Injection Molding Tips for Improving Quality

It takes a thorough discussion and evaluation of options to turn your customer’s idea into a reality. The professional team over at Wunder Mold showed what to consider, from resin, to surface design needed for appearance and functionality. For instance, while plastic injection molds are an efficient method of manufacturing plastic parts, there are various aspects to consider before opting for the right approach. This will ensure steady production and satisfied customers. These are some of the tips I picked up:

Surface Selection

Surfaces are not only significant for visual reasons but also because they reflect previous production decisions and material choices. In addition to choosing a material, the surface finish will also vary. Therefore, it is wise to decide the finish early in the planning process because it will influence the rest of the project.

Using texture to create undercuts and soften parting lines is also essential. Furthermore, the texture is relevant not only for aesthetics and style but also for practical purposes. The right grip is needed so that the paint sticks well to the surface, and it’s just as critical to allow for gas expulsion during the injection.

Level of Thickness

During the process, it is paramount to maintain a constant thickness level. Variations could negatively impact the flow. Generally, a 2-3mm stream should be sufficient, but a steady stream is difficult. The walls of most plastic appliances around your home are roughly 1mm-4mm thick which is the optimal thickness for molding. If you take apart any of these appliances, you will find that they are uniform in thickness.

Drafting Process

Parts are released from injection molds through drafting. Adapting the drafting angles correctly will ensure a steady flow without forcing them out and will also increase their lifespan. Molds with no texture should have a radius of 1 degree, while fully textured molds should have a radius of 3 degrees. The more draft you have, the easier it is to remove the part from the mold, but it also has a major impact on the quality of the parting lines and the utility of the tools when you are running fast injection molding operations.

Material Selection

Choosing the right resin requires consideration of several factors. To design a successful product, you must first consider its final use, the environment it will be exposed to, and its final use. Is it better to have a firm or an elastic part? Do you plan to expose it to extreme temperatures? Added safety to the equation is also imperative. There is no need to always go for the newest and most expensive option. Maintaining quality without increasing costs is critical. The smart idea is to present your idea to an experienced engineer who knows their materials and let them decide what material will work best for you.

Mold Flow

Simulate a constant flow during the design process to ensure the part is designed correctly. Quality production is enabled by a well-thought-out flow, similar to drafting. Several elements of the simulation can be adjusted, including the location of the gate, the allocation of water, and the layout of runners. The simulation’s complexity increases with the complexity of the part. Different materials flow into molds differently based on their properties. Flow-friendly plastics are polypropylene, K-Resin, HDPE, LDPE, and unfilled nylons.

Finishes and Coatings

These should be minimized as much as possible. The purpose of coatings and finishes is to reduce wear on surfaces by adding texture. Due to the complexity of finishes, they extend production time and also add costs. To ensure cost-effective production and sufficient quality, it’s vital to balance time, resources, and complexity.