Post-Molded Part Finishing PLET 370

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Post-Molded Part FinishingPLET 370

• Mike Alabran
• Andrew Magenau
• Bret Neese

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Objective

• Introduce and give a brief overview of the
  different methods of gate and flash removal.

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Outline

• Gate Removal
• Theory and background
• Basic operation with examples
• Gating Designs

• Flash Removal
• Theory and background
• Basic operation with examples
• Design requirements

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Introduction to Gate Removal

• Manual
• Hand-held tools
• Automatic
• 3 plate molds
• Pneumatic sprue cutters
• Floor or robot beam-mounted fixtures
• Punch presses
• CNC gate cutters
• Robots
• Lasers

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Theory and Background-gate removal

• Reasons for de-gating
• Remove runner from part
• Visual aesthetics
• Medical applications
• Assembly purposes

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Theory and Background-gate removal (continued)

• Advantages-manual de-gating
• Low equipment cost
• Disadvantages
• Inconsistent cut
• Increased operator cost
• Cycle time issues

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Basic Operation-gate removal

• Hand-held tools
• Blades

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Basic Operation-gate removal (continued)

• Side Cutters
• Saws
• Pneumatic cutters

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Basic Operation-gate removal (continued)

• Pneumatic sprue cutters
• Integrated onto robotic EOAT (end of arm tooling)
• Additional air circuits and programmed sequence
  from robot
• Work best on cylindrical or rectangular runners
• Estimated gate vestige (.015-.025 inches)
• Can be cost effective

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Basic Operation-gate removal (continued)

• Floor or robot beam-mounted fixtures
• Framework mounted to robot beam or floor
• Pneumatic sprue cutters or cutting blades mounted
  to pneumatic cylinder
• Prolongs life of robot
• Doesnt support weight of cutters
• Change-over tooling
• No extra air circuits

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Basic Operation-gate removal (continued)

• Floor-mounted

• Robot beam-mounted

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Basic Operation-gate removal (continued)

• Punch Press Degating
• Used when vestige is critical
• Between .003 and .01 in
• Operated automatically or manually
• Components
• Pneumatic slide
• Ram cylinders
• Slide table with rods and bearings

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Basic Operation-gate removal (continued)

• Punch Press

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Basic Operation-gate removal (continued)

• CNC degating
• Ideal for Multiple gate-cutting applications
• Robot beam-mounted or floor mounted
• Holds up to 20 different programs
• Robot Beam Mounted
• Equipped with a pneumatic sprue cutter
• Floor Mounted
• Works in conjunction with a sprue picker

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Basic Operation-gate removal (continued)

• Robot Beam Mounted

• Floor Mounted

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Basic Operation-gate removal (continued)

• Robotic Degating
• 5 or 6 axis robot
• Gate vestige - .005 to .015 in
• Advantages
• Multiple gate types
• High repeatability

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Basic Operation-gate removal (continued)

• Robotic Degater

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Basic Operation-gate removal (continued)

• Laser Degating
• Usually not cost effective
• Driven by pneumatic cylinder or electric motor
• Gate vestige - .002 - .010 in

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Gating Designs

• Automatically Degated
• Tunnel Gate, Cashew/Banana Gate, Jump Gate,
  Pinpoint Gate, Chisel Gate
• Manually Degating Required
• Sprue Gate, Edge Gate, Fan Gate, Film Gate, Ring
  Gate, Diaphragm Gate

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Theory and Background Flash Removal

• Causes
• High injection pressure
• Low clamp tonnage
• Oversized shot dosage
• Excessive melt temperature
• Improper Drying
• High residence time

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Theory and Background Flash Removal (continued)

• Locations of flash
• Parting line
• Part features
• Holes, small features, or vents

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Background Flash Removal (continued)

• Reasons to eliminate flash
• Visual aesthetics
• Functional purposes
• Medical applications
• Assembly requirements
• Tolerance issues

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Basic Operation- Flash Removal (continued)

• Methods of flash removal
• Manual Trimming methods
• Knives
• Cutters
• Flame

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Basic Operation- Flash Removal (continued)

• Methods of flash removal
• Other methods
• Wire brushes
• Hot wire deflashing
• Electric resistance heated wire
• Flash removal machines
• High pressure water
• Liquid nitrogen

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Basic Operation- Flash Removal (continued)

• Flash Removal Machine

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Basic Operation- Flash Removal (continued)

• High Pressure Water

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Basic Operation- Flash Removal (continued)

• Liquid Nitrogen

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Design requirements Flash Removal

• Strong clamping mechanism
• Rigid mold
• Strong support plate or pillars

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Conclusion

• Gate removal
• Application sensitive
• Recommendations
• Costs
• Flash Removal
• Application sensitive
• Recommendations
• Costs