fastening technique for hybrid auto body structures€¦ · design and material changes in...

EJOT GmbH & Co. KG • April 2012 • Ralf Birkelbach Folie 1

Fastening Technique for Hybrid Auto Body Structures

Ralf Birkelbach, EJOT GmbH & Co. KG


Design and material changes in automotive industry

Joining requirement specification

Basic fastener development:

Fastener design and assembly principles

Automotive applications with clearance hole

Further developments:

Optimized screw design and assembly principles

Automotive applications without any hole

Multi layer applications

Content











Content


Quelle: Cluster „Neue Werkstoffe in Bayern“ 2006

SteelAluminumGlassPlasticsOthers



Structure Steel

Hang- ons Steel

Structur Steel

Hang- ons AlStructure Steel

plate parts Al

Hang- ons Al

Al- Die castAl- Extruded profileAl- SheetSt – High strength (22MnB5)

Structure Al/Steel

plate parts Al

Hang- ons Al

Various stages of light weight design in the body in white structure

Source: AUDI AG





Basic developments:







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Joining different materials together (with minimized preparation)

Solutions for fixing, attachement and structural (high strength) joints

Assembly with and without adhesive between the layers

One side access for fixing into aluminum extrusions (e. g. Space-frame-design)

Accurate assembly without distortion

High dynamic resistance

Crash safety

Fully automated assembly process

High reliability / process control


Joining Requirement Specification











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FDS® screw design

Head with recess inside / outside

Usable thread length

Thread forming part

Flowdrilling section

Point (tip) of the screw


Stages of the FDS® assembly

1. Warming up the sheetmetal by axial end load and high speed

2. Penetration into the material

3. Forming of the extrusion

4. Chipless forming of afemale machine thread

5. Installation

6. Tightening with the pre-set torque

2.1. 3.

4. 5. 6.


Torque plot of an FDS® joint

1. Forming of the extrusion2. Thread forming 3. Engagement of full threads4. Tightening

Ti = installation Torque

TT = tightening Torque

TS = stripping Torque

torq

ue (N

m)

time (sec.)

1.2.

3.

4.Ti

TT

Ts


System for fullautomated FDS Robot-assembly (left) and feeding system (right)


Fully automated FDS® assembly (with clearance hole)

n: speedM: torqueF: endload

2.1. 3.4. 5. 6.

Finding Warm up Draft forming Thread forming Drive in Tightening


EN AW-5754 t=1,15 mm

EN AW-6082-T6 t=3.2 mm

FDS® Example in Aluminum (with clearance hole)




Basic developments:







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Series Applications with Selfpiercing and Extruding Screws


Application examples (with clearance hole)Lamborghini Gallardo: fully automated assembly at Thyssen Krupp Drautz

• Fixation of the base plate (1 mm) onto Aluminum body frame (3 mm)

• 160 FDS® M5 x 18 without pilot hole

source: Audi AG


Assembly of 100 FDS® M5x18 screws without pilot hole into:

• Aluminium profile with thicknesses:- 1,25mm EN AW-6181-A T4- 1,5mm EN AW-6181-A T4- 2,0mm EN AW-6063 T6- 3,9mm EN AW-6063 T6

Clamped part:• Aluminium die-cast material

- 2mm C611 T5with 7mm clearance hole

Application examples (with clearance hole)Ferrari California: assembly of the tunnel


Application examples (with clearance hole)Audi TT Coupe/Roadster: fully automated robot assembly in the „body in white“ production

Robot-assembly (12 systems) for 229 FDS® M5 screws (255 for Roadster) without pilot hole into:

• Aluminium profile: thickness 1,5 up to 3,5mm

• Aluminium die-cast material up to 3mm• Clearance hole diam.: 7mm• 80% of the FDS assembly into

aluminium profile• 75% in combination with adhesive

(no adhesive in the clearance hole)

source: Audi AG


Application examples (with clearance hole)Audi TT Coupe/Roadster:fully automated robot assembly in the „body in white“ productionMaterial– mix assembly

Steel plate 1,2 mm on aluminium profile 2,5 mm


Application examples (with clearance hole)Audi TT Coupe/Roadster:fully automated robot assembly in the „body in white“ production

Fixation of aluminium sheet 1,15mm on

- 1,5 mm aluminium frame rail

- 3 mm aluminium die-cast

- 2 mm aluminium cross beam

with different tightening torques

Fixation of car body shell 1,15 mm on

aluminium die-cast 3 mm

A-pillar

Demo Video




Basic developments:







Content


Further optimized FDS® screw design

Head with recess outside / inside


Thread forming part



Increased underhead bulge


4. 5. 6.

