Choosing the right plastic injection moulding company for your project

Most industries use plastic injection moulding as plastic components and custom moulds are highly versatile, and they can be designed to the client’s exact specifications. With this technology, EMS (electronics manufacturing services) providers work with companies from different industries to create specific, high-quality products.

However, for the final product to have the proper functionality, customers must work closely with their EMS provider to ensure that the plastic injection moulding tool has the correct specifications. A lack of communication between the two parties can lead to costing issues, delays in time to market, or even product recalls. 

Several considerations should be discussed before starting a plastic injection moulding project. Doing so will ensure it runs smoothly and that the final product is a success.

Provide a full data package

Understandably, customers want to get their product to market quickly, but it's important to remember that rushing the process could ultimately lead to higher costs. For the manufacturer, having complete information before stating the project is the most critical contributor to its success.

For example, before the manufacturer can submit an accurate quote, the customer must provide them will the tooling file, the 3D file, and the CAD file. Without this information, mistakes could be made, ultimately leading to a less successful outcome.

Moreover, providing a full data package and the complete requirements leads to a more accurate lead time for tools. If this is done, the manufacturer can quote a realistic lead time. Without it, the EMS provider might be forced to provide a 'standard' lead time which is then subject to change while they wait for more information—inefficient for both the EMS provider and their OEM (original equipment manufacturer) customer. 

Communication is key

Mistakes are made when there is a lack of communication in any relationship—especially one with as many moving parts as the OEM/ EMS relationship. 

The right balance is when the EMS provider asks the right questions and the customer provides the correct information. If this happens, the manufacturer will be able to get the best tool steel for the project, which can always be upgraded later to extend its lifecycle even further. However, a lack of communication could lead to the project beginning with low-grade steel, which will produce a suboptimal final product. 

Also, communicating requirements as soon as possible is the best way to get the most detailed quote, which will likely pave the way for a smooth relationship and successful project. Invest the time in the beginning, and you will save time in the future. 

Identify the yearly volume of the part to be produced

In addition to the right tooling files, to help choose the correct tool, the manufacturer needs information on the expected product lifecycle as well as expected yearly volumes. This will help them decide which injection moulding tool to purchase. 

If the volumes are high enough, they might decide to get an upgraded tool to maximise its lifecycle. However, if the customer is unsure about their expected product volumes, the most prudent course of action might be to purchase a cheaper tool that will produce a lower volume. There is always the option of purchasing another tool if product volumes increase. 

Consider the lifecycle of the plastic injection tool machine

The yearly volume of the part to be produced is directly related to the lifecycle of the plastic injection moulding tool, which will wear over time. How long the tool machine will last is an important consideration and is affected by the following considerations: 

What material the mould is made of: Soft aluminium moulds will wear far quicker from the plastic material compared to steel moulds, which will, generally, last for millions of shots. 

What material the mouldings are made of: Glass-filled nylon, for example, is abrasive and will cause quicker wear. However, other materials are corrosive and will rust normal steel moulds. In this case, aluminium alloy or stainless steel moulds would make a logical alternative, despite the quicker wear, the yearly volume will determine the final steel choice. 

Choose the right resin

Understanding what the final part will be used for dictates the type of resin that should be used. For example, parts that must endure high temperatures over long periods must use appropriate plastic.

Different resins are also suited to specific applications, including chemical exposure, resistance to low temperatures, or use in food and pharmaceuticals. Whether the part is mechanical or electrical is also an important issue.

OEMs and their EMS partner must discuss the purpose of the part to decide upon the appropriate resin to be used. The more information about the part, the more chance that the correct resin will be chosen. For example, if the plastic is designed to hold a liquid, what is the exact type of liquid? 

Here are questions that should be asked about the use of the part: 

  • As part of the manufacturing process, what treatments or processes will the part be exposed to before it is used?
  • What chemicals will the part be exposed to, and in what environmental conditions?
  • In terms of product design, will the final part be embedded within another material, such as a metal component within plastic?
  • Will the part have any wear and tear or be put under any temperature stress?
  • What weight will the part be exposed to, or will it need to withstand the weight of any other objects?
  • Is the appearance of the finished part significant to the project as a whole? Some resins are matte in appearance, while others produce a glossy finish.

The type of resin chosen based on the requirements of the part also has an effect on the type of steel to be chosen for the plastic injection moulding tool. For example, if the resin contains any fibre filler, it is best not to use a cheaper steel grade—a soft or prehardened tool—as there will be extensive wear and tear of the steel. An exception to this may be if the customer only wants a relatively low number of units produced (around 1,000 a year).

If the OEM and their EMS partner understand what the part does and choose the right resin, there is more chance that the customer will be given the correct lead time and price. Starting with a suitable resin will also save money as it will not be necessary to change the prototype and start again.


Before starting a plastic injection moulding project, both the OEM and their EMS provider need to know that they are starting at the right point. Understanding critical issues that could go wrong and addressing them before the project has started will result in reduced costs, a faster time to market, and a successful project.

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Written by Martin Gram

Based in Johor Bahru, Martin brings a wealth of technical and leadership experience to ESCATEC. Known for his adept management of advanced manufacturing technologies across diverse cultures, Martin is an expert in high precision plastic injection moulding across a wide range of market sectors, including medical, industrial, transportation and luxury consumer goods.