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Notch
a variety of angles with one set of 3-way corner notching
tools
This is another application for an auto index station.
A three-way corner notching tool can cut any angle larger
than the smallest point by programming single or multiple
hits. 15o is the smallest angle available.
Clearance
corners in dies control corner burrs.
A radius in the corners of rectangular and square dies
with clearance greater than .020(0.5mm) keeps
clearance uniform around the corner of the punch. If
the die is sharp cornered too, then distance between
punch and die corners would be greater than side clearance,
resulting in large burrs. Ordering rectangle and square
punches with .030 radius corners will drastically
reduce corner wear on the punch. Punch corner wear can
be a problem when punching thick, highly abrasive materials.
Shaving
makes straight-walled holes without drilling
When you need a smooth, straight-walled hole, shaving
can save the time and trouble of performing a second
operation on another machine. To do this, you need to
punch the hole twice. First use a punch with total clearance
taken off equal to 20% of material thickness, and a
die with total clearance .004(0.1mm) over the
desired finished shaved hole size. Then, program a second
hit in the same place using the same size die and a
punch the size of the desired finished hole. The second
operation will shave the sides of the hole, removing
most of the rollover and fracture effects caused in
the first step, and enlarge the burnished area. This
operation works best on mild steel and other materials
that shear well. The example shown is a finished shaved
hole of 1.000(25.4mm) diameter in .187(4.7mm)
thick material. Use Mates fully guided tools for
best results when hole-shaving materials thicker than
0.120.
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