Plastic Fabrication with LEISTER

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Plastic Fabricationwith LEISTER
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Summary Theory

• Introduction Plastic Fabrication
• Basic Welding Principles
• Pendulum Welding and Draw Welding
• Hot Air Extrusion Welding
• Arrangement of Welding Constructions
• Test of Welding Connections

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Summary Theory

• Introduction Plastic Fabrication
• Basic Welding Principles
• Pendulum Welding and Draw Welding
• Hot Air Extrusion Welding
• Arrangement of Welding Constructions
• Test of Welding Connections

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Introduction Plastic FabricationScope
pipeline construction
tank construction
plastic ventilators
plastic fabrication
environment engineering
ventilation system
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Introduction Plastic Fabrication Tank
Construction
Scouring water container for flue gas
cleaning Material - PP Fabrication - draw
welding - extrusion welding
Storage container for chemicals Material - PVC
and PVDF Fabrication - draw welding- extrusion
welding
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Introduction Plastic Fabrication Tank
Construction
Potable water container Material -
PE Fabrication - draw welding - extrusion
welding
Waste water treatment plant Material -
PE Fabrication - draw welding - extrusion
welding
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Introduction Plastic Fabrication Ventilators and
Ventilation Construction
Exhaust air decontaminationin a sewage
plant Material - PP Fabrication - draw
welding- extrusion welding
Exhaust air decontamination in a
foundry Material - PE Fabrication - draw
welding - extrusion welding
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Introduction Plastic Fabrication Plastic
Fabrication
Part for production line of print rolls Material
- PP Fabrication - draw welding- extrusion
welding
Drip pan for machine Material - PP Fabrication
- draw welding
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Introduction Plastic Fabrication Plastic
Fabrication
Material UV-resistand PE
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Summary Theory

• Introduction Plastic Fabrication
• Basic Welding Principles
• Pendulum Welding and Draw Welding
• Hot Air Extrusion Welding
• Arrangement of Welding Constructions
• Test of Welding Connections

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Basic Welding PrinciplesMaterials in Plastic
Fabrication
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Basic Welding PrinciplesMaterials in Plastic
Fabrication

• Basically, only identical thermoplastics can be
  welded together (exceptions are e.g.
  PVC-P/PVC-U).
• Not all thermoplastics are weldable, structure
  and molecular mass determine the practical
  feasibility. Not weldable are e.g. - high
  molecular PE-HD (molecular mass gt 1000000) -
  PMMA (in cast form) - PTFE

In case of uncertainty please contact the
manufacturer of the material or LEISTER Process
Technologies (application).
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Basic Welding PrinciplesWelding Procedure

• With Leister
• Pendulum Welding (PW)
• Draw Welding (DW)
• Hot Air Extrusion Welding (EW)

• Other Welding Procedures
• Heating element butt welding
• Heating element groove welding
• Heating element bend welding
• Heating element socket welding
• Heating element helix welding

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Basic Welding PrinciplesChoice of Welding
Procedure
Hot Air Extrusion Welding(EW)
Pendulum Welding (PW)
Draw Welding (DW)

• better seam quality than with PW/DW
• more economic than DW/PW as much faster
• for wall thickness of up to 40mm

• for confined spaces
• for short seams and repair work
• for wall thickness of up to 5-10mm

• DW is faster than PW
• PVC-U cannot be welded with DW (wire tears)
• for wall thickness of up to 10mm

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Summary Theory

• Introduction Plastic Fabrication
• Basic Welding Principles
• Pendulum Welding and Draw Welding
• Hot Air Extrusion Welding
• Arrangement of Welding Constructions
• Test of Welding Connections

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Pendulum Welding (PW)
F (1.5 2 kg)
extension
compression

• The welder has to pay attention to the
  following
• even heating up of basic and additional material
• vertical guidance of the additional bar
• sufficient welding force

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Draw Welding (DW)
F (0.5 3.5 kg)
draw nozzle

• Advantages over pendulum welding
• higher welding speed
• bigger cross sections of the welding addition
  possible (profile welding rod)

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Draw Welding (DW)
TRIAC PID
WELDING PEN R
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Hot Air Welding Welding Parameters (according
to DVS 2207 part 3)
PW Pendulum WeldingDW Draw Welding
The hot air temperature is measured in the hot
air stream, approx. 5mm in the middle of the
nozzle.
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Hot Air Welding Welding Seam Preparation

• Welding area and welding rod
• dry, clean, free of oil and grease
• free of splints
• free of notches
• free of oxidation(joining area has to be scraped
  off right before the welding process)

• Air pressure
• The use of air pressure requires the installation
  of pressure reducer with oil and water separator.

