1. Features of low pressure die castings:
(1) During the casting process, casting pressure and velocity can be adjusted, which are applicable for different types of die castings, like metal die castings, sand castings and so on, thus allowing the forming of various alloy die castings of all sizes.
(2) Bottom casting type filling process is adopted. Molten metal filling process is steady without splash phenomena to avoid gas entrapment and the shock to die casting walls and die casting cores, increasing qualified rate of die castings.
(3) Die castings are crystallized under certain pressure with compact structure, clear outline, smooth surface and relatively strong mechanical property, which are favorable for the forming of large-diameter and thin-wall die castings.
(4) Feeding head is unnecessary, which help increase utilization ratio of metals to 90~98%.
(5) Low labor intensity, good working conditions, simple device and easy realization of mechanization and automation.
2. Taking metal-type gravity die castings for instance, low pressure die castings have the following advantages:
(1) Very high utilization ratio of castings, reaching 85~95%. No feed head and runner with small sprue, greatly reducing material cost and processing time.
(2) Fine die castings easily formed with directional solidification and few internal defects.
(3) Seldom inclusion of gas and impurities, ability to change pressure speed, and molten metal used for filling with laminar flow method.
(4) Allowable to use sand casting cores.
(5) Easy realization of automation, allowing multiple machines to work or coexistence of multiple processes.
(6) Not affected by whether operators are skilled or not.