Showing papers on "Machining published in 1986"

Handbook of High-Speed Machining Technology

Abstract: One General Theory.- 1 Historical Background.- 2 Cutting Theory and Chip Morphology.- 3 Machine Dynamics.- 4 Cutting Fluids in Industry.- Two Turning.- 5 Turning.- Three Milling.- 6 General Theory and Its Application in the High-Speed Milling of Aluminum.- 7 Machine System Design and Performance.- 8 Operational Data.- Four Drills and Drilling.- 9 Introduction to Part Four.- 10 A Mathematical Model for Drill Point Geometry.- 11 Microcomputer-Controlled Seven-Axis Drill Point Grinder.- 12 Drill Analyzer.- 13 Multifacet Drills.- 14 An End Effector for Robotic Drilling.- Five Grinding.- 15 Grinding.- Six Laser Applications.- 16Laser Applications.- Seven General Management Considerations.- 17 General Management Considerations.- 18 Factory Models.- 19 Economic Models for Process Development.- 20 Quality Control Circles: The Key to Employee Performance Improvement.- 21 Leadership: The "Right Stuff" for Management of Human Productivity.

Dynamic phenomena in laser cutting and cut quality

Abstract: The quality obtained with laser cutting, one of the most important processes of laser machining, is characterized by a nearly periodic pattern of striations that cause a certain roughness of the cut surfaces Improvements of the cut quality, that would be of major technical importance, can only be obtained if the mechanism that leads to the formation of these striations is entirely understood The present author has argued already in 1984 that temporal fluctuations of laser power can induce oscillations of the liquid layer formed at the momentary end of the cut and its temperature, thus causing distortions of the cut surfaces due to the movement of that layer in cutting direction The numerical evaluation of the theoretical model yields satisfactory agreement of the “wavelength” of the striations and their dependance on the thickness of the workpiece with experimental values So far, no attempt has been made to calculate not only the wavelength but also the depth of these striations It is the purpose of this paper to determine the depth of the striations and to compare the numerical values with the experimental situation Moreover, the paper is devoted to the explanation of the fact that the laser cut surfaces are showing not only one but usually two different striation patterns, one with a finer structure adjacent to the upper surface and one with a coarser pattern adjacent to the lower surface of the workpiece

Generating NC data at the machine tool for the manufacture of free-form surfaces

Abstract: SUMMARY This paper describes the progress to date in the development of a software package for the machining of free-form surfaces by the real-time generation of NC control blocks at the machine tool. The salient features of the system are the complete elimination of paper-tape from the machining process and increased flexibility at the machine tool, particularly allowing production-orientated decisions to be made on the shop-floor rather than on the CAD system.

Allowing for End Cutting Edge Effects in Predicting Forces in Bar Turning with Oblique Machining Conditions

Abstract: Oblique machining tests are described which were made to determine how the cutting which occurs at the end (secondary) cutting edge in bar turning affects the direction of chip flow and the cutting forces. Normally in developing a predictive machining theory only the cutting action at the side (main) cutting edge is considered, with no account taken of the contribution of the end cutting edge. By introducing the concept of an equivalent cutting edge which in essence combines both the side and end cutting edges it is shown how the influence of the latter can be accounted for in predicting cutting forces.

TiN‐coated high‐speed steel cutting tools

Abstract: TiN‐coated cutting tools have gained a wide acceptance in the marketplace over the last few years. This has largely been due to the increased productivity, short machining times, and increased tool life benefits obtained using coated cutting tools. However, the successful coating of tools imposes requirements both in terms of coating processes and/or tool design and substrate materials. This prerequisite of optimizing tool designs, metallurgy, and surface finish to obtain optimum tool benefits when coated can only be achieved by close cooperation between manufacturing operations. This presentation addresses the issues of coatings, tool design, metallurgy, and surface finish quality to yield superior coated cutting tools.

Micro-electrodischarge machining using water as a working fluid—I: micro-hole drilling

Abstract: Micro-electrodischarge machining ( medm ) using water as a working fluid is systematically studied to find its characteristics. As a result, the unique advantages of high removal rate, low electrode wear and consequently higher working efficiency, without formation of carbonaceous materials are found under optimum experimental conditions, as compared with the case when kerosene is used. This was achieved by the choice of suitable combinations of electrode and workpiece materials and electrode polarity. Use of a tungsten electrode with straight polarity is exceedingly good with respect to high removal rate and low electrode wear. This makes it possible to obtain a non-tapered straight micro-hole around 0.1 mm in diameter with a certain anticipative working gap. The advantageous properties of this machining method are effectively utilized to drill deep micro-holes with a ratio of depth to diameter of the order of 10–17 as in the case of 2.9 mm depth and 0.17 mm diameter, which is superior to the limits achievable with both electrodischarge drilling ( edd ) using kerosene and mechanical drilling with a micro-drill.

