What Is Plastic Extrusion: A Definitive Process Guide (2023)

Plastics are everywhere because of their versatility, longevity, and simpler manufacturing requirements. Plastic extrusion, along with injection molding, is one of the most common processes for high-volume production. Generally, extrusion is common for continuous profiles that use pipes, tubes, door profiles, and other bulky items.

Industrial applications of plastic extrusionstarted over a century ago and continued to advance with time. Even today, it is the go-to method for many plastic manufacturingprojects because its simple, efficient, and delivers accurate results.

The following text takes a look at the basics of the plastic extrusion process. Its advantages, limitations, types, and finally the common applications across different industries.

An Overview of Plastic Extrusion

Plastic extrusionis a process where granular pieces of plastics go through different components of the extruder to end up in a continuous profile with the help of heat and pressure. To understand the process better, it’s important to first understand the extruder and how it works.

What Is Plastic Extrusion: A Definitive Process Guide (1)

The above picture is a common plastic extruderthat has the following components:

  • Hopper:This is the first stage of the plastic extruder. Hopper stores the plastic in granulates and keeps it ready for the next stage of the process.
  • Feedthroat:The feed throat directs the coming plastic from the hopper towards the barrel.
  • Breaker Plate:This component acts as a filter for the barrel and helps maintain the pressure
  • Barrel:This is a heated component that softens the plastic and takes it close to the melting point. Moreover, the rotating screw in the barrel forces the material to the feed pipe.
  • Feed pipe:Acts as a conduit for the molten plastic coming from the barrel
  • Die:This is the rigid metal part through which the material is pushed to get the desired profile.
  • Cooling System:Finally, the last stage where the extrusion profile solidifies through rapid cooling.

How Does Plastic Extrusion Work?

The plastic extrusion processbegins with filling the hopper with smaller plastic pieces that are simpler to process. The feed throat uses gravity to transfer that plastic to the barrel for further processing.

When the material enters the barrel, it starts to be warmed by means of at least three intensity zones, where the temperature intensity increases as you move away from the feed throat.

As the temperature increases, the barrel uses a continuously rotating screw to push the molten plastic towards the next component of the machine. The screw and pressure additionally create heat, so the intensity zones themselves don’t need to be basically as hot as the expected extrusion temperature, thereby saving energy and facilitating the extrusion process.

The liquid plastic leaves the barrel through a screen supported by the breaker plate. This screen eliminates foreign substances from the material and maintains the internal pressure. The material goes through a feed pipe into the uniquely fabricated die, which has the same shape as the extrusion profile you want from the project.

At the point when constrained through the die, the molten material creates the same shape as the die opening, which completes the extrusion process.

When completely through the die, the extrusion profile is cooled in a water shower or by means of a bunch of cooling rolls to ensure that the shape of your thermoplastic extrusion profile becomes permanent.

Plastic Extrusion Through the History

Extrusion has always been a high-volume manufacturing process. It started in Germany when Paul Troester created the first plastic extruder. Since then the fundamentals of the process haven’t changed much.

However, there is a lot of improvement in the process when it comes to its efficiency and material handling capabilities. In the past, extrusion machines could only handle specific types of plastics and had many requirements. With time, this improved, and today, plastic extrusionis more versatile, flexible, and capable of handling different kinds of plastics together.

Another common problem with extruded plastics is the fact that they don’t possess the right mechanical properties and strength. This was a significant problem in the past but new developments in technology improved things. Today, custom plastic extrusionis the go-to process of choice as it delivers the quality, consistency, and functionality you expect from modern industrial applications.

Different Types of Plastic Extrusion Processes

The type of extrusion process you deal with depends on the die shape. While the fundamental process of plastic extrusionremains the same, the different types of processes allow you to efficiently deal with the complexities and intricacies of dealing with different shapes.

Here are the 4 main types of plastic extrusion processes that the industries use today.

1 – Tubing Extrusion

This process is for long tubes, pipes, and other similar items. Generally, processing hollow equipment becomes more difficult. Despite this, this extrusion process remains the same till you reach the die. At that stage, the process uses positive internal pressure to overcome the higher power requirements of dealing with hollow parts.

What Is Plastic Extrusion: A Definitive Process Guide (2)

2 – Blow Film Extrusion

The blow film extrusionprocess is quite common as it creates many everyday items like shopping bags and other packaging materials. Once again, the process is just like any other type of extrusion (like the aluminum extrusion process). However, the main difference is in the die stage where the material goes through cooling before leaving the die.