Heating PenetratingExtrusion forming

Thread forming

= Downholder

Engagement of full threads Tightening

2.1. 3.

Process steps of FDS® assembly without part preparation


Assembly principlesMaterial combination and downholder design for assembly without clearance hole

Note:

Preferred material combination:

• „Thin“ on „Thick“ and/or.

• „weak“ on „hard“

Adjustable downholder force

Fastening direction

Clamped part (without clearence hole)

Installation part


Fully automated FDS® assembly (without holes)

n: speedM: torqueF: endload

Finding Warm up Draft forming Thread forming Drive in Tightening

2.1. 3.

4. 5. 6.


EN AW-5754 t=1.5mm

EN AW-6082-T6 t=3.8mm

FDS® Example in Aluminum (without holes)

Demo Video




Basic developments:







Content


Application examples (without holes)Audi R8: Fully automated robot assembly in the „body in white“ production

Assembly of 310 FDS® M5 screwswithout pilot and clearance holeinto:

• Aluminium profile: thickness 1,5 up to 3,5mm

• Aluminium die-cast:up to 3mm

• Max. clamped part thickness 1,15mm

source: Audi AG


Application examples (without holes)Audi R8:Fully automated robot assembly in the „body in white“ production


Application examples (without holes)Audi A8 (D4): FDS® Screw M5x20

Assembly:• Installation parts:

- 1,0 bis 4,8mm Aluminium profile- 2,5 bis 3,5mm Aluminium die-cast

• Clamped parts:- Aluminium (with and mostly without

clearance hole)

• 740 FDS® M5 x 20 (per car)

• 18 joints as 3-layers

source: Audi AG

Fully automated robot assembly in the „body in white“ production


Preferred conditions:

• clamped part thickness <= installation part thickness

• clamped part thickness max. 30% higher than underhead bulge

• clamped part hardness <= installation part hardness

• max. tensile strength installation part: ~ 800 MPa

Advantages:

• no hole operation at all

• no consideration of tolerances

• structure fixing with or without adhesive

• one side access assembly

Disadvantage:

• special headstyle required

• screw more expensive than with ordinary headsytle

Guideline and recommendations




Basic developments:







Content


Multi layer FDS® screw design



Thread forming part



Increased underhead buldge

Calibration part


FDS M5x25

• Installation part: HC 340 LA (2mm)

• Clamped part 1: Aluminium EN AW-6181 (1,5mm)


Multi-layer application (3-layer Material Mix Aluminum/Steel)

Ti Ts t Process (Nm) (Nm) (sec.) end


Multi- layer application (3- layer stack-up of Aluminum)

FDS M5x25

• Installation part: Aluminium EN AW-6181 (2,0mm)





Multi- layer application (4- layer stack-up of Aluminum)

FDS M5x25

• Installation part: Aluminium EN AW-6181 (1,5mm)






Multi layer FDS® screw design



Thread forming part



Increased underhead buldge

Calibration part

Can and is also being used for the 2 layer joints


Joining different materials together

Solutions for fixing, attachement and structural joints

Assembly with and without adhesive between the layers

One side access for fixing into aluminum extrusions (e. g. Space-frame-design)

Accurate assembly without distortion

High dynamic resistance

Crash safety

Fully automated assembly process

High reliability / process control


Fulfillment of Joining Requirement Specification


Thank you for your Attention !

www.ejot.de

fastening technique for hybrid auto body structures€¦ · design and material changes in...

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