MultiMaterial assembly -...

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MultiMaterial assembly « thermal process »

Richard Tomasi

[email protected] / 06.42.10.43.24

mailto:[email protected]

3

jeudi 9 février 2017

« Thermal process » in multimaterial assembly

Presentation

I. Welding thermoplastic composites

Theory about welding of thermoplastics composites

Process and machine used

Tests & results

Development & future works

II. “Warm bonding” thermoplastic composites

Theory about hot bonding metal / thermoplastics composites


Tests & results


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In order to weld composites parts, the matrix should be THERMOPLASTIC

This is a 5 steps process :

Welding thermoplastic composites

Step Parameter to monitor

1 Fusion Time / Temperature

2 Contact between surfaces Time / Pressure

3 Interpenetration / diffusion Time / Temperature / Pressure

4 Cicatrization Time / Temperature / Pressure

5 Solidification Time / Temperature

Step 2 Step 3 Step 4

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3 important parameter for welding :

Temperature : 10 – 20°C above T°f

Time : Enough for fusion, interpenetration but no more to avoid oxydation

Pressure : Enough for the contact between parts but no more to sqeeze the matrix

Which process to weld thermoplastic composites ?

Welding thermoplastic composites

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Presentation




Tests & results





Tests & results


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Induction welding is an electromagnetic process that heat materials which can

conduct electricity.

Eddy Current from induction generator can heat conductive parts by Joule effect. If there is no

conductive parts, a susceptor is required.

Carbon fibers : No need of susceptor because CF can heat himself…

Glass fibers & others : Need metallic mesh, powder… between parts to weld.

Welding thermoplastic composites Induction welding

Main parameters for induction welding :

Distance between inductor – susceptor (mm)

Pressure (N)

Power from generator (kW)

Welding time (s)

Susceptor characteristic (geometry,

material…)

Inductor geometry

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Induction system :

Welding thermoplastic composites Induction welding

PAGF50 + Copper

mesh

Pyrometer to monitor external

temperature

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Ultrasonic welding is a mechanical process. The mechanical vibrations at 20kHz to

40kHz heat the interface between.

The heat fuse the matrix and polymer can melt. The vibrations should be focused to the interface…

Focused vibration : Need energy director at the interface…

Diffused vibration : Poor weld but no need of energy director.

Welding thermoplastic composites Ultrasonic welding

Main parameters for induction welding :

Sonotrode geometry

Pressure (N)

US Frequency (kHz)

Welding time (s)

US range (µm)

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Ultrasonic system :

Welding thermoplastic composites Ultrasonic welding

Induction generator

CEIA 25-SA/80Sonimat

SONIMAT ESW

GP 20kHz

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Presentation




Tests & results





Tests & results


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Material tested

PA66 / GF 50 – PA66 / GF 50

PA6 / GF50 – PA6 / GF 50

Surface preparation before welding

Only degreasing

Degreasing + PA66 or PA6 film between parts

Pressure for welding:

20N to 50N (induction)

800N (US)

Welding thermoplastic composites Configuration tested

Welding time:

5s to 20s (induction)

0,5s to 2s (US)

Welding process :

Induction welding

Ultrasonic welding

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Welding thermoplastic composites PA66 / GF 50 – results

FASTLITE ASSEMBLAGE Project :

Single Lap Shear S=12,5 x 38mm

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Welding thermoplastic composites PA66 / GF 50 – results



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Welding thermoplastic composites PA66 / GF 50 results


Induction welding

Surface preparation : Degreasing + PA66 film

Pressure : 50N

Failure : 100% cohesive

SLS result : 22,1MPa

Ultrasonic welding

Surface preparation : Degreasing + PA66 film

Pressure : 800N

Failure : 100% cohesive

SLS result : 32,6MPa

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US welds seems to be stronger : 27MPa Vs 18MPa

US vibrations promote contact between parts. Induction is a “static” process

The PA66 film between parts improve the strength from 10 to 20%

The matrix is not sucked from the part. We observed less voids

US welding is quicker than induction welding : 1 – 2s Vs 10 – 15s

Induction welding PA66 GF50 / PA66 GF50

Surface preparation Pressure Single Lap Shear

results Std dev.

