TWI Industrial Member Report Summary 166/1981
By M Amin
Microcomputer control based on the 8080 microprocessor has been developed for Synergic pulsed MIG welding, so that appropriate pulse parameters are adjusted automatically according to the operator-selected wire feed speed and arc length. The parametric constants relevant to a given wire material and diameter, which must initially be programmed manually in the previously used hard-wired Synergic control unit, can be stored in the microcomputer memory for a wide range of wire material/diameter/droplet volume combinations. As these can be retrieved automatically simply from specifying any required combination, the operation of the Synergic system has been further simplified.
The microcomputer control also provides five preprogrammed welding conditions, corresponding to five pulse repeat frequencies for a given wire feed speed (or heat input rate), compared with only one pulse condition provided by the hard-wired control unit. Thus the microcomputer control allows the optimisation of a welding condition not only relative to feed speed but also relative to pulse repeat frequency.
The control system was tested for bead-on-plate runs with mild steel/1mm dia. wire/1mm3 droplet volume, stainless steel/1.2mm dia. wire/1mm3 droplet volume and aluminium-magnesium alloy (NG61)/1.6mm dia. wire/1.5mm droplet volume combinations, using both the steady and gradually variable feed speeds. The microcomputer control was found capable of performing the Synergic operation successfully, merely from specifying the required wire material/diameter/droplet volume combination.