Corso di Studi di Fabbricazione - hydroforming.pdf3 Università di Bergamo –DIGIP Tecnologie e...

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Università di Bergamo – DIGIPTecnologie e Sistemi di Lavorazione

Studi di Fabbricazione – 2018 – 3c

Corso diStudi di Fabbricazione

3c

Richiami dei processi tecnologici di trasformazione

TUBE & SHEET HYDROFORMING

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Tube & Sheet

Hydroforming

Copyright ERC/NSM at OSUAll rights reserved

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Studi di Fabbricazione – 2018 – 3c 3

1 2

3 4

Closing the press Filling with water

Controlling the process:

Axial cylinder, Water pressure

Counterhoulder

Opening the press

Ejecting the part

Process Overview

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Process Variations

• THF with and without axial feeding

• THF with warm / hot medium

• THF with counter pressure punch

• Liquid Impact Forming

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Conventional Stamping/ Welding

Hydroforming

Hydroformed Parts

Stamping Versus Tube Hydroforming

Exhaust Components

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Bend

Tee shape

Y shape

Hydroformed Parts

Exhaust Components

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A. Roof HeadersB. Instrument Panel SupportsC. Radiator Supports

D. Engine CradlesE. Roof RailsF. Frame Rails

Car Frame Components

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Chassis systems

Audi A2Space Frame Technology

extruded aluminum partshydroformed

Hydroformed Parts

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Chassis systems

BMW 3-series convertibleHydroformed wind shield

Hydroformed Parts

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Chassis systems

BMW 3-series convertibleA-column and windshield header

Hydroformed Parts

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Aluminum rear axle part, BMW, 1997

BMW Rear Axle (500 series)

Hydroformed Parts

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GM Front axis - engine cradle

GM/Opel Astra and Zafira

Hydroformed Parts

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Volkswagen a-platform 4 x 4 Rear axis Parts

+ +

Filler tube

Main tube

Control arm

Hydroformed Parts

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# parts

Mass

Stamping

6

12 kg

THF

1

8 kg

Sub frame

Advantages of THF vs. Stamping

Source : Siempelkamp

# parts

Mass

Stamping

17

16.5 kg

THF

10

11.5 kg

Radiator Support

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Tube Hydroforming System

Tool/Die

Tube/Workpiece Tool/WorkpieceInterface

DeformationZones

Equipment/Press

Product

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Tube Hydroforming as a System

1. WORKPIECE / BLANK (Tube)(Mechanical, Thermal and Physical Properties, Flow Stress, Formability, Surface Conditions, Relations between Process Variables and Properties)

2. TOOLING / DIE SET(Geometry, Surface Finish, Material and Hardness, Temperature)

3. TOOL-MATERIAL INTERFACE(Friction/Lubrication, Heat Transfer)

4. DEFORMATION (WORK) ZONE(Deformation Mechanics, Material Flow, Stresses, Temperatures)

5. EQUIPMENT / PRESS(Speed and Production Rate, Rigidity and Accuracy, Force/Energy)

6. PART / PRODUCT(Geometry, Tolerances, Surface Finish, Properties)

7. ENVIRONMENT(Manpower, Pollution, Plant and Production, Facilities)

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Process

Interface

ProcessControl

Simulation& Modeling

Mat

eria

lB

ehav

ior

Pre

cisi

on&

Met

rolo

gy

Equ

ipm

ent

Design

Sensors

To

olin

gW

ork

space

Equipment

Work

piece

Materia

l

Process Components andEnabling Technologies

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Incoming Tube Hydroformed Part

Tubular Workpiece/Product

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Incoming Pre-Bent Tube Hydroformed Part

Pre-bent Tube/Product

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Process Sequence

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Tube Material Formability

Hydraulic Bulge Test

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Tube Material Formability

Bulged & Burst Samples

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Die

TransitionZone

ExpansionZone

GuidedZone

Axialforce

Fluidinlet

Axialforce

Friction at Tool/Workpiece Interface

Friction Zones

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Metal Deformation

Dies

Tube Punch

Counter

Punch

Pi

Fc

Fa Fa

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Tooling Components

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Time (seconds)

Right Axial feeding

Pressure

Pre

ssu

re

(M

Pa

)

Axia

l fe

ed

ing

(m

m)

Left Axial feeding

Loading Paths

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Hydroforming EquipmentConcepts

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APPENDIX A

Video of Y-Shape FormingSource : DaimlerChrysler

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APPENDIX B

Source : ThyssenKrupp Stahl

Tube/Sheet Hydroforming Press

Click here to see animation

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Pressure Sequence Hydroforming

hydroforming press.pps

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Example of a THF Tooling

Axial cylinder

with console

Axial punch

Quick-filling

hole

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Example of a THF Tooling

Axial cylinder mounted with bars

Axial cylinder

Mounting bars

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Production tool with inserts

Basic die

Material: P20

Tool insert

Material: H13

Shim plates

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Production tool without inserts

GuidingMain die

Hydroformed part

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Feeding insert as ejector

Feeding insert

as ejector

Springloaded

or

hydraulic driven

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Tube Preforming and Bending

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Purposes of Preforming

Improve the hydroforming result by providing:

tubes that can fit into the die cavity

tubes with allowable thickness distribution

tubes with uniform deformation when hydroforming

tubes to reduce friction when axial feeding

tubes to reduce residual stresses after hydroforming

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Processes of Preforming

Tube Crushing

Tube Bending

Annealing

Others

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Tube Crushing Process

Die Movement

Upper Die

Note: This tooling also shows the possibility of the combination processes of preforming and hydroforming.

