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FIGURE 2

Cutting Board for PLEXIGLAS® Acrylic Sheet

applying compressed air or an approved liquid coolant to the saw blade and material to reduce heat buildup.

Small wood blocks may be lightly nailed to the top of the cutting board to cut other than rectangular shapes.

Clamp the stack if possible. Make sure that the saw arbor runs true and the blade plate is flat to prevent rubbing. Some fabricators with special cutting problems have found it helpful to purchase a circular saw blade with additional clearance behind the teeth, such as the “no melt” blade from Forrest Manufacturing Co., Inc., in Clifton, NJ (1-800-733-7111). With this blade, increase the feed rate up to 6 inches/second, and increase the height of blade above the plastic sheet, short of developing chipping of the sheet. Stabilizing discs are recommended to minimize saw blades from wobbling and developing heat.

Miter must be square (90°) to the steel guides and saw blade.

Table 2 (shown on page 6) summarizes some circular saw cut- ting problems, with some possible corrections.

Band Saws

Steel guides to fit into the grooves in the saw table. The guides must work smoothly.

Narrow saw kerf is cut on saw after securing steel guides on bottom to ensure that the kerf is parallel to the saw blade.

Band saws should be used when curves are cut in flat sheets or when formed parts are rough trimmed. They are also used for making straight cuts in thick pieces of Plexiglas® acrylic sheet. For production work, large saws with a 30- to 36-inch throat are best, although smaller band saws are satisfactory for small work. The blade should run at a speed of 2,300 to 7,500 feet per minute. As a general rule, as the thickness of the Plexiglas® acrylic sheet increases, the number of teeth per inch on the blade should decrease. See Table 3 for recommendations.

For Plexiglas® MC acrylic sheet, circular saws should operate at speeds of approximately 3,450 rpm and the material feed rate should be about 4 inches per second. The saw blade should be set at a height only slightly greater than the thickness of the material being cut, to ensure a smooth, chip-free edge on either single or stacked cutting of sheets. Elimination of gumming or welding of the sheets during stack cutting can be reduced by

Metal cutting blades and, in particular, bimetallic blades stay sharp longer than blades designed for cutting wood and are better for use on Plexiglas® acrylic sheet. They are supplied by several manufacturers in 100-ft. coils and can be cut to the proper length and brazed or welded. The weld must be annealed and dressed.

Blade thickness, width, and the number and type of teeth depend on the size of the band saw, the thickness of the material to be cut, and the minimum radius to be cut. Band saw blades

Band Saw Blade Recommendations (Metal-Cutting Blades Should Be Used)

Thickness To Be Cut

Up to .118" .118”-.472" .472”-2.00"

Blade Width

No. Teeth

(Front to Back)

Per Inch

18 10-14 6

3 8

"

2 1

"

3 4

"

Tooth Style

Regular (Raker Set) Regular (Raker Set) Skip or Buttress

TABLE 3

7

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