extrusion coating dies and feedblocksthe extrusion coating die • precisely distributes the...
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Extrusion Coating Extrusion Coating Dies and FeedblocksDies and Feedblocks
Gary Oliver
Extrusion Dies Industries, LLC
Understanding Application Needs
““If we do not learn from history, we are doomed to repeat it.If we do not learn from history, we are doomed to repeat it.””George SantayanaGeorge Santayana
Important Considerations for Extrusion Coating Applications
• Trouble-free coating width variation for versatility and efficiency
• Ability to reduce edge bead size to minimize waste• Precise control of coat-weight uniformity so that
desired mono-layer or coextruded physical properties are achieved with the least amount of material
The Extrusion Coating Die
• Precisely distributes the extrudate across a changeable exit width.
• Enable easy coating width changes.• Manipulates the edge bead effect for efficient use of
the coating materials.
External Deckles
Jyohoku Seiko Co., Ltd., Tokyo, Japan - Patent 4,248,579 8-February-1981
Internally Deckled Bead Reduction DieInternally Deckled Bead Reduction Die
Internally Deckled Bead Reduction DieInternally Deckled Bead Reduction Die
Jyohoku Seiko Co., Ltd., Tokyo, Japan - Patent 5,395,231 7-March-1995
Internally Deckled Bead Reduction DieInternally Deckled Bead Reduction Die
Cloeren EBR™
Internally Deckled Extrusion Coating Die
• Flow channel is streamlined at all operating widths. • Internal blades can be adjusted to minimize edge
bead size.
Internal Only Deckles
Can require rigorous procedures to adjust and maintain
Advantages of Internal/External Deckle
• The internal deckles can be repositioned during extrusion and provide the primary seal at the die lip.
• The external deckle provides a secondary seal and eliminates the need to clamp the deckle with the flex lip.
The Deckle Mechanism
• A guide system drives the movement of both the internal and external deckle components.
• Solid deckle blades fill the die channel for a more effective seal.
Internally Deckled DieInternally Deckled DieEach Component Independently AdjustableEach Component Independently Adjustable
Deckle ComponentsDeckle Components
Manifold Manifold DeckleDeckle
Secondary Secondary DeckleDeckle
Deckle RodDeckle Rod
Lip FlagLip Flag
External External DeckleDeckle
Edge Control
• Internal deckles can be stepped to reduce the edge bead size.
Edge Control
Edge Control
Particle Path As It Relates To Internal Deckle Position
Deckle Position Data
Accumulated Material
Understanding Die Swell
Polymer Flow
Lip Land Length
• Internally deckled dies utilize various land lengths at the exit of the die.
3mm lip land 12mm lip land
Experimentally Determine Land Length Impact
• Examine Land Length– As related to Pressure– As related to Die Swell
• Examine Lip Gap– As related to Pressure– As related to Die Swell
Test Instrument
Thermo Scientific HAAKE PolyLab
Capillaries for Test Device
Land Length
3 mm6 mm
12 mm19 mm25 mm
Capillary Diameter - 0.7 mm
• All rates converted to kg/h/mm die slot.
• Average rate 1.0kg/h/mm die slot.
Draw Down Device
Draw Down Rate = 25 m/min
Testing Rates
• All rates converted to kg/mm slot opening– Lip gap initial set point 0.75 mm– Average rate 1.0 kg/mm slot opening– 2000 mm slot = 2000 kg/hr– Range 0.1 kg/mm – 6.0 kg/mm
• 2000 mm slot opening–200 kg/hr minimum–6000 kg/hr maximum
Resins Tested
• INEO4S 18R430 15.0 998 69 250 17• INEOS 19N730 7.5 1056 73 326 22• INEOS 2OP730 8.8 1100 76 385 27• INEOS 23L430 4.1 1402 97 495 34• DOW 5004 4.2 1276 88 435 30
Resin Grade MFI 25 mm Land Pressure 3 mm Land PressurePSI Bar PSI Bar
• Higher pressure can lead to leakage issues and may limit output.
Test Photos
25 mm Capillary: No visible die swell but excessive back pressure.
12 mm Capillary: Minimal die swell with reasonable back pressure.
3 mm Capillary: Excessive die swell and low back pressure.
• Lip Land Length Significantly Impacts Die Swell– Short land lengths produce greater die swell– Die swell impacts die lip buildup
• Lip Land Length Impact Pressure– Deckle Sealing
• Larger Gap Decreases Die Swell– Increasing die gap reduces swell– Increasing die gap increases DDR– Increasing gap can increase neckin
Conclusions
Die Lip Face
• Precise release point for the polymer
• Minimizes contact with the lip face
Lip Edge
Die Lip Gap Adjustment
• Manual Adjustment– Sliding lip adjustment– Flex lip adjustment
• Automatic Profile Control– Thermal die bolt– Open or Closed loop feedback
Automatic Profile Control
Thermal actuators are the common method for lip adjustment.
Coextrusion Feedblock Systems
Structure Arrangement Capability Fixed or Variable Geometry Design
Fixed Geometry Cross Sectional View
Davis Standard – BC Micro-Layer Feedblock
Cloeren Vane Feedblock
Adjustable Feedblocks
Product Changeover
Exchangeable selector spools have a slip fit and
allow convenient changes to the layer sequence.
Selector Spools
Product Changeover
Bolted plates with metal to metal seals ensure leak-free performance and provide streamlined (fully round) flow paths.
Selector Plates
Internal View of Flow Channel
Summary• Solid deckle blade design completely fills the die
channel.• External deckles back-up the internal deckle.• Internal deckles can be stepped to reduce the edge
bead size.• A 12mm lip land provides good distribution control,
effective deckle sealing and reduced die swell. This prevents lip build-up and streaks.
• Automatic lip control produces rapid and precise automatic coat weight control.
• Feedblocks are used to form composite coating structures which produce desirable performance properties without multi-pass lamination or coating.