Why can't the mold be opened on the injection molding machine?

First of all, this equipment must have been used for a long time (but there is basically no problem with pressure and flow), and the connecting rod, steel sleeve, copper sleeve, pin shaft and other parts of the mold opening and closing mechanism have been seriously worn out. The lubricating device is broken, and the parts are not lubricated for a long time. You can try the following methods, but you will have to overhaul or the equipment will be scrapped later.
 
It should be noted that the following methods have certain risks, and the repair personnel must have a certain working time and repair experience before they can operate.
 
1) First, loosen the nut connecting the piston rod of the clamping cylinder and the cross to about two-fifths of the original, and then set the pressure speed of the equipment to open the mold to the maximum (pressure 140kg/cm2, speed 99﹪) for use Pressing (to prevent the mold from opening to the end at a high speed) method to open the mold can generally be opened (because there is a certain distance between the nut and the piston rod of the mold clamping cylinder, the mold opening action is performed by impact, so the mold opening is increased. pressure);

2) If it still doesn't work, loosen the guide rods on both sides of the clamping cross. It can basically be opened;
 
3) If it still doesn't work, put the jack between the crank arm cross and the ejector cylinder to make it tight, and then use the mold opening force of the machine slightly (this action can be done repeatedly, little by little) ;

4) If it doesn't work, on the basis of the third work, after the equipment is stopped, remove the oil return pipe of the clamping cylinder (reduce the air pressure), and the mold should be opened.