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  • Publicado : 5 de agosto de 2010
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2. Radius grinding attachment. This attachment is designed for grinding radii (90 degree arc) on the teeth of shell end mills, face mills and similar cutters. It has a capacity of 4 inch to 12 inch diameters, and will grind radii of 0 to 1 inch. However, the ingenious operator can grind smaller cutters and larger radii, by adjusting the attachment slides beyond the range of the micrometer. Thecutter can first be ground on its diameter, while mounted in the attachment as illustrated here, and then follow with the radius and face grinding operation in one pass. In this way, an accurate radius and a perfect blend will be obtained. Assuming that we are going to grind a ¼ inch radius on a 6 inch shell and mill, proceed as follows.

1. Mounting grinding wheel. Fasten a 4” spindleextension on left and of spindle. Mount grinding wheel on end of spindle extension (6” diameter X 1/8” wide. 60K-8 aloxite resinoid wheel – Cincinnati milling machines Ltd. Shape nº 28). Fasten proper grinding wheel guard in position. Change spindle belt to smallest pulley diameter. Fasten diamond bracket to table. Raise or lower wheel head until diamond is on center, start machine and true grindingwheel. Slightly round corners with carborundum stick.
2. Mounting attachment and cutter. Stop machine and wipe grit from table surface. Mount radius grinding attachment on left and of table with standard work head housing fastened in horizontal (zero) position. Fasten cutter securely in work head housing with draw – in bolt. The t- slot nearest the grinding wheel is for small diametercutters while the other t – slot is for large diameter cutters.
3. Centering cutter. Position attachment so face of cutter is toward wheel- head using the standard centering gauge from top of wheel head, raise or lower wheel head until pointer on center gauge is approximately in centre of cutter. Position center gauge so pointer contacts corner of cutter tooth. Turn pointer around (180) andmove centre gauge so pointer contacts corner of cutter and raising or lowering the wheel head it is possible to get the two teeth the same height from machine table and on centre with the grinding wheel spindle. This is necessary and important because the amount of cutter setting will not be disturbed.
4. Selection of clearance angle. Select proper clearance angle (refer to table, page 89).Example: to grind a 5º clearance with a 6” diameter wheel, lower the wheel head .261” this means that the centre of the grinding wheel is .261” below the cutting edge of the cutter and the arc ground behind the cutting edge will be equivalent to a 5º clearance angle.
5. Mounting tooth rest assembly. Using the saddle and table controls of the machine, position the attachment so corner ofcutter tooth is approximately 1/64” to 1/32” from face of wheel (fig. 68 A). mount tooth rest assembly on top of wheel head, adjust the blade to contact cutter tooth and as close to face of grinding wheel as possible. The point or portion of the grinding wheel and shuld be the cutter is to mill a true radius after it is ground. Loosen screw “a”. (see figure 69A for recommended shape of tooth restblade. It can readily be made from a standard blade.)
6. Grinding periphery. Position attachment so grinding wheel is perpendicular to periphery (side) of cutter and tighten screw “B”. start machine and move saddle hand wheel until wheel contacts periphery. Proceed to grind periphery as you would any helical cutter. Take light cuts and make by swiveling table of machine.
7. Positioningcutter for radius. Stop the machine, move cutter away from grinding wheel using machine controls, and back up attachment slides far enough to allow micrometer gauge to be mounted in tapered hole of attachment. Locate against stop pin “ C” set micrometer barrel to proper height (use centering gauge) and adjust to desired radius. (a ¼ radius set micrometer at .250”) turn crank “D” until periphery of...
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