Performance of sialon cutting tools when machining nickel-base aerospace alloys

Abstract: A range of sialon compositions have been used to machine the nickel-base alloy Incoloy 901. Wear measurements, taken throughout the machining tests, have shown that tool life and flank wear resistance increase with α-sialon content. An examination of the wear mechanisms involved suggests that this can be ascribed to the increased resistance to dissolution into the work piece, afforded by the higher aluminium and oxygen levels in α-sialon compared with those in β–sialon. At higher cutting speeds one of the main mechanisms of tool wear was rake face flaking, and resistance to this mechanism was found to increase with tool material grain size. A model has been proposed for the initiation and propagation of the cracks which produce this type of failure. At lower cutting speeds depth-of-cut notch wear was of major importance, and resistance to this mechanism was found to decrease with increasing grain size.MST/249

Method for machining workpieces of brittle hard material into wafers

Abstract: A method for machining a disk-shaped workpiece, for example having a thickness of between 350 and 1200 microns, formed of brittle crystalline material having a Vickers hardness greater than about 7,000 N/mm 2 in the manufacture of a wafer having a fine thickness, such as in the range of between about 60 and 250 microns, comprises a "cross" grinding operation including the steps of situating the workpiece in opposed relationship to a flat grinding surface of a rotating cup-type grinding wheel and infeeding or plunging the grinding wheel with respect to the workpiece in a direction substantially parallel to the axis of rotation of the grinding wheel at a controlled rate while maintaining the workpiece fixed and stationary with respect to the axis of rotation of the grinding wheel until a layer of the workpiece having a specifically predetermined optimal thickness has been abraded. The method of the invention provides increased yields of wafers with improved surface quality and precision and with decreased depth of damage of the crystal lattice structure.

Software for an Automated Machining Workstation

Abstract: The invention relates to a device for webbing a rotary printing press. There is a rack guide rail track leading from adjacent the web supply in the printing press between the inside of the frame and the adjacent edge of the paper web being threaded through the printing press and printing couples. The rail track follows the desired path through the press. There are branch-off tracks connected by pivoted switch sections. Also, there are track sections connected by cross over centrally pivoted switch sections. A motorized carriage is propelled along the rail track and movably affixed to the rack guide rail track as it is moved therealong by suitable drive gearing cooperating with the rack on the track. The carriage has a gripper which is at its trailing end and it grips the leading edge of the paper web being threaded through the press. Suitable controls including programmed controls for the switches are provided for different lead-in paths through the printing press.

Machine tool for multiple surface machining

Abstract: The invention relates to a machine tool for multiple surface machining having a work supporting device provided on a base and having a work supporting portion which is freely rotatable and freely adjustable in a vertical position, a slide base freely adjustably movable on the base in a horizontal direction toward and away from the work supporting device, a tool supporting table provided on the slide base, the tool supporting table being freely adjustably movable in a horizontal direction orthogonal to the direction of movement of the slide base, a vertical machining device mounted on the tool supporting table to perform machining from the upper direction on a workpiece that is supported by the work supporting portion, and a plurality of horizontal machining devices mounted on the tool supporting table to perform machining on the workpiece from the horizontal direction.

Predicted wear resistances of binary carbide coatings

Abstract: A mechanistic model of the tool wear process has been presented [B. M. Kramer and P. K. Judd, J. Vac. Sci. Technol. A 3, 2439 (1985)] that includes the effects of both the abrasion of the tool material by inclusions within the workpiece and the chemical dissolution of the tool material into the matrix of the workpiece. Machining tests have been run on steel with titanium carbide coated tooling and the resulting test data have been employed to produce a rough calibration of the proposed model. This model has been used to predict the wear resistances of the other group IV B carbides and of the (Ti,Hf)C system in the machining of steel.

The development of an electrodischarge machine for micro-hole boring

Abstract: This paper describes an electrodischarge machine † for micro-hole boring capable of improved accuracy and performance in boring precision small diameter holes in components such as ink jet nozzles for printers, electron gun apertures for graphic displays, micro-connectors for high-speed computers, and optical components for telecommunications Micro-energy discharging permits machining of 15–300 μm diameter micro-holes with a roundness accuracy of 05 μm or better and a surface roughness less than 01 μm No bending stress is applied to the tool electrode, therefore high precision machining of cylindrical surfaces, machining with very thin side-walls, and machining of overlapping multiple-holes are all possible, regardless of the hardness of any electrically conductive material Tool electrodes of any diameter are machinable using reversed-polarity electric discharge and are replaceable in the same way as conventional drills Travel of the tool electrode is controlled automatically by microprocessor, thus eliminating the need for a skilled operator

Tool Condition Monitoring Using Multi-Component Force Measurements

Abstract: Automatic in-process detection of the condition of the cutting tool is an important capability required in unmanned machining. This paper describes the use of multi-component force measurements for the purpose of tool condition monitoring during adaptively-controlled metal-cutting on a turret lathe.

Path-controlled machining method

Abstract: A CRT or other screen display represents a preliminary trace during an EDM or other electrical machining operation upon which can be superimposed a trace representing the action position of the tool vis-a-vis the workpiece or which may be optically scanned so that deviations of the actual machining path from the visible trace can be detected and used for shutdown of the machine.

Factors influencing laser cutting of wood

Abstract: Etude des facteurs lies au faisceau laser, a l'equipement, aux conditions operatoires et a la piece de bois elle-meme

Automatic programming system including machining accuracy optimization

Abstract: An automatic programming system is incorporated in a numerical controller which controls the operation of a machine tool connected thereto in accordance with a numerical control program. The programming system is designed to automatically program the numerical control program based upon machining information which is manually input by means of a data input device in an interactive mode for defining machinings to be effected on a workpiece. The programming apparatus includes means for automatically determining the machining order of a plurality of machinings on a workpiece in such a manner that any machining needing a higher accuracy is carried out later than any other machining needing a lower accuracy.

Milling cutter for machining T-shaped grooves

Abstract: A milling cutter for machining T-shaped grooves comprises a shaft (1), the free end of which has a disc-shaped head (2) which comprises first blind recesses (3) opening toward its periphery and toward its frontal face (4) and second blind recess (5) angularly displaced with respect to the first recess (3), opening toward the periphery of the disc ad toward its rear face. Each of these recesses (3,5) comprises a seating (7), against which an indexable hard metal cutting insert (11) is fastened.