What Is Plastic Extrusion: A Definitive Process Guide (3)

At that stage, the material doesn’t solidify completely. That’s why it later goes through an additional process of expansion through blowing. The process is only limited to thinner plastic films. For thicker sheets, you’ll have to go through some other process.

3 – Sheet Film Extrusion

This process is very similar to the aforementioned blow film extrusion. However, it’s for workpieces that are too thick for blowing. In that case, the material goes through a pulling and rolling process to get the shape you need.

What Is Plastic Extrusion: A Definitive Process Guide (4)

The rolling process also cools down the plastic and allows it to solidify permanently. Generally, this process allows you to create ice cream boxes, juice cartons, wine boxes, and other thicker plastic packaging easily.

4 – Over Jacket Extrusion

The next type of extrusion is for insulation wires and other similar applications where you cover something entirely with plastic. The process is simple. You pull the material that needs the coating through the die to give it a plastic cover.

What Is Plastic Extrusion: A Definitive Process Guide (5)

Depending on your requirements and application, you might need adhesion between the plastic and the material as well. In that case, all you need to do is to use pressure tooling. This simple addition applies enough pressure on the material to offer excellent adhesion that lasts for a long time.

Types of Plastic Extruders

If you are thinking of investing in a plastic extruder, you’ll have the option of going with either a single screw or twin-screw extruder. Both devices have the same capability to perform all the processes discussed before. However, the type of extruder can affect your production speed, mixing capability, and overall flexibility of operations.

Here are the details of what each kind of extruder brings to the table.

Single Screw Extruder

As their name suggests, single-screw extruders are simple contraptions with one rotating screw in the barrel. Generally, single-screw extruders are ideal for situations where you need simple profiles like pipes and sheets. While single screw machines work quite well, they are a bit slow, don’t mix well, and may not be the best choice for any complicated shape.

What Is Plastic Extrusion: A Definitive Process Guide (6)

Twin Screw Extruders

As their names suggest, twin-screw extruders have parallel screws in the barrel. Depending on the application, the twin screws can rotate in the same direction or different ones. Because of their design, twin-screw extruders offer greater stability, exhaust performance, speed, and mixing performance.

What Is Plastic Extrusion: A Definitive Process Guide (7)

Advantages of Plastic extrusion

Extrusion is a popular high-volume production method that offers the perfect combination of versatility, flexibility, and consistency. Here are some of the main advantages of the extrusion process for plastic.

  • Cost-Effectiveness:When compared with other processes, extrusion is quite cost-effective. Generally, plastic parts are developed with either injection molding service or extrusion. However, extrusion doesn’t have elaborate tooling requirements and is much simpler, resulting in lower costs. Moreover, extrusion machines can also run continuously without any breaks, which offers 24-hour manufacturing to reduce the chances of inventory shortages.
  • Unparalleled Flexibility:As long as there is a consistent cross-section, you can create any shape or profile with the plastic extrusion process. From complex shapes to sheets, pipes, and other products, extrusion can deliver almost all kinds o designs.
  • Alterations:Before the cooling process, hot plastic remains quite malleable. This means that you can easily perform other shaping operations to make sure that the final product is of the size you need.

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The Main Applications of Plastic Extrusion

As one of the main methods of creating plastic parts, the overall applications of the extrusion process are too widespread. However, the following are some of the most prominent areas where plastic extrusion technologiesplay an integral part.

Pipes and Tubes

Pipes and tubes are among the most common plastic extrusion products. The die requirements are also the simplest as the only thing you need is a simple cylindrical profile. PVC pipes are also extremely common in the industry but you can find other alternatives as well. Whatever material you use, there are high chances that pipes and tubes went through plastic extrusion.

What Is Plastic Extrusion: A Definitive Process Guide (8)

Wire Insulation

Plastics naturally have excellent electric insulation properties. Moreover, their natural flexibility and thermal stability make them a perfect choice for insulating live wires and jacketing. Generally, most jacketing and insulation work uses the extrusion process as it’s the easiest and offers long-lasting results.


Window frames are another common application of extruded plastics. Many people use PVC for that purpose because it lasts a long time and has a natural resistance to UV radiation from the Sun.


Just like the windows, door frames are another common application of extrusion because of their continuous profile and constant cross-section. Once again, PVC is quite popular when it comes to door frames and other household fittings because of its stability and superior mechanical characteristics.

Blinds and Shades

This is another classic example of how common extrusion is. Blinds and shades often have multiple identical slots that combine for functionality. Extrusion of Polystyrene, a popular plastic choice can give you the faux-wooden look that you often see in common blinds.

