(1) Confirmation of number of cavities and type of gating system
The equipment model is disa230x, and the mold plate specification is 750mm × 535mm. Considering the safety distance of the mold plate, that is, the distance between the cavity or the gating system and the edge of the template, which is related to the thickness of the model, the brake caliper parts can be arranged with four acupoints, two lines and two columns, and the middle part adopts common riser feeding to improve the production rate. Balance the appearance quality requirement and yield of parts, and select the design of vacuum gating system.
(2) Equipment cycle time standard
Tmax = cycle time sand conveying time gating system filling time
(3) Principle of unsatisfied pouring
For the convenience of calculation, the pouring time is 7.5 s.
(4) Selection of gate cup size
The estimated yield is 50%,
(5) Calculation of runner section area
In the vacuum gating system, the vertical runner is pressurized to control the overall filling speed. It is calculated by the following formula:
Due to the increase of heat loss and flow loss over a long distance, it is not recommended to use a sprue less than 48mmm2,
The flow velocity of FF7 in the upper horizontal flow channel should be the same as FF3, and the cross section should be slender trapezoid to improve the slag avoiding ability,
The calculation of the overlapping section FF6 is half of the sum of the upper runner size and the vertical runner size,
The overlap should not exceed 1 / 6 of the vertical dimension of 24mm of the upper horizontal runner, so the thickness should be 40.5 × 4mm, and the fastest velocity of the system is at F1 section,
The velocity of molten metal must be controlled within 1 m / s before it enters into the casting cavity. Therefore, the cross-sectional area of metal from F1 runner to gate F0 must be 1.49 times larger than that of F1
After finishing, the mold layout is designed as shown in Figure 1. The bottom pouring openis adopted, and the foam filter is set at the top of the riser, and the two sides of the sprue and the runner are overlapped to avoid the impurities coming from the initial molten iron into the lower gating system.
The figure 2 above shows the 2D drawing of the gating system of the mould according to the calculation. The blue runner is located at the counter pressing plate, the green runner is located at the positive pressing plate, the red is the feeding system, and the shadow is the cross-section size and shape of the corresponding runner.