Physics dictates that forcing
too much material into
too little space destroys die
life. Though they may be
tempted to exceed tonnage
limits by time, budget or
other constraints, operators
are well-advised to abide by
tonnage charts from the brake
or tooling manufacturer.
Exceeding tonnage limits may
damage the entire brake, or
worse yet, shatter a punch and
“If you’re developing a
new product line or taking on
doing a volume of work and
don’t have the right tooling for
it, better to invest in the right
tooling rather than put undue
wear on the tooling you have,”
Taking proper tonnages
punch and die degradation is
to harden them by induction
(with a coil) or a laser, perhaps
even with an oxyfuel torch.
However, simple torch heating
can expand tool material
haphazardly and knock it out
In general, the goal of any
hardening treatment is to
harden the surface of the tool
while leaving the core intact.
“I recommend that most
production tools be surface
hardened to about 1/8-in.
[ 3.175 mm] deep, only in the
areas where the tools touch
the bend parts,” says Frank
Arteaga, head of product
marketing for Bystronic,
With induction hardening,
an electric coil is run over
the surface of the tool (on
the lower dies’ shoulders
and punch tips of upper
tooling). The metal is heated
to between 25° and 1,050°C,
then quenched with water.
Most induction hardening
penetrates about 3 mm into
FABRICATING Bend Tooling 74
To buy or not to buy
Whether you need specialized bend tooling for
certain press brake jobs really depends on the
material you are bending and the demands of the
customer being served, industry pros say.
one consideration is that payback on specialty
tooling—a set of hardened sectionalized tooling,
for example—may take a long time because
the parts you’re making with it don’t get ordered
regularly. Frank Arteaga, head of product
marketing at Bystronic, elgin, iL, notes that tooling
that is seldom used often gets abused.
“Because specialty tools are dedicated to
special parts, they tend to be outside the press
brake most of the time, where they often just sit
loose somewhere and are subject to accidental
abuse,” Arteaga says.
However, if a fabrication shop needs to improve
the surface quality of parts coming off its brakes,
it may want to consider a specialty tool like Wilson
Tool’s V-Series Black Die. The die uses two spring-loaded inserts that pivot and hug the workpiece
as it gets pressed down by the punch. This allows
material to flow against a flat surface rather than
a stationary angled one—a distinct advantage
for someone who needs minimal marking on the
material and a replicable way to achieve it.
The idea isn’t new to Wilson, but over the last
four years, the company has refined the design
and gotten good reports back about it.
“When we do a trade show or do internal
customer events, we save that for last,” says Steve
Brown, press brake product manager at Wilson
Tool, White Bear Lake,Mn.
And while specialty tools tend to be made
of the same material as standard tools and
generally have the same life expectancy, tools
that are very specialized tend to have lower
tonnage rates than their standard counterparts,
says Tom Bailey, TruBend product manager for
TruMPF Farmington, cT.
“Special tooling is dictated by the product that
you’re making,” Bailey says. “Pay more attention to
what the tonnage rating is.”
the surface. Some manufacturers claim that induction
hardening can increase tool life by a factor of eight.
“It provides more endurance to the tool,” says Steve
Brown, press brake product manager for Wilson Tool,
White Bear Lake, MN. However, “the manufacturing
process changes with induction. You have to heat it up
Laser hardening is more targeted and can pinpoint-
harden punch tips and die shoulders, typically at a depth
integrated tooling storage is a good way to maintain your bending
tools, say suppliers.
IMAGE: TOOL STORAGE IN BYSTRONIC'S XPERT 40 PRESS.