Cleaning Equipment

Wipers, squeegees, and other cleaning equipment use plastics for their handles. Some products even have a rubber-like plastic that offers better cleaning and you need extrusion to create them in high volumes.

RapidDirect: The Best Choice for Quality Plastic extrusionServices

Plastic extrusionis a common choice because of its relative simplicity, cost-effectiveness, and versatility. However, that doesn’t mean that anyone can get started with the process. The extrusion technologies have multiple pre-requisites, design requirements, and other important considerations that ensure consistent results. Moreover, you also need to invest in multiple types of equipment and other setups to get started.

For small to medium businesses, investing so much time and resources is impractical. For them, a comprehensive and experience extrusion service like RapidDirect is the best choice.

At RapidDirect, we aim to be more than just a simple service provider. We are a one-stop shop for all your manufacturing needs starting from the designing phase to the optimization. We have the latest machinery and the most experienced team to deliver the best combination of quality, reliability, and performance in the shortest time possible.

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One thing that sets RapidDirect apart is the complete online quotation platform. We have the most advanced system that delivers you an immediate quotation for your project.

Simply add your designs and other specifications for the project and we will get back to you with the expected costs to get started. Not only that, but we also offer a free Design for manufacturing (DFM) report to help you optimize your design and streamline the entire process for the best results.

Bonus: Plastic vs Aluminum Extrusion

Extrusion is not limited to plastics only. You can use the process for metal parts with a continuous profile as well. Generally, Aluminum is one of the most common metals that goes through the extrusion process because of the material’s strength, density, recyclability, and other mechanical characteristics.

Today, Aluminum extrusion is a common manufacturing process that creates products like bars, tracks, pipes, heatsinks, and numerous other items. Generally, the requirement of your material having a continuous profile and an even cross-section holds true in the case of Aluminum as well.

Moreover, an important distinction between the plastic extrusion processand Aluminum extrusion is the temperature.

Unlike plastics, Aluminum extrusion can be both hot and cold. Cold extrusion generally delivers materials with high strength but requires more power. Contrarily, hot extrusion takes place between 350oC to 500oC, which becomes easier to process but at an expense of the mechanical properties.


What Is Plastic Extrusion: A Definitive Process Guide? ›

Plastics extrusion is a normally high volume manufacturing process where a polymer material, enriched with the desired additives, is melted and formed in a continuous process. The raw material (polymer) in the form of granulates, is gravity fed into the hopper and through the feed throat, drops on a rotating screw.

What are the 5 steps of extrusion? ›

The processes include material preparation, preprocessing, extruding, cutting, and reforming. The porous products can be obtained after drying, pre-sintering, and sintering of the extruded green body. It is an effective way to produce a long porous tube with a small diameter.

What is the importance of plastic extrusion? ›

Money saver: plastic sheet extrusion is efficient and also low cost. It is considered the most economical manufacturing option for plastic products. Plastic extrusion machines operate continually which reduces time wasting and allows for 24-hour manufacturing.

What does a plastic extrusion engineer do? ›

An extrusion engineer develops and evaluates the extrusion process for a manufacturing company. Your duties in this career are to support the production and engineering needs through the set-up and operation of the extrusion equipment and processes.

What is the process of extrusion? ›

Extrusion is a process where a material undergoes plastic deformation by the application of a force causing that material to flow through an orifice or die. The material adopts the cross-sectional profile of the die and if the material has suitable properties, that shape is retained in the final extrudate.

What are the two types of extrusion processes? ›

There are different types of extrusion processes, however, including cold, hot, friction and micro.
  • Cold Extrusion. With cold extrusion, metal is forced through the die while at or near room temperature. ...
  • Hot Extrusion. ...
  • Friction Extrusion. ...
  • Micro Extrusion.
Jan 18, 2019

What are the principles of extrusion? ›

Q: What is the principle of extrusion? Ans: The principle of extrusion is the process of forcing a material through a die or nozzle to produce a specific shape or cross-sectional profile. This is done by applying pressure to the material, typically using a screw or ram, which pushes it through the die or nozzle.

What is the disadvantage of plastic extrusion? ›

Disadvantages of extrusion
  • Variations in size of product.
  • Product limitations because of only one type of cross section can be obtained at a time.
  • High initial cost setup.
Aug 25, 2018

What are the common defects in plastic extrusion? ›

The defects, or rejects, from an extrusion run may be named by such terms as: voids in extrudate, contamination, degradation, granules/nibs in the output, gassing, color distribution or poor surface finish on the output.

