting conditions, i.e. speeds, feeds and depths of cut for two consecutive passes are described, together with the degree of optimality in terms of the total machining cycle time, and power requirements. Power, deflection and surface finish constraints, and tool wear criteria are involved, and variations in operating conditions occasioned by changing the surface finish and power constraints are illustrated. Test cases are presented to illustrate the effects of workplace geometry on the nature of the optimal conditions, or the constraints on reaching them, arising from the machine-tool-workpiece system. The difference between multiple-cut and single-pass machining economics is illustrated thereby.

Method of electrochemical machining

Abstract: An apparatus and method of electrochemically machining a surface of revolution on a rotating workpiece includes rotating the workpiece about its axis and positioning an electrochemical machining tool having an essentially flat machining surface adjacent the workpiece to form a gap. The tool includes a machining surface having a straight edge in a plane which also includes the axis of the workpiece. The machining surface is oriented essentially perpendicular to the plane so that the smallest gap dimension exists between the straight edge of the tool and the workpiece. Electrolyte is introduced into the gap in a direction so that it flows across the machining surface and between the tool and the workpiece in a direction parallel to the direction of relative movement and toward the smallest gap dimension.

Methods for the manufacture of lightweight optical parts

Abstract: A process for the manufacture of lightweight optical parts, comprises forming at least one optical surface on a solid blank by machining and mechanical polishing, ultrasonically machining cavities underlying the optical face in at least one of the remaining faces of the blank to reduce the weight of the article and finally depositing an optical coating on the optical surface. The weight reducing recesses can be made in the face of the blank opposite the optical surface or they can be formed in lateral surfaces of the blank. An ultrasonic generator is disclosed with an electrode serving as a machining tool.

Workpiece manufacturing and machining device

Abstract: An arrangement wherein a plurality of machine tools are arranged in a row with each machine tool having an spindle and a tool changing device on each side for inserting tools into the spindle or removing tools from the spindle. On each side of each machine tool is a tool storage element for cooperation with the tool changing devices and each having an endless tool supporting conveyor. The storage elements between adjacent machine tools can cooperate with the machine tool on each side thereof while all storage elements cooperate with a main storage element extending along the row of machine tools. Each machine tool also has a workpiece supply conveyor leading from the machine tool to a main workpiece conveyor and storage device adjacent the main tool storage element. The installation is under automatic control for the supply of tools to the machine tools and the movement of workpieces therebetween and for the exchange of tools between the machine tools and between the main tool storage element and the machine tools or the storage elements adjacent the machine tools.

A bimetallic high-speed cutting blade

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

Multi-electrode electrical discharge machining apparatus

Abstract: Electrical discharge machining apparatus comprising a frame, a plurality of substantially parallel electrodes, a carriage mounted on the frame for guided movement in a vertical direction, and a cartridge assembly supporting the electrodes and removably mounted on the carriage so that the electrodes extend vertically. Manually operable gripper means is provided for feeding the electrodes downwardly after each machining operation into engagement with the workpiece so as to compensate for electrode wear experienced during one or more preceding machining operations. Positive stop anti-short power means is combined with the carriage to enable retraction of the electrodes out of engagement with the workpiece into a predetermined spaced relation with the workpiece at least as great as the desired spark gap spacing between the electrodes and the workpiece during machining. The cartridge assembly includes a cartridge member provided with contact blocks connected to a supply of current and engaged with the electrodes during machining.

Edm apparatus for finishing rolls

Abstract: Rolling mill rolls, such as the final rolls for a sheet cold rolling operation, are machined by electrical discharges in a lathe-type machine with a roll length electrode tool. High areas of the roll shape the adjacent surface of the electrode tool, either by a mechanical or electrical wear-in operation, so that such surface substantially complements the desired final roll contour. The shaped electrode tool is subsequently used for electrical discharge machining (EDM) the roll to the level of the lowest roll portions so as to impart a very uniform matte texture to the roll surface and provide a roll with substantially perfect cross-sectional circularily. If the machining is carried out with a segmented electrode tool, the tool is preferably moved slightly from time-to-time axially of the roll during at least the final stages of the machining process. Following the machining, the roll may be used without further processing as an improved substitute for rolls textured by the conventional shot blasting technique or it may be ground to a bright polish.

Electrode for electrical machining

Abstract: An electrode for the electrical machining of a conductive workpiece by ECM or EDM is produced by high energy rate forming simultaneously with an index formation engaging in an electrode holder whereby a large number of such electrodes can be massproduced and identically positioned. The electrode defines a space with the holder through which a coolant is circulated to limit thermal deformation in use.

Method and means for preventing regenerative chatter in a machine tool, particularly in a lathe

Abstract: The invention relates to a method for suppressing regenerative chatter of the kind which occurs during the machining of workpieces by a tool of a machine tool, said method consisting of changing repeatedly the cutting speed of the tool whilst the latter machines the same surface of the workpiece, thereby making the frequency with which the waves or ripples on the surface which is being machined impact on the tool dissimilar to the inherent frequency of the mass system on which the cutting force acts, so that these waves or ripples when impacting on the tool do not increase the amplitude of the vibrations which product chattering. Moreover the invention relates to a machine tool for carrying out such method, more particularly to a lathe.

