With the various characteristics of different plastics, injection molding processes have become increasingly popular as a safe, fast and cost-effective option in producing medical devices.
Working with medical product design experts familiar with the injection molding process as well as with design and material requirements in the medical device industry can help to reduce the time in design and the speed to market of the product. This is accomplished by addressing production considerations in the design stage.
Designing the Mold
When developing a medical product design to be produced by the injection molding process, the designers need to consider all aspects of the process. This includes the type of plastic used, the volume of production required, the shape and components of the device as well as the costs of both the mold as well as the materials.
Sizing of the mold is critical. All types of molds require a draft, which is a slight tapering of the mold to allow for easy ejection of the cooled product. This needs to be combined with the very slight shrinkage that occurs when all plastics cool in the mold.
Wall thicknesses and the shape of the specific medical product design have to incorporate the concepts of both drafts as well as shrinkage. In addition, the choice of similar thicknesses in the walls of the design is essential for the even flow of the plastic into the mold and equal cooling and shrinkage.
With irregular wall thicknesses or thick and thin sections or segments of the design, there is a greater risk of warping, problems with removal of the part from the mold and challenges in developing the process speed for injection molding. With experts on the design team familiar with these issues, common design mistakes can be avoided, saving both time and money for the OEM.
