Impulse welding process

The Resistance Impulse Welding process is a modification of Resistance Welding, based on the principle of the transformed capacitor discharge system, with the advantage of very high reproducibility and low operating costs..

Two parts are welded through the combined application of mechanical pressure to the parts and discharge of constant electrical energy. Both these two components of the welding process are closely controlled and monitored through electrical control loops. The goal is to concentrate the released energy to the spot where the joining is to take place so that the maximum weldcurrent has to pass through the minimum of contact area between the two parts.           The quality of the joint depends beside the pressure from the following factors:

  • High weld energy

  • Short weld time

    A simple principle schematic will explain to get this:

                     

The electrical energy is stored in a capacitor [C] which makes the system independent of voltage fluctuations in the mains supply as well as prevent voltage drops when the weld pulse is triggered. The capacitor is charged via the controlled power supply [G]. The stored energy is discharged through a high performance Thyristor [V] to the primary side of the impulse transformer [T]. Because the special design of the transformer a very high current is induced on the secondary side of the transformer which is conducted directly to the electrodes. This current can be as high as 100 000A. Projections on the parts to be welded provide a very high contact resistance [minimum area of contact]. The current flow through the contact area creates rapid temperature rise which will meld the material. A special mechanical set down spring mechanism will transmit the pressure and produce an even lattice structure on the joint surfaces.          

The Weldimpulse looks as follows:      

         

The weld time [t1- t0] is between 4 und 12 ms depending on machine type and required energy. Since the released energy is delivered exlusively to the weld zone, the surrounding material is not effected. Should however in adjacent zones occur a change in the metallurgical structure, then a second defined discharge pulse (annealing) can partially correct this occurrence.           Because of the special characteristics which are part of the Impulse-Welding process, there are a number of technical and economic benefits which recommend this process for many joining applications.          
  • Special Applications:
      - IMPULS - Welding of different material components
      - IMPULS - Welding of coated materials
      - IMPULS - Welding of thin foils
      - IMPULS - Welding of metal sheets with different thickness          
  • Improved Quality:
      - tight tolerances assure reproducibility
      - Process control make easy integration in automated production lines
      - Weld parameter control guaranty fluid and gas tight welds each time          
  • Return of Investment:
      - low energy cost since small energy loss during welding cycle
      - storage of energy in capacitor, therefore independent of mains fluctuations
      - long electrode life, no damage to the part surface
      - high throughput, because of short weld cycle
      - no cooling necessary          
  • Cost Savings:
      - no distortion of part due to temperature increase during welding cycle
      - parts surface is maintained clean
      - because of short weld discharge time, the lattice structure of material is not changed and the   material characteristics
        are maintained      

Is Impulse Welding the right process for your application ?          

  You can get a fast answer from us if you provide the following information:
- Inform us about your application
- Send us drawings of your parts
- Tell us the material components of your parts          

Should your application lend itself for Impulse Welding, we would be pleased to run test samples for you to prove the performance of our process to you. We will return the welded parts for your own testing.        

Please contact us!

 

pulse welding gmbh, Am Hasselt 20c, DE 24576 Bad Bramstedt, info@pulsewelding.de