DN series of pneumatic spot welding machine, as well as spot and projection welding machine have been widely applied to automobile, aviation, architecture, machinery, metal wear, switching electric appliance, and other manufacturing industries. Able for high-quality welding of various low-carbon steel, stainless steel, low alloy steel, non-ferrous metal sheet materials and wire barsUser may select volage stabilized gas shield according to his own operation condition(adaptable to high-tempo welding occasions, and occasions where the condition of gas source is fairly poor)Matchable with high-performance microcomputer control box for different process conditions. It is provided with seven program segmentations of precompression/rise/peak value/valley value/drop/retention/compensation. Time of respective program segmentations and initial value, peak value, valley value, and terminal value of electric current, as well as amount of compensation are all in the way of digital setting and display