The largest domestic SMT machine company is Aoyu Kexin in Beijing. In 2008 and 2009, it was the heyday of the mold patch repair machine. At that time, the small patch machine had just been launched and sold for a sky-high price of more than 100,000 yuan. Its welding gun is a copper rod. The principle is to place an iron piece of appropriate size at the defective location of the metal product, and then use a short-circuit spark between the copper rod and the workpiece to roll the iron piece back and forth in an attempt to cover the defective location. The advantage is that it is simple to operate and requires no technical skills. Its disadvantages include slow work efficiency, low patch firmness (the corner of the iron sheet can be pried open with a file), and the inability to fundamentally repair defects in metal products (only surface patch repairs are performed, and the pores under the iron sheet remain exists!), the surface repair effect of irregular workpieces is not good. So this repair method is actually a failure. ?

Metal repair must completely integrate the welding material with the product, otherwise the wear resistance, corrosion resistance, impact resistance, etc. required by the product during use will not be achieved. There is now an imitation laser welding machine (precision repair welding machine), also known as a mold repair machine. Compared with the patch repair machine, it still uses the welding method to melt and fuse the welding material with the base metal, fundamentally solving the problem. The principle is to apply cold welding technology to pulse arc to realize low-temperature repair and welding of metal products. The welding machine adopts microcomputer chip control, which realizes the adjustment of pulse voltage (1~99) and time (1~99), so that the optimal welding repair power can be adjusted according to the characteristics of welding repair defects, so that the welding machine's The welding repair accuracy can reach or even exceed the welding repair accuracy of laser welding machines (the finest 0.2mm welding wire can be used), and at the same time it has the speed and flexibility of argon welding.

Since this welding machine can complete the welding of the welding wire and the workpiece within tens of milliseconds (1 second = 1000 milliseconds), compared with argon welding, it conducts less heat to the workpiece, and the base area outside the welding point is The temperature rise is small, so the substrate will not cause problems such as annealing, discoloration, and undercutting. When used with a special tungsten needle, the molten pool generated by each welding pulse is less than 0.5㎜?, so the matrix stress is also small. Although one solder joint requires many molten pools, the stress direction of the solder joint is dispersed, and the concentrated stress on the workpiece is also small, so the deformation of the workpiece after welding repair is very small.