Degreasing + PA66 film 20N 50N

13,5MPa 18,3MPa

2,6 4,2

Ultrasonic welding PA66 GF50 / PA66 GF50

Degreasing + PA66 film 800N 27,0MPa 4,9


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DEMOS Project :


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DEMOS Project :


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DEMOS Project :

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US welds seems to be stronger : 22MPa Vs 18MPa

US vibrations promote contact between parts. Induction is a “static” process

The PA66 film between parts improve the strength from 10 to 20%

The matrix is not sucked from the part. We observed less voids

US welding is qucker than induction welding : 1 – 2s Vs 15s

Induction welding PA6 GF50 / PA6 GF50

Surface preparation Pressure Single Lap Shear

results Std dev.

Degreasing + PA6 film 50N 18,6MPa 0,1

Ultrasonic welding PA6 GF50 / PA6 GF50

Degreasing + PA6 film 500N 22,2MPa 0,8 MPa

DEMOS Project :

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Presentation




Tests & results





Tests & results


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In welding the mechanical strength is only due to the mechanical strength of the matrix. To

improve the strength, we are working on :

Texturing the interface (Z-pins for example)

Surface treatment such as atmospheric plasma, solgel…

To go further, we already weld the arm suspension for PSA but we will test the weld in

dynamic conditions :

Dynamic solicitation of the welded zone

Comparison between welding and bonding

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Presentation




Tests & results


II. “Warm bonding” metal / thermoplastic composites

Theory about Warm bonding metal / thermoplastics composites


Tests & results


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Warm bonding uses only THERMOPLASTIC matrix

This is a 4 steps process :

Warm bonding metal / thermoplastic composites CETIM Patent

Step Parameter to monitor

1 Fusion Time / Temperature

2 Contact between surfaces Time / Pressure

3 Wetting Time / Temperature / Pressure

4 Solidification Time / Temperature

3 important parameter for welding :

Temperature : 10 – 20°C above T°f

Time : Enough for fusion but no more to avoid oxydation

Pressure : Enough for the contact between parts but no more to sqeeze the matrix

Which process to bond thermoplastic composites ?

Induction on metallic part

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Presentation




Tests & results





Tests & results


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Induction is applied on metallic part that will heat.

Eddy Current from induction generator can heat the metallic parts by Joule effect then the

composite part will melt by conduction

Main parameters for induction hot

bonding :

Distance between inductor – susceptor

(mm)

Pressure (N)

Power from generator (kW)

Welding time (s)

Metallic part(geometry, material…)

Inductor geometry

Warm bonding metal / thermoplastic composites Induction process

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Presentation




Tests & results





Tests & results


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Material tested

PA66 / GF 50 – Aluminium 5182

PPS / CF 50 – Aluminium 5182

Surface preparation before welding

Only degreasing

Degreasing + PA66 film between parts

Texturation of metallic surface + PA66 film between parts

Pressure for welding:

20N to 50N (induction)

Warm bonding metal / thermoplastic composites Configuration tested

Welding time:

10s to 60s (induction)

Welding process :

Induction welding

Ultrasonic welding : no assembly !!!

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Warm bonding metal / thermoplastic composites PA66 / GF 50 – Aluminium 5182 results

Assembly is done is less than 1 min

Important improvement due to the texturation : 8MPa Vs 26MPa

H7 ageing is not destroying the assembly


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Warm bonding metal / thermoplastic composites PA66 / GF 50 – Aluminium 5182 results

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Warm bonding metal / thermoplastic composites PPS / CF 50 – Aluminium 5182 results

Assembly is done is less than 30s

Pressure can improve the matrix and fiber flow in grooves


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Metal

Composite

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Presentation




Tests & results





Tests & results


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The mechanical strength is improved by fiber incrustation in the grooves. To improve the

strength, we are working on :

Geometry of the texturation

Machining of the texturation

Density of the texturation

Warm bonding can replace classical bonding process :

This process is quicker (less than 1min) for 20 – 30MPa

IF we can propose NDT to verify the good fiber incrustation

Searching an industrial Partner to improve and

transfer this technology

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Multi-material assembly Engineer

Richard Tomasi

02 40 37 35 83

06 42 10 43 24

[email protected]

Many thanks for your attention

mailto:[email protected]

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