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Magnesium Products Limited has been very successful in converting from machining magnesium die castings dry to machining with oil-in-water emulsions, more commonly called water soluble oils. When machining with water soluble coolants one can expect; 1) excellent fire protection; 2) improved tool life; 3) ease of housekeeping, and 4) improved productivity. Problems previously encountered with water soluble coolants such as splitting out of solution, hydrogen gas generation, and salt deposits on tools and machines have been singled out and addressed, with solutions tested in production environments.

The wide assortment of metals and alloys used for structural purposes in the aerospace industry is classified in terms of machinability. Applications of these materials to important aerospace components, as well as major machining operations on these components, are indicated. The preponderance of metal removal is accomplished by conventional machining methods. Recommended cutting conditions for milling, turning, and drilling of important alloys are presented. Electronic machining methods are applicable to special operations. A summary of these is presented, which includes applications, surface finish, dimensional tolerance capability and practical rates of metal removal.

This paper describes the University of Illinois machining system research program. This program focuses on the development of mechanistic models for machining process simulation and the use of these models for the simultaneous engineering of products and processes. Models are presented for end milling, face milling, and cylinder boring which take into account the cutting conditions, tool geometry, workpiece geometry, and system element dynamics. Furthermore, these models explicitly recognize the presence of machining process noise factors such as cutter runout and tool wear. Representative applications for these models are given. A methodology is described for the simultaneous engineering of products and manufacturing processes which incorporates models for the unit manufacturing processes, the manufacturing system, and the product to be produced.

Three typical PM-forged steels made from Höganäs powders have been studied with regard to their machining behaviour, utilizing a special machinability test developed and utilized since 1960 by Volvo AB in Sweden. This test permits to rate steels relative to a standardized free-machining steel. Guided by the results from this test, recommendable cutting data for turning, milling, drilling, tapping and reaming of the three PM-forged materials have been established empirically. It is concluded that all three materials machine notably better than a common tough-hardening steel, two of them as good and one of them better than a common constructional steel. Measured cutting and machine parameters for the PM-forged materials scattered notably less than those for comparable wrought steels.

STANDARDS of accuracy in forging are subject to constant revision. Accuracy depends on the equipment used, and the limit of forging accuracy was thought to have been reached because of the structural limitations in machines of existing types. However, the development of a new type of pressure machine has again caused a revision of our ideas of the accuracy attainable. Finish forging on this machine can be done on the heat remaining from forging or annealing, at a temperature below that at which scale is formed. Cold coining is also done with this machine with a high degree of accuracy and uniformity. What may be referred to as pressure machining of forgings eliminates roughing cuts, reduces the number of handlings and, in some cases, entirely eliminates further machining. Other economies resulting from uniformity are the facility with which work fits into chucks, jigs and hoppers and the uniformity in weight of parts such as connecting-rods.

Particulate reinforced metal matrix composites (PMMCs) based on aluminium alloys are used in automotive industry because of their low cost and improved mechanical properties at high temperature. Automotive producers are testing prototypes in aluminium PMMCs such as brake disk and drum, callipers, piston and cylinder liners. For many components the production of a good surface finish is essential and therefore will necessitate some machining. The presence of hard abrasive ceramic particulates results in rapid tool wear and high machining cost. Today, this cost effective problem is the main obstacle to aluminium PMMCs wider acceptance in the automotive market. Machining practices have not been optimised, but some studies has stated that roughing with carbide tools (especially uncoated WC tools) and finishing with polycrystalline diamond (PCD) tools are the most economical way in machining aluminium PMMCs.

A machine tool with four-control axis for machining of engine cams is presented and built to improve a machining efficiency in this study. A workpiece is fixed at a spindle chuck and placed between two cutting tools on the machine tool. Positions of the cutting direction of two cutting tools are controlled independently with two linear servomotors set on a linear rail guide. The linear servomotors are controlled with a PC, various products with non-circular cross sections can be then machined by the machine tool. Machining experiments shows that the machine tool is effective to reduce machining time and improve machining accuracy.

SURFAPT is a powerful processor allowing multiple-surface gouge-free machining with different types of milling cutter over complex-surface assemblies typical of industrially manufactured parts and tooling. SURFAPT operates as an integrated application within a CADCAM environment and can run on a stand-alone engineering workstation.

With the change of many mechanical components from cast iron to formed sheet steel, there comes an attendant need to machine the part to provide the proper finish and/or dimensional control. This paper investigates various tool designs to select an appropriate geometry for machining sheet steel and then develops a series of speed, feed, and depth of cut relationships to permit the manufacturing engineer to select the parameters necessary for his production requirement. This is the first time such relationships have been developed.

