Many people, including many those who are new in their manufacturing careers or engineering or purchasing functions who deal with plastic part design and new product development, do not understand what a ‘mold’ is. What is a mold? The first thing to understand is that an injection mold is a complex piece of machinery. The part that is produced by the mold is relatively low-cost compared to the cost of the mold that produces the part, which is something people don’t often understand. “How come the parts are $1.00 each and the mold that produces the parts is $100,000?”
There are several “rules of the road” when it comes to design a part for the injection molding process. These are not only meant to be beneficial for the mold designer, but to ensure that the mold runs in an optimum way. This will result in greater productivity and efficiencies, and better quality with less scrap/non-conforming parts, which will give you better return on your mold investment and provide high-quality parts to maintain your products’ brand integrity.
Proving the design of your plastic components is a critical step in the mold building process – something that should be done before steel is cut. This can be done by computer aided material flow analysis (MFA). Using the 3D image of the mold design, along with inputting the data points and the characteristics of the plastic material chosen for the component, a molding simulation can be performed showing how the material will flow through the mold given that specific design. If problem areas are encountered, design changes can be made prior to cutting steel – a much more cost-effective and efficient way to make needed changes.
When it comes to producing injection molded plastic parts, design is everything. In fact, design-for-manufacturability (DFM), or as we say in the plastics industry Design for Moldability, is critical to the success of your project. Just about any new idea for a component or product can be computer-designed using any number of CAD programs. However when it comes down to whether or not the design is viable for the injection molding process, that’s something the mold designers and engineers must determine through their expertise and the use of software technology.