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Hot Air Welding Welding Seam Shapes (DVS data
sheet 2207 part 3, 2205 part 3 and 5)
V-Seam
X-Seam (double-V-seam)
X-seam for thickness of 5mm and more
Angle Joints
Fillet weld
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Hot Air Welding Evaluation of the Welding Seams

• Correctly welded seams
• slight flattening of the welding rod
• no notches between the welding layers
• flat seam raise
• in particular for PVC
• - foamy to smooth bead
• - no discolouring (e.g. brownish colour)
• in particular for PE, PP, PVDF
• - smooth double bead on both sides
• - dull surface in the area of the welding zone

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Hot Air Welding Evaluation of the Welding Seams

• Flawed welding seams
• no building of bead or welding rod hardly
  flattenedgtgt temperature too low or gtgt speed too
  fast orgtgt welding force too small
• notches between the welding layers gtgt distance
  between the layers too big

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Hot Air Welding Evaluation of the Welding Seams

• Flawed welding seams
• in particular for PVC brownish discolouring of
  the welding bead gtgt temperature too high or
  speed too slow
• in particular for PE, PP, PVDF shiny welding
  zonegtgt temperature too high or speed too
  slow

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Hot Air Welding Tools
External air supply with air pressure or Robust
integrate air supply
External air supply with blower or pressure air
DIODE
TRIAC
Blower
MINOR
WELDING PEN
Blower
HOT JET S
ROBUST
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Summary Theory

• Introduction Plastic Fabrication
• Basic Welding Principles
• Pendulum Welding and Draw Welding
• Hot Air Extrusion Welding
• Arrangement of Welding Constructions
• Test of Welding Connections

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Extrusion WeldingInfluences During Extrusion
Welding

• Plastic temperature control survey- to be
  measured with insertion thermometer approx. 5mm
  in welding shoe
• Hot air temperature for preheating control survey
  - with probe 5mm in the middle of the nozzle
• Measurement of mass flow rate of the Extruder at
  the output in kg/h - to be evaluated by weighing
  the out-flowing plastic
• Adjustment of temperature differences between
  components - avoid higher temperature
  differences between the components gt strain!gt
  steel tube of 10m length gt rise in temperature
  10C gt expansion 1.2mmgt PE tube of 10m length
  gt rise in temperature 10C gt expansion 34.0mm

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Extrusion Welding Influences During Extrusion
Welding

• Temperature of the plasticized zone on the basic
  material- Difficult to be measured during the
  welding process. Check possible by insertion. The
  minimum melting depth should be approx. 0.5mm
  (check by insertion!)
• Welding speed depends on the output capacity of
  the extruder and the seam volume- The welding
  speed must be constant. - The welding speed and
  hot air temperature must be harmonised with each
  other so that the required minimum melting depth
  of 0.5mm is guaranteed.
• Welding force (welding pressure)- Depends on
  shape and length of the welding shoe. Welding
  force cannot be measured, and depends on the
  welders experience.

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Extrusion Welding Influences During Extrusion
Welding
Preparation of Welding Seam
Welding surface has to be scraped off with a
scraper right before the welding process
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Extrusion Welding Influences During Extrusion
Welding
Welding Parameters (DVS 2207-4 supplementary
sheet 1)
1) measured with insertion thermometer at the
extruded product output of the welding machine2)
measured 5mm in the middle of the nozzle
opening3) drawn-in cold air volume at ambient
pressure 4) PE 63, PE 80, PE 100
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Extrusion Welding Environmental Influences
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Extrusion Welding Welding Mistakes

• Building of blowholes and vacuoles
• temperature of mass too high
• rest humidity in the welding addition
• humidity too high
• welding beads or wet hands
• welding shoe too cold

vacuoles with V-seam (material PP)
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Extrusion Welding Welding Mistakes

• Rough surfaces of the welding seam
• welding shoe too short
• welding shoe too cold (always pre-heat welding
  shoe!)
• welding shoe sliding surface too rough

