Plastic injection molding is one of the most efficient manufacturing processes available for a wide range of products and parts. It produces less waste material than CNC machining and can also be used for longer or repeat runs with better consistency. However, there are many nuances to the process that need to be understood in order to achieve a successful outcome.
During the design phase of any project, it is important to consider the type of manufacturing process that will be utilized. Choosing the right one will have a significant impact on the overall cost of the product or part, as well as the delivery time frame. The right production process will depend on factors like the type of product or part, its size, and complexity, the price point you want to hit, and any desired aesthetic.
The first step in plastic injection molding is designing and building the mold that will house the finished product or part. This will require an experienced and knowledgeable engineer to take a CAD design and turn it into a physical mold. While the upfront costs of this step can be high, it is crucial to the overall success of your product or part.
Once the mold is designed, it will need to be built in an appropriate size and shape for your project. Injection molding machines use hydraulic or electrical systems to create tremendous forces that will close the two halves of the mold together. This is done in the same way as a car door is closed, and it will ensure that no air escapes or contaminants enter during the injection molding process.
Once both the mold and the injection molding machine are ready, the injection process can begin. The plastic pellets or granules will be fed into a heated barrel using a reciprocating screw. This will heat the material to a temperature that will allow it to flow and melt, and will also cause Van der Waals forces to weaken between individual chains, resulting in a reduction of viscosity. The melting plastic will then be injected into the mould through a gate, which joins the melt-delivery channels (sprue and runner) with the part forming cavity. This will produce a molded part with a number of visible marks known as the parting line, sprue mark, and ejector pin mark.
The molded part will need to cool down and harden before it can be removed from the mold, and this can take as little as a few seconds to a few minutes. The cooling time will depend on the thickness and properties of the plastic, as well as how complex its design is. The ejector pins that hold the molded part will then pull back, releasing the pressure and allowing the injected plastic to flow away from the nozzle.
Injection molding can be a very efficient and reliable plastics manufacturing process, but it requires the right team to get the job done properly. CBM’s experienced experts know the ins and outs of injection molding machines and plastics manufacturing, and are waiting to help you find a solution that works for your next project. Contact us today for more information on how we can help..