What is the difference between plastic extrusion and injection molding? ›

Simply put, the EXTRUSION process is required to create continuous linear, two-dimensional shapes. INJECTION MOLDING produces three-dimensional shapes that do not remain constant in a parallel line.

What is the highest salary of plastic engineering? ›

Highest salary that a Plastic Engineer can earn is ₹5.1 Lakhs per year (₹42.5k per month).

What is the job description of extrusion worker? ›

As an extrusion machine operator, your primary responsibilities are to monitor the use and maintenance of the industrial equipment in a factory. Your day-to-day duties include performing maintenance, preparing machinery for use, and running the controls in compliance with current occupational regulations.

What are the responsibilities of extrusion manager? ›

In this position, your duties include ensuring safety during production, and your primary responsibilities revolve around working to plan, schedule and provide a budget or price quotes for the creation of a product or components.

Why is the extrusion process important? ›

Extrusion enables mass production of food via a continuous, efficient system that ensures uniformity of the final product. Food products manufactured using extrusion usually have a high starch content.

What is the conclusion of the extrusion process? ›

One benefit of an extrusion process is that this ratio can be very large while still producing quality parts. This process has the ability to create very complex cross-sections and to work with brittle materials. This is because the material only faces compressive and shear stresses.

What are 3 products made by extrusion? ›

Extrusion produces items such as pipe/tubing, weatherstripping, fencing, deck railings, window frames, plastic films and sheeting, thermoplastic coatings, and wire insulation.

What is the most common type of extrusion? ›

Direct extrusion, also known as forward extrusion, is the most common extrusion process. It works by placing the billet in a heavy walled container. The billet is pushed through the die by a ram or screw.

What machines are used in extrusion process? ›

Plastic Extruding Machine Types

There are three basic types of plastic extrusion machinery: single screw, multiple screw, and ram extruders.

What is the most important property for a material for successful extrusion? ›

For successful extrusion to happen the metal should be plastic. Plasticity: Plasticity is the ability of a material to undergo some degree of permanent deformation without rupture or failure.

What are the 3 types of extruders? ›

Extruders may be divided into three general types :
  • Single Screw Extruder.
  • Twin or Multiple Screw Extruder.
  • Ram Extruder.

What is the formula for extrusion? ›

The total extrusion pressure (p) in MPa for the above process is related to extrusion ratio (r) as σ p = K s σ m [ 0.8 + 1.5 l n ( r ) + 2 l d 0 ] where σm, is the mean flow strength of the billet material in MPa, l is the portion of the billet length remaining to be extruded in mm, d0 is the initial diameter of the ...

What are the limitations of extrusion? ›

Disadvantages: Low surface finish due to scale formation on extruded part. Increase die wear. High maintenance required.

How does plastic extrusion process work? ›

Plastics extrusion is a normally high volume manufacturing process where a polymer material, enriched with the desired additives, is melted and formed in a continuous process. The raw material (polymer) in the form of granulates, is gravity fed into the hopper and through the feed throat, drops on a rotating screw.

Which material is not suitable for extrusion process? ›

1 Answer. The best explanation: Extrusion process is not suitable for any of the iron alloys, neither is it suitable for iron metal. For extruding stainless steel or other non-ferrous alloys or steel alloys, extrusion process can be used.

What are two defects that are usually present in extruded products? ›

The common defects in extrusion process are: Improper System Engineering/Installation, Improper Operation, Resin Defects, Improper Materials Addition, Surging, Poor mixing, Melt toughness or fracture, Overheating, Moisture release, Trapped air, Contamination.

What causes bubbles in plastic extrusion? ›

The bubbles are due to air entrapped in rough substrates, whereas the voids origin can be entrained moisture or outgases in extrusion, too rapid cooling or improper flow.

How can extrusion defects be prevented? ›

Increase the temperatures especially in the compression zone. Check the zone temperature resistance. If there are any crosslinked particles on the surface, reduce the screw rpm and the zone temperatures in order to prevent degradation.

What is the hardest plastic for injection molding? ›

Polycarbonate (PC): Polycarbonate is a transparent thermoplastic that offers some of the strongest, most shatter-resistant construction available for plastic injection molded products.

Is plastic extrusion safe? ›

The plastic extrusion process can be extremely dangerous if employees are untrained or unprotected, however, with the right training and protective gear, organisations can ensure the health and safety of all those employees working with extrusion machines.

