In many areas, tools like injection molding are used to produce parts such as compression springs. This method isn't limited to simple applications, it's also used in large-scale manufacturing. This article focuses on using injection molding to create plastic compression springs, which can replace traditional metal springs in some cases. Plastic springs weigh less than metal ones, making them a valid option if the weight is a significant factor in your design. You will learn about the technical details, from how to calculate deflection in plastic springs to understanding the key steps in the injection molding process. This information will help you apply this method in your spring manufacturing activities.

Calculating Deflection in Plastic Compression Springs

Deflection in plastic compression springs refers to the measurable vertical displacement seen when the spring experiences applied pressure. The value of deflection is beneficial to discern the response of the spring to a specific force, a factor that informs the steps taken in designing and manufacture.

Utilize the formula D= F/k to compute deflection in a compression spring. Letters D, F, and k in this formula correspond to deflection, applied force on the spring, and spring constant respectively. The last mentioned, the spring constant, measures the stiffness of the spring and is typically denoted in units like pounds per inch or newtons per meter. To provide an illustration, a compression spring with a constant value of 10 pounds per inch, when subjected to a 20 pound-force, yields a deflection value of 2 inches.

Plastic springs exhibit a lower modulus of elasticity in comparison to metallic springs, resulting in higher deflection when subjected to identical force. Exploiting this difference in material properties, an engineering design incorporated a plastic spring that was lighter and flexible in fulfilling the requirements of a specific application. Hence, comprehensive knowledge of these properties facilitates tailoring spring designs to meet the demands of its intended use.

Differences Between Traditional and Injection Molded Springs

Requirements for the Injection Molding Process


Through understanding the deflection calculations and the differences between traditional and injection molded springs, your design skillset has grown. Correct application of requirements for injection molding can save production costs. Learning to work with injection molded compression springs may initially seem complex, but with practice and guidance, it will become a regular part of your work. Being proficient with these springs is beneficial as they can improve the functionality and affordability of the products you design.