Showing papers on "Machining published in 1974"

Materials and Processes in Manufacturing

Abstract: INTRODUCTION AND OVERVIEW. MATERIALS. Properties of Materials. Nature of Metals and Alloys. Equilibrium Diagrams. Heat Treatment. Processes and Properties of Ferrous Metals and Alloys. Processes and Properties of Nonferrous Metals and Alloys. Nonmetallic Materials: Plastics, Composites, Ceramics, Elastomers. Material Selection. PROCESS QUALITY CONTROL. Measurement and Inspection. NDT and Inspection. Process Capability and Quality Control. CASTING AND FORMING. Fundamentals of Casting. Expendable Mold Casting Processes. Permanent Mold Casting Processes. Powder Metallurgy. Fundamentals of Metal Forming. Hot Working. Cold Working. Nonmetal Fabrication Processes. MACHINING PROCESSES. Fundamentals of Machining Processes. Cutting Tools for Machining. Turning, Boring, and Related Processes. Drilling and Related Processes. Milling Processes. Other Machine Processes: Broaching, Sawing, Filing, Shaping, Planing. Abrasive Machining Processes. Workholding Devices. Machining Centers - NC - CNC. Thread Manufacturing Processes. Gears Manufacturing Processes. Nontraditional Machining Processes. ASSEMBLY, JOINING AND FINISHING PROCESSES. Gas Flame Processes. Arc Processes. Resistance Processes. Other Welding Processes. Brazing and Soldering. Adhesive Bonding and Mechanical Fastening. Surface Treatment and Finishing. Design/Manufacturing in Welding and Joining. MANUFACTURING AND PRODUCTION SYSTEMS. Manufacturing Systems and Automation. Production Systems. Integrated Pad Manufacturing.

Using the Finite Element Method to Determine Temperature Distributions in Orthogonal Machining

Abstract: Temperature distributions for typical cases of orthogonal machining with a continuous chip were obtained numerically by solving the steady two-dimensional energy equation using the finite element method. The distribution of heat sources in both the primary and secondary zones was calculated from the strain-rate and flow stress distributions. Strain, strain-rate and velocity distributions were calculated from deformed grid patterns obtained from quick-stop experiments. Flow stress was considered as a function of strain, strain-rate and temperature. The chip, workpiece and tool (actual shape and size) were treated as one system and material properties such as density, specific heat and thermal conductivity were considered as functions of temperature.

Multi machining output—multi independent variable turning research by response surface methodology

Abstract: A finish turning case is presented where an increase in tool Life was obtained without sacrificing surface finish. This was obtained by developing mathematical models for tool life and surface roughness in terms of the cutting speed, feed and depth of cut. Their contours were obtained utilizing PL 1 language and an IBM 360/50 computer, then the contours were superimposed in order to select the proper combination of cutting conditions.

Adaptive control of cutting machining operations

Abstract: For adaptive control of cutting machining operations, measured quantities characterizing optimized productivity are utilized. These quantities are connected with the wear of the tool and with the wearing rate. To measure the wear, the face wear (also called crater wear) of the tool, its flank wear and its minor-flank wear are used. Other parameters used are: the dimensions of the workpiece, its vibrations, its deflection, its surface roughness, cutting force, and cutting power. In a calculating unit, the shortest time is calculated until a given wearing criterium is reached. This time, and cost constants for the machining process, are fed into a control unit for calculating the optimized (maximum) productivity, and for performing the machining operation with cutting parameters kept within predetermined values. Machining is interrupted for tool changing when one of said wearing criteria is reached.

Fracture toughness and cutting

Abstract: An exploratory model for cutting is presented which incorporates fracture toughness as well as the commonly considered effects of plasticity and friction The periodic load fluctuations Been in cutting force dynamometer tests are predicted, and considerations of chatter and surface finish follow A non-dimensional group is put forward to classify different regimes of material response to machining It leads to tentative explanations for the difficulties of cutting materials such as ceramics and brittlo polymers, and also relates to the formation of discontinuous chips Experiments on a range of solids with widely varying toughness/strength ratios generally agree with the analysis

A surface roughness model for a turning operation

Abstract: A mathematical model for the surface roughness in a turning operation was developed in terms of the cutting speed, feed and depth of cut. Utilizing PL1 language and an IBM 360/50 computer, the model was used to generate contours of surface roughness in planes containing the cutting speed and feed at different levels of depth of cut. The surface roughness contours were used to select the machining conditions at which an increase in the rate of metal removal was achieved without sacrifice in surface finish.