bad
good
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Extrusion Welding Welding Seam Shapes (according
to DVS guidelines 2207 part 4 and 2209 Part 1)
V-Seam
z seam covering
b max. 30mm
h (0.1 to 0.4) x s
Rework output bead and webs if possible!
penetrated welding seam root
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Extrusion Welding Welding Seam Shapes (according
to DVS guidelines 2207 part 4 and 2209 part 1)
Fillet weld
a 0.7 x s a max a 0.4 x a
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Extrusion Welding Welding Seam Shapes (according
to DVS guidelines 2207 part 4 and 2209 part 1)
X-Seam
mechanically fixed or tacked
rework seam root if necessary
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Extrusion Welding Welding Seam Shapes (according
to DVS guidelines 2207 part 4 and 2209 part 1)
Overlap seam
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Extrusion Welding Design of Welding Shoes (DVS
guidelines 2207 part 4)
Material of welding shoe PTFE
Measures of Length- LA pressure length- LN
length of shoe nose
seam thickness a of V-seams s (mm)
Lengths (mm)
nose
up to
to
to
The nose prevents an overflow of the melting mass
and makes the required pressure build-up possible.
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Leister Extruder Overview
Weldmax
Weldplast EC4
Weldplast S4
Fusion 2
Fusion 3C
Fusion 3
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Digital controled Extruder
Weldmax
Weldplast S4
Weldplast EC4

• Air and plast seperate heated and controled
• Display for air and plast temperature
• Weldplast integrated menue for typical materials

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Air heated Extruder
Fusion 3
Fusion 3C
Fusion 2

• Air heating for pre-heating and plast
• Simple handling
• Compact and light

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Extrusion Welding

• WELDMAX

• Separately, steplessly regulated temperature gt
  air / plastic
• Ideal for confined spaces
• Smallest hand extruder of its size
• Low noise
• Complies with DVS and CE conformity

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Extrusion Welding

• WELDMAX

digital display- set air temperature- set
plastic temperature- set plastic output
heating chamber
360 degrees adjustable handle
welding rod feeder- twist-free- d4 mm
hot air blower
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Extrusion Welding

• WELDPLAST S4

• Brushless and maintenance-free blower motor
• Low noise
• Complies with DVS and CE conformity

• Separately, steplessly regulated temperature gt
  air / plastic
• Menu with functioning program to regulate welding
  process

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Extrusion Welding

• WELDPLAST S4 /EC4

digital display- set air temperature- set
plastic temperature- set plastic output-
service display- language choice (D, E, F,
Esp)- program
Worm
180
welding rod feeder- double-sided- twist-free-
3 and 4 mm
hot air blower- brushless motor
simple change to different welding directions
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Extrusion Welding

• WELDPLAST EC4

• Brushless and maintenance-free driving and blower
  motor
• Low noise
• Other features according to WELDPLAST S4
• Complies with DVS and CE conformity

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Extrusion Welding ... with Leister

• WELDPLAST EC4
• Welding plastic tank

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Extrusion Welding

• FUSION 3

360
two positions L/R

• Compact and handy
• Very simple handling
• Unique price/performance ratio
• Protection of drive with overload and temperature
  protection

potentiometer output control
potentiometerair temperature
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Extrusion Welding

• FUSION 3C

2 Potentiometer for plast output and temperature
360

• Very compact and handy
• Easy to use
• Good relation price/performance
• Motor protection

Handle free adjustable
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Extrusion Welding

• FUSION 2

2 Potentiometer for plast output and temperature
360

• Very compact and handy
• Easy to use
• Good relation price/performance
• Motor protection

Handle free adjustable
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Leister Extrusion Welding
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Extrusion Welding Welding Shoe Assortment
X-seam
V-seam
pay attention to the maximum welding speed
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Extrusion Welding Welding Shoe Assortment
X-seam
V-seam
pay attention to the maximum welding speed
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Extrusion Welding Assortment
pay attention to the maximum welding speed
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Extrusion Welding Assortment
pay attention to the maximum welding speed
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Summary Theory

• Introduction Plastic Fabrication
• Basic Welding Principles
• Pendulum Welding and Draw Welding
• Hot Air Extrusion Welding
• Arrangement of Welding Constructions
• Test of Welding Connections

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Arrangement of Welding Constructions

• Angle Joint

Frame Corners
favourable
unfavourable
unfavourable
favourable
Put welding connections to the outside of the
main exposure zone.
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Arrangement of Welding Constructions

• Changes in Cross Section

Frame Corners
wrong
right
wrong
right

• Cross joints are not allowed in carrying parts.

• Avoid abrupt changes in cross section.

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Summary Theory

• Introduction Plastic Fabrication
• Basic Welding Principles
• Pendulum Welding and Draw Welding
• Hot Air Extrusion Welding
• Arrangement of Welding Constructions
• Test of Welding Connections

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Test of Welding Connections Test Method in
Plastic Fabrication

• Destroying Test Methods
• tensile test DVS 2203-2
• impact-tensile test DVS 2203-3
• long-time tensile test DVS 2203-4
• technological bending test DVS 2203-5

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Test of Welding ConnectionsTest Method in
Plastic Fabrication
Non-Destructive Test (Visual Check)
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Many Thanks