Lower Die

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Deformation of Tube Cross-section during Hydroforming

(Böhm, 1998)

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Crushing and Expansion

A) B)

D)C)

A) INITIAL STAGE

B) PARTIALLY CRUSHED TUBE

C) TOTALLY CRUSHED TUBE

D) TUBE EXPANDED TO THE DIE

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Crushing Simulation

Click to see simulation

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Crushing + Expansion Simulation


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(Koehr, 1998)

Tube Crushing withMultiple Tool Motion

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Tube Bending (2D)

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Tube Bending (3D)

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Incoming Pre-Bent Tube Hydroformed Part

Pre-bent Tube/Product

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Bending for Hydroforming

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Process Sequence

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Examples

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T-Shape Geometries

WithoutCounter Pressure

WithCounter Pressure

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T-Shape

w/o Counter Pressure

ThicknessPrediction


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T-Shape

w/ Counter Pressure

ThicknessPrediction


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3. Hydroformed part

2. Crushed tube

1. Pre-bent tube

Process Sequence

Case Studies / Frame

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Frame / Modeling of Bending

Structural Frame PartLow Carbon SteelLength, Lo = 2.5 meterWall Thickness, to = 3 mm

Thickness Distribution

Material: 1008 AKDQ

Bending angle: 90o

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Frame / Thickness Prediction

Structural Frame PartLow Carbon SteelLength, Lo = 2.5 meter Thickness, to = 3 mm

CrushedTube

HydroformedTube

Thickness Prediction

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ThicknessPrediction

Frame / Thickness Prediction


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Maximum Thinning is 37 %

Frame / Maximum Thinning

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L1

L2

L3

h1 h

2

American Hydroformer Inc. (2 Protrusions + Bend)

Case Study / Twin Protrusions


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Finite Element Analysis of Hydroforming of an Aluminum Automobile Roof Frame (Audi)

Case Study / Aluminum Frame


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Bending and tube hydroforming of a structural part (Kawasaki Steel)

Case Study / Structural Part


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Crushing of a tube(Schuler Hydroforming)

Case Study / Crossmember


SchPreform112901.AVI

SchPreform112901.AVI

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Hydroforming of a crossmember(Schuler Hydroforming)

Case Study / Crossmember


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Case Study / ‘Y-Shape’

Simulation Data

• Geometry: Y-Shape

• Tube Diameter : 50mm

• Application :

Automotive Exhaust

• Peak pressure = 600

bar

• Axial feed (left) = 40

mm

• Axial feed (right) = 80

mm

• No Counter punch


P

Material Flow & Thinning

SchSelfFeedExpt112901.AVI

SchSelfFeedExpt112901.AVI

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Simulation Data• Geometry : Simple Bulge

• Tube Diameter 45 mm

• Peak pressure = 50 bar

• Axial feed 10 mm on

each end

• Conventional loading paths

(non-adaptive)

• Result : Wrinkling in bulge

area

Case Study / Non-Adaptive Simulation of Bulge


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Simulation Data• Geometry : Simple Bulge

• Tube Diameter 45 mm

• Peak pressure = 50 bar

• Axial feed 10 mm on

each end

• Adaptive loading path

• Result : Good part with no

wrinkles

Case Study / Adaptive Simulation of Bulge


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Sheet Hydroforming

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Introduction

In sheet hydroforming a blank is formed between a hard tool (punch or die) and a pressurized liquid, viscous, or elastic medium.

Various Hydroformed Parts (Schuler,1998)

Engine hood (Schuler,1998) Fuel Tank

(Aust,2001)

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Video of Sheet Hydroforming

Source: Amino Corporation Click picture above to view the video

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System variables in Sheet Hydroforming Process

The system variables affect the process and product quality

1. Workpiece / Blank2. Tooling / Die Set3. Tool/Material Interface4. Deformation Zone

5. Equipment / Press6. Part / Product7. Hydraulic Medium8. Environment

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Comparison- Conventional forming vs. Hydroforming

Source: Amino Corporation

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Introduction – AHM Process Sequence

Combination of hydraulic stretch forming and hydromechanical deep-drawing (Source: Schuler)

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Viscous Pressure Forming

Simulation

Model using LS-DYNA3D

Click picture to view the animation

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Source: Schuler SMG GmbH

Equipment and Tooling Schuler “Active-Hydro-Mech”

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Source: Universität Dortmund

SPS/Univ. of Dortmund Horizontal Press

Click picture to view the

animation

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Different material ( AKDQ material)

Internal Pressure Curve

0

0.005

0.01

0.015

0.02

0.025

0.03

0 2 4 6 8 10 12 14Time (ms)

Pre

ssure

(G

Pa)

AKDQ has better formability than that

of Al5182. Maximum pressure needed

is higher than that for Al5182 since it

increases with material yield stress.

Maximum

thinning: 32%

FEA Case Study: SHF of an Aluminum Part

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AKDQ material

FEA Case Study: SHF of an Aluminum Part

Click picture to view the

animation

Corso di Studi di Fabbricazione - hydroforming.pdf3 Università di Bergamo –DIGIP Tecnologie e...

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