Trusted by over 2,000 engineers & purchasing leaders worldwide
The FormexMold Knowledge Base provides information on plastic injection mold processes and various topics related to plastic molding and plastic tooling. Download the Design Guide below or read on to learn more about plastic molding. The Design Guide will help you avoid costly and time-consuming design mistakes. The guide provides essential information on important requirements that should be incorporated at the initial design stage.
Plastic injection molding is a manufacturing process used to make a variety of plastic parts, typically at high volumes, for a wide range of industries. Plastic resin pellets are melted and then the liquefied plastic is forced into a metal mold cavity. After cooling, the mold is opened, the part is ejected, and the process is ready to start again. Plastic molding is ideal for producing thousands, hundreds of thousands, or even millions of the same part or part set.
The injection molding process starts with a Computer Aided Design (CAD) file that contains a digital version of the part. The CAD file is used as a blueprint to create the metal mold, also known as the tooling. The mold is typically comprised of two halves with the design machined into the middle of the two pieces. The mold is then placed into the injection molding machine. Plastic material, in the form of small pellets, is poured into a hopper on the machine. The pellets then move to a heating chamber where the plastic is melted. The molten plastic is forced into the mold once it has reached the right temperature. A screw or a ram mechanism controls the pressure and speed of the injected material. The short phase between the injection and the cooling of the object into its solid form is referred to as the dwelling phase. This step ensures that the mold cavities are completely filled before cooling begins. After the part has cooled, the mold is opened and the part is ejected. The mold is then closed and the process can start over.
The plastic molding process has nearly limitless applications. Carrying bags, packaging material, beverage bottles, accessories for the computer, automotive parts, and toys can all be manufactured using advanced plastic molding technology. Plastic injection molding technology is capable of manufacturing complex parts of the highest quality.
To help avoid costly and time-consuming design mistakes, we created a plastic injection molding design guide. It provides information on the most important design requirements so they can be incorporated at the initial design stage. The sample tips below illustrate the type of information provided in the complete guide.
The cooling process starts after the molten plastic is injected into the mold. Cooling can account for nearly two-thirds of the cycle time for each part. Calculating and then optimizing cooling time is a critical part of the injection molding process, saving the customer time and money. Cooling also has a major impact on both the quality of the part and the productivity of the mold. Improper or non-uniform cooling will cause defects like stresses, shrinkage, and warping. Improper cooling can also shorten the lifecycle of the mold.