DESIGNING FOR INJECTION MOLDING
Our fundamental principles for plastic injection molding encompass crucial design considerations aimed at enhancing part moldability, elevating cosmetic appearance, and streamlining production time.
What Are Injection Mold Design?
Mold design is crucial in injection molding, directly impacting the cost-effectiveness and quality of the final molded parts. Factors like gate size, shear edge, flow assist, cooling, and ejector technology all contribute to the overall outcome.
The design process starts with a 2D layout, determining mold size, gating type, parting line, ejection method, cavity arrangement, mechanical design, and materials.
After customer approval, the design progresses to detailed 3D design and NC programming, taking 3-7 days for comprehensive molds. Complex molds may require more time for mold flow analysis and iterations based on customer feedback.
Design considerations include ensuring smooth plastic flow into all cavities and easy part removal, achieved through draft angles on mold walls.
Injection Molding Applications
Plastic injection molding is the preferred process for manufacturing plastic parts. Injection molding is used to create many things such as electronic housings, containers, bottle caps, automotive interiors, combs, and most other plastic products available today. It is ideal for producing high volumes of plastic parts due to the fact that several parts can be produced in each cycle by using multi-cavity injection molds. Some advantages of injection molding are high tolerance precision, repeatability, large material selection, low labor cost, minimal scrap losses, and little need to finish parts after molding. Some disadvantages of this process are an expensive upfront tooling investment and process limitations.
Applications Include:
- Packaging
- Consumer goods
- Medical devices
- Electronics & telecommunications
- Mechanical parts (including gears)
- Most other common plastic products available today
Mold design process
Product analysis
Start the mold design by designing the product. You can open any standard CAD files or select parts designed with NX. Ensure desired design intent and manufacturability by modeling, making design changes and analyzing geometry.
Core and cavity development
Streamline the design process of core and cavity geometry using automated capabilities, enabling you to: Use automated shutoffs and a parting of core/cavity Design parting surfaces quickly and associatively Split mold to accommodate complex slider designs Automatically check the core/cavity design for interference
Mold structure
Define the entire mold structure, including the core, cavity, component systems and mold base for both prototype and production-scale multi-cavity molds. Configure the mold using libraries of standard parts, component systems and mold bases. Quickly add and trim ejector pins and insert cooling channels with parametric patterns. Include runners, gates, screws, pins and other standard components.
Design validation
Analyze the manufacturability of part designs using tools to check wall thickness, identify undercut regions and evaluate corner radii. Validate the mold design by checking the distances and reliefs in various positions and by analyzing the requirements for electrodes. Use the motion simulation capabilities to verify the entire range of movements of the mold, including dynamic collision detection.
Reuse of company standards
Reduce tool development time by reusing your company's standards, including: Repurpose project templates and adapt proven designs to new molds Accelerate the mold design process by standardizing components Automate generation of NC toolpaths and project data structures Develop reusable mold base configurations and save them in custom libraries
Design change and propagation control
Use the associativity with the part model to facilitate rapid propagation of design changes through the process, from mold design to machining operations. Ensure that the entire team works with the correct data by integrating the Teamcenter software, which provides a single source of data and process knowledge.
Commonly used injection molding materials
- Polyethylene (PE)
- Polypropylene (PP)
- Acrylonitrile Butadiene Styrene (ABS)
- Polycarbonate (PC)
- Nylon (PA)
- Polyoxymethylene (POM)
- Polyurethane (PU)
- Polystyrene (PS)
- Polyethylene terephthalate (PET)
