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JOINING & ASSEMBLING

JOINING & ASSEMBLING. Methods of Joining & Assembling. Gluing Welding Mechanical Connections. Functions of Joining. For Permanent Joining Gluing Welding For Disassembly Mechanical Connections. Bolted Assemblies Self Tapping Screws Snap Fits Threaded Metal Inserts

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JOINING & ASSEMBLING

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  1. JOINING & ASSEMBLING CORPORATE TRAINING AND PLANNING

  2. Methods of Joining & Assembling • Gluing • Welding • Mechanical Connections CORPORATE TRAINING AND PLANNING

  3. Functions of Joining For Permanent Joining • Gluing • Welding For Disassembly • Mechanical Connections CORPORATE TRAINING AND PLANNING

  4. Bolted Assemblies Self Tapping Screws Snap Fits Threaded Metal Inserts Hook and Loop Type Fasteners Moulded-in-Threads Boss Cap Push-on / Turn-on Fasteners Rivets Press Fits Types of Mechanical Connections CORPORATE TRAINING AND PLANNING

  5. The main mechanical connections used for plastic assembly CORPORATE TRAINING AND PLANNING

  6. Types of Gluing • Solvent Bonding • Adhesive Bonding CORPORATE TRAINING AND PLANNING

  7. Adhesive bonding CORPORATE TRAINING AND PLANNING

  8. Solvent Bonding Advantages • Homogeneous distribution of mechanical loads • Good aesthetics • Economic assembly • Low weight, no heavy screws, bolts and nuts • Heat sensitive constructions or materials, which welding would distort or destroy, can be joined • Good sealing and insulating properties. CORPORATE TRAINING AND PLANNING

  9. Solvent Bonding Limitations • Entrapment of solvent in the joint • Stress cracking or crazing • Dissimilar materials can only be joined if both are soluble in a common solvent or in a mixture of solvents • Differences in thermal expansion of components are not compensated if dissimilar materials are bonded • Reproducibility/process control • High solvent evaporation time due to its entrapment in the polymer matrix • No disassembly possible • Assembly hazards such as fire or toxicity. CORPORATE TRAINING AND PLANNING

  10. Adhesive Bonding Advantages • Application on various substrates like thermoplastics, thermosets, elastomers and metals • Homogenous distribution of mechanical loads • Differences in thermal expansion of components can be compensated for by using a thick adhesive layer • Good aesthetics / no special requirements to hide the bond. • Economic assembly • Low weight, no heavy screws, bolts and nuts • Heat sensitive constructions or materials, which welding would distort, can be joined • No thermal stresses introduced • Good sealing and insulating properties. CORPORATE TRAINING AND PLANNING

  11. Adhesive Bonding Limitations • Long term behavior may not be very good • Stress cracking or crazing of the plastic may take place • Dissimilar materials can only be joined if both are compatible with the adhesive • Reproducibility/process control • Curing time can be high depending on the adhesive • No disassembly possible • Assembly hazards such as fire or toxicity CORPORATE TRAINING AND PLANNING

  12. Welding An effective method of permanently joining plastics components together. CORPORATE TRAINING AND PLANNING

  13. Welding Principle • Inter diffusion of Molecular Chains • Phase Change from Solid to Liquid. • Followed by Solidification Phase at the Interfaces to be joined together. CORPORATE TRAINING AND PLANNING

  14. Uniqueness of Welding • Good Aesthetics • Clean • Strong Bond CORPORATE TRAINING AND PLANNING

  15. Schematic representation of the welding process CORPORATE TRAINING AND PLANNING

  16. Vibration welding Spin welding Ultrasonic welding Hot-plate welding Induction welding Laser welding Radio freq. welding Resistance welding Hot gas welding Staking Types of Welding CORPORATE TRAINING AND PLANNING

  17. Vibration Welding • the two plastic parts to be joined are vibrated (rubbed) against each other at a certain frequency, amplitude and pressure which results in frictional heating of the surfaces, causing the polymer to melt at the interface. • The molten polymer flows out of the weld-zone giving rise to flash. When vibration stops, the weld cools down and solidifies. CORPORATE TRAINING AND PLANNING

  18. Vibration welding process CORPORATE TRAINING AND PLANNING

  19. Vibration welding equipment CORPORATE TRAINING AND PLANNING

  20. Advantages of Vibration Welding • Cost Effective • Short Cycle Times • Large Batch Sizes Possible • Melted Polymer Not Exposed to Open Air • Strong Bond CORPORATE TRAINING AND PLANNING

  21. Disadvantages of Vibration Welding • Welding Thermoplastic Elastomers is problematic. • Product is exposed to vibrations during welding. • Much flash is formed. • 3D Contours can’t be welded. CORPORATE TRAINING AND PLANNING

