利用压缩空气将型砂均匀地射入砂箱预紧实，然后再施加压力进行压实。常用的有垂直分型无箱射压造型机和水平分型脱箱射压造型机。
The moulding sand is evenly injected into the sand box by compressed air for pre-compaction, and then pressure is applied for compaction. Vertical parting boxless injection moulding machine and horizontal parting boxless injection moulding machine are commonly used.
垂直分型无箱射压造型机造型不用砂箱，型砂直接射入带有模板的造型室，所造砂型尺寸精度高，因砂箱两面都有型腔，生产率很高，但下芯比较困难，对型砂质量要求严。
Vertical parting box-less injection moulding machine does not need sand box. Sand is directly injected into the moulding room with template. The size precision of sand moulds is high. Because there are cavity on both sides of the sand box, the productivity is high, but the core setting is difficult, and the quality of sand moulding is strictly required.
水平分型脱箱射压造型机利用砂箱进行造型，砂型造好后合型脱箱，下芯比较方便，生产率高。
Horizontal parting ejection moulding machine uses sand box for moulding. After sand mould is made, the closing ejection moulding is convenient for core setting and high productivity.