Consideration of Cavity Layout
● Try to use Balances Layout.
● Die hole layout and gate opening strive to be symmetrical, in order to prevent uneven force of the mold to produce partial load and the overflow of mold support.As shown in figure 2
The design is better with symmetry.
● Die hole layout as compact as possible to reduce the size of the mold.The design in Figure 3(b) is superior to the design in Figure 3(b) in terms of mold size.
Flow guidance considerations
● Can successfully guide the molten plastic to fill the cavity, no eddy current, and can be smoothly exhaust.
● Try to avoid the plastic melt to impact the small diameter of the front Core and metal inserts, to prevent Core Shift or deformation.
Heat loss and pressure drop considerations
● The less heat loss and pressure drop, the better.
● Keep the process short.
The cross sectional area of the runner should be large enough.
● Try to avoid the flow channel bending and sudden change of flow direction (by arc Angle change direction).
● The surface roughness should be low when the runner is processed.
● Multi-point feeding can reduce the pressure drop and the required injection pressure, but there will be suture problem.
Flow equilibrium considerations
● Multi Cavity Cavity filling, the flow channel should be balanced, and each Cavity should be filled with plastic at the same time to ensure each Cavity
Quality consistency of the molding products.
● Naturally Balanced Layout should be adopted in the shunt channel.
● Unable to balance the natural balance when the artificial balance method to balance the flow channel.
Waste Considerations
● Under the premise of smooth filling without affecting the flow and pressure loss, reduce the flow channel volume (length or cross-sectional area) to reduce
Runner waste production and recovery costs.
Cold slug consideration
● Appropriate Cold Slug Well and overflow groove are designed on the flow channel system to fill the plastic wave front which is Cold in the initial stage, so as to prevent the Cold material from entering the cavity directly and affecting the filling quality.
Exhaust Considerations
● The plastic should be successfully guided to fill the cavity, and the air in the cavity can escape smoothly, in order to avoid the problem of sealing and burning.
Consideration of forming product quality
● Avoid short shot, burr, encapsulation, suture, flow mark, jet flow, residual stress, warping deformation, die core deviation and other problems.
● When the flow process of the runner system is long or Multiple Gating, the warpage and deformation of the finished product caused by unbalanced flow, insufficient holding pressure or uneven shrinkage should be prevented.
● The appearance of the product is good, easy to remove and trim the Gate, Gate Mark (Gate Mark) is non-destructive to the appearance and application of plastic parts.
Productivity considerations
● As far as possible to reduce the required post-processing, so that the forming cycle is shortened, improve production efficiency.
The consideration of the ejection point
● Appropriate ejection position should be considered to avoid demoulding and deformation of formed products.
Consideration of using plastic
● For plastics with high viscosity or short L/ T, avoid using too long or too small size runner