Principles of Rotary Bending Technology & Use of Rotary Bending Technology for Processing of Advanced, High-Strength Steels (AHSS) L. Ray Osborne rosborne@anchordanly.com Mechanical Engineer / Business Development Manager
What is Rotary Bending? Rotary 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 2
Where is Rotary Bending Used? Progressive Stamping Dies Value Proposition: Reduced Part Marking Precise Control of Final Bend Angles Press Brake Tooling Value Proposition: Ergonomics and Safety Reduced Part Marking 3
How Does Rotary Bending Work? Step 2 Step 1 Downward force clamps the part. Induced rotation of the Rocker bends material around the anvil while requiring less force Step 3 Rocker bends material beyond final part angle to compensate for material-memory memory springback Step 4 Rocker releases material to allow springback to desired final part angle 4
Rotary Bending Replaces Wipe-Action Tooling Part Hold-Down Wiping Action Bottoming Action Wipe Punch Coining Part Hold-Down Stripper Surface of part is scraped, leaving long marks 5
Rotary Bending replaces V-type Brake Tooling Brake Punch Minimal shine marks with standard polished Rocker and no marks with Delrin Insert Work Piece Back Stop Brake Die Press brake V-dies V require higher tonnages Pronounced tool marks from press brake V-die 6
Most Common Bend Types (cross sections) 90º Bend Over Square Channel Bend Zee Bend 7
Other Bend Types Short Leg Hat Bend Return Bend Large Radius Under Square Open Zee 8
Common Rotary Bender Sizes Capability 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 9
Common Construction Materials LINER = Self-Lubricating C95400 Aluminum Bronze SADDLE = Hardened AISI 4140 Steel ROCKER = Induction-Hardened S7 Shock-Resistant Tool Steel 10
Common Construction Materials 11
Rotary Bender Options Dart Stiffeners can be produced in the bent part with the simple addition of hardened dowels spaced as needed across the throat of the Rocker. Dart Stiffeners create an integral gusset in the part and give it rigidity. 12
Rotary Bender Options Delrin is a special polymer which can be inserted in the hardened steel Rocker to bend pre-painted painted materials, soft materials or stainless steel without leaving tool marks. Delrin provides long-lasting lasting durability with little to no abrasive effect during part contact. Delrin is mounted to the Rocker using screws and can be easily replaced. 13
Market Segments for Rotary Bending Appliance 40% Specialty Equipment 20% HVAC 10% Transportation 5% Furniture 10% Aerospace 5% Electrical Enclosures 10% 14
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 15
Test Bending Services For Application Verification: Determine Extent of Part Marking (if any) Determine Amount of Material Springback Guarantee Final Bend Angle and Desired Part Geometry 16
AHSS Springback Study 17
AHSS Springback Study 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. 18
Special Applications Material = DP1000 Ultimate Tensile Strength (min.) = 1,000 MPa (145,000 psi) 19
Special Applications 20
Special Applications Interlaced, Two- Stage Bending Concept 21
Special Applications Rotary-Bender on Pressure Pad + Conventional Aerial Cam 22
Special Applications Rotary-Bender on Pressure Pad + Conventional Aerial Cam 23
Special Applications Rotary-Bender on Pressure Pad + Roller-Actuated Cam 24
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