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A Complete Guide to Precision Molded Plastic

December 23, 2020

Introduction to Precision Molded Plastic

With the technological advancements in injection molding industries, precision molded plastic parts are the leading innovation. Precision molding is a modern process of molding plastic, recognized as an expensive method in mold designing.

Although, the plastic injection molding companies do not use the process of precision molding to develop the entire plastic product. However, they infrequently use plastic injection molding during the manufacturing process. For example, when product development requires the plastic injection molding in an oddly precise form.

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Injection Molding

Manufacturers produce precision molded plastic parts through the process of Injection Molding.  The process involves heating molted materials and inserting them in a mold. Then it is cooled to obtain the molded plastic. Industries normally use it for complex molds or for high-volume production.

precision molded plastic

As discussed earlier, precision injection molding is a highly specialized process that is crucial to the availability of precision machines and molds. It differs from conventional injection molding techniques.  Industries use the plastic made through this process to serve as a substitute for metal parts. The injection mold determines the precision of the plastic part and if the quality fulfills the engineering design demands.

Injection Molding – its origin and History.

John Wesley Hyatt, an American inventor, and his brother Isaiah patented the original injection molding machine in 1872. The first machine was comparably simpler than the ones used nowadays. However, it worked efficiently just like a hypodermic needle. It injected plastic into the molds through a plunger. Since then, the industry began expanding, offering products such as hair combs and buttons in its line of production.

A Jewish German Chemist known as Arthur Eichengruin invented the original injection molding press in 1919. After that, the injection molding industry rapidly grew in the 1940s, mainly during World War II.

Consequently, it increased the demand for inexpensive and mass-produced products. in 1946, James Watson Hendry invented the first screw machine. It helped to improve the injection's precision speed and control, as well as the entire production quality. Furthermore, the materials were able to be combined before being injected into molds.

Hence, it enabled the proper mixing of colored and recycled plastic products to virgin materials before being injected. Hendry also developed the process of gas-assisted injection molding. The process allowed the production of modern pieces that rapidly cooled off. It consequently increased flexibility, reduced production time, the weight and cost of plastic parts. By the year 1979, steel production had surrendered to plastic production.

As the years passed by, the plastic injection molding industry rapidly evolved. It emerged with the production of buttons and combs to producing a wide array of products for industries like automotive, toys, consumer products, pharmaceutical, and many other industries.

The precision of injection molds

The precision of a mold depends on multiple factors, including the following;

  • Material choice.
  • The number of mold design cavities.
  • Proper cavity positioning.
  • The precision mold material used.
  • Engineering and Design.
  • The bottom plate thickness.
  • The precision in cavity size of the mold.
  • Precision mold material.
  • Size of the runner.


How does the process of Precision plastic molding work?

The computer numerical control machine or CNC molds the plastic into specific shapes and sizes at a reasonable cost. This method of plastic molding is known as polymer optics.

With technological growth, the world needs refined processes to serve the industries that use precision molded plastics.

Let us look at some more precision molding guidelines:

  • Previously, consultants and experts created molds manually. But as of now, production is far-and-wide, inexpensive, and highly precise. Thus, perfect for mass-production.
  • Industries find the precision molding process cost-effective, reliable, and practical.
  • The run time of the process is reduced compared to its counterparts.
  • Low weight design is the main attribute. A lighter weight optical polymer facilitates the production of less weight designing since the glass density is half. Furthermore, making it an inexpensive option.
  • Precision injection molding uses polymer optics. It plays a pivotal role in providing various benefits to the production of the plastic injection process to manufacture good quality and high precision molds.
  • For product building precision, industries need to apply a combination of precision optics and glass optics. It also generates an economical yet high image quality control.
  • It allows to creation of plastic parts in all shapes and sizes without the incurrence of any additional costs.
  • The plastic parts are produced precisely and in a lesser time as it does not require extra steps to be followed.



The tools used to produce plastic parts are commonly known as a die or mold. Since manufacturing is expensive, mass-production is ideal.

The material selection of mold depends on product cost. The cost of steel molds is comparably higher than others, but in the long run, their durability and long-life nullifies the price tag. The types of molds are;

  • Pre-hardened steel
  • Hardened steel
  • Aluminum
  • Beryllium-copper

The production of low-scale and large molded parts call for pre-hardened steel molds. On the contrary, manufacturers use hardened steel molds for special products requiring better resistance and longer life spans. Aluminum molds are economical. Use of aluminum is required in computerized equipment such as aircrafts and helicopters. However, the application of beryllium copper ensures the molds cool-off rapidly.


Application – How Industries use Molded Plastics?

Industries make the best use of precision molded plastics in a variety of areas such as in the making of; storage bins and cartons, packaging of different food items, combs, and hairbrushes, bottles, children toys, table, and chairs, toiletries, and many other daily-use products. Some of the advantages associated with the application of molded plastics are; high-volume production helps in cost reduction, ease in production of repeated articles, minimal waste, precision molded plastics, quality, decreased labor cost, and precision tolerance.

We briefly discussed the uses of molded plastics. Now, we will see examples of how it applies to industrial applications.

Construction Industry

Businesses all over the world have been using precision molded plastic parts in their industrial applications. The construction industry uses it to produce inexpensive building parts and materials.

The construction industries use injection molding for the following reasons;

  • It is lightweight.
  • Cheaper than wood and metal.
  • Material durability.
  • Recyclable materials.

Food and Beverage

The food and beverage industry uses injection molding to comply with FDA regulations. Hence, they produce non-toxic plastic products, having food grade, and are BPA-free.

precision molded plastic

Mold manufacturer selection

The production of high-quality molded products also depends on the selection of the right manufacturer. The usage of high-precision tools and molds ensures the precision of molded plastic parts. Therefore, industries need to select a manufacturer specializing in the relevant area.

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