Machinery's Handbook, 31st Edition
1246 BAND SAW BLADES To break in a new blade, first set the band saw speed at the recommended cutting speed for the material and start the first cut at the feed indicated on the starting feed rate graph below. After the saw has penetrated the work to a distance equal to the width of the blade, increase the feed slowly. When the blade is about halfway through the cut, increase the feed again slightly and finish the cut without increasing the feed again. Start the next and each successive cut with the same feed rate that ended the previous cut, and increase the feed rate slightly again before the blade reaches the center of the cut. Repeat this procedure until the area cut by the new blade is equal to the total area required as indicated on the graph below. At the end of the break-in period, the blade should be cutting at the recommended feed rate, otherwise adjusted to that rate. 100 Starting Feed Rate
90 80 70 60 50 40 30 20 10 0 40 ft/min. m/min. 12
80 120 160 200 240 280 320 360
24
37
49
61
73
85
98 110
Band Speed (Machinability) Total Break-In Area Required
100 in 2
645 580 cm 2 515 450 385 320 260 195 130 65 0
90 80 70 60 50 40 30 20 10 0
40 ft/min. m/min. 12
80 120 160 200 240 280 320 360
24
37
49
61
73
85
98 110
Band Speed (Machinability)
Cutting Fluids for Machining The goal in all conventional metal-removal operations is to raise productivity and re- duce costs by machining at the highest practical speed consistent with long tool life, few- est rejects, and minimum downtime, and with the production of surfaces of satisfactory accuracy and finish. Many machining operations can be performed “dry,” but the proper application of a cutting fluid generally makes possible: higher cutting speeds, higher feed rates, greater depths of cut, lengthened tool life, decreased surface roughness, increased dimensional accuracy, and reduced power consumption. Selecting the proper cutting fluid for a specific machining situation requires knowledge of fluid functions, properties, and limitations. Cutting fluid selection deserves as much attention as the choice of ma - chine tool, tooling, speeds, and feeds. To understand the action of a cutting fluid it is important to realize that almost all the energy expended in cutting metal is transformed into heat, primarily by the deformation of the metal into the chip and, to a lesser degree, by the friction of the chip sliding against the tool face. With these factors in mind it becomes clear that the primary functions of any
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