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After years of research,
TFB has developed and patented a system of bending tube/pipe that
is compatible with the material flow. The outer wall of the tube wants
to stretch or thin out, ( Figure 1 ). When it does, it also tends
to collapse.
An Empty-Bending pressure die compensates for this by having a proprietary-designed,
multiple-radius and a round tube groove, ( Figure 2). It does not
have a tube groove that is a true radius or heart shaped for the length
of the die. The multiple radius tube groove forces the tube / pipe
to bend, but only touches that portion of the tube that has the least
tendency to collapse. The very outer wall of the tube is NOT in contact
with the die and receives the least bending pressure. The surface
of the tube groove is conditioned to provide maximum grip or traction
to the tube. This allows much more pressure die assist force to be
used, which minimizes wall thinning and collapse.
To bend a tube / pipe, the inner wall must compress. Like the pressure
die, TFB's Empty-Bending bend die also has a true radius and a multiple
radius groove, (Figure 2). The multiple radius groove forces the tube
to assume a configuration that induces material compression and can
also eliminate wrinkles. In bending heavy-walled pipe, this proprietary
design also provides a space that allows the material to thicken.
Testing and field reports have demonstrated that Empty-Bending does
minimize wall thinning, reduces tooling set-up time, reduces required
clamping lengths, and eliminates mandrel and wiper die humps and scratches.
Empty-Bending can also bend a "lower" elongation tubing
than with conventional dies.
Obviously, a bending lubricant is not used, a big savings from applying
the lube and de-greasing operations.
Fewer Tools. Increased Production. Improved Quality.
• Lower tooling cost
• Improved production
• High quality bends
• Faster set-up time
• No lubrication
Potential Savings
If you could bend 40 percent of your production without a mandrel
or wiper die, how much would your production increase? How much time
and money would you save? Here are the answers from customers using
TFB’s proprietary Empty Bending tooling.
“Initially saved money by eliminating the cost of a
mandrel, wiper die, and jig.”
“The real bonus with Empty Bending is that the quality of the
bend is equal to or better than when using a mandrel and wiper die.”
“Reduced set-up time.”
“Literally doubled our production.”
“Did not need to lube the tube or clean the tube after bending.”
“Less collapse, much better ovality.”
“Improved cosmetic bending, no wiper die or mandrel marks.”
“Reduced our length of clamp area...we saved on tubing material
and sets of compound clamp dies.” |
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 Note:
The proper style of bend dies to be used will be indicated by such
factors as Tube OD x CLR, bender size, degree of bend, etc. Hardened
dies are 60-62 Rockwell C with a penetration of .035" - .040"
deep. Bending applications requiring precision tools have ground tube
grooves, counter bores, and all other crucial dimensions.
You don't have to re-invent the wheel or make a costly tooling mistake.
Describe your bending application and allow our expertise to provide
the bend die and family of tools.
Specify:
1. Tube OD and Wall
2. Center Line Radius
3. Make and Size of Bender
4. Degree of Bend
5. Rotation of Bender
6. Interlock Dimension
7. Desired Production |
TFB
PRESSURE AND CLAMP DIES |
 Pressure
Dies for benders with pressure die assist can benefit from grit blast
or carbide spray tube grooves. This allows for more advancing force
without slippage. Even serrated tube grooves can be used for automotive
or for rough surfaced pipe. Length of pressure die equals the arc
length of largest bend die + 2 x O.D. or minimum length required to
mount on bender. For longer tool life, pressure dies can be machined
to allow either end to be located at tangent. Pressure dies with worn,
slick or oversized tube grooves prolong set-up time and allow wrinkles
and excessive collapsed bends.
Clamp die surface options include: carbide spray, serrations, grit
blast, or knurl.
Clamp die length generally equals 3 x Tube O.D. Without a sufficiently
long straight clamp area, special tube groove surfaces can be used;
grit blast, carbide spray, serrations, etc. Less than 2 x O.D. for
grip sections may require compound clamp die and matching bend die
clamp inserts. For multiple bend die machines, we can furnish stacked
tooling from your bent tube print.
Specify:
1. Tube O.D. and C.L.R.
2. Make and Size of Bender
3. Degree of Bend
4. Tool Material and Hardness
5. Location of Half Round |
Chrome and Ampco Bronze
mandrels in 46 sizes, (.375" OD to 3.500" OD). Basic Mandrels
and More.
Tube bending has come a long way since wet-packed sand cerrobend or
cable mandrels. In addition to the basic mandrels described below,
TFB has designed these and many other specialty hybrid mandrels: hydroforming,
wave guide, tube-within-atube, bend-on-a-bend, sizing, bullet-nosed,
expanding, plastic, and sheathed mandrels.
Among the many factors which influence the type of mandrel selection
and number of balls, these are the most important considerations:
• "D" of Bend ( center line radius - tube OD )
• Wall Factor ( tube OD - wall )
• Ovality and wall
thinning requirements
• Tubing materials
• Cosmetic
considerations
• Size and location of weld flash
We provide a selection of mandrels for any conceivable requirement.
We also furnish the "H" style universal flexing, link mandrels.
Our single-plane "Brute" mandrel has superior strength and
straight ball alignment, ideal for high production or larger tubes.
Mandrels are available for literally any size of tube / pipe, as well
as any square, rectangle, or shape. All mandrels are available in
standard pitch, close pitch, or for extremely thin wall tubes, the
ultra-close pitch configuration. Mandrel materials are Ampco bronze
or tool steel. Steel mandrels can be hardchrome plated, Kro-Lon' plated,
or titanium nitrided. |
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Note:
The most popular type of ram and wing dies are the R-1 and W-1. The
adjustable tube groove ram die (R-2) is fabricated from two plates.
The plates are aligned on dowel pins and secured by cap screws. This
die will accommodate large variations in tube O.D. and can be adjusted
for wear. The washout ram die (RW-4) helps eliminate inside humps
but is used only for a specific degree of bend. All ram and wing dies
are hardened tool steel 60-62 Rockwell C. Chromed tube grooves available
on request. Adapters supplied when required.
SPECIFY:
1. Tube O.D. and Wall
2. Center Line Radius
3. Maximum Degree of Bend
4. Tube Material
5. Make and Size of Bender
6. Type of Die
7. Special Requirements |
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 It's
not the price of the wiper die itself that makes it costly or inexpensive.
it's how the wiper die performs. A precisely machined TFB wiper die,
one that can be positioned quickly and is properly supported by the
bend die, will produce good bends, have a longer tool life, and will
be the most cost efficient. Conversely, the most expensive wiper die
is the one that takes longer to position, produces marginal bends,
requires frequent operator repairs, and has more down time than running
time. And it may even cost more.
TFB wiper dies are available for round, square, and rectangular tubes
and for shapes and extrusions. You can choose either Ampco bronze
or steel, with optional Kro-Lon© surface.
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| With moderate
thumbnail Pressure the wiper's leading edge must deflect evenly all
around, often 0.005" to 0.010" ( 0.13 mm to 0.26 mm ). |
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| To prevent tube scratches
and prolong tool life, the new TFB wiper die finishing process provides
extraordinary polished tube grooves and C.L.R. machined surface. |
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Replaceable, round back,
wiper die tips, available in aluminum bronze or alloy steel. Inventoried
sizes range from 1" ( 25.4 mm ) to 3" ( 76.2 mm ).
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| The Ultimate wiper die,
with Kro-Lon® on special steel and lube holes on both tube groove
and C.L.R. surfaces. |
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| Conventional, square back,
wiper die and wiper die tips, with standarc and offset holders to
clear collet and reduce drop length. |
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