Emitter-Material A complex system. Marios Constantinou, M.Sc. Professorship of Plastics Engineering Technische Universität Chemnitz

Transcription

1 Emitter-Material A complex system Presenter: Marios Constantinou, M.Sc. Professorship of Plastics Engineering Technische Universität Chemnitz 1

2 Agenda 1. The infrared (IR) welding process 2. Interactions between emitter and material 3. Approach to the IR-welding of plastics 4. Summary 5. Outlook / Current research 2

3 Joining pressure Joining path Joining path The infrared (IR) welding process Process phases IR welding I. Radiation II. Changeover III. Joining I II III I II III Joining path Time Time 3

4 The IR-welding process Process comparison Relevant parameters IR-welding Hot plate welding Emission behaviour - Emitter: Type of emitter (short-, midwave) Hot plate temperature Power of emitter Emitter distance Absorption behaviour - Material: Absorption Heat conduction Reflection Heat conduction Heating time Joining pressure Joining path Hold phase Heating time Joining pressure Joining path Hold phase 4

5 The IR-welding process Common infrared emitters used for the welding of plastics Medium-wave metal strip radiator Surface temperature C Usual Components : Aluminum housing Ceramic carrier Metal foil MW Short-wave twin tube quartz glass radiator Surface temperature C Usual Components : Evacuated quartz glass tube Gold reflector Metal wire SW 5

6 The IR-welding process Applications Source: Frimo Source: Frimo Source: Frimo 6 Source: Odelo

7 Agenda 1. The infrared (IR) welding process 2. Interactions between emitter and material 3. Approach to the IR-welding of plastics 4. Summary 5. Outlook / Current research 7

8 Emitter-material interactions Main influences on emitter-material interactions Emission behaviour of emitter Absorption behaviour of material Type of emitter (SW, MW) Emitter distance Power of emitter Material Fillers (e.g. carbon black, glass fibres) Morphology of material 8

9 Emitter-material interactions Main influences on emitter-material interactions Emission behaviour of emitter Absorption behaviour of material Type of emitter (SW, MW) Emitter distance Power of emitter Material Fillers (e.g. carbon black, glass fibres) Morphology of material 9

10 Melt layer thickness L 0 [mm] Emitter-material interactions Emission behaviour Influence of emitter type (PP-natural coloured) Medium-wave Short-wave MW SW Emitter distance x [mm] MW: Required emitter distances are lower. 10 SW: Influence of distance changes is lower. Source: Diss Fuhrich, Technische Universität Chemnitz, 2013

11 Emitter-material interactions Emission behaviour of emitter/ Absorption behaviour of material Absorption spectrum of material results in emitter-material interactions. Depth of optical penetration/ Absorption behaviour is depending on: Wavelength of IR-radiation Chemical composition of plastic Fillers Near-surface absorption Volume absorption Plastic part Intensity decrease Plastic part Intensity decrease T T x x x x 11

12 Radiation intensity Radiation intensity Emitter-material interactions Absorption behaviour of material Influence of fillers Natural coloured MW SW Carbon black filled MW SW Layer thickness Layer thickness Equal heating parameters (SW) 12

13 Melt layer thickness L 0 [mm] Emitter-material interactions Absorption behaviour of material (PA66) Influence of fillers 1,4 1,2 1,0 0,8 0,6 MW Natural coloured Black GF natural coloured GF black 0,4 0,2 0, Heating time t E [s] Carbon black and glass fibres cause a reduction of the heating time 13 Source: Diss Fuhrich, Technische Universität Chemnitz, 2013

14 Melt layer thickness L 0 [mm] Emitter-material interactions Absorption behaviour of material (PA66) Influence of fillers 1,4 1,2 1,0 0,8 0,6 KW Natural coloured Black GF natural coloured GF black 0,4 0,2 0, Heating time t E [s] Carbon black leads to a change from volume to near-surface absorption 14 Source: Diss Fuhrich, Technische Universität Chemnitz, 2013

15 Equal joining pressures Structures of welded joints PP-H natural coloured MW Emitter-material interactions Welding factor 1,0 SW 15 Welding factor 1,0 Failure behaviour of IR-welded natural coloured PP-H in tensile creep test acc. to DVS (SW, joining pressure = 0,25 N/mm², test duration = 1630 h)

16 Emitter-material interactions Processing effects Local fibre orientation Material: PA66-CF20 Emitter: SW Equal material/ equal heating parameters Different fusion behaviour Influence of fibre orientation 4 mm Near the gate (cutted edge) Gate 3-layer-structure (schematic) Flow direction of melt Injection moulded sheet Away from the gate (moulded edge) 4 mm 16

17 Tear strength [N/mm²] Emitter-material interactions Processing effects Global fibre orientation Material: PA66-CF20 Emitter: SW, MW Fusion behaviour is affected by the fibre orientations Mechanical weld properties determined by fibre orientations PA66 (unreinforced) IR-Emitter SW Sample [No.] MW Injection moulded sheet (PA66 CF) 17

18 Agenda 1. The infrared (IR) welding process 2. Interactions between emitter and material 3. Approach to the IR-welding of plastics 4. Summary 5. Outlook / Current research 18

19 Approach to the IR-welding of plastics Initial input Part design Material IR-welding of plastics 1. Selection of emitter system (SW, MW) Depends on part dimensions, radii, warpage, wall thicknesses etc. 2. Fusion tests on parts Influence of fillers on heating times etc. Determination of material resistance against thermal oxidation Definition of emitter distance-heating time-combinations 3. Welding trials (optional) Variation of process parameters, e.g. joining pressure, changeover time Transfer of optimum parameters to production process 19

20 Agenda 1. The infrared (IR) welding process 2. Interactions between emitter and material 3. Approach to the IR-welding of plastics 4. Summary 5. Outlook / Current research 20

21 Summary Advantages of IR-welding No physical contact to parts during heating phase (no material sticking, wear) High flexibility in weld design High degree of automation High weld strengths possible Without alternatives for specific applications made of technical/ fibre reinforced plastics IR-welding offers high potential e.g. for the joining of FRP Challenging correlations require an accurate process planning 21

22 Agenda 1. The infrared (IR) welding process 2. Interactions between emitter and material 3. Approach to the IR-welding of plastics 4. Summary 5. Outlook / Current research 22

23 Current research Joining of hollow parts made of organic sheets Motivation State of the art: Flanged butt joint Source: LKT Erlangen Source: Johnson Controls Twin-O-Sheet sample CAMISMA backrest Objective: Overlap joint in hollowparts made of organic sheets Advantages of overlap joints Fibre orientation in direction of load path Maximum utilisation of fibre orientation Increased potential of light weight construction by material savings possible 23

24 Breaking force [kn] Non-welded - Organic sheet PA6-GF46 Welded - Overlap Joining of hollow parts made of organic sheets Results 16 Current research Welded- Flange 87 % 5 % Welding setup Breaking force PA6-Matrix = 3,2 kn Breaking force of overlap joint considerably higher than matrix value 24 Reinforcement by fibres along the joint plane is possible

25 Thanks for your attention! Contact: TU Chemnitz Professorship of Plastics Engineering Marios Constantinou Tel.: +49 (0)