Resistance Spot Welding Flashcards
What does the resistance spot welding process involve?
The resistance spot welding process involves heat being generated by the resistance to the flow of electric current.
When does fusion take place in resistance spot welding?
What does this cause to happen?
Fusion takes place when the resistance is high enough to cause the two metals being joined to melt at the contact point.
What are the principles of resistance spot welding?
Principles:
The resistance to the passage of current is greatest at the interface of the plates being joined.
Pressure is applied between the electrodes and current is passed through.
The resistance to the current causes local rapid heating at the interface, resulting in nugget type spot weld.
What is the ideal function of resistance spot welding?
Function: Ideal method of joining light sheet metal.
What are some suitable applications of this welding process?
Application: Used for welding car bodies, suitable for robotic control.
Permanent joining of products like filling cabinets and equipment casings
When drawing a diagram of resistance spot welding, what must be labelled?
The forces applied from above and below,
the two copper electrodes,
the weld,
the AC power supply
List the 6 steps of the automated process of resistance spot welding
- The materials to be joined are overlapped.
- Two electrodes press in on the materials from either side.
- A large current is passed between the electrodes.
- The materials melt and fuse in one ‘spot’ or ‘nugget’.
- The electrodes open, and move on to, or get ready for, the next spot weld.
- Portable spot welders are also available.
What is the heat source of resistance spot welding?
Electric current flowing against the electrical resistance of the material creates heat
List 3 pros and 1 con of resistance spot welding
pros:
1. fast, high-quality, consistent, efficient
2. easily automated
3. No filler, flux, gas, cleaning afterwards needed
Cons:
1. Joins are not as strong as other forms of welding
