Thermoplastic Welding. Udo Wagner Wegener GmbH, Aachen/Germany

Transcription

1 Thermoplastic Welding Udo Wagner Wegener GmbH, Aachen/Germany

2 Thermoplastic Materials in Industrial Applications Storage and processing tanks Dual laminate construction Concrete protective liners Ventilation Systems Wastewater treatment Secondary containment Piping systems

3 Thermoplastic Welding Terminology Thermoplastic Welding - the connection of thermoplastic materials by means of heat, time and pressure Thermoplastic state - the heated temperature range in which molecular flow permits interconnection

4 Common Characteristics Use a filler material (welding rod) to perform the connection between two parts Require gas (air) as heat transfer medium to heat up parent and filler material Manual processes Compatibility between parent and filler material Material preparation Require proper CORRELATION between TEMPERATURE, TIME and PRESSURE

5 Primary Welding Processes utilized in thermoplastic Fabrication Hot Air Hand Welding Hot Air Extrusion Welding Butt Welding Bending

6 Hot Gas Welding System The three main components: Hot gas hand welder Welding tip Clean air supply

7 Hot Gas Welding Equipment Hot gas hand welder (torch, gun) requires temperature control, preferably temperature setting capability

8 Hot Gas Welding Equipment Welding tip (nozzle) needs to suit task

9 Hot Gas Welding Equipment Air Supply clean, oil and water free air volume gauge

10 Hot Gas Welding Process 1. Tack welding primary process only intended to keep materials in place 2. Free hand welding generally used in areas where high speed welding is not possible 3. High speed welding most common hot gas welding process SCRAPE PRIOR TO EACH PROCESS

11 High Speed Welding 1. Weld bead 2. Wash 3. Welding direction 4. Hot air stream 5. Welding gun 6. Welding rod 7. Rod in preheat chamber 8. Pressure

12 Weld Geometries single V-butt weld double V-butt weld with counter root corner weld with counter root double V-butt weld full penetration T-joint accessible one side only full penetration T-joint accessible both sides

13 Hot Gas Welding of Thermoplastic Direction Sheet and Pipe DVS Welding Parameters (I) Supplement 1 (Draft 11/00) This supplement contains parameter guidelines for hot gas free hand and hot gas high speed welding. The parameters published by the material manufacturers should also be observed. By correlating the parameters air temperature, air volume and welding speed, it needs to be assured that the material in the weld zone is plasticized mm in depth and adjacent to the weld bead. Welding Process Materials Hot Gas (1) Temperature ºC Air volume (2) l/min Welding Speed cm/min Welding Pressure (N) Rod ø 3mm Welding Pressure (N) Rod ø 4 mm Free Hand Welding WF HDPE PP-H, PPB, PP-R PVC-U PVC-C PVDF ) Measured 5 mm (3/16 ) inside main opening of nozzle 2) Standard cubic liters/minute

14 Hot Gas Welding of Thermoplastic Direction Sheet and Pipe DVS Welding Parameters (II) Supplement 1 (Draft 11/00) High Speed Welding WZ HDPE PP-H, PPB, PP-R PVC-U PVC-C PVDF E/CTFE Inert gas N 2 FEP MFA No information PFA PTFE/PFA (1) No information 1) Welding rod PFA

15 Temperature Measurement Most accurate reading performed 3/16 inside main outlet of welding tip with needle style probe.

16 Hot Gas Extrusion Welding Designed to replace multiple pass hand welds no physical constraints material is extrusion weldable

17 Hot Gas Extrusion Welder EXWELD alpha

18 Hand Held Extrusion Welders EXWELD alpha F small / medium size unit with self contained air source EXWELD beta high output model with external air requirement

19 Equiqment Set-Up 1. Adjustment of Extrudate Temperature 2. Shoe Design 3. Adjustment of Preheat Temperature (Air Temperature / Preheat Extension)

20 Extruder Shoe Design T- or K- Joint

21 Extruder Shoe Design

22 MATERIAL PREPARATION SHOE DESIGN

23 Material Preheat - Key to Quality External air supply - higher air volume Self contained - lower air volume Influence of preheat air nozzle design on plastification of parent material

24 Fracture Behaviour at different Velocities

25 Verification of Preheat

26 The Key Factor The Operator Equipment Welding Parameters Material Preparation Environmental Conditions Execution of Weld Temperature Pressure Welding speed External Influences

27 Welding Without Filler Material Butt Welding Bending Machine performed processes higher weld quality repetitive weld quality faster

28 Butt Welding No transfer medium / air required Direct contact of material against heated surface Material / surface specific temperatures Material / surface specific pressures Material / surface specific cycle times

29 Butt Welding Process Three Cycle Process 1. High pressure melting cycle 2. Low pressure heating cycle 3. High pressure welding cycle

30 Butt Welding Machine 90 welding device

31 Sheet Bending No transfer medium / air required Direct contact of material against heated surface Material specific temperatures Material / thickness specific cycle times

32 Sheet Bending Process Bending of Thermoplastics Top Heating Bar Polyolefins Lower Heating Bar PVC/CPVC Two Stage Process 1. Heating 2. Bending V-Groove & Butt Weld Radius Bend

33 Material Types Common Processes Hot Air Welding Hot Air Extrusion Welding Butt Welding Bending PP X X X X PE X X X X UHMWPE / / PVC X O X X CPVC X O X X PVDF X O X X FEP X O ECTFE X O MFA X ETFE X O X common process / common process with limited weld strength O newly developed

34 References DVS DVS DVS 2205 DVS 2207 DVS 2209 DVS 2211 DVS 2212 AWS G1.10

35 Thank you for your attention! Wegener GmbH, Aachen/Germany