What is Precision Molding? A Complete Guide

What is Precision Molding? A Complete Guide

What is Precision Molding? A Complete Guide

Today we discuss the rarely ever elaborated upon topic of precision molding.

Precision molding is a type of plastic injection molding that is the most expensive and sophisticated process of mold design in the market.

The process of precision molding is never used in the development of the entire product by the mold manufacturer. It is only used in the manufacturing process in small and infrequent occasions when product development calls for an unusually precise form of plastic injection molding.

How Does Precision Molding Work?

The process of molding plastic by cnc machining into an exceptional price and calculated shapes is known as polymer optics.

As the technology grows in precision and sophistication, the world needs more and more sophisticated processes for industries served to mold plastic into specific shapes that are used in specialized industries such as automotive, pharmaceutical, medical, information technology, and other industries served.

Here’s a little extra information about precision molding by molding consultants:

  • This process is advantageous because it is economically more viable.


  • The process is also a new and far enhanced solution to the optic issues that occur in the contract manufacturing of technical products and scientific molding.


  • The custom injection molding is not the appropriate method of developing optical parts that are needed in various high precision products. The precision injection molding process allows the producer to customize the process to meet the needs of the molding product.


  • The resulting research and development lead to Precision Injection Molding (PIM) technology that will allow the development of plastic equipment by the mold manufacturer at reasonable prices but with very high quality control and precision.


  • The polymer optic in the precision molding is the key to developing a high-quality product and gives the development process of plastics injection various unique edges.


  • They are ideal for large production of products at a low cost by the mold manufacturer. Before PIM, these products had to be developed manually by molding experts and molding consultants. Now, these products are developed on a large scale and are highly precise.


  • Integrated optical and mechanical functionality is a unique feature of the product that gives it precedence over the other custom injection molding processes.


  • Low weight designing is the main feature of the custom injection product. A low weight optical polymer has half the density of glass and it allows for the development of low weight designing. A low weight optical polymer will stay from 5-30 euros per kg and is much cheaper than its alternative.


  • The process does not require any additional steps and will always complete in one straightforward step. It means that the product is developed in lesser time and more accurately through contract manufacturing.


  • The cycle time of the process is lower than its counterparts. Thus the process becomes more suitable for mass production of molding materials.


  • The process also allows for production in any design or shape in the injection molder without any extra charges or cost.


  • Glass optics and precision optics through polymer are sometimes combined to enhance the precision building of the product as they allow for the development of high image quality control within reasonable costs.

Automation Potential:

The process is highly celebrated for its potential for automation processes.

The entire process is automated and is conducted through computers in every aspect through automation handling systems. The advanced process control allows for fluid and customizable manufacturing cells.

The process is conducted through cells that can also perform plastic injection molding, coating, testing and even packaging through the computer programing.

The mechanical functionality of the process is highly customizable where mechanical mounts such as lens mounts, snappers, and various other fixtures can be easily installed or removed as required.


Precision moulding is used in the development of a wide variety of products as stated earlier. But the technology truly revolutionized the development of lenses in various applications as it allowed for the contract manufacturing of glass free lenses that were cheaper and much stronger.

Glass lenses are highly delicate, harder to make, and expensive, but plastic optic lenses have truly revolutionized the optics industry.

Precise molding is used in the development and mass production of precise spherical, diffractive, freeform, aspheric and other types of lenses that are high-quality products and have perfect optical surface finishing.

Surface Specifications:

There are certain limitations to the utility of precision molding because of the manufacturing technology.

The polymer optical components allow for a diameter of the lens from 1mm to 100 mm and the lens thickness has to remain between 1 to 30 mm. The diameter to thickness ratio will remain between 1:1 to 5:1.

Tips and Tricks:

If you are opting for the precision molding process as a way to develop your product, then there are a few facts you should thoroughly understand and keep in mind.

Areas of Precision:

1. Tolerance Issues:

As stated earlier, precision molding is not done on the entire structure of the product but only the parts where scientific molding is required.

Precision molding is used when a product requires tight tolerance. Tight tolerance means that the requirements of the product have to be followed precisely and accurately otherwise the product may break in the injection molder.

If a part of the machinery breaks while the cnc machining is still moving then it could be dangerous. The parts that are the focus of this kind of pressure are developed through precision scientific molding.

These tolerances are, alternatively, achieved through injection molding, but precision custom injection molding is a better solution when developing these products.

Precision molding will only be applied to the parts that are connected with other parts so that they are fixed in the correct form. This means that you need to make sure that you understand the precision requirements of the product or you will end up wasting money on the wrong segment.

The development of the entire product in an injection molder through precision molding is too expensive and will be a waste of money in another sense.

The best solution is to enquire which parts of the product require precision molding and then conduct precision molding accordingly.

Usually, the product is developed through insert molding and upon complete development of the product, the parts that require precision molding are molded accordingly.

The required tolerance is achieved through precision molding.

2. Materials:

The molding materials that is used for precision moulding is different from other materials.

The process of precision molding can cause shrinkage in the plastic. If the molding materials have a high shrinkage capacity than the material will shrink while undergoing the process and the entire product will be ruined.

A common plastic polymer, polyethylene, has a high shrinkage range of +/- .014″ to +/- .022. This is a commonly used polymer in plastic product manufacturing.

In precision molding, using this polymer will certainly affect the quality control of the developed product. A decent replacement for polyethylene is Acrylonitrile Butadiene Styrene (ABS).

ABS is a thermoplastic polymer, which means it is can retain its elasticity through high temperatures. It has a reduced shrinkage of =/-.006. It is still considered not appropriate for precision molding, which usually requires a shrinkage of +/-002.

This shrinkage capacity is usually achieved through the addition of glass or another resin that is mixed with the plastic. The external material keeps the plastic in its place and absorbs the excessive heat, thereby reducing shrinkage.

It should be noted that the induction of this material into the product does not ensure that the product will not shrink. The resulting product will shrink in parallel to the induced resin.

Now that the product has more structure, shrinkage can be taken into account and a product development plan can be developed that will keep the product straight.

3. Technique:

The process of precision molding requires that every piece of the product is developed identically and will be attached in an identical manner.

If a product is not identical to the mold design then the precision product will also not be accurate. A precise mold is the only way to ensure that there is no change in the design in any way.

When you are in need of a precision molded product, make sure that the manufacturer understands this aspect of development.

Precision molding is a slow and steady process that requires time and focus. Do not choose a manufacturer who specializes in rapid tooling, as they are not too familiar with the precision molding process. The rapid tooling process finishes the mold design quickly.

This is the main idea of precision tooling and we hope to have covered all the basics.

There is not much information on the process available online so we decided to present the process through our experience.

If you ever require a precision modelling process for your products, it is best to truly understand the mechanics of the process as best as you can.

If the manufacturer can see that you know what you are talking about, they will be more motivated to deliver the product that you asked for.

We are the best precision molding consultants in Malaysia. Call now and get a quote!

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