Posted by Chip Owen

One of the most important factors in ensuring the quality of injection molded parts is uniform wall thickness. Having uniform injection molding wall thickness is crucial because it helps achieve a better structural part, yielding an aesthetic appearance. Parts with varying wall thicknesses can look distorted or incomplete, while uniformed wall thickness gives the part a more professional and seamless look. In addition, it can reduce manufacturing costs by eliminating the need for secondary operations like trimming, and overall reworking of parts.

Benefits of Maintaining Uniform Wall Thickness for Injection Molded Parts

Injection molding is the production of parts and accessories from plastic materials. This manufacturing process can mold large and intricate parts in various shapes and forms, as required in different industries. The most common injection molded components are made from polyethylene (PE), polypropylene (PP), acrylonitrile butadiene styrene (ABS), nylon (PA), polycarbonate (PC), NDPE, and polystyrene (PS).

Keeping a nominal, uniform wall thickness offers more advantages:

Resistance to Warping During the Cooling Process

During the injection molding process, the plastic material is melted, injected, and held under pressure in a mold, which is then cooled solidifying the material into the desired shape. If the cooling process is not managed correctly, different sections of the part will cool at different rates, causing warping or bending. This can result in substandard parts.

Uniform wall thickness helps reduce the risk of warping during the cooling process by ensuring that the plastic cools consistently throughout the part. This improves the accuracy of the critical dimensions of the part and ensures that it fits and functions as intended. Additionally, reducing the risk of warping can lessen the need for additional finishing processes or rework due to dimensional inaccuracies.

Strength and Durability

Uniform injection molding wall thickness increases the strength and durability of the component. The consistency also improves dimensional accuracy over time, resulting in better performance and longer usable life.

Improved Aesthetic Appearance

Parts with consistent wall thickness create a much more aesthetically pleasing appearance than parts with varying walls. This is especially important in consumer products or components where visual appeal plays an important role in the product’s success.

Overall Cost Savings

Since wall thickness uniformity helps reduce shrinkage and residual stress in the injection molded part, it lowers the required cycle time needed to mold an acceptable part, resulting in cost savings. In a design for manufacturing/assembly (DFM/DFA) review, Engineering will evaluate the part design for strength, and include various elements like ribs to reduce the overall amount of plastic needed. It also eliminates the need for additional finishing operations, such as sanding or painting, furthermore reducing production costs.

Guidelines for Determining Nominal Wall Thickness Uniformity

There are several guidelines manufacturers can follow to ensure uniform wall thickness in injection molded parts:

Use Accurate Tools for Nominal Thickness Measurement

Manufacturers should use specialized equipment to measure the wall thickness of their parts during production. It is also beneficial to adjust parameters as needed to ensure that all components have consistent wall thickness throughout the manufacturing process.

Adjust Cooling Parameters

It is crucial to carefully control the cooling process by adjusting temperature, pressure, and other parameters to prevent warping and reduce sinking. If the part has a wide range of thicknesses, it will cool at different rates which can lead to dimension changes.

Select the Appropriate Materials

Selecting the correct resin, based on the part requirements and environment, is crucial.

Maintain Quality Control Standards

Manufacturers should practice strict quality control standards and inspect parts before shipment. Doing so can ensure that all their products meet customer specifications.

Precision Plastic Injection Molding With D&M Plastics

Maintaining uniform wall thickness is important for ensuring the quality of injection molded components. It provides several advantages, including improved strength, durability, aesthetics, and reduced production and finishing costs.

With five decades of experience and expertise, D&M Plastics has an unwavering commitment to provide nothing less than the highest of standards to our clients. By following these guidelines and using the right tools and processes, manufacturers can achieve consistent wall thickness in their injection molded parts. This will produce higher-quality components with improved aesthetics and durability at a lower cost.

Why Is Uniform Wall Thickness for Injection Molded Parts Important?