Automatic set-up electroerosion machining method and apparatus

Abstract: Electroerosion machining (EDM or ECM) is carried out with a minimum of manual intervention. Under control of recorded data an electronic control system utilizing control logic directs the set-up operations as well as the actual machining process. The operations automatically (i.e., without the necessity of manual intervention) include loading and removal of workpieces and electrode material, trueing up of the workpiece (which may be by providing a transformation of the data rather than by adjusting the position of the workpiece), making starting bores, threading the electrode through a starting bore, applying a low melting alloy or other conducting adhesive to cement a core in the process of being cut out by machining, cutting the electrode after completing a starting bore and joining electrode ends after rethreading in a new starting bore. In threading the electrode it may be pushed simply or with the support of a surrounding jet of pressure medium, or it may be pulled by a grapple member.

Automatic set-up electroerosion machining method

Abstract: Electroerosion machining (EDM or ECM) is carried out with a minimum of manual intervention. Under control of recorded data an electronic control system utilizing control logic directs the set-up operations as well as the actual machining process. The operations automatically (i.e., without the necessity of manual intervention) include loading and removal of workpieces and electrode material, trueing up of the workpiece (which may be by providing a transformation of the data rather than by adjusting the position of the workpiece), making starting bores, threading the electrode through a starting bore, applying a low melting alloy or other conducting adhesive to cement a core in the process of being cut out by machining, cutting the electrode after completing a starting bore and joining electrode ends after rethreading in a new starting bore. In threading the electrode it may be pushed simply or with the support of a surrounding jet of pressure medium, or it may be pulled by a grapple member.

Apparatus for machining work pieces

Abstract: The apparatus defines at least two work stations, at one of which is disposed an abrading machine having an operating surface, and above which carrier means is movable. Power actuated means on the carrier means selectively serves to raise and lower at least one work piece, to transfer the work piece from one work station to the other, and to forcibly urge the work piece against the operating surface.

Predicting a Material's Machining Characteristics Using Flow Stress Properties Obtained from High-Speed Compression Tests

Abstract: A theory is given for calculating chip geometry, cutting forces, etc., from fundamental work material properties and cutting conditions. The flow stress properties of the work material (0·16 per cent carbon steel) used in the analysis are taken from high-speed compression test results. The theory predicts the main trends observed in machining experiments and a limited comparison with experimental results shows good quantitative agreement. A possible explanation for the occurrence of a built-up edge, involving the dynamic strain ageing (blue-brittleness) of the chip along the tool-chip interface, is considered and found to be consistent with the results.

Spark discharge and electro-chemical erosion machining apparatus

Abstract: In electro-erosion machining using a filamentary erosion electrode, a dielectric flushing medium (for spark-discharge erosion) or an electrolyte fluid (for electrochemical erosion) is fed from an outlet to the working area of the electrode in the direction of the electrode axis and in contact with it so as to cool the electrode and to reduce changes in the machining characteristics with changes in cutting direction. A continuously operable regenerating system, including deionising apparatus which is brought into, and out of, operation under the control of a conductivity measuring device, is provided for regenerating the used dielectric flushing medium in spark-discharge erosion machining.

Laser machining with modulated zone plates.

Abstract: Machining of small holes with arbitrary contours can be performed by focusing a laser beam with a modulated zone plate (MZP). MZP's use the structure of the Fresnel zone plate as the carrier of a modulation function, which contains complete information about the contour to be machined. Spherically corrected MZP's produce aberration-free images within a field angle of 10(-3) rad. It is shown that the background noise due to higher diffraction orders is unimportant under typical machining conditions. A manufacturing procedure for high resolution MZP's with up to 2500 zones etched in chromium or quartz layers deposited on glass substrates is discussed. As in-line holograms have properties similar to MZP's, a simple method of recording wavelength-shift corrected in-line holograms is described. Experiments performed with a stable single-mode Nd(3+)-YAG laser demonstrate that the MZP can be important tool for laser machining purposes.

Methods and equipment for machining electrodes

Abstract: A rough-cut blank is machined to provide a spark erosion electrode for use in the manufacture of an extrusion tool by bonding the blank to a base plate, fixing the base plate to a milling machine table and milling the blank. The milled blank is subsequently detached from the base plate by breaking the bond between the blank and the base plate.

Method and apparatus for machining workpieces

Abstract: Light radiation is generated and conducted by an optical fiber so that it is incident on a machining tool. The dimensional distortion of the tool, including cracking and fracturing, results in the reception of the generated light by another optical fiber. The received light is detected by a transducer and, in response, the position of the machining tool is arrested and a warning signal is generated.

