5 Things to Know Before Buying automotive injection molding

07, Apr. 2025

 

5 Factors to Consider When Buying Plastic Injection Molding ...

As many of us in the machine industry are aware, Plastic Injection Molding is just as relevant and important as any other machining process. There are many things to consider when considering purchasing plastic injection molding equipment, such as: Shot Size, Tie Bar Spacing, Ejector Stroke, Platen Size, and Tonnage.

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Shot Size

Shot size is best defined as the maximum amount of plastic that the injection molding machinery is capable of injecting into the molding cavity during one molding cycle. The amount is rated in ounces of “general purpose polystyrene” (GPPS) for U.S. machines, and cm3 for European and Asian machines.

When searching for a machine, it's always a best practice to look for a machine that is capable of producing 30-40% greater shot sizes than what your parts require.

Tonnage

In this case, I mean “clamp tonnage or clamping pressure.” This could be considered the same concept as when you're examining press brakes. With press brakes, tonnage capabilities are measured by how many tons of downforce the machine is capable of directing towards a workpiece. However, with plastic injection molding machines, tonnage is measured by how many tons with which the machine is capable of pressing together the platens, which hold the mold cavity and form the plastic that is injected into said cavity to produce the desired part.

Platen Size

The platen is the "table" or tool that holds the mold cavity. Spaced apart, the mold is inserted and clamped securely to the platens. Once the two platens come together and are held under the pressure of tonnage, the plastic is heated, injected under pressure, and then allowed to cool through a molding cooling cycle. Here, the plastic takes on its hardened, final shape while continuing to be kept in place with many tons of pressure to retain the desired shape.

Tie Bar Spacing

Tie Bar Spacing is defined as the space between the horizontal tie-bars on an injection molding machine. Basically, this measurement, along with the platen max spacing, determines the maximum size of molds that can be placed in the molding machine.

Ejector Stroke

Simply put, Ejector Stroke is the action of the machine pushing out (ejecting) the final workpiece from the platens using ejector pins. The ejector in the molding machine pushes against an ejector plate on the mold, Ejector "Pins" or rods are attached to this plate and perform a pushing operation on the molded part after the plastic has hardened and the mold has opened.

Once the action of molding the workpiece is completed, the mold opens and then the ejector pins slowly extend outwards, pushing (or ejecting) the finished part out of the mold cavity. Pin movement is timed with the mold opening—because pins that move too quickly could impact the plastic workpiece and damage the final product and pins that move too slowly may not fully eject the molded part.

Automotive Injection Molding: Everything You Need to Know

Did you know the worldwide injection molding automotive industry was estimated to be worth $261.8 billion in ?

Automotive companies need a reliable and cost-effective way to mass-produce plastic parts.

Traditional methods of production are expensive, time-consuming, and often unreliable. You need a solution that can keep up with the demands of your business without breaking the bank.

Automotive injection molding is the answer! This process offers an efficient and cost-effective way to produce large quantities of high-quality plastic parts quickly and reliably. Keep reading because, in this article, we’ll cover everything you need to know about automotive injection molding so you can make an informed decision for your business.

What Is Automotive Injection Molding?

Automotive injection molding is a manufacturing process that uses a high-pressure plastic injection to form a variety of automotive parts, such as body panels, interior components, and engine parts. It is one of the most commonly used processes for mass-producing plastic parts because it can produce large quantities quickly and cost-effectively.

Injection molding is used in both the automotive OEM (Original Equipment Manufacturer) and aftermarket sectors.

Automotive injection molding involves melting plastic resin and injecting it into a precision-machined mold at high pressure. Once inside the mold, the plastic is then cooled and solidified to form durable parts with complex shapes and intricate details. Automotive injection molded parts are often made from polypropylene, ABS, nylon, or other specialized plastics.

Benefits of Injection Molding

Now that you know what automotive injection molding is, let’s take a look at some of the advantages of using injection molding materials:

1. Cost-effectiveness

Injection molding is one of the most widely used manufacturing processes in the automotive industry, and for good reason. Its cost-effectiveness is highly attractive for businesses because production rates with injection molding are often much faster than other methods.

Additionally, injection molding also results in significantly lower material wastage, meaning that companies can save even more money while producing high-quality parts and components. By investing in injection molding machinery, automotive companies can capitalize on these benefits to get ahead of their competitors.

2. Speed

Making things quickly has always been important. Injection molding is a way to make parts using automated machines and computers. This method is fast and efficient and it reduces the amount of time it takes to make the parts.

This not only helps to increase productivity but also allows companies to keep costs low, something that is essential in today’s competitive market.

3. Quality

Quality assurance is critical in today’s automotive industry, and injection molded parts provide the consistently high quality that manufacturers need to achieve superior results. By using precision injection molding techniques, all parts are created with uniform thickness, meaning that there are no structural deficiencies that could cause problems down the line.

In addition, the close tolerances of these techniques make sure that parts meet or exceed industry standards. This ensures repeatable performance with every part while delivering the dependability carmakers depend on.

4. Durability

It is important to think about how long a material will last when you are choosing it for automotive injection molding. Plastics such as ABS and polypropylene are strong and will last a long time, even in harsh conditions like in cars.

Plastic parts are strong and can handle different temperatures. They don’t break easily and last a long time. This makes cars better and helps them last longer.

5. Design Flexibility

Injection molding also allows for greater design freedom than traditional manufacturing methods. Automotive companies can now experiment with the size and shape of various components, making formerly impossible designs a reality.

Car manufacturers can use 3D printing to make parts for cars. These parts are usually more complicated than parts made using traditional methods. This allows car manufacturers to make one-of-a-kind cars that will get people’s attention when they see it driving on the road.

6. Versatility

Automotive injection molding offers an unmatched level of versatility when it comes to manufacturing parts for various vehicles. You can use it to produce components and fixtures for classic cars, coupes, sedans, boats, airplanes, and more.

There are lots of things that can you can make using injection-molding technology. For example, exterior features like grilles, bumper covers, and wheel flares. Plus, you can create whole interior design systems can using this technique too. This makes it easier for automakers to produce vehicles more efficiently.

Automotive injection molding is a process that you can use to create car parts. This process is essential for manufacturing vehicles.

How Injection Molding Automotive Works

The Automotive injection molding process is well known, offering many benefits to car manufacturers. Let’s delve into the details of just how this process works. The first step is to create a virtual model of the desired part using CAD software, which is then used to produce a mold for injecting molten material.

This material is then injected into the mold at high pressure and cooled until it solidifies. Finally, specialized machines are used to eject and collect the parts, enabling them to be sent for assembly or further finishing processes. With these simple steps, it’s no wonder that automotive injection molding has become such an important asset in creating efficient manufacturing methods.

Ready to Try Injection Molding?

In conclusion, automotive injection molding automotive is an effective way to mass-produce plastic parts for your automotive company. With the right materials and equipment, you can create high-quality components that are cost-effective and efficient.