Installation Guide

high-speed steel blades designed to cut Plexiglas
®
acrylic sheet may
be used instead. These blades are made of alloy steel and are
tempered to permit filing. The teeth should have a positive rake
angle of 0
°
to 10
°
and should be of uniform height and shape.
When cutting 0.150 inches or thinner sheet, the blade should be
hollow ground rather than set. Teeth of uneven height will cause
chipping of the Plexiglas
®
acrylic sheet and will place undue
cutting strains on a few teeth. This may cause the saw blade to
crack. The saw blades should be machine filed or ground.
For cutting very small quantities of Plexiglas
®
acrylic sheet,
standard hollow ground, fine-tooth blades used for cross cutting
wood or ply-tooth blades may be used. Table 1B lists the
recommended high-speed steel circular saw blade information
for cutting various thicknesses of Plexiglas
®
acrylic sheet.
Circular Blade Saw Operation
To minimize both chipping and overheating tendencies, circular
saw blades should protrude approximately
1
⁄
2 inch more than the
thickness of the Plexiglas
®
acrylic sheet. The work must be held
firmly against the fence, which must be parallel to the saw blade.
Several sheets of Plexiglas
®
acrylic sheet can be cut at one
time by stacking one on top of another. Suitably designed
holding fixtures must be used when stacks of sheets are to be
cut to close tolerances.
When unmasked sheets of Plexiglas
®
acrylic sheet are cut, it is
necessary to take care to avoid scratching the surface of the
sheet. Working surfaces should be covered with some soft material
such as medium-density felt. The surface should be kept free of
dirt and chips.
Sawdust and chips remaining on the surface of the Plexiglas
®
acrylic sheet after cutting may be removed by blowing with
compressed air. Wiping the surface of the sheet with a damp
cloth will remove sawdust that clings to the material because of
static electricity. The damp cloth will also dissipate the static charge.
When cutting Plexiglas
®
acrylic sheet on a table saw, a cutting
board should be used for cutting stacked/clamped material or
making a cut not parallel to another edge (angle cut). Figure 2 shows
a suitable cutting board. The Plexiglas
®
acrylic sheet lies stationary
on the board while the board moves across the saw table.
When cutting stacked Plexiglas
®
acrylic sheet to final dimensions
with a panel saw, hold-down clamps should be used when feasible.
This procedure will also help reduce chipping. The manual feed
rate should be 3 to 4 inches per second (15 to 20 feet per minute)
and should be uniform. The saw should be allowed to cut freely
while maintaining the rated speed of the motor. Coolants are not
required for most sawing operations, although, if exceptionally
smooth cuts in thick sheet are needed, a fine spray mist of detergent
in water or 10 percent soluble oil, compatible with Plexiglas
®
acrylic sheet, in water can be directed against the saw blade.
6
High-Speed Steel Circular Saw Blade Recommendations
Thickness To Be Cut
.030”-.080”
.098”-.150”
.177”-.354”
.472”-.708”
.944”-2.000”
Blade Thickness
1
⁄
16
”-
3
⁄
32
”
3
⁄
32
”-
3
⁄
8
”
3
⁄
32
”-
1
⁄
8
”
1
⁄
8
”
1
⁄
8
”-
5
⁄
32
”
Type Blade
Hollow Ground
Hollow Ground
Spring Set or Hollow Ground
Spring Set or Swaged
Spring Set or Swaged
Teeth
Per Inch
8-
14
6-8
5-6
3-4
3-3
1
⁄
2
Notes: Recommendations are for hand-fed operations (3"-4"/sec.). The number of teeth can be increased proportionately to the feed rate for automatic feed operations, short of overloading the motor.
Typical Circular Saw Cutting Problems and
Possible Corrections
Chipping
1. Slow Feed Rate
2. Decrease Blade Penetr
ation
3. Support Material Continuously
(Narrow Saw Slot)
4. Provide Hold Down
5. Increase Tooth Rake Angle
6. Ensure Teeth Are of
Uniform Height
Burning
1. Increase Feed Rate
2.
Increase Blade Penetration
3. Ensure Fence Is Parallel to
Blade
4. Use Blade Stiffener
5. Decrease Tooth Rake Angle
6. Ensure Blade Has Been
Properly Sharpened
7. Use Blade With Greater
Side Clearance
TABLE 1B
TABLE 2