Spot Resistance Welding

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Spot (Resistance) Welding
Rebekah Osborn Brett Green Patrick
Colsher Trent Kososki
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Description

• A resistance welding process
• Joins two or more metal parts together
• Copper Alloy electrodes apply pressure and
  current
• Heat develops at interface between sheets
• Materials melt together forming weld nugget

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Description Continued
Heat generated is expressed by EI2Rt   E
is heat energy I is current R is the electrical
resistance t is the time that the current is
applied.      Copper used in electrodes
because low resistance high thermal conductivity
(ensuring heat generates in workpieces instead of
the electrodes. 
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Applications

• One of the oldest welding processes
• Used on very thin foils, lt 6mm thickness
• Wide range of applications - assembly of sheet
  steel vehicle bodies (gt100 million welds are made
  per day in Europe alone)
• High quality welds made in stainless steels,
  nickel alloys, aluminum alloys and titanium for
  aerospace application
• Other Applications
• Automotive body panels
• Appliance housings
• Lawn/garden equipment
• Office furniture
• Cooking utensils

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Benefits

• Spot Welding Advantages include
• high speed
• ease of automation
• energy efficiency

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Risks Issues

• Some limitations on material weldability
• Main Hazards
• crushing fingers or hands
• burns or eye damage
• from splash metal
• Little fumes produced, caution necessary when
  welding coated steels or if oils or organic
  materials are present

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Our Application

• Alternate approach to using Kanthal heating wires
  (saves space, energy)
• Fastening bimetal strips to wires
• Small width of bimetal strips makes attachment
  difficult
• Standard soldering not viable b/c low melting
  point of solder

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Acknowledgements

• http//www.kawasakirobotics.com/Applications/Appli
  cations_Resistance.asp
• http//www.portablewelders.ltd.uk/spotbasprin.html
  
• http//ducati.doc.ntu.ac.uk/uksim/dad/OR42paper-se
  pt00.doc
• http//www.key-to-steel.com/Articles/Art76.htm
• http//www.twi.co.uk/j32k/protected/band_3/kssaw00
  1.html