Why is injection moulding good for mass production?

Table of Contents

Overall, the main advantage of injection molding is the ability to produce the same plastic parts in large quantities, usually thousands or even millions of times on a formal production scale.

Once the advanced injection machines and molds are ready, the price per product during production is very low, and as more parts are produced, the price drops dramatically and can be as low as 0.001USD per product, making it suitable for high volume production.

What is injection molding?

Injection molding is a method in which completely molten plastic material is stirred by a screw at a certain temperature, injected into the mold cavity with high pressure, and cured by cooling to obtain molded products.

This method is suitable for the mass production of complex-shaped parts and is one of the important processing methods.

Why use injection molding?

1. High-efficiency

Mass production using the injection molding process can achieve higher processing efficiency, once the user has chosen a specific high volume manufacturing method, the plastic molding process does not take long, enabling mass production and improving product quality.

2. High strength in plastic materials

The use of glass fiber additives is very common, these highly engineered composite plastics are highly durable and can meet the characteristics and functions required by different products.

Most importantly, the density of the plastic is high when it is first molded, and this is when plastic injection molding can provide flexibility that other molding processes cannot provide.

3. Low-cost injection molds offer impressive surface finishes

While also withstanding high pressures and featuring good product quality and a detailed, superb appearance.

So injection molding can provide excellent detailing of molded parts and save time and cost on secondary processing.

4. Injection molding is a highly repeatable process

Injection molding is a highly repeatable process, that is, the second part of production will be exactly the same as the first part, which can be well controlled for product consistency and component reliability in mass production.

History of Injection Molding

In 1872, American inventor JohnWesley Hyatt, together with his brother Isaiah, patented the first injection molding machine.

The machine was relatively simple compared to those currently in use: it resembled a giant hypodermic needle and used a plunger to inject plastic into a mold through a heated cylinder.

The industry developed slowly in the late 19th century, producing products such as collars, buttons, and hair combs.

In 1903, German chemists Arthur Eichengrün and Theodore Becker invented the first soluble polymer, cellulose acetate, which was more flammable than cellulose nitrate.

It was eventually offered in powder form and was easier to injection mold.

In 1919, Arthur Eichengrün developed the first injection molding machine in the true sense of the word.

In 1939, Arthur Eichengrün received a patent for plasticized acetate injection molding. Injection molding then expanded rapidly in the 1940s, as World War II created a huge demand for cheap, mass-produced products.

In 1946, American inventor James Watson Hendry built the first screw injection molding machine that allowed for more precise control of injection speed and product quality.

This machine also allowed the material to be mixed before injection, allowing pigments to be added to the plastic material and thoroughly mixed before injection.

In the 1970s, Hendry developed the first gas-assisted injection molding process that could produce complex, hollow products that cooled quickly.

This greatly improved design flexibility as well as the strength and finish of manufactured parts, while reducing production time, cost, weight, and waste.

The plastic injection molding industry has evolved over the years from producing combs and buttons to producing a wide range of products for many industries including automotive, medical, aerospace, consumer products, toys, plumbing, packaging, and construction.

Injection molded products can be seen in many industries, especially in automotive, industrial, and household products.

Advantages of injection molding

1. Suitable for producing complex and precise products

One of the main advantages of plastic injection molding technology is the ease with which complex plastic precision parts and assemblies can be designed.

Compared to other techniques, injection molding will be found to feature very small tolerances.

For this reason, it is also widely used for the production of automotive parts.

2. Freedom to choose from a wide range of materials

There are a large number of plastic materials available for the plastic injection molding process.

There are materials such as antistatic plastics, thermoplastic rubber, chemical resistant plastics, and bio-compostable materials with color matching or masterbatch coloring. 

3. Automated process to reduce manufacturing costs

Injection molding is an automated process. One operator can often manage two or more injection molding machines, especially if the plastic injection molded parts can be unloaded automatically, so the labor required is relatively low.

Most injection molding processes are performed using machines and robots. Since automation reduces molding manufacturing costs, overhead costs are also reduced.

Also, with the reduction in labor, the total cost of manufacturing the product is reduced.

4. Highly efficient production method

Around the industry, most molding professionals agree that there are fundamental design elements that must occur during the injection process to work correctly.

They include wall thickness, rib design, boss design, corner transitions, weld lines, gate placement, and properly placed vents are designed.

Once the injection mold according to the specifications given by the customer and the injection moulding machine is pre-programmed, the actual moulding process used to produce the part becomes very fast.

The entire molding process of closing, charging, plasticizing, injecting, opening, and unmolding is all done by the action of injection moulding, thus injection moulding manufacturing process easy to fully automate and realize program control.

As a result, more products can be produced from a single mold. High productivity makes plastic injection molding service efficient and cost-effective as well.

5. Produce less waste and go green

For injection molding, the repeatability factor of parts is very high. The scrap produced during the molding process can be reused, so there is very little waste of raw materials when injection molding.


From this article, we have learned why injection molding is suitable for high volume production, and as the quantity increases, the unit price of the product drops dramatically.

If you have a large volume of plastic products to make, consider this plastic parts manufacturing process.

Of course, it takes a long time for each plastic product to increase from development to market demand.

In the early stage of development, if the number of products is not too sure, you can choose a single cavity injection mold, so that the mold price will be lower and the product price is relatively higher.

Once the number of products increases dramatically, you can consider multi-cavity injection molds, which will not only reduce the mass production processes cost of products but also greatly improve the production efficiency to quickly meet the market demand.

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