The formwork made of 45# steel has only upper and lower die holders and fixed plates. If it is the upper and lower die holders, both sides can be polished directly (the thickness accuracy of the upper and lower die holders is not high). If it is a fixed plate, it is recommended to turn it over and press it down to minimize the deformation, then the grinder will see the light on both sides, and then measure the difference between the actual thickness and the design thickness. If the difference is less than 0.5, argon arc welding can be used to spot weld the back of the fixing plate (the side without tire countersunk head), and pile up the points as close as possible, and then grind them to the design height with a grinder. If the thickness is too different from the design, you can put a gasket in the contour sleeve, put the gasket between the stripper plate and the fixed plate, and then the contour sleeve passes through the middle. There is another way, if there are not many punches, you can lower all the punches.