BEND TOOLING INC.: Rotary-Draw Tube-Bending Tools ~ Die Sets ~ Mandrels ~ Wipers ~ Mandrel-Bending Tools
PRODUCT FAQ'S
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ANSWERS TO PRODUCT FAQ'S
I need tooling. Where do I start?
We can supply you with a complete set of tooling for almost any rotary-draw tube-bending machine. We can also supply you with replacement bend dies, clamp dies, pressure dies, mandrels, and wipers for tools sets you already heave. To get a quotation from us, gather the information we need to recommend a set of rotary-draw tube-bending tools for your tube-bending job and then contact us by phone, fax, or e-mail. See our Customer Service section for details on what information is needed and whom to contact at Bend Tooling. Or click here for a quotation request form to print out.
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Do I need a mandrel?
It depends. The rotary-draw method of tube-bending is
characterized by the use of a mandrel, because it
is a process that fixes the line of tangency in space and therefore makes it
practical to fixture a mandrel there to control the flow of material at the
point of bend. (See the Bend Tooling
Encyclopedia for more detail.) However, not all tube-bending jobs need
a mandrel. One is required only when the tubing material lacks the
strength to support itself at the point of bend. That is why thick-walled
tubes bent on large radiuses generally do not need a mandrel.
The factors that determine whether a tube is strong enough to be bent without a mandrel are tube diameter, wall thickness, centerline radius, degree of bend, and tubing material. With this information we can accurately determine whether or not you need a mandrel for your job and if so, how balls the mandrel must have. There are also a couple of rules of thumb you can use to get a quick take on whether a mandrel is likely. The first is to calculate the wall factor. Divide the tube diameter by the wall thickness. If the result is 15 or more, a mandrel will probably be needed. The second is to calculate the "D" of bend. Divide the centerline radius by the tube diameter. If the result is 1.5 or less, a mandrel is almost always needed. (For details on these and other bending formulas, click here.)
It should also be noted that some tube-benders will dispense with a mandrel if bend quality is not an important consideration. In those cases, heart-shaped dies are often used to flatten the tube in the plane of bend to give it additional resistance to the wrinkling on the inside radius and the flattening on the outside radius that would normally occur without a mandrel. However, compromises in quality, process control, and production rates have greatly limited this substitute for mandrel bending in recent years.
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Do I need a wiper?
Like the mandrel, it depends. The primary purpose of the
wiper to prevent the
hump that forms at the end of the bend during the rotary-draw process from
setting into a permanent wrinkle. (A secondary purpose is to function as
backstop opposite the pressure die in a high-pressure application.) If the
tubing material is strong enough, the hump will not set upon completion of the
bend.
The same factors that determine the need for a mandrel also apply to the wiper: Tube diameter, wall thickness, centerline radius, degree of bend, and tubing material. However, there is a marginal range of bends that require a mandrel but not a wiper. Generally speaking if the wall factor is 20 or more and if the "D" of bend is 3 or less, a wiper will be needed.
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Who specifies the tools I need: Bend Tooling or me?
If you supply us with your tube and bend specifications, we will completely spec out your tooling for you. However, if you want a particular tooling specification, we can usually accommodate that at no additional charge. Click on the following links for the list of the information we need from you for the specification of die sets, mandrels, and wipers.
Does Bend Tooling use name-brand or "generic" aluminum-bronze for its mandrels and wipers?
We purchase only the highest quality
aluminum-bronze and
nickel-aluminum-bronze certified by the mill.
Certification ensures that the material we buy has the proper chemical
composition. Therefore, whether certified material is a name-brand or
a generic has no bearing on its quality.
Actually the most significant quality problem in
aluminum-bronze is not the precise chemical composition. It is porosity -- i.e., air
pockets as large as a quarter-inch (6 mm) or more hidden inside the raw
material. The problem of porosity is endemic to the manufacturing process
for certain types of aluminum-bronze when production of the material is rushed
through the mill to reduce costs. Our twenty years of experience has
helped us to find mills whose production methods keep porosity to a minimum.
That means we manufacture your tools with high-integrity certified aluminum-bronze that allows us to use high-speed machining (which saves you money) and to make a more precise product, especially the feathered edges of our wiper products (which improves your bend quality).
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I know exactly what I need in tooling. In that case isn't my in-house tool room or local job shop a better bargain than Bend Tooling?
Usually the primary consideration in using an in-house tool room or local job shop rather than a specialty supplier such as Bend Tooling is cost. However, that cost savings can be more apparent than real.
First of all, if you require high enough quantities of a particular rotary-draw bending tool that makes in-house or job shop production practical, you should have us quote that tool. You will probably find that Bend Tooling is actually less expensive part for part, period. If not, we'll be close.
Second, these tools are our bread and butter. We know how to make them,
and we make them more precisely than any of our competitors, let alone a tool
room or a job shop making them on the side. This is not to denigrate the
quality of such operations, but to emphasize the importance of a consistently
achieved level of precision not previously associated with tube-bending tools,
especially inserted mandrels and wipers. This precision improves tool
life, repeatability, and process control, all of which reduce the number of
units of tooling you will need from us compared to another supplier to complete
the same job. Therefore, you should consider overall tooling costs, not
just unit cost, when comparing an inexperienced source with us.
Furthermore, our Datafacturing® factory automation embeds all of this accumulated design and machining knowledge into every manufacturing process needed to make bending die, mandrel, and wiper products. That gives our plant a productivity advantage in this arena that a general purpose tool room or job shop can't match.
Finally, you get our support and service. We don't make anything else but rotary-draw tube-bending tools. Your tooling needs don't have to compete for time with other projects the tool room is busy with. Your tools from Bend Tooling will be there when you need them.
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I'm a machine-builder. Does Bend Tooling manufacture OEM tooling?
Yes. In addition to supplying end users, we also manufacture original tool sets for builders of rotary-draw tube-bending machines. Furthermore, we only make tooling. Unlike a number of our competitors, we don't build tube-bending and other sorts of tube-forming machines. Therefore, we are not in competition with our machine-builder customers.
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MAIL
TO:
Bend Tooling Inc. ~ 1009 Ottawa Avenue, N.W. ~ Grand Rapids, Michigan 49503,
U.S.A.
TOLL-FREE (U.S.A. & Canada): 1-800-BTI-TUBE (1-800-284-8823) ~ WORLDWIDE: 616-454-9965
FAX: 616-454-9958 ~ E-MAIL: info@bendtooling.com
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©Bend Tooling Inc., 2006