Why Companies Outsource Injection Molding to China!

Business is all about cutting costs. There is always a search for ways to save money and increase profits in every business, regardless of its size. The most common method of doing this today is outsourcing.

Increasingly, companies are outsourcing their manufacturing to Chinese factories due to their fast pace, efficiency, and low prices. The production they need at the price they can afford has even been outsourced to China by American companies.

Injection molding costs in China

Compared to other countries, China has lower labor and raw material costs, which is one of the reasons companies outsource injection molding to them. Profitability can be increased by reducing production costs.

Companies specializing in high volume production and seeking cost savings are particularly likely to benefit from this. China’s large population also means that there is a readily available workforce that can meet the needs of your company. This can help reduce training costs and increase productivity.

Quality by China suppliers

Many Chinese companies have invested in advanced manufacturing equipment and have trained their employees in the latest manufacturing techniques, which can help to improve the quality of their products. China has also invested heavily in research and development, which means that many Chinese companies have access to advanced technologies that can help them produce more innovative products. This is especially true for companies who specialize in high tech manufacturing such as aerospace, electronics and medical equipment.

Capacity of Injection molding

China has a well-developed manufacturing sector- with a large pool of skilled labor. This can increase capacity and meet demand for mass production. In recent years, China has made an effort to improve its labor force . This has led to more skilled workers entering the workforce, which can boost productivity.

China also has a large number of universities and technical colleges that produce graduates in engineering and science-related fields ,such as engineering,material,aerospace or electronics manufacturing.

Lead times:

Outsourcing to China can often lead to shorter lead times compared to domestic manufacturing, thanks to the well-developed infrastructure and the fact that China is located closer to many of the major markets in Asia.

The speed of the Chinese manufacturing process is also important; many Chinese factories can turn around products in just a few weeks. This can be particularly helpful for businesses looking to launch new products or introduce seasonal lines, ensuring sufficient supply before the release date.

Experience of China injection molding industry:

Chinese suppliers boast abundant expertise in the manufacturing sector, presenting a comprehensive array of services including design, prototyping, mold creation, injection molding, and assembly. Their hands-on experience is particularly valuable to novice companies seeking a factory that can provide direction. Furthermore, numerous Chinese suppliers possess established connections with local providers, enabling them to connect clients with specialized factories for services like packaging and shipping.

Here’s a step-by-step guide on the injection molding process:

  1. Design the mold: This involves creating a 3D model(design softwares:solidworks,ug,pro-e…) of the product and mold, taking into account factors such as material(PP,PE,ABS,PA…), wall thickness, gate size, and cooling time.
  2. Fabricate the mold: The mold is usually made of steel or aluminum and must be fabricated to precise specifications. A list of plastic mold steels with hardness:
    • P20 Steel – 28-32 HRc
    • 420 Steel – 48-52 HRc
    • H13 Steel – 48-52 HRc
    • S7 Steel – 45-49 HRc
    • NAK55 Steel – 50-55 HRc
    • NAK80 Steel – 38-43 HRc
    • DC53 Steel – 50-58 HRc
    • A2 Steel – 60-64 HRc
    • D2 Steel – 60-64 HRc
    • Note: HRc refers to the Rockwell hardness scale, which measures the hardness of a material.
  3. Install the mold: The mold is mounted onto the injection molding machine and clamped between 2 plates on the machine.
  4. Load the plastic material: The plastic material is loaded into the hopper of the injection molding machine via gravity and some hopper would try the plastic material while the injection molding is on.
  5. Melt the plastic: The plastic material is melted by heat and pressure within the barrel of the injection molding machine.
  6. Inject the plastic into the mold: The melted plastic run into the mold via nozzle and sprue under high pressure, and go thru runner,gate then fill the mold cavities.
  7. Cool and solidify: The mold is cooled to allow the plastic to solidify inside the mold cavity for a while,and most of time,the cooling time would be 2/3 of whole cycle period.
  8. Open the mold: The mold is opened and the molded product is removed from the mold,then the mold close and the next cycle begins.

Necessary tools and materials: Injection molding machine, mold, plastic material, drying machine,temperaturer controller(for very high and very cold demands for injection molding)

The molded part can suffer from various issues including excess material at the edges (Flash), which can result in a weakened structure. Warping or distortion can occur when the molded part doesn’t keep its shape or size due to uneven cooling. Black spots on the molded part are a result of poor material processing or contamination. Poor surface finish, characterized by uneven texture or roughness, may be caused by improper mold design or material selection. Sink marks, indentations in the molded part, can be caused by improper filling of the mold or insufficient pressure during molding. Additionally, the molded part may become difficult to eject, leading to production downtime and increased costs, or it may become damaged during ejection.

The importance of safety measures cannot be overstated in the injection molding process. To prevent injury, workers must utilize protective equipment such as gloves and safety glasses as the melted plastic reaches extremely high temperatures, sometimes up to 300 degrees, and has the potential to splatter. It is crucial for operators to receive proper training on safe operating procedures.


It is important to carefully consider all the factors involved in outsourcing to China, including logistics, shipping costs, and the potential impact on your supply chain.

Working with a reputable and experienced sourcing partner can also help to ensure a smooth and successful outsourcing experience.