Sprue Bush is a channel used to guide molten metal into the mold.
Sprue Bush is made of high-silicon molten 140 and Al-Si materials.
Strong corrosion resistance, high geometric accuracy, smooth casting surface, long life and low maintenance cost.
Specification (Based on the alloy diameter)
| 3in | 3.5in | 4.5in | 5in | 5.5in | 6in | 6.5in | 7in |
| 8in | 9in | 10in | 12in | 14in | 16in | 18in | 20in |
Technical parameter for high silicon 140 sprue bush
| Item | Denisity (g/cm3) |
Compression Strength (Mpa) |
Thermal Expansivity (X*10-6/℃) |
Max Working Temperature (℃) |
| Index | 1.4-1.5 | 15-16 | 4-4.5 | ＞1000 |
A large amount of impurities will be generated during the melting process of aluminum liquid. If impurities enter the casting, it will destroy the structure of the casting and affect the performance of the casting. Generally, impurities will float on the liquid after precipitation.
When the molten metal enters the mold through the gate, it is easy to produce vortices, and the vortices will bring impurities and air floating on it into the casting, thereby affecting the quality of the casting.
Sprue Bush Design Points
1. In order for Sprue Bush to be pulled out from the main channel smoothly, the main channel (inner hole of the sprue bush) needs to be designed into a conical shape with a cone angle of 2 ° ～ 6 °
2. If the taper is too large, the pressure will be reduced, and a large flow will be generated, which is easy to be mixed into the air to generate pores.
3. Too small taper will increase the flow rate.
4. The inner wall finish is Ra = 1.6-0.8μm, the diameter of the small end is usually 4-8mm, and the diameter of the small end should be larger than the nozzle diameter by about 1mm.
5. The diameter of the sprue bushing should be 1-2mm larger than the nozzle hole diameter, so as to avoid the accumulation of residual materials, which will cause the pressure drop and the sprue to break easily.
6. Generally, rounding (R = 1-3mm) is set at the big end of Sprue Bush to facilitate the material flow.
