Q & As

What is Studwelding?

A process of welding a fastener to parent material using an electric arc.

How does it work?

An electric arc is set up from the fastener (stud) to the parent material (workpiece).  This arc melts the end of the stud and a shallow depth into the workpiece under the stud.  Spring pressure from the tool that holds the stud then forges it into the workpiece.

How strong is the joint?

There is complete fusion across the joint such that the weld is stronger than the stud or the workpiece.

Are there different processes?

There are three processes, capacitor discharge, short cycle and drawn arc.

What determines the process to be used?

The diameter of the stud, the thickness and condition of the workpiece and the electrical supply available.

What are the main industries that use studwelding?

Electrical, electronic, mechanical and environmental engineering, food production equipment and vehicle manufacturing.

What materials can be studwelded?

Mild steel, stainless steel, aluminium, aluminium alloy and lead free brass.

What stud diameters can be welded?

Capacitor discharge and short cycle: M2.5 to M10

Drawn arc: M6 to M24

Are all studs round and externally threaded?

No!  Studs can be different shapes. Popular designs are internally threaded bosses (tapped pads), unthreaded plain pins and earth tags.

Must the workpiece surface be specially prepared?

No!  However  it should be clean and conductive.

How fast are the processes?

Capacitor discharge takes no longer than 3 milliseconds.  Short cycle takes up to 100 milliseconds.  Drawn arc can be longer than 1 second for larger diameters.

How many studs per minute can be welded?

With good jigging 6 studs per minute can be achieved with capacitor discharge.  The drawn arc process is slower due to the use of ceramic ferrules (arc shields).

Is automation possible?

Yes.  Generally the capacitor discharge process is used in automation.  Semi or fully automated systems are available.  CNC control of the welding head is possible and robots can be integrated into the process.

How much training is required?

Very little.  Proficiency can be achieved quickly within  a few hours.