An approach to machining process optimization

Abstract: Optimization is rightly claimed to be the most significant factor distinguishing the modern approach to machining processes from the orthodox one. Practical results can be obtained from the application of mathematical modelling and optimization techniques. The paper presents a procedure for solution of machining process optimization problems, with the use of theory of graphs and Bellman's optimum principle. The finite graph G=(N, A) (where -N denoted a set of nodes and A the set of arcs) here presents the set of feasible solutions. Each are represents a corresponding machining operation and each path the feasible machining process. A number can be associated with each are : the increment of criterion for optimality. Using the optimum principle we can find the shortest possible path in the graph, thus solving given problems of choice for the optimal machining process. There is a variety of ways in which the performance criterion can be formulated. In this paper only those performance measures having suffic...

Pulse narrowing and cut-off protection system for electrical discharge machining

Abstract: A protection circuit is provided which senses and responds to gap short circuit condition during machining pulse on-time. Responsive to such condition, a machining current cut-off function is exercised by a complementary pair of electronic switches which operate with positive action to control pulser operation by decreasing the "on" time of the pulser and decreasing off-time. An additional means is provided for appropriate limiting machining current by sensing gap open circuit condition during pulse on-time and correspondingly, through the operation of a complementary pair of electronic switches, increasing the "off" time of the pulser.

Apparatus for controlling chucking pressures on workpieces in machine tools

Abstract: The present invention provides a method of and apparatus for controlling chucking pressures on workpieces in machine tools carrying out machining operations by chucking the widths, outer surfaces or inner surfaces of workpieces with hydraulic pressure, magnetic forces or mechanical force, the principal arrangement thereof being such that in order that the internal stresses in a workpiece may be dissipated or relieved in accordance with changes in the cutting speed in an automatic working cycle thereby to improve the accuracy of finishing, the chucking pressures are properly adjusted. It also provides methods of and apparatuses for controlling chucking pressures on workpieces in machine tools, having sub-arrangements based on said principal arrangement. Advantages and details of such arrangements will be made clear.

Fluid handling system for electrical discharge machining equipment

Abstract: Electrical discharge machining equipment including a worktable reservoir tank, a fluid storage and settling tank and a source of clean fluid under pressure. Clean fluid under pressure is directed to a gap between an electrode and a workpiece in the reservoir tank during machining, Fluid is pumped between the tanks by a jet pump. Clean fluid under pressure powers the jet pump. A side arm of the jet pump can be connected to each of the tanks alternately to draw fluid therefrom. The discharge of the jet pump is connected to the other tank to discharge into the other tank.

Apparatus for producing a pulse of liquid for machining operations

Abstract: Apparatus for producing a high velocity jet pulse of liquid suitable for cutting or fracturing such materials as rock, metal, concrete and wood. A barrel is provided with a bore that intersects a rotatable valve which in a first position receives a liquid or gel charge and which in a second position is colinear with the barrel bore. Compressed gas expells the charge from the barrel through a nozzle to form a pulsed jet of liquid. Means can be provided for positioning the nozzle adjacent an extrusion as it issues from an extruder, permitting on-line cutting of the extrusion and for rotating the nozzle about a horizontal axis to permit operation at the optimum angle of cut.

Rotary machine cutting tools

Abstract: A rotary machine cutting tool, such as a milling cutter, with a cutter head having a plurality of axially extending slots distributed around the periphery thereof adapted to receive flat indexable cutters of heavy duty machining alloys, which are adapted to be clamped herein with a uniform protrusion beyond the cutter head to distribute the cutting load uniformly between the several cutters. In order to compensate for any longitudinal variations in the positioning of the cutters fitted therein, rugged adjustable support for each cutter is provided at each slot comprising an angularly disposed threaded bolt having a supporting head at its outer end and a shank on the opposite inner end fitted within a threaded bore against a sufficiently strong resistance to retain the threaded bolt in its set position and with sufficient stability to withstand vibration and other stresses incident to the machining operation. The rotary adjustment of the bolt results in a comparatively slight translatory movement of the bolt head to critically vary the level of the support of the cutting insert to a tolerance of as little as 0.0001. The frictional drag to the movement of the adjusting bolts may be imposed by springs of any type, for example, Belleville springs, between the threaded bore and bolt head, or by resilient locking threads between the threaded bore and the threaded shank of the bolt. The invention is also applicable to other rotary machine cutting tools such as boring heads.

Manufacture of extrusion tools

Abstract: A method of manufacturing extrusion dies or ''''tools'''' produces a tool with an accurately and well-finished tool opening in an economic manner which allows relatively unskilled labour to be employed. In the method of spark-erosion electrode is formed by machining an electrode blank to a profile complementary to the desired tool aperture, such machining employing a cutting tool which during the machining operation traverses in the general plane of the electrode, that is at right-angles to the direction in which the electrode enters the extrusion tool blank during a subsequent spark-erosion step to produce an apertured tool blank. The side wall of the aperture is thereafter finished by forcing an abrasive compound through the tool. The abrasive compound is preferably a solid wax containing abrasive particles, and heat treatment of the tool blank may be effected before abrasion or between separate abrading steps. The method is of particular application to the manufacture of tools for extruding aluminium sections.