Assembling

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Assembling
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Assembling

• Assembling process is the technique used to join
  parts into products.
• Mechanical assembling- includes the use of
  screws, bolts, nails, rivets, staples, or clips
  to join parts together.
• Bonding assembling includes the use of
  adhesives (adhesion) or heat and pressure
  (cohesion) to join parts together.

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Mechanical Assembling

• Mechanical fastening uses physical force to hold
  two or more parts together.
• 1. Temporary can be easily disassembled,
  assembled or adjusted.
• 2. Semi-permanent can be disassembled but not
  often done.
• 3. Permanent disassembly destroys the fastener
  and sometimes the part.

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Bonding

• Cohesion and Adhesion
• Cohesion uses forces that create an internal
  structure of the material and cause the surface
  molecules of two or more parts to grip to one
  another. Heat and or pressure is used to bring
  the parts together.
• This cause the parts to become one uniform
  monolithic layer. Welding is an example of
  cohesion.

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Bonding

• Adhesive bonding- is used to hold two different
  materials together.
• Adhesion causes to materials to bond or grip
  together.
• Adhesives are glues or cements.

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Joints

• Joints are the parts of a structure where two or
  more parts meet.
• The five most common groups of joints are
• 1. t-joints 2. Corner joints 3. Butt joints 4.
  Lap joints 5. Skarf joints

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Welding

• Uses heat , pressure or both to permanently join
  two or more materials together.
• It is a cohesive process.
• Three basic types Heat welding, Pressure
  welding, and Heat and pressure.

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Heat Welding Processes

• Gas welding most common is oxyacetylene
  welding. Produces a bond of two materials often
  by use of a filler rod which is melted to fill
  the joint area.
• Arc welding uses an electrical arc between a
  rod or electrode and the work piece. The
  electrical circuit is completed when a spark is
  produced between the electrode and the work.

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Pressure Welding Process

• Pressure welding -Parts are fused or forced
  together by great pressure. The pressure breaks
  down oxide layers existing on the parts and
  molecules are forced together to produce a
  cohesive bond without changing the surface into a
  liquid.
• Cold welding is an example. No heat is generated
  from an outside force. Used on nonferrous metals
  because they do not easily work harden and are
  highly ductile. Pressure is introduced by dies,
  punches, rollers or explosives.

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Heat and Pressure Welding

• Heat and pressure welding- Heat is used to change
  the material surfaces to their molten state and
  pressure is applied to form them together.
• This includes forge welding, roll laminating,
  resistance, induction, energy beam, friction, and
  diffusion.

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Bibliography

• Wright, R. T. (1999). Processes of manufacturing
  pp. 334-357 Tinley Park, IL Goodheart-Wilcox.