How to create a precision injection mold

A perfect precision injection mold, need to spend a lot of time and precision. It can also represent the largest investment in the manufacturing process, and we have only one purpose, that is, the project's success. If your goal is to create a large volume of high-precision parts, the production becomes more complicated.

Plastic and mold

The customization of tools and processes is based on the type of plastic. This amorphous plastic is not free-flowing and tends to shrink less than crystalline or semi-crystalline plastic, which provides better flow but higher shrinkage. For this reason, many projects require engineering resins that provide a better melt without shrinking. Plastic suppliers provide information on the shrinkage of the resin with temperature and the melt flow rate recommendations.

Processing to the exact standard

Resin shrinkage affects the design and machining tool cavity. The cavity must accommodate the amount of shrinkage that may occur. Using modern CAD software, design engineers will create a partial cavity that is more than what is actually done. The size of this subsidy is based on the properties of the resin. Some such shrinkage can be solved by adjusting the mold package and holding rate, but all the plastic shrinks when it cools and even partially dies. Worse, some deformation pressure may occur during deformation. This pressure may cause problems with pressure, temperature, flow, gate position or ventilation.

A mold design leads to mass production quality

Precision parts design. The proper melt flow and pressure must be placed. The appearance of the final section can be improved by positioning the door slightly indifferently. The size of the door is also an important consideration. The door must be large enough to not extend the cycle time into the proper packaging material. If the door is too small the package may not be enough to fill the cavity (also known as short shot) or the part may show other defects.

Mold design must include vents. Vents allow molten resin to escape the air of the tool. Positions with gating, size and vents are key factors in the production quality department. The spout is too large to allow the plastic material to escape and cause flickering. The mouth is too small, may not have enough air and gas release. These bubbles can cause improper filling (short shots) or worse. Part of the reason the gas can burn burns traces

Proper cooling is the key

An effective cooling system is characterized by a quality injection mold. Molds need to maintain a consistent temperature, avoiding shrinkage and warping, while minimizing cycle times and maximizing production throughput. This delicate balance is part of a well-designed cooling system.

Jetting components

The final step in the molding process is to consider the thimble position of the injection system, the catapult mechanism, and the type of cycle that need to be calculated precisely to avoid any defects in the design of the mold. This is usually done with a series of carefully placed rams, whose shape and size determine the size and wall thickness of the part.

Improve quality during operation

Avoid any unnecessary rework mold cavity, the long run will save time and money. Experienced design mold created for the production of part of the trial run. This step is crucial to determine if adjusting the mold, choice of resin, or forming parameters such as temperature and flow needs. If there is any quality problem with the test run, the project team will work together to determine the cause and redesign the plan until the customer's standards are met.