Pin-point gate also has it’s disadvantages

All gates force molten plastic under pressure into the cavity which accelerates and heats the plastic as it does so. This creates a variety of effects which may need a change to gate design strategy. The most common defects include:
Jetting
If the gate is too small the resulting pressure drop through the gate will cause jetting, that is, spraying into the cavity rather than flowing smoothly. Jetting causes wavy distortions called “worming”. This may require a decrease in pressure, an enlargement of the gate or both.
Overheating
High injection speed through the gate creates heat through friction. Too much heat at this point may cause the resin to decay by destroying molecular bonds.
However, slowing down the injection speed to avoid degradation may cause other defects such as poor mechanical strength at weak weld lines. And slower cycle times means fewer parts per hour, increasing processing costs.
It’s possible therefore to divide a given volume of resin over a number of separate gate openings. This helps to dissipate pressure and avoid overheating, but it also creates multiple flow fronts which may cause weld lines and gas traps where these fronts meet inside the cavity.

“Gate” has a large influence on formability and internal stress of injection molding mold. Usually, appropriate form is determined according to shape of molded products, and it can be classified into two types: “restricted gate” and “unrestricted gate”. The former is made into a narrow part at the entrance of runner and cavity, is easy to process and easy to cut molded article from runner, which can reduce residual stress. Gates of most of plurality of shaped products are easily formed at one time, cavity is easily balanced. Plastics are not easy to countercurrent, and this form is generally used. It can also be divided into Side Gate, Overlap Gate, Tab Gate, Fan Gate, Film Gate, Ring Gate, Disk Gate, Point Gate, Submarine Gate and so on. The latter is a gate that directly injects plastic into cavity from down sprue as a representative of unrestricted gate. Type, position, size, and number of gates directly affect appearance, deformation, forming shrinkage, and strength of molded products.