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INDUSTRIAL PROCESSES II INDEN 3313

INDUSTRIAL PROCESSES II INDEN 3313. Lecture 8 – Completion of Joining (Adhesives and Mechanical) Introduction to Part Location. OVERVIEW. Adhesives Mechanical Fastening Part Location Theory. QUESTIONS TO START ??. ADHESIVES. Adhesive Joining (Definition)

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INDUSTRIAL PROCESSES II INDEN 3313

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  1. INDUSTRIAL PROCESSES IIINDEN 3313 Lecture 8 – Completion of Joining (Adhesives and Mechanical) Introduction to Part Location Industrial Processes II

  2. OVERVIEW • Adhesives • Mechanical Fastening • Part Location Theory Industrial Processes II

  3. QUESTIONSTO START ?? Industrial Processes II

  4. ADHESIVES • Adhesive Joining (Definition) • Joining Process in Which Physical Bonds are Used to Hold Two (or More) Base Materials (Which May be Different) Fast • Adhere - (From The Random House Dictionary) • 1. to stick fast, cleave, cling, ... ; 3. to hold closely or firmly. from the Latin “adhaerere” meaning to stick/cling. Industrial Processes II

  5. ADHESIVE PROCESSES • Adhesive ‘Wets’ Surfaces to be Joined • Dry -> 1% of Surface in Contact • Emollient May be Used to Reduce Surface Tension of Adhesive • Bonding Strength is a Function of Surface Tension of Adhesive • Achieved via Change of State • Solidification (Fusion, Chemical Change, Loss of Solvent, ... Industrial Processes II

  6. ADHESIVE PROCESSES • Major Consideration • Physical Performance of Bond • Strength • Relative Strength (to Adherents) • Which Breaks First • Setting Time • Life • Toxicity • Ease of Cleaning (Spills, Equipment) • Compatibility with Base/Contacting Materials • Insulator/Conductor Industrial Processes II

  7. ADHESIVE PROCESSES • Considerations • Design Considerations • Properties of Adhesive, Adherents, and Operating Environment • Porosity of Substrate (Higher Porosity, Weaker Joint) • Fixturing Required, Ability to Clean • Known Service Requirements • Economics • Application Costs • Acquisition Costs • Cost of Failure Industrial Processes II

  8. ADHESIVE JOINTS STRESSES Groover, Figure 30.10 p. 783 Industrial Processes II

  9. ADHESIVE PROCESSES • Considerations • Application • Compatible Method/Product • Spread Lower Surface Tension on Higher • Processing Rate/Curing Time • Temperature/Pressure Requirements • Ability to Automate (Production Rate, Toxicity) • Joint • Cleanliness • Area of Contact • Thickness of Adhesive Layer Industrial Processes II

  10. ADHESIVE JOINTS Groover, Figure 30.11 p. 783 Industrial Processes II

  11. APPLICATION METHODS • Roller • Brush • Extrusion • Trowel • Spray • Roll Coaters • Dip Emersion Industrial Processes II

  12. ROLL COATING Groover, Figure 30.14 p. 786 Industrial Processes II

  13. CLASSES OF ADHESIVES • Class I -- Chemically Reactive • Set by Cross-Linking of Polymers • Generally, Endothermic (Thermosetting) Plasitic • High Shear Strength, Low Peel Strength • Three Sub-classes • IA -- Plural Component • Epoxies, Phenolic Resins • IB -- Heat Activated • Endothermic Reactions • Pre-mixed, Short Shelf Life • IC -- Moisture Activated • Silicone/Urethanes, Cynoacrylates, Concrete Industrial Processes II

  14. CLASSES OF ADHESIVES • Class II -- Evaporative Adhesives • Cures as Solvent Evaporates • One Substrate Must Absorb the Adhesive • Generally, Long Drying Times • Examples • Acrylics, Vinyl Resins, Asphalt • Elmer’s Glue® • Airplane Glue • Class III -- Hot Melt Adhesives • Melted, Allowed to Cool/Fuse • Rapid Setting • Ethylene Copolymers, Polymides, Polyesters, Polyethylene, Polyvinyl Buteral Industrial Processes II

  15. CLASSES OF ADHESIVES • Class IV -- Delayed Tack Adhesives • Non-tacky Solids that Upon Heating Become Tacky and Remain so for Extended Periods (up to Days) • Polyvinyl Acetate, Polystyrene • Class V -- Film Adhesives • One or More Layers of Adhesives • Individual Layers May Also Belong to Another Class • Class VI -- Pressure Sensitive Adhesives • Pressure Used to “Wet” Surface • PolyAcrylates, Polyvinyl (With Plasticizers), Alkyl Ethers Industrial Processes II

  16. CLASSES OF ADHESIVES • Class VII -- Electrically and Thermally Conductive • Fillers added to Adhesive to Improve/ Change Electrical Resistance or Heat Transfer Properties (Typically Add Metals) • Used for Electronic Device Attachment (Surface Mount Technology) Industrial Processes II

  17. INTRODUCTION TO JOINING PROCESSES • Mechanical Fastening - Definition • Processes in Which a Mechanical Device or Deformation (Elastic or Plastic) is Introduced to Hold Two or More Components Together. • Why Use ? • Can Join Any Materials • Easier/More Economical/Lower Skill Requirements Than Other Joining Methods • Use of Fasteners Allows Disassembly for Maintenance/Repair • May Be Made Permanent • No Temperature, Chemical Processes Introduces • Other Joining Method Unavailable, Inaccessible Industrial Processes II

