Industrial Plastic Molding: What to Consider for Production Parts
When a plastic part becomes part of an equipment assembly, machine, or finished product, the manufacturing process must be consistent from one run to the next, meet dimensional requirements, and remain practical to produce at the required volume. For many applications, industrial plastic molding provides an efficient way to produce repeatable plastic parts at production volumes. Material, part design, tooling, tolerances, production requirements, and secondary operations all influence whether a molded part will perform as expected and remain economical to produce.
What are the Part’s Requirements?
A plastic component used inside industrial equipment may need to withstand repeated mechanical stress, impact, heat, chemicals, moisture, or continuous movement. Another component may have much less stringent mechanical requirements but require tight dimensional control because it interfaces with other components.
Production volume must also be considered. The requirements for a few hundred parts are different from those for thousands or tens of thousands of parts. Expected production volume, part complexity, material, and tooling investment all need to be considered together. Defining these requirements early helps determine whether a molded plastic part is appropriate and what the manufacturing process needs to deliver.
Choosing the Right Material
Plastic materials can have significantly different properties, even when they appear to offer similar performance on paper. Material selection may involve considerations such as:
Strength and stiffness
Impact resistance
Operating temperature
Chemical exposure
Wear and friction
Dimensional stability
Moisture absorption
UV exposure
Regulatory or application requirements
Fillers and reinforcements can further change a material's characteristics. For example, adding glass fiber can improve stiffness and dimensional stability while also affecting flow, shrinkage, and the material's behavior during molding. The material, therefore, needs to be evaluated as part of the complete molding process, not simply selected from a list of general specifications.
Part Design Influences the Molding Process
A part designed for another manufacturing process, such as metal machining, may need to be adjusted before it is suitable for injection molding. Wall thickness, transitions between sections, ribs, bosses, openings, draft angles, and other geometric features can affect how plastic flows into the mold and how the finished part behaves as it cools.
Even relatively small design decisions can influence manufacturability. Uneven wall thickness, for example, can contribute to differences in cooling and shrinkage. Features without adequate draft or undercuts can make ejection more difficult. Designing with the molding process in mind can help avoid changes after tooling has already been developed.
Additional Reading; Basics of Injection Mold Design
Consider Secondary Operations
Molding does not always represent the last manufacturing step. Depending on the part, production may include operations such as trimming, machining, drilling, assembly, printing, marking, insert installation, or other finishing processes. These operations should be considered when selecting parts and materials. A plastic that works well for the molded component may present different considerations when the finished part must be bonded or assembled with another material. Considering the complete production sequence can help prevent a problem from simply moving downstream.
Additional reading: How Value-Added Services Support High-Quality Plastic Components
The Importance of Communication Between Design and Manufacturing
A plastic part can meet the drawing specifications and still present manufacturing challenges. Conversely, a design that looks complicated on paper may be straightforward to mold with the right approach.
Early communication between the product team and the injection molder gives both sides an opportunity to identify potential issues before they become expensive changes. This can include reviewing part geometry, material selection, tolerances, tooling requirements, and production expectations.
Working With E-S Plastics for Industrial Plastic Molding
E-S Plastics helps manufacturers turn part requirements into production-ready molded plastic components. Their team can review part design, material needs, tooling requirements, secondary operations, and production expectations before a project moves too far into development. This is especially important for industrial plastic molding projects where fit, function, repeatability, and cost all need to be considered together.
If you need help evaluating material options, part design, or production planning for industrial plastic molding, E-S Plastics can review the application and help identify the next step.