Общий каталог Ingersoll 2011 - страница 303

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MILLING APPLICATION & SELECTION Effective lead angles. Cutter lead angles Fig. 4 also affect performance. A 45° lead tool reduces chip thickness about 30 percent as compared Advance to a 0° lead tool (Fig. 4). This allows you to per Tooth maintain a given chip load at a higher feed rate, increasing the metal removal rate. A proper lead angle allows a cutter to enter and Chip exit the cut more smoothly, minimizing shock Thickness to the cutting edges. Workpiece edge break- out, a common problem when machining cast Lead Angle iron, can be significantly reduced or eliminated by use of increased lead angle. The lead angle Lead Angles allows the cutting edge to exit the workpiece gradually. This reduces radial pressure and minimizes breakout. However, the cutter must have sufficient It is desirable to have at least one insert in density to keep at least one insert in the cut at contact with the workpiece at all times. Fine Remember that increasing the lead angle to all times. Failure to do this could cause severe pitch tools, though primarily for cast iron, are reduce radial pressure does increase axial pounding which can lead to chipped cutting also good for shallow or narrow cuts in high- pressure. This can cause deflection of the edges, a damaged cutter, and excess wear to temperature alloys where light chip loads are machined surface when the workpiece has a the machine (Fig. 5). taken. Small chips require less gullet, allowing thin cross-section. more inserts per inch. Coarse pitch tools, with 1 to 1-1/2 inserts per Choosing cutter density. The cutter density inch of diameter, allow for greater chip gullet Although selecting a face mill can be a must allow chips to form properly and clear the space. These tools are recommended for soft complicated and somewhat subjective process, cut. Inadequate chip space can cause chips to materials that produce continuous chips, and in these guidelines can give you a good starting plug the gullet, breaking the cutting edge and wide cuts with a long insert engagement. point. By using and expanding on these possibly damaging the workpiece. principles, you will be able to select a face mill for any operation in your plant. Fig. 5 Insert Engagement Insert Engagement Insert Engagement 6 Inserts 12 Inserts 20 Inserts 4" diameter 4" diameter 4" diameter Coarse Pitch Medium Pitch Fine Pitch 1 to 1-1/2 inserts per inch of dia. 2 to 3-1/2 inserts per inch of dia. 4 or more inserts per inch of dia. Cutter Density 305