Aluminum alloys containing medium and high silicon contents were effectively machined with the same styles of cutting tool. AA 380 aluminum, containing 8% silicon, represented the medium silicon-containing alloy; and AA 390, containing 16% silicon, represented the high silicon-containing alloy. Either non-coolant feeding high-speed steel drills or tungsten carbide tipped coolant feeding drills effectively machined both alloys. It was necessary to maintain high penetration rates in machining the high silicon material. The medium silicon material was insensitive to penetration rates. Adequate coolant flow and application were also necessary for effective machining of both alloys. Proper choice of tool style and cutting conditions will allow for cost effective machining of the medium and high silicon-containing aluminum alloys.

Distortion and buckling of aluminum aerospace components can be caused by machining-induced residual stress or by residual stress induced earlier in material processing. This stress is characterized through layer removal experiments and measurements of surface location. This stress is correlated to two machining process parameters, which can be changed, in order to control distortion and buckling of machined metallic components. Experiments are presented which compare distortion of thin machined parts to distortion of chemically milled parts in order to uncouple material bulk stress from machining-induced stress.

This paper discusses the history, theory, operation, and refinements of one of the oldest limited-slip vehicle axle and tandem interaxle differentials that has remained in continuous production. The design uses a cam and wedge principle, but is a true differential in the manner of a conventional geared unit. Its unique drive principle provides frictional bias in a ratio between 2-3:1 to increase vehicle drawbar pull on split-coefficient surfaces.

Mack Trucks' E7 direct injection heavy-duty diesel engine is a four cycle, in-line six cylinder design. The 728 cu in. (12 1) engine is turbocharged and chassis mounted air-to-air aftercooled. The E7 is being introduced in 1989 with power ratings of 250 hp to 400 hp (186 kW to 298 kW) at 1700 to 1800 rpm, calibrated to 1990 EPA standards. Highlights of the E7 engine's design, development and performance are presented. Information is included which illustrates the strategies utilized to attain program goals of controlling weight and cost while extending power ratings, reducing emissions levels, and improving fuel economy, serviceability, durability and reliability.

A new 998 CID V8 engine series has been developed by Mack Trucks, Inc. to supplement its line of heavy duty diesel engines. These engines, the E9 Series, are available in two configurations--a 400 bhp (298 kW) high torque rise version and a 440 bhp (328 kW) conventional torque backup version. Increased horsepower and improved fuel economy were achieved through the development of a chassis mounted charge air cooler and a new four-valve cylinder head. In addition, significant durability improvements were obtained due to the reduced thermal loadings resulting from the lower charge air temperatures. Additional noteworthy features include a new injection pump, improved lube oil system, advanced piston design, and proper selection of seals and gasket materials.

A new cylinder head gasket “fire ring” combustion seal has been developed which met the requirements for our higher output diesel truck engines. New accelerated bench and engine tests were developed that proved very useful in the evaluation and development of cylinder head gasket designs.

The application of an advanced state-of-the-art air inlet system has produced a high specific output, high torque rise, heavy-duty diesel truck engine. By integrating a compact plate-fin air-to-air heat exchanger with the cooling air driven by a novel tip turbine fan, a 25% increase in power output has been achieved with minimal increase in mechanical engine loads. The use of an aluminum two-piece piston which prevents side thrust loading on the ring-carrying head section results in improved ring life and reduced oil consumption.

The maximum power output of the Mack 4 cycle 672 in3 six cylinder engine has been increased from 224 HP in 1967, to 285 HP in 1973, and now to 350 HP. The 350 HP version model ETSZ677 was made possible by the development of an advanced charge air cooling system which improved engine combustion efficiency while effectively controlling emissions and maximum engine thermal loads. A long service life is assured, since the higher rating was achieved while still adhering to proven Mack engine design parameters. All power ratings in this paper are corrected to the SAE J816b standard. The 1967 224 HP engine is known in the field as a 237 HP engine because it was originally rated according to an earlier standard using 60°F air and 29.92 inches Hg barometer.

Continued improvements and the demand for greater power has resulted in a complete redesign of the well-proved Mack ENDT673 diesel. That the new model END673is capable of meeting this need for increased power and long life is evident from the values and specifications given in this paper. A comparison with the old model and full description of the new design leaves little doubt of the durability and economy predicted for the V-8 Thermodyne diesel.

The paper discusses recent developments in the macro element methodology. Newly developed macro elements: tapered super beam, thin-walled super joint, and deformable barrier allow for simulation of the crash response of space frames in arbitrary crash configurations. The paper discusses underlying modeling concept and calculation methodology used in the development of new macro elements and demonstrates its effectiveness in the calculation/design process. A number of crash simulation examples are given which illustrates the accuracy of the macro element method in comparison to time consuming FE calculations.