Through production test and research, the following problems exist in shell:
(1) mold shell deformation: mold shell deformation mainly occurs in the following three production processes:
In the hot sand coated shell making, the mold is deformed due to heating, and the deformation at this place is generally 0.2mm/400mm (crankshaft length);
Deformation during bonding: it is mainly caused by uneven clamping force;
Deformation during pouring: caused by insufficient strength and rigidity of mold shell and compactness of filled iron shot during solidification of molten iron.
Therefore, for the crankshaft with strict requirements for the runout tolerance of the main journal of multi cylinder machine, careful consideration or sufficient process demonstration should be made.
(2) hot metal feeding problem: in order to fully feed, heating riser or pressure riser shall be added to the crankshaft of single cylinder engine to enhance feeding.
(3) chilling problem of fan plate: since the area of crankshaft crank fan plate of single cylinder engine is too large, it is recommended to add chilling iron at the crank.
(4) sand sticking of castings: in order to prevent sand sticking of castings, the crankshaft with length ≥ 300mm must be coated at the upper 1 / 3 of shell casting.
(5) productivity problem: in order to improve productivity, the single station shell making machine can be designed into multi station or rotating structure, and shall be bonded by hot automatic gluing machine.