Features: 1 The whole machine is in sheet plate welded structure, with internal stress eliminated by vibration aging technology, high strength and good rigidity of machine. 2 Double hydraulic oil cylinder is applied for upper transmission,provided with mechanical limit stopper and synchronous torsion bar,typical of stable and reliable operation,as well as high precision. 3 Electrical control and manual fine-tuning mode are adopted for distance of rear stopper and stroke of gliding block,and fitted with digital display device,easy and quick in use. 4 Upper die is fitted with deflection compensation device.