Engineering an injection molded plastic part requires a molder who is experienced in tool design and process optimization. This ensures the molder is familiar with the vital methodologies for creating a highly efficient production process. There are many types of plastic molding and tool and process engineers will ensure consistent and repeatable parts manufacturability.
Steps Involved in Injection Molding
Below are the steps involved in this process:
- Product Design. This step involves determining the product objectives that include function, aesthetics, and assembly as well as the requirements to accomplish the objectives. Engineers will identify and improve upon solutions to meet the certain needs of a project including materials selection for the final injection molded part and tool.
- Tool design. Apart from picking the appropriate material for tool construction, it is important to design for proper gate location. This will prevent costly project missteps.
- Product manufacturing. To achieve successful outcomes, the product and tool designs work together with resins to deliver what the project needs like heat tolerance, strength, and sterility. Also, they are meant to meet moldability requirements such as tight tolerances, heating, uniform wall thickness, cooling, and consistent, repeatable cycling.
Importance of Scientific Molding and Design of Experiments (DOE)
Scientific molding and DOE are important to injection molding projects because they take the injection molding process to a higher level of precision. In turn, this helps in lowering costs in the long run by making it possible to identify and correct tooling issues before production.
Experienced injection molders make use of scientific molding and DOE as the foundation for a reliable and optimized injection molding process which results in the successful manufacture of plastic parts. They achieve this by introducing a series of progressive balances and checks.
How to Optimize the Molding Process
Tool and process engineers work together to identify and correct any tooling weaknesses. They follow the steps below along with other steps.
- Examine the functionality of the tool. Engineers evaluate every aspect of the mechanical functionality of the tool to ensure everything works as designed. They make use of material settings that the material supplier will provide.
- Test for short shot. Sample parts are used to determine and document dynamic pressure and cavity imbalance. The viscosity curve is also established to determine the best fill rate and pattern.
- Examining the gate seal. This involves observing the pressure curve and sample parts weight to see if the gates fully seal and what point sealing takes place.