Ford Kuga

 Service Manual

Body Repairs - General Information » Tools and Equipment for Body Repairs
Welding gear

As in the past, the dominant process in body construction is resistance welding, in particular spot welding. Depending on body type, up to 5000 spot welds are applied, either by welding robots or in the multi-point welding machine.

Resistance spot welding permits very high energy to be concentrated on a relatively small area of the workpiece in the shortest possible time and when high pressure is applied, a permanent joint is formed. During repairs the resistance spot welds used in production must be re-created accordingly.

NOTE: If a suitably powerful welding machine is not available and multi-layer panel joints with a total thickness of over 3 mm need to be made, puddle welding must be used.

Although in principle, high and ultra-high-strength panels are adequately or well suited to resistance spot welding, considerable problems may arise because of low welding power, especially where thicker panels or triple or multi-layer panels have to be welded together in the workshop. In particular, older welding equipment does not have the latest welding technology nor welding power and therefore cannot reliably join panel thicknesses greater than 3 mm.

NOTE: When installing body components made of ultra-high strength steel (e.g. boron), only inverter welding equipment certified by Ford may be used.

Equipment with inverter technology allows better spot weld quality because of a constant high welding current. In addition the high welding current makes shorter welding times possible and the electrodes therefore have a longer working life.

Inverter welding is a further development of electrode welding. In addition, a much higher electrode force (contact pressure of welding tongs) can be achieved with modern equipment.

Further advantages of the new inverter welding equipment are:

• good welding performance with constant quality, even with high switch-on times
• recognition of and compensation for disruptive factors: e.g. primer, adhesive, rust-prevention paint
• own and pre-set welding programs which can be saved and called up
• quality confirmation through logging of all important welding data
• fast changing of spot welding clamps or spot welding guns as required

The following functions can be controlled and monitored by programming the welding equipment:

• Control of the start conditions by resistance measurement (dirt, paint, bodywork adhesive, shunt circuit through the next spot weld).
• Ensuring the optimum welded connection.
• Checking the energy balance, resistance and quality.

In the case of resistance spot welded connections, faults in the weld are difficult to see from the outside. It is therefore absolutely vital to know the particular properties of the welding machine being used. A test weld with subsequent peeling test will provide information on the quality of the weld. The spot weld itself must not separate, it must tear away leaving a hole.

In the production of vehicle bodies, MIG welding plays a minor role as a joining technique. It is used for components subject to high demands, such as threaded plates for axle mountings, or at locations which cannot be spot welded for access reasons.

Alignment systems

Measuring systems

Welding gear