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CNC Technology

OTHER ABRASIVE PROCESSES

Some abrasive processes use abrasive material applied to the workpiece at low surface speeds. One type uses free abrasive grains flowing in a slurry on a hardened steel plate (Figure L-30) to generate a flat surface on the workpiece. This type is capable of comparatively large amounts of stock removal, but not highly refined finishes, because …

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TOWARD A SCIENCE OF GRINDING

Grinding is moving from its earlier status as an art into that of a technology by the work of research programs at universities working in cooperation with abrasive manufacturers and machine builders. One of the factors promoting this development is the need for ever smaller tolerances on parts such as fuel injectors (widely used in vehicles). Turning alone no longer provides the …

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ADAPTIVE MACHINE CONTROLLERS

Adaptive machine controls that respond to the actual machining conditions while the grinding is in progress have been developed for production grinding machines. In general, the grinding force is sensed and a constant force is maintained by the controller,or machine deflections are fed back to a computer/controller for processing and making changes in grinding parameters. Acoustic emission …

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GRINDING MACHINE COST EFFECTIVENESS

Grinding is an expensive process. It is estimated that from one quarter to half the money spent on machining in industrialized nations is spent on abrasive operations. Extensive research has been done to optimize the process to make it more cost effective with regard to removal rates and minimizing machine cycle times. Because the objective of manufacturing is to obtain …

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TYPES OF GRINDING MACHINES

The versatility and wide application of the grinding processes have led to the development of many types of grinding machines. Your shop will probably have two, three, or more of the common types. As a machinist, you should be familiar with the many types of these machine tools and the processes they perform. Surface Grinders One of the most common grinding …

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USE OF FACE MILLING CUTTERS

The lead angle, which is the angle of the cutting edge measured from the periphery of the cutter, varies from 0 to 45 degrees, depending on the application. Small lead angles of 1 to 3 degrees can be used to machine close to square shoulders. A small lead angle cutter, when used with a square insert, will …

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TYPES OF FACE MILLING CUTTERS

Face milling cutters of less than 6 in. diameter are sometimes called shell end mills. The cutter body, made from heattreated alloy steel,can be used almost indefinitely, and only the cutting inserts need to be changed. Face milling cutters are usually mounted directly on the spindle nose and held in position by four cap screws. The …

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SIDE MILLING CUTTERS AND SIDE MILLING

Milling cutters with side teeth are called side milling cutters. These are used to machine steps and grooves or, when only the sides of the workpiece are to be machined, in straddle setups. An example is cutting hexes on bolt heads. Grooves are best machined in the workpiece with full side mills that have …

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SQUARING A WORKPIECE

Often, a piece of stock shaped like a parallelogram (Figure K-62) must be machined square. This can be accomplished by machining all four sides in the correct sequence. The workpiece should be set up in a mill vise; it may be placed on parallels if necessary. This will facilitate measurements and will also raise a short part above the vise jaws. Step 1 Set the …

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PLAIN MILLING

Good milling practice is to take roughing cuts and then a fin-ish cut. Better surface finish and higher dimensional accuracy are achieved when roughing and finishing cuts are made. The machining time of a workpiece is dependent to a large extent on how efficiently material is removed during the roughing operation. The depth of …

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