DESIGN OF AUTOMATIC FOUNDRY WORKSHOP
Forced by the current situation, many foundries that produce small and medium-sized castings all want to invest in automated casting workshops, but suffer from lack of experience and lack of corresponding professionals So there are many blind, blind, inadequate preparation, unreasonable workshop design, too low operation rate, poor casting quality, management chaos, and even automation foundry shop difficult to continue the situation, therefore, some knowledge and experience were summarized for those who want to invest in small and medium-sized casting automation foundry industry reference.
1. The vertical parting line is suitable for medium and small-sized castings without sand cores
Because of the high efficiency and low investment of the vertical line, we should choose the vertical line first for the small and medium-sized castings without sand cores, but at the same time, we should consider several points:
(1) for plate castings with high dynamic balance requirements, the vertical line is usually not suitable for gravity segregation due to vertical parting.
(2) The gating system of vertical molding line is different from that of the horizontal molding line.
(3) for Castings with the deep core, pay attention to whether the strength of the core suspension is enough.
(4) it is difficult to set the riser for the complicated and Special Ductile Iron Castings.
(5) The horizontal parting line is suitable for all small and medium castings, especially those with sand cores.
(6) it is generally not recommended to use horizontal parting line to produce middle and small castings, not only because of high investment but also because of high operation cost, high failure point, and high casting cost.
Because of the special technological characteristics, the mechanical properties of the castings have been improved greatly, and the machining allowance has been reduced remarkably. Moreover, the yield of the products is higher than that of other casting processes Batch production of small and medium-sized castings has obvious advantages.
(1) the iron-type investment is big, therefore the iron-type design is very important, otherwise may create the biggest waste.
(2) the choice of resin coated sand should be very careful.
(3) there should be several options for the final optimization of the exhaust duct design.
(4) it is not suitable for casting complicated-shaped castings.
(5) not suitable for cores or complex castings.
(6) it is not suitable for products with small quantity and large size.
3. The quality of sand treatment system and the level of management determine the success or failure of the automatic foundry shop
In reality, too many foundry shops, due to the construction of automated foundry shop, neglect, neglect of sand processing system design and cast, as well as molding materials, resulting in molding sand quality instability, difficult to control Finally, it results in the low starting rate of molding line, high reject rate of casting and poor quality.
Sand temperature control, mud content control, quantitative control, the quality of the main sand treatment equipment itself, raw and auxiliary material quality are the key factors to guarantee the properties of molding sand.
4.Matching of melting ability and automatic molding line
The automatic foundry is different from the traditional foundry, molding and pouring are carried out at the same time. So follow these principles:
1) Several small electric furnaces are selected for differential time melting casting. The demand for molten iron per unit time of the automatic line for medium and small-sized castings is about 2 ~ 3 T. it is suggested that 3 ~ 4 sets of 1 ~ 1.5 t / H electric furnaces should be opened every 20 min in order to realize differential time melting pouring and ensure continuous supply of Molten Iron In order to meet the needs of molding line assembly line production.
2) To ensure that the molding line does not stop, melting capacity of the selection principles are Melting amount of molding line= Molten Iron *1.2
5. ‘Pouring level’ is an important link in the automatic foundry
Automatic casting machine is preferred in automatic casting plant, but domestic automatic casting machine is still in the growth stage, the price of foreign automatic casting machine is surprisingly high! At the same time, the casting ladle should not be large, 100 ~ 150 kg casting ladle should be used for many manufacturers to choose the common i-type steel rail structure, the disadvantages are:
(1) the roller does not roll on the linear cold round steel but rolls on the plane, the resistance is big, the casting ladle moves inconvenient.
(2) casting ladle hanging trolley side without ball beads, pouring ladle sway from left to right unstable.
(3) the structure of two rollers is easy to make the pouring ladle sway, but the structure of four rollers can solve the stability of pouring ladle when pouring and moving.
(4) The annular casting line of double ball rail and four rollers can meet the requirements of smooth casting, accurate casting, smooth moving and following the line.
Many manufacturers because of the “pouring level” is poor, resulting in spatter, pouring off the flow, cannot follow with the casting, bag, and other results, labor intensity, casting reject rate is high, the basic reason is that the casting ring structure is unreasonable Or pouring bag selection caused by improper.
The above-mentioned reminders and explanations are not enough to cover everything, but they are enough to make investors alert. We should use scientific thinking and correct methods to guide the construction of automatic foundry shop.