Assembly of sand mold
Be familiar with the casting process drawings and related documents before assembly.
Check whether the sand mold and sand core are defective or partially broken. The damaged parts must be repaired carefully before use.
The floating sand on the surface of mold cavity, pouring system and sand core shall be removed before core lowering.
The core shall be aligned according to the center line of the sand mold to ensure the size and wall thickness of the sand mold. The gap between mud cores must be blocked and leveled,
When laying the core, the leather shoes shall not be stepped on the mold surface, and rags or straw bags shall be padded if necessary.
The hanging core shall be fastened with iron wire or special screw hook. After turning over the box, hang it tightly.
The air passage of the sand core must be smooth, and the air hole of the complex sand core must be checked.
The height of the core support of the top fixed sand core shall conform to the wall thickness and tolerance standards of the casting. The card pad shall be placed in the inner cavity of the casting surface, and the sand core support shall have sufficient strength and uniform distribution. The sand core support with groove shall be used for the oil test casting, and the hard top and open top shall be used for the easily floating sand core or the sand core with a riser which is not easy to be fixed.
Place the inner chill according to the process and casting requirements. The inner chill shall be clean, rust free, oil free, paint free and fixed firmly
The spiral cold iron shall be fixed at the center of the hot spot. Sectional forming, internal cold iron shall be firmly welded with each other.
In case of multi-layer sand core, it is necessary to cover the sand layer by layer to prevent falling into the sand.
After the equipment is completed, check the main dimensions of the sand mold according to the drawings.
Closed box
When turning over the box, pay attention to safety to prevent damage to the sand mold. When it is necessary to drill to the bottom of the box for work, the four corners of the box must be well framed.
Before closing the box, sand shall be filled around the vent hole and it shall be higher than the box surface. The exposed riser shall be connected 50-100mm higher than the pouring height specified in the process, repaired and dried smoothly. The sprue cup shall be placed stably and the joint must be tight.
Carefully pump the floating sand in the sand mold and pouring system before closing the box.
Before closing the box, the box must be inspected to see if there is any deviation of the box, if the wall thickness is appropriate, if the box mouth is tight, if the air hole is tight, if the position is correct, if the mud core and inner cold iron are fastened well, and if the sand mold is crushed or dropped.
The sand mold with deep cavity or thin sand intake at the bottom shall be stabilized to prevent fire leakage at the bottom. The bottom shall be placed and padded properly. If necessary, it shall be buried in the pit for pouring. After the box is closed, it will not be moved at will.
When closing the box, asbestos rope or sealing strip shall be padded around the core head of parting surface, gate and air hole. Take the yellow mud pile and put the appropriate clips.
When closing the box, the upper box shall be lifted flat and aligned according to the box closing mark.
When modeling the box, fasten it after closing the box. When necessary, seal the box by hand with sand.
After closing the box, the pouring riser and air outlet shall be tightly covered to prevent falling into sand and other articles.
The weight of the pressing iron shall be sufficient, the placing shall be stable, the uniform distribution shall be ensured, and the pressing iron shall be prepared before pouring.
When the upper box is to cover the core, iron block shall be padded at the butt joint, and the gap shall be blocked well, and each sand core shall be backed on the pressing iron.
For the sand mold with a large amount of internal cooling iron, the preheating time shall be more than 4 hours. For the general sand mold, it must be poured within 6 hours after the box is closed. If it is more than 6 hours, it shall be poured after the sand mold is heated by the sand mold dryer for 2 hours.
If the sand mold after closed box is placed for more than 24 hours, it must be unpacked and dried again, and can be poured after closed box. If the sand mold after closed box is dried again, and there is no pouring after 48 hours, it shall be discarded and cannot be used again.