Home / Tag Archives: milling office

Tag Archives: milling office

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, …

Read More »

OPERATING THE CNC MACHINE TOOL

Manual Data Input Manual data input, or MDI, as its name implies, is the mode in which program data may initially be entered using the CNC’s keyboard. MDI mode also allows for editing or deletingn existing program data. A complete block or complete program may be entered and run in MDI mode. However, once the data are …

Read More »

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 …

Read More »

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 …

Read More »

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 …

Read More »

SURFACE GRINDING BASICS

Horizontal spindle surface grinding is becoming ever more important as equipment and machined parts are miniaturized and dimensional tolerances shrink. A few years ago, ;.0001 in. was considered a close tolerance. Now, half that amount (.000050 in.) is seen more frequently on drawings, especially in the advanced technology areas. These pressures for increasingly closer work are …

Read More »

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 …

Read More »

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 …

Read More »

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 …

Read More »

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 …

Read More »