Tube Bending Guide poster0 pages

"AddisonMckee Tube Bending Guide nn

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Bend DieClamp DiePressure DieMandrelsWiper Dies

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Selected according to tube OD (outsidediameter) and CLR (centre line radius)
requirements.Dies are manufactured from various grades of steel dependant upon the type of application. The dies should be a good fit onto the machined register on the bend head, and must always be securely
fastened down. Selected to match the Bend Die. Clamp
Dies may be manufactured with various
finishes to improve tube grip. The Clamp
should be adjustable for vertical alignment
and parallel contact along its length.Use of Ballђ type Mandrels, selectedaccording to our Mandrel Selection Guide
below, will ensure quality bends.When setting up Ball Mandrels it isimportant to ensure that the leading end of
the Shank is on Centre Line when bending.
The Balls should be forward of this point.The Wiper Die is selected for use with aBall Mandrel. The purpose of a Wiper Die is
to stop wrinkles from forming on the inside
of the bend at the tangent point. Wiper Die
requirements are listed on our Mandrel
Selection Guide.Wiper Dies are available in the followingmaterials: Mild Steel, Tool Steel, Ampco
Bronze. It is important to ensure that Wiper
Dies are lubricated at regular intervals. For fitting instructions see below. Selected to match the CLR (centre lineradius) of the Bend Die. Die length is critical
and is determined by the following formula,
assuming that full 180 degree bends are
required:CLR x 3.14 180 x 195 + 3 x tube ODExample:1 OD tube x 4Ԕ CLR4 x 3.14=12.56Ԕ 180
x 195=13.60 + 3Ԕ=16.60The Die should be adjustable for vertical
alignment. ._.._. >
IMPORTANT: Setting of the Mandrel should be carried out with the Mandrel fully forward not retracted. Mandrels are manufacturedin the following materials: Case Hardened Steel; Tool Steel; Ampco
Bronze; and are provided with lubrication grooves. A variety of
finishes can be provided according to your requirements.

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FAULT FINDER

nnMarking on tube centreline Hump at the end of a bendDeep scratches in bend/Wiper Die AreaTool marks on tube nn

a) Check the alignment of Pressure Die and Clamp.b) Check dimension of tube in relation to tool set.
c) Check to ensure all tools are free of dirt and scale -if not clean all tools.d) Check that tube is clean and free of oil and grease.
a) Check alignment of Clamp.b) Check Pressure of Clamp on Tube.
c) Check that Clamp is clean and free of oil and grease.
a) Check for Clamp Slip.b) Check that there is sufficient Pressure Die Boost.
c) Check position of Mandrel.
a) Mandrel advanced too far forward - reset totangent.b) Check free movement of Pressure Die.
a) Check condition of Wiper Die - if worn recut or replace.b) Decrease rake on Wiper Die.
c) Advance Wiper closer to tangent point and check that position is correct and that Wiper is
secured correctly.
a) Increase rake or relief of Wiper Die.b) Check Wiper Die edge for pitting or scores - if present recut or replace.c) Check that Wiper Die is not dry. Lubricate if required.
a) Check that elongation of material is suitable for bending.b) Check Clamp and Pressure Die settings.
c) Check position of Mandrel.
e) Check that Pressure Die is moving freely.
a) Check Mandrel size and fit.b) Increase Pressure Die force.a) Check that Pressure Die is not holding the tube back during bending.b) Check ductile strength of tube and programme overbend to compensate.

nnin clamp areaWrinkling in bend areaTube breakage in bending Tube collapses either with or without wrinkling
through full bendWrinkles on bendwith all tools in
correct positionExcessivespringback nn

BALL MANDREL SELECTION CHARTFITTING A WIPER DIE

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i)Mount the Wiper Die onto its bracket with the bolts finger tight.ii)Load a sample tube to be bent, clamped so that it extends back past the end of the Wiper Die.iii)Close the Pressure Die and tap the Wiper Die forward into the Die Bend groove with a soft mallet. Tighten all Wiper Die mounting bolts.iv)Open the Pressure Die and remove the tube. The Wiper Die should reach almost to the Bend Die tangent point. When a straight edge is held in the bottom of the Bend Die grip area, it should lie flat along
the bottom of the die grooves.v)Check that the heel of the Wiper Die lies close to the bend die butdoes not dig in. The shape of both mating faces should match exactly. The chart on the left details when a ball mandreland/or wiper die is required.The calculations to determine this criteria are basedon the following:ARatio of Tube OD to Wall ThicknessBRatio of Tube OD to Centre Line Radius
On a 2D bend a Ratio of 50 indicates that a 4 BallMandrel and Wiper Die should be selected. In some cases reducing the specification by one ballwill reduce the drag and give satisfactory bend.
Trials are the only real way of gauging this. Ratio of TubeTube ODWT 30 40 50 60 70 80 90 100 125 150 175 200 11.522.53
5
1020 1212122
2 33333323232 343434333312 454545443423 555545454433 555545454535 555545454544 555555555555 555555555555 5 5 555 5655555555 6 6 5 >
Ratio of TubeODWT 50mm1mm Ratio of 50= 56555656 5 6 6 5 >
Ratio of CLRTube OD 10050 Ratio of 2= 585867 6 5 >
Ratio ofCLRTube OD 5 5 710 >
FERROUS NON-FERROUS i) Numbers indicate number of balls required on Mandrel. ii)Light blue indicates Wiper Die recommended.

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For more information please contact

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AddisonMckee, Canada AddisonMckee, USA AddisonMckee, UK AddisonMckee, China 31 Adams Boulevard Brantford, Ontario
N3S 7V8 CanadaTel:+1 (519) 720-6800 1637 Kingsview Drive Lebanon, Ohio 45036 USATel:+1 (513) 228-7000 UK188 Bradkirk Place, Walton Summit Centre Bamber Bridge Preston, Lancashire PR5 8AJ UKTel:+44 (0) 1772 334511 No. 6 Xiang Road, Western Part of Block "A" Xiang Factory Building Phase IITEDA Tianjin, 300457, PR China
Tel:011 (86) 22 5982 3158

nninfo@addisonmckee.com nn

www.addisonmckee.com

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