Principles of Rotary Bending Technology

&Use of Rotary Bending

Technology for Processing of Advanced, High-Strength Steels

(AHSS)L. Ray Osborne

rosborne@anchordanly.comMechanical Engineer / Business Development Manager

2Rotary Benders are rotating rocker-lever devices that work on

the principle of mechanical advantage, and are used to

simplify tooling, improve part quality and reduce tooling costs.

Rotary Bending provides tool designers, tool builders and metal

formers a consistent means for holding angular part tolerances

What is Rotary Bending?

3Progressive Progressive Stamping DiesStamping DiesValue Value Proposition:Proposition:

Reduced Part MarkingReduced Part Marking

Precise Control of Final Bend AnglesPrecise Control of Final Bend Angles

Press Press Brake Tooling Brake Tooling Value Value PropositionProposition::

Ergonomics and SafetyErgonomics and Safety

Reduced Part MarkingReduced Part Marking

Where is Rotary Bending Used?

4Step 3

Rocker bends Rocker bends material material beyond beyond final part angle to compensate final part angle to compensate for for materialmaterial--memory memory springbackspringback

Step 1

Downward Downward force force clamps clamps the part.the part.

Step 4

Rocker releases Rocker releases material to allow material to allow springback to springback to desired desired final part final part angleangle

Step 2

Induced Induced rotation of the rotation of the Rocker Rocker bends bends material around material around the anvil while the anvil while requiring less requiring less force force

How Does Rotary Bending Work?

5Part Hold-Down

Hold-Down Stripper

Surface of part is Surface of part is scraped, scraped, leaving long leaving long

marksmarks

Coining Part

Wipe Punch

Rotary Bending Replaces Wipe-Action Tooling

Wiping Action Bottoming Action

6Press brake VPress brake V--dies require dies require higher tonnageshigher tonnages

Brake PunchBrake Punch

Work Work PiecePiece

Brake DieBrake Die

Back StopBack Stop

Minimal shine marks Minimal shine marks with standard polished with standard polished Rocker Rocker and no marks and no marks with Delrinwith Delrin InsertInsert

Pronounced tool marks Pronounced tool marks from press brake from press brake VV--diedie

Rotary Bending replaces V-type Brake Tooling

79090 BendBend Over SquareOver Square

Channel BendChannel Bend Zee BendZee Bend

Most Common Bend Types (cross sections)

8Short LegShort Leg Hat BendHat Bend Return BendReturn Bend

Under SquareUnder SquareLarge RadiusLarge Radius Open ZeeOpen Zee

Other Bend Types

9Capability of Common Rocker Diameters 20mm: 25 19 gauge material (mild CRS) 25mm: 19 14 gauge material (mild CRS) 35mm: 14 11 gauge material (mild CRS) 50mm: 11 8 gauge material (mild CRS) 65mm and 80mm are available for thicker and/or

high-strength materials

Common Rotary Bender Sizes

10

ROCKER = Induction-Hardened S7 Shock-Resistant Tool Steel

SADDLE = Hardened AISI 4140 Steel

LINER = Self-Lubricating C95400 Aluminum Bronze

Common Construction Materials

11

Common Construction Materials

12

Dart StiffenersDart Stiffeners can be produced can be produced in the bent part with the simple in the bent part with the simple addition of hardened addition of hardened dowels dowels spaced as spaced as needed across the needed across the throat of the Rockerthroat of the Rocker. .

Dart StiffenersDart Stiffeners create an integral create an integral gusset in the gusset in the part and give it part and give it rigidity.rigidity.

Rotary Bender Options

13

DelrinDelrin is a special is a special polymer which polymer which can be inserted in the hardened can be inserted in the hardened steel steel Rocker Rocker to bend to bend prepre--painted painted materials, soft materials or stainless materials, soft materials or stainless steel without leaving tool steel without leaving tool marks.marks.

DelrinDelrin provides longprovides long--lasting lasting durability with little to no abrasive durability with little to no abrasive effect effect during part contact.during part contact.

DelrinDelrin is mounted is mounted to the Rocker to the Rocker using using screws screws and and can can be easily be easily replacedreplaced..

Rotary Bender Options

14

Appliance 40%

SpecialtyEquipment 20%

HVAC 10%

Transportation 5%

Furniture 10%

Aerospace 5%

ElectricalEnclosures 10%

Market Segments for Rotary Bending

15

Application Engineering

Technical Data Required: Material Properties Material Thickness Part Length Bent Leg (Part Height) Bend Radius Part Angle (and Tolerance) Areas Where Marks Are Unacceptable Part Channel Dimensions, if Applicable

16

For Application Verification:

Determine Extent of Part Marking (if any) Determine Amount of Material Springback Guarantee Final Bend Angle and Desired Part

Geometry

Test Bending Services

17

AHSS Springback Study

18

Vertical clearance

The effective strain field of rotary bending is shown here at the overbending stage.

Springback from FEM simulations using elastic modulus E=150 and 210 Gpa is compared with springback from experiments at Anchor Danly in bending DP1000 at different vertical clearances.

AHSS Springback Study

19

Special Applications

Material = DP1000Ultimate Tensile Strength (min.) = 1,000 MPa

(145,000 psi)

20

Special Applications

21

Special Applications

Interlaced, Two-Stage Bending Concept

22

Special Applications

Rotary-Bender on Pressure Pad + Conventional Aerial Cam

23

Special Applications

Rotary-Bender on Pressure Pad + Conventional Aerial Cam

24

Special Applications

Rotary-Bender on Pressure Pad + Roller-Actuated Cam

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