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Tag Archives: milling workshop

CUTTING TOOLS IN HIGH-SPEED MACHINING

Metal removal rates are faster today than ever before. What was considered high-speed machining a few years ago is now regarded as conventional. Two major factors in high-speed machining are sfpm (surface feet per minute) for the machine tool and ipt (inches per tooth) or inches per revolution for the cutting tool.For heavy metal removal, …

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INCREMENTAL POSITIONING DIMENSIONS—G91 MODE

In incremental mode, each programmed motion is independently measured from the previous point (Figure M-35). For example, the drawing shows a four-hole pattern with each feature dimensioned relative to the other features. If the part were to be drilled starting from the setup point indicated, each tool positioning move would be an increment equal to the drawing dimensions. Positioning from the …

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CAPABILITIES OF THE CENTER-TYPE CYLINDRICAL GRINDER

Most common is simple traverse grinding (Figure L-119). This may be done on interrupted surfaces (Figure L-120) where the wheel face is wide enough to span two or more surfaces. Multiple-diameter-form grinding (see Figure L-13) is a type of plunge grinding in which the wheel may be form dressed to a desired shape. In …

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WORK HOLDING AND CENTER-HOLE GRINDING

The workpiece in on-centers cylindrical grinding is mounted between the head and footstock centers. This effectively provides a single point mounting on each end of the workpiece, permitting maximum accuracy to be achieved in the grinding operation. The angle and finish of center holes in the workpiece is extremely important. The results of a cylindrical grinding job depend on …

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GRINDING-IN A MAGNETIC CHUCK

The first step in surface grinding is to check, and if necessary grind-in, or true, the chuck. Truing the chuck is usually not necessary unless it has been removed and reinstalled or a new chuck is being used for the first time. Any grinder chuck should be checked occasionally and, if necessary, trued by grinding a …

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GRINDER CHUCKING SETUPS

Odd-Shaped Workpieces A magnetic or vacuum chuck will exert the most reliable holding power on an odd-shaped workpiece, if the area of contact with the chuck is large enough. Whenever possible, place the workpiece so that the largest surface area possible is on the chuck. Sometimes it is necessary to block a small or thin …

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TYPES OF GRINDER CHUCKS

Magnetic Chucks The most common work-holding device for the surface grinder is the magnetic chuck. The three types are the permanent-magnet (Figure L-79), the electromagnet (Figure L-80), and the electro-permanent-magnet chuck.Permanent-magnet chucks, which are the most widely used chucks in the job shop setting, are composed of a series of alternating plates consisting of powerful …

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ACCESSORIES

The versatility of the horizontal surface grinder can be extended by the use of accessory equipment. Several of these pertain to work holding and will be discussed in the next unit. Accessories that increase the grinding capability of the machine include the following. Centerless grinding can be accomplished using the centerless attachment (Figure L-77). Parts …

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CLEANING THE GRINDING FLUID

However, many grinding machines have self-contained grinding fluid systems. Several methods are used for grinding fluid cleaning. Cleaning of the fluid should be carefully done and monitored. A fundamental technique is settling. Grinding fluid is pumped to the settling tank, where swarf settles out by gravity. Settling tanks should have a series of baffles and enough …

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TYPES OF GRINDING FLUIDS

Water-Soluble Chemical Types Water-soluble chemical types of fluids, called synthetic fluids, are typically mineral-oil free. They are usually transparent, which helps with visibility. Some are compounded to provide good rust control; others are chemically active, to promote cutting, and can damage machines that are not carefully maintained. They are not prone to bacterial growth. They provide …

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