Full Product Manual

7
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
applying compressed air or an approved liquid coolant to the
saw blade and material to reduce heat buildup.
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.
Table 2 (shown on page 6) summarizes some circular saw cut-
ting problems, with some possible corrections.
Band Saws
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.
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
Small wood blocks may be lightly
nailed to the top of the cutting board
to cut other than rectangular shapes.
Miter must be square (90
°
) to the
steel guides and saw blade.
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 Saw Blade Recommendations (Metal-Cutting Blades Should Be Used)
Thickness To Be Cut
Up to .118"
.118”-.472"
.472”-2.00"
Blade Width
(Front to Back)
3
⁄
8
"
1
⁄
2
"
3
⁄
4
"
Tooth Style
Regular (Raker Set)
Regular (Raker Set)
Skip or Buttress
No. Teeth
Per Inch
18
10-14
6
Cutting Board for PLEXIGLAS
®
Acrylic Sheet
TABLE 3
FIGURE 2