Plastic Vs Metal: Why plastics are replacing metals in industries

Those who work in the manufacturing industry might be aware of metal to plastic conversion nowadays. It was all started with the automotive industries and now every industry is following the same path. Plastic offers a chunk of benefits over metals and industries has numerous reason to move to plastic. In this article, we will try to figure out why the industry trend is moving towards using more plastic than metals, how it is benefiting the industry, and what could be the drawbacks.

It’s true there are certain applications where plastic cannot be used like automotive engines, but still, plastic is getting used in many critical applications where we never thought that plastic can be used. More than 60% of automotive parts are now made in plastics. The same goes with other industries as well. Aircraft industries use more plastic compared to metal due to less weight. One of the best parts of using plastic is that it can combine many metal parts into one. For that reason, industries that have a problem with inventory management will get benefited from using plastic parts.

Why plastics are replacing metals in industries

Below are certain benefits and drawbacks that plastic has to offer.

1.Design Flexibility

Many metal parts cannot be fabricated just because it is to complex. Even if it can be fabricated but the cost would be too high which sometimes does make sense compare to the benefit that you expecting. Thankfully plastic offers a great level of flexibility and you are free to mold almost anything. There is numerous plastic molding method available nowadays. So no matter how complex your part is, it can be molded and it is way cheaper than fabricating the same in metals.
If you are looking for parts that have to offer good aesthetics, plastic is the way you have to go. In metals, to get the same aesthetic you might need to go for powder coating or paint. But in plastic, you don’t need anything. While molding itself you can choose the color resin. Also, those colors don’t get faded over time.

2.Cheap to manufacture

A part made in plastic can save over 40% cost against metals. It’s true that the initial tooling cost for plastic is high but the recurring cost for a part made in plastic is low. Since plastic can be molded into complex shapes so the cost-saving is more when compared to metals. You can also save costs from storing plastics. Since plastics are stored in pallets and weight is very less, so storing is very easy as it takes less amount of space.

3. Plastic is durable

Some people have an opinion that plastic is weak and prone to break. But that’s not the fact. In fact, plastic is more durable than metals in many applications. Metals are usually brittle and are prone to break or crack under impacts. On the other hand, plastic can take more impact load and under extreme load, it can just deform. Thankfully that deformation is also temporary as you can bring back the actual shape easily. You might notice that the car bumper is made of plastic. Have you wondered why? It’s because it has more impacts. And under impacts, it gets dented but the same dent can be repaired at a very cheap price. Right? Just think how much you usually pay for a dent in door panels which is made of metals.

It’s a fact that virgin plastic does not offer much durability or strength. But you will hardly find applications where virgin plastics are used. Most of the time multiple polymers are used to mold a part. On top of that, if you are some additives, it becomes more strong. Have you ever noticed that most of the ride car in amusement parts are made of plastics? They use glass fiber with plastic to creates those cars which is much stronger than metals.

4. Plastic is recyclable

Meals parts cannot be recycled and have to be scrapped. On the other hand, plastic can be reused multiple considering it has retained its actual property. Industries usually crush old plastic into pallets and use the same for molding new parts. In fact, nowadays it became a standard practice to use 10-20% recycled plastic to mold new parts. This percentage is more if the application does not require too much strength and accuracy. Most of the china products that you see in the town use more than 50 % recycled plastic and that the reason they are cheap

5.More material options

In metals options are limited and sometimes you end up choosing a metal which is costly. But you ignore that as your application needs that. On the other hand, plastic has many material options to choose from. If you are not happy with one type of plastic, you can mix it with other plastic and mold your parts. So you have the option of mixing many types of plastics which is not possible in the case of metals.

6.Plastics weights less

If you need a part to weigh less for certain applications like aircrafts then plastic is the material industry chooses. As I said before that aircraft uses more than 50% plastic parts due to the lightweight of those parts. Less weight can also give benefits to logistics. The transportation cost of sourcing plastics is cheaper. On top of that handling cost is also low as we don’t need an expensive process to safeguard those parts.

7.Inventory Management

It became a trend nowadays in the industry to combine multiple parts into one. Either convert metal to plastic or combine multiple plastic parts into one. In both ways, the industry gets a major benefit. When they convert multiple plastic parts into a single part, they face less hurdle for inventory management. As there are fewer parts, less headache for managing the inventory.

8.Faster production

Plastic can be molded much quickly than the fabrication of those parts in metals. On top of that if you multi-cavity mold the production rate is much faster. Personally, I have seen industries manufacture thousands of plastic parts in a minute which is kind of a dream if the same part is made in plastic.

9.Chemical Resistance.

One of the major problems with metals is rusting unless you use an expensive coating or some expensive metals. But plastic is not prone to rust and usually provide resistance to many chemical reactions such as oxidations.

10. No secondary operation

Most of the metal parts need to go for a second operation to get the finished parts. Plastic parts hardly need any expensive secondary operation as the finished part is molded in a single shot. However, you might need to remove some excess materials which are usually very cheap.

Now let’s talk about the disadvantages of using plastics.

Limited heat resistance

No matter what type of plastic you use, it can’t offer the same level of heat resistance metal offers. That is the reason plastic is not used in an application where heat resistance is a concern like engine parts.

Limited structural strength

Some applications like heavy machinery, building materials where structural strength is a major criterion of choosing a material, plastic finds no place and plastic cant offer that level of strength that metal offers.

Let’s Wrap Up!

Plastic is the future. Researches and innovations are going on to use plastic in many applications. Though it has some limitations over metals in many applications but in coming years that also will be eliminated.

That all I have in this article. If you have any queries please do write in the comment section and I will be happy to answer. If you find this article helpful please rate us five stars.


A 2004 batch Mechanical Engineering graduate From NIT, Agartala. Close to 16 years of experience in the field of consumer electronics and appliances domain as a Sr. Design Engineer and Team Leader in India and the United States. A GD&T practitioner, with expertise in Lean Manufacturing and Six Sigma. Crazy about exploring CAD-CAM tools and in his free time love to go for a ride with his champ, Rian.