RESISTANCE PROJECT WELDING

                          RESISTANCE PROJECT WELDING

In this process on the work piece being joined in simple at the point to be welded, that is small projection is made on one of the sheets hence the name is projection welding.

                         The projection is melted projection become the welds this process is thus similar to spot welding this type of welding is widely used in reaching small component and flatness to structure member forgings of mechanical parts.

                                       Projection welding is another variation of spot welding small projection are raised on one side of the sheet or plate where it is to be welded to another plate the projection serves to concentrate the welding heat at these areas.and facilitate fusion without the necessity of employing a large current.during the welding process the heat and softened projection collapse under the press of electrodes there by forming the welds.

Advantages

1.this method gives longer electrode life.

2.outer or top surface can be produced with no electrode marks.

3.a no of welds can be made simultaneously the ideal number of projection is three.

4.the electrodes also serve as a part of an assemble the metal pieces in their correct relatives position.

5.the current per weld is slightly less than for spot welding.

Disadvantages

1.all projection should be seated in on blow.

2. a prior operation is necessary to form the projection.

3. most jobs are required special electrodes.

4.the metal pieces must be embossed first to made projection hence an embossing machine is also incorporated in the system.

5.the projection welding machines should have greater current and pressure capacity since more than on weld are made simultaneously.

Application

A common used of projection welding is attaching small fasteners nuts special bolts stuck and similar parts to large components.