In this resistance welding process, a bank of capacitors is charged to a pre-set voltage and then discharged through a pulse transformer. Very high current is passed in very short time resulting in fantastic projection welding quality. As the machine requires power just for charging the bank of capacitors, the power (Kva) requirement is negligible as compared to any other process of resistance welding. This results in great saving of connected load as well as power usage. As the weld time is very less (ideally 3 to 12 milliseconds), there is negligible heating or blackening of welded components and water cooling for the electrodes is not required. 

This technology is ideal for projections welding, dissimilar metal welding and thin sheet spot welding. Machine users requiring excellent aesthetics, high regard for power saving and consistency in projection welding should adopt this technology. 

Machine Control - Important Features

• Fully digital and micro-controller based.
• Digital setting and display of all operating parameters like weld voltage, weld delay etc.
• 8x Presettable weld programs - Eases m/c setting-up in case of a job change.  You just need to change the weld program and all the corresponding weld parameters would be recalled.
• Pass-word protection for change of parameters. Provides security of weld parameters by preventing un-authorized change of parameters.
• Weld Quality Monitoring - Measurement and display of peak current, peak time, RMS current and half peak time for each weld. Facility to set acceptance band for peak current (i.e. lower limit and upper limit).This feature facilitates on-line quality assurance.
• Total weld counter - non-resettable.
• Lap counter - This settable counter provides a PLC compatible output when the lap counter overflows and resets itself. Lap counter is presettable and resettable.
• Built in over voltage protection - protects capacitor bank from over charging.
• 4x deep non volatile fault history with time stamp.

Projection Welding

Projection welding is a resistance welding process. Projections are made on any one of the components before welding. The weld area and location is defined before welding in projection welding unlike in spot welding where weld area depends on the shape of the electrodes. After passing the weld current for specific time, the projection collapses under the electrode pressure and the parts are welded together. 

The advantages of projection welding are that multiple projections can be welded in one shot, flat electrodes are required for welding, minimum dents and marks after welding etc.

Advantages

• Large scale reduction in power (Kva) demand as compared to conventional resistance welding machines. For example our 10Kva CD projection welder can weld components, which are welded on 50 to 75 Kva conventional A.C. projection welder.
• No water-cooling required for electrodes due to very short weld times. Cost of manufacturing electrodes is reduced.
• Negligible blackening and distortion at weld joint. Excellent aesthetics. No mark on the other side of the weld.
• No effect of normal voltage fluctuation on weld quality. Machine will not discharge (weld) unless capacitors are charged to the pre-set voltage.
• It's a three-phase machine and it can work on Generator set.
• Welding near heat sensitive parts is possible.
• Welding of similar and dissimilar metals possible.
• Installation and operating cost of the machine is very very less. The more you weld, the more you save.

Applications