Method and apparatus for regulating the gap distance in electroerosin machining

Abstract: A workpiece-supporting table of an electro erosion machining equipment is provided with a mechanism for subjecting the workpiece to a circling motion of continuously variable radius during operation from zero to a maximum value. The same tool electrode can be used, without withdrawal from the work, for coarse machining at first and fine machining under circling movement immediately thereafter.

Arrangement for control of a boring tool and a machining tool in a direction distinct from the axial direction

Abstract: An arrangement for the control of a boring tool and a machining tool in a direction distinct from the axial direction, the tools being mounted on a tool holder integral with a boring head and formed of a first tool holder part and a second tool holder part movable relative to the first tool holder part, wherein a single rod is movably disposed in one of the tool holder parts for movement in a first direction and in a second reversing direction thereof and the control rod is connected to the boring tool and the machining tool to provide in succession, upon movement of the control rod in the first direction, adjustment of the position of the boring tool to compensate for deviations in the bore and retraction of the machining tool in a direction distinct from the axial direction, and upon movement of the control rod in the reverse direction, retraction of the boring tool and advancing motion of the machining tool in a reverse direction of the direction distinct from the axial direction. The machining tool may be performing dressing, chamfering or grooving operations.

Pulse generator for electro-erosion machining apparatus

Abstract: A pulse generator for an electro-erosion machining apparatus wherein electrical discharges occur at a machining zone formed between an electrode workpiece and an electrode tool, the pulse generator comprising a capacitor charged from a source of direct current through an inductance and a switch for discharging the capacitor through the primary of a transformer, the electrode tool and the workpiece being connected across the secondary of the transformer, the capacitor being charged at a predetermined current rate and being discharged when the voltage across the capacitor reaches a preset level.

Straightening device for wire electrode used in an electro-erosion machining apparatus

Abstract: A device for straightening a wire electrode fed through the machining zone between the electrode and a workpiece in an electro-erosion machining apparatus, comprising a heating and straightening zone having means for heating the wire while simultaneously placing it under traction. The wire is passed through the heating and straightening zone prior to passing through the machining zone, and means are provided for maintaining the wire under a greater traction while simultaneously maintaining its temperature at a lower temperature while passing through the machining zone.

Grinding machine for machining polygonal workpieces

Abstract: The invention concerns a grinding machine whereby diverse polygonal workpieces may be ground in a manner similar to conventional roll grinding and internal grinding.

Cutting tool for the continuous machining of metals and the method of making same

Abstract: A cutting tool made of a material having a high red hardness for the continuous machining of metals and having a geometry determined by the change in measurements of a sample of the metal being machined when the sample is externally loaded to failure. The sample is subjected to a tensile load to produce the failure. Elongation and neck down are caused in the failure area according to the ductility of the metal. The effective cutting or rake angle of the cutting tool is established as a function of the elongation and neck down of the sample. The relief angles of the cutting tool geometry are determined to maintain a self-sharpening cutting edge under the abrasive characteristics of the workpiece material and erosion characterisitcs of the cutting tool material for given machining conditions. The effective rake angle of the cutting tool is also established as the minimum angle producing chips of maximum hardness during the machining operation.

Machine tool with rest apparatus

Abstract: A machine tool for uniformly performing machining operations on a plurality of portions of a workpiece wherein the machine tool is provided with a rest apparatus which supports the workpiece during the machining operations, and wherein the feeding cycle of the rest apparatus toward the workpiece is changed in accordance with the rigidity of the portions to be machined.

Wire electrode protection system for electrical discharge machining

Abstract: A wire feed protection system for an electrical discharge machining apparatus and machine tool. The workpiece is supported for movement along two coordinate axes in the "X" and "Y" direction through electrically controlled stepping motors in a manner which is well known to the art. The electrode is of a wire or band configuration and is so supported, guided, and driven that the cutting portion of the electrode which is aligned with the workpiece before and during cutting remains properly oriented and travels without bend or distortion in its path. When the wire breaks, bows or otherwise is caused to lose tension, a switch is operated to interrupt machining power pulses being supplied to the machining gap. For this purpose, a switch is located at one or more critical and predetermined locations in the wire electrode path, with the switch actuator in each case in engagement with the wire during transversal.

Machining unreinforced polymers with high-velocity water jets

Abstract: Sapphire nozzles of 0.076-mm to 0.178-mm diameter have been used with a water intensifier, operating at pressures up to 4.2 kbar, to produce continuous jets with velocities around 6.6×104 cm/s. These jets have been used to machine (slit) sheet specimens of polymethylmethacrylate (PMMA), polycarbonate and acetal at feed rates up to 4 cm/s.