| Taking the weld marks and bubbles in the process of injection moulding of aircraft branch frame as the optimization objective, the weld marks and bubbles near the gate were eliminated by optimizing the gate position and changing the gate form. At the same time, the consistency of the position and shape of the weld marks and bubbles in the process of moulding was found. The orthogonal test was carried out with the process parameters of the gate diameter, mold temperature, melt temperature, injection time, V/P conversion volume and pressure holding. Through optimization of process parameters, multi objective optimization of weld marks and bubble defects was carried out. It was found that gate diameter had a great influence on weld marks and bubbles. The optimum combination of process parameters was obtained as follows: die temperature of 60 ℃, melt temperature of 245 ℃, injection time of 5 s, V/P conversion volume of 99%, holding pressure of 245 MPa, gate diameter of 1 mm. Meantime, the consistency of weld marks and bubbles affected by process parameters was found, which proved the consistency of weld mark and bubbles in formation mechanism, forming position and shape, and the degree of influence of process parameters. The final weld line length was optimized by 35.66% and the bubble area was optimized by 26.74%. The study on two influencing factors of gating system and process parameters optimization provides reference for future research on weld marks and bubble defects and eliminating weld marks and bubble defects in engineering production. |
