Plastic Design

Plastic Design

Plastic design involves a number of complex variables.plastic design & manufacturing These variables must be balanced to produce a part that will perform and look good in its final form. Designing a part for manufacturing requires compromises between the mechanical, thermal and electrical requirements of the product and the limitations of the injection molding process. Plastic designers must learn as much as possible about a variety of different plastic materials and their processing characteristics to achieve the optimum cost/performance ratio.

Plastic parts are usually designed to withstand many types of environmental conditions.plastic design & manufacturing This includes exposure to sunlight, moisture, temperature extremes and chemical or corrosive substances. Parts must also be able to withstand the stresses of assembly and transportation. Injection molders and plastic engineers know how to design a product for manufacturing while taking into account the limitations of the molding process. Plastic design is a process that requires a combination of skills and knowledge, which can only be gained with years of experience in the industry.

Uniform wall thickness is a critical component of successful plastic designs.plastic design & manufacturing A lack of uniformity in wall thickness may result in warping, sink marks or other defects in the final product. Thinner areas of the part may melt and cool more quickly than thicker areas, leading to inconsistent material flow. Depending on the plastic used, uneven wall thickness may also increase production costs or reduce strength and rigidity.

Another important consideration is how the ejector pins, which are used to release plastic parts from the mold, are located within the mold.plastic design & manufacturing This is important because ejector pin placement can affect how the plastic parts are molded and can cause surface indentations and marks in the finished part. Plastic manufacturers can save a great deal of time and money by planning ahead and determining how the ejector pins will be placed in the plastic part before it is designed.

Sharp transitions and corners are a common source of stress concentration in plastic parts, which can eventually lead to cracking and failure under load or impact.plastic design & manufacturing Rounding these corners to generous radii not only improves appearance, but also facilitates smoother flow of the plastic during molding and easier ejection of the finished product. It is generally recommended that the radii be equal to or greater than the plastic’s yield strength.

The use of ribs and bosses can greatly improve the structural integrity of a plastic part while reducing production costs. These features add structure to the plastic and also help keep the wall thickness in a desired range, allowing the plastic to shrink during cooling without losing its shape. However, ribs and bosses must be carefully planned so as not to create “knit lines” where the plastic flows around a feature and welds to the adjacent areas. Knit lines are a result of the two different plastic flows colliding and sticking together, and they can be weaker than the surrounding parts. This is particularly important for high-pressure applications where the ribs must resist pressure from other components or from the tooling.

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