  18. INTRODUCTION TO JOINING PROCESSES • Mechanical Fastening - Key Elements in Definition • Mechanical Devices -- Specifically Designed Devices, Commonly Referred to As Fasteners, e.g., Nails, Nuts and Bolts, Screws, Rivets, ... . • Elastic Deformation -- Material Displacement (Strain) in Reaction to an Applied Force (Stress) Which Returns to Its Original Position/Condition Upon Removal of the Force. • Plastic Deformation -- Material Displacement (Strain) in Reaction to an Applied Force (Stress) Which Does Not Return to Its Original Position/Condition Upon Removal of the Force. Industrial Processes II

  19. MECHANICAL ASSEMBLY/JOINING • Definition • Use of One or More Fastening Methods or Devices to Attach Parts to One Another • Reasons • Ease of Assembly • Ease of Disassembly • Low Skill Requirements • Can Be Automated • Low cost Industrial Processes II

  20. MECHANICAL ASSEMBLY/JOINING • Types • Threaded Fasteners • Rivets and Eyelets • Press Fits • Shrink and Expansion Fits • Snap Fits • Stitching, Stapling, and Sewing • Cotter Pins • Molding Inserts • Integral Fasteners Industrial Processes II

  21. THREADED - SCREWS, NUTS, BOLTS Groover, Figure 31.1 p. 791 Industrial Processes II

  22. FASTENERS - HEAD STYLES Groover, Figure 31.2 p. 791 Industrial Processes II

  23. FASTENERS - SET SCREWS Groover, Figure 31.3 p. 792 Industrial Processes II

  24. FASTENERS - SELF TAPPING Groover, Figure 31.4, p. 792 Industrial Processes II

  25. FASTENERS - STUDS Groover, Figure 31.5, p. 792 Industrial Processes II

  26. FASTENERS -THREADED INSERT Groover, Figure 31.6, p. 793 Industrial Processes II

  27. FASTENERS -CAPTIVE THREADED INSERT Groover, Figure 31.7, p. 793 Industrial Processes II

  28. FASTENERS - WASHERS Groover, Figure 31.8, p. 794 Industrial Processes II

  29. FASTENERS - RIVETS Groover, Figure 31.10, p. 797 Industrial Processes II

  30. FASTENERS - EYELETS Groover, Figure 31.11, p. 797 Industrial Processes II

  31. FASTENERS - INTERFERENCE FITS Groover, Figure 31.12, p. 799 Industrial Processes II

  32. FASTENERS - SNAP FITS Groover, Figure 31.13, p. 800 Industrial Processes II

  33. FASTENERS - RETAINING RINGS Groover, Figure 31.14, p. 801 Industrial Processes II

  34. FASTENERS - STITCHING Unclinched Std.Loop ByPass Loop Flat Cinch Groover, Figure 31.15, p. 801 Industrial Processes II

  35. FASTENERS - COTTER PINS Groover, Figure 31.16, p. 802 Industrial Processes II

  36. FASTENERS - MOLDED IN INSERTS Groover, Figure 31.17, p. 803 Industrial Processes II

  37. FASTENERS - INTEGRAL Groover, Figure 31.19 a-c, p. 804 Single Lock Seam Industrial Processes II

  38. FASTENERS - INTEGRAL Groover, Figure 31.19 d-e, p. 804 BEADING DIMPLING Industrial Processes II

  39. PART LOCATION THEORY • Part in Space Has Six/Twelve Degrees of Freedom (Possible Movements) Industrial Processes II

  40. PART LOCATION THEORY • To Arrest Motion, Six Contact Points are Sufficient • Three Points to Define First Datum Plane and Arrest One Translational and Two Rotational Modes • Two Points to Arrest One Additional Translational Mode and One Additional Rotational Mode • One Point to Arrest Final Translational Mode • This is the 3-2-1 Principle for Jigs/Fixture Design Industrial Processes II

  41. PART LOCATION THEORY • Minimize Area of Contact • Least Likelihood of “Hitting Irregularity” • Minimize Area for Inspection, Dirt/Chip • Maximize Distance Between Locators • Minimizes Impact of Dirt/Irregularity on Surface Location • Other Two Major Jig/Fixture Design Principles SHIFT LOCATOR Industrial Processes II

  42. EXAMPLE • In Class Demonstration • Location of Red Box in Space Industrial Processes II

  43. OTHER DESIRED JIG/FIXTURE DESIGN FEATURES • Allow for Wear • Slip Renewable Bushings • Replaceable Locator Pins • Part Visibility • Hinged Tops • Minimum Enclosure • “Fool Proofing” • Ease of Attachment to Machine Tool • Use of Legs and Feet (Attach/Clearance) • Cleaning/Drain Holes Industrial Processes II

  44. OTHER DESIRED JIG/FIXTURE DESIGN FEATURES • Use Standard Parts • Locators • Correct Size • Use Shims as Necessary • Drill Bushings • Chips Clear Before Bushing • Chip Pass Through Bushing • Clamps • Quick Acting • Accommodate Part Size Variation • Simple, Reliable Industrial Processes II

  45. QUESTIONSOR CLARIFICATIONS ??? Reminder : Industrial Processes II

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