  22. Spin Welding • The two parts to be welded are pressed against each other. • One part is held fixed and the other rotates at high speed. • The friction between the two parts generates heat which causes the polymer to melt at the interface. • The molten polymer flows out of the weld-zone giving rise to flash. When rotation stops, the weld cools down and solidifies. CORPORATE TRAINING AND PLANNING

  23. Spin welding equipment CORPORATE TRAINING AND PLANNING

  24. Advantages of Spin Welding • Efficient, Simple Process • Simple Equipment • Short Cycle Times • Large Batch Sizes Possible • Melted Polymer not Exposed to Open Air • Strong Bond CORPORATE TRAINING AND PLANNING

  25. Disadvantages of Spin Welding • Welding Thermoplastic Elastomers is problematic. • Only Circular Contours can be Welded. • 3D Contours can not be Welded. • Relative Position of the Parts can not be Adjusted. CORPORATE TRAINING AND PLANNING

  26. Ultrasonic Welding • The process uses low amplitude and high frequency vibrational energy. • Parts to be joined are fixed firmly. • Mating part is subjected to sinusoidal Ultrasonic Vibrations of the order of 20,000 cycles per second. CORPORATE TRAINING AND PLANNING

  27. Ultrasonic welding process CORPORATE TRAINING AND PLANNING

  28. Equipment for ultrasonic welding CORPORATE TRAINING AND PLANNING

  29. Advantages of Ultrasonic Welding • Cost Effective • Short Cycle Times • Large Batch Sizes Possible • Melted Polymer Not Exposed to Open Air CORPORATE TRAINING AND PLANNING

  30. Disadvantages of Ultrasonic Welding • Welding Thermoplastic Elastomers is problematic. • Product is exposed to vibrations during welding. • Restricted to Small and Medium Size parts. CORPORATE TRAINING AND PLANNING

  31. Hot Plate Welding Uses thermal energy to melt the welding zone through conduction. CORPORATE TRAINING AND PLANNING

  32. Hot plate welding process CORPORATE TRAINING AND PLANNING

  33. Advantages of Hot Plate Welding • Cost Effective • Large Batch Size is Possible • Suited for Soft Materials • No Electrical Fields, No Mechanical Vibrations. • Strong Bond CORPORATE TRAINING AND PLANNING

  34. Disadvantages of Hot Plate Welding • Long Cycle Times • Molten Polymer Expose to Open Air • Weld Strength is Poor for Certain Heat Sensitive Materials. CORPORATE TRAINING AND PLANNING

  35. Induction Welding • Uses Inductive Energy to heat the Plastic. • The bonding material melts and the parts are joined under low pressure. CORPORATE TRAINING AND PLANNING

  36. Induction welding process CORPORATE TRAINING AND PLANNING

  37. Advantages of Induction Welding • Short Cycle Times. • 3D Weld Surfaces are Possible • Thermoplastic Elastomers can be welded. • Can be used for highly filled materials • Welding process is reversible (Repair, Recycling). • Tolerances on Part Dimensions not tight. CORPORATE TRAINING AND PLANNING

  38. Disadvantages of Induction Welding • Electro-magnetic Welding gasket Material is required. • Not well suited for parts containing electromagnetic sensitive items (Metal Inserts). CORPORATE TRAINING AND PLANNING

  39. Hot Gas Welding • Uses Hot Air or Nitrogen to Melt the Surfaces to be joined. • Process is extensively used for assembling large parts. • Suitable for field assembly and repair. CORPORATE TRAINING AND PLANNING

  40. Hot gas welding CORPORATE TRAINING AND PLANNING

  41. Hot gas welding process CORPORATE TRAINING AND PLANNING

  42. MACHINING OF PLASTICS CORPORATE TRAINING AND PLANNING

  43. Different Types of Cutting • Sawing • Laser Cutting • Milling • Turning & Boring • Punching, Blanking and Die Cutting CORPORATE TRAINING AND PLANNING

  44. Different Types of Finishing • Filing • Sanding • Grinding • Polishing and Buffing CORPORATE TRAINING AND PLANNING

  45. SURFACE TREATMENT CORPORATE TRAINING AND PLANNING

  46. Uniqueness of Surface Treatment • Transforms the materials into more workable substrates. • Surface Treatment is a must before printing for non-polar materials. CORPORATE TRAINING AND PLANNING

  47. Types of Surface Treatment • Mechanical Abrasion • Flame Treatment • Chemical Etching • Corona Treatment • Plasma Treatment CORPORATE TRAINING AND PLANNING

  48. Different Types of Finishing • Filing • Sanding • Grinding • Polishing and Buffing CORPORATE TRAINING AND PLANNING

  49. METALLIZATION CORPORATE TRAINING AND PLANNING

  50. Uses of Metallization • Enhances Reflectivity • Improves Abrasion Resistance • Has High Electrical Conductivity • Provides Electromagnetic Shielding CORPORATE TRAINING AND PLANNING

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