Is extrusion cheaper than injection molding? ›

Meanwhile, The extrusion process is less costly upfront, with tooling costs 80% to 90% less than injection molding, but slightly more expensive over time as it produces parts at a more medium cost per part.

Who is the highest paid Engineer in the world? ›

Petroleum Engineers

Which Engineer has the most money? ›

Top 10 Highest Paying Engineering Jobs of 2022
  1. Environmental Engineer. ...
  2. Biomedical Engineer. ...
  3. Systems Engineer. ...
  4. Electrical Engineer. ...
  5. Chemical Engineer. ...
  6. Big Data Engineer. ...
  7. Nuclear Engineer. ...
  8. Aerospace Engineer.
Mar 24, 2023

What type of Engineer makes the most money? ›

What are the Highest Paying Engineering Jobs?
  • #1 Engineering Manager. Median Salary: $144,830. ...
  • #2 Computer Hardware Engineer. Median Salary: $117,220. ...
  • #3 Aerospace Engineer. Median Salary: $116,500. ...
  • #4 Nuclear Engineer. ...
  • #5 Chemical Engineer. ...
  • #6 Electrical & Electronics Engineer. ...
  • #7 Construction Manager. ...
  • #8 Materials Engineer.

What is one example of an extrusion? ›

Examples of extrusion include pasta, pipes, window panes, gears, many snack foods, aluminum cans, railings, shower stalls, and windshield wipers.

Is extrusion cold working? ›

Cold extrusion can also be defined as the process of shaping of a cold metal by striking a slug. This striking is done with a punch (in closed cavity), which forces the metal in upward direction around the punch. This process is also called Cold Forging, Cold Pressing, Extrusion Pressing, and Impact Extrusion.

What is a extruder assistant? ›

The Assistant Extruder Operator is responsible for assisting the Operator in the operating the Extruder, to fabricate corrugated plastic sheets according to specified gages and dimensions in order to maintain the company's goal of 100% on time delivery to our customers.

What is extrusion supervisor? ›

The Production Supervisor oversees all shifts of extrusion production ensuring safety procedures are followed, products are on-schedule and within specified quality standards.

What is a synonym for extrusion? ›

synonyms: bulge, bump, excrescence, gibbosity, gibbousness, hump, jut, prominence, protrusion, protuberance, swelling.

How do you improve extrusion process? ›

Tips for Improving Extrusion Efficiency and Preventing Problems
  1. Adjust feed throat temperature. ...
  2. Maintain a consistent regrind form. ...
  3. Cool screws when processing polymers to minimize degradation.
Apr 19, 2012

Which of the following is a disadvantage of extrusion? ›

Disadvantage – Product Limitations

The nature of the extrusion molding process places limits on the kinds of products it can manufacture. For example, plastic soda bottles narrow at one end to accommodate a cap, which normal extrusion molding cannot achieve.

What are the characteristics of extrusion process? ›

Key features
  • Extrusion is a low-cost process due to reduced wastage and has a high rate of production.
  • It can form brittle materials as it applies only compressive and shear forces on the billet.
  • The resultant products have an excellent elongated grain structure in the material direction.
Jan 18, 2021

What is the process of metal extrusion? ›

Metal extrusion is a forming process in which we force a metal (either hot or cold) through a die. This imparts the die shape to the extruded metal as it passes through the cavity. The material emerging from the die is known as “extrudate”. The metal endures compressive and shear stress to achieve the die shape.

What are the examples of extrusion process? ›

Examples of extrusion include pasta, pipes, window panes, gears, many snack foods, aluminum cans, railings, shower stalls, and windshield wipers.

What are the main steps in Aluminium extrusion process? ›

The 6 Steps of Aluminum Extrusion
  • Step 1: Preheating the aluminum billet and steel die to a specified temperature. ...
  • Step 2: Loading the billet into the steel extrusion press container. ...
  • Step 3: Extrusion. ...
  • Step 4: Controlled cooling. ...
  • Step 5: Stretching. ...
  • Step 6: Cutting and final packaging.
Dec 27, 2021

Which of the following is true about the extrusion process? ›

3. Which of the following is true about the extrusion process? Explanation: No time is lost in changing the shape as the dies may be readily removed in the process of extrusion.

What are the classification of extrusion? ›

Extrusion is classified in general into four types. They are: Direct extrusion, indirect extrusion, impact extrusion and hydrostatic extrusion. In extrusion process, the billet is placed in a container, pushed through the die opening using a ram and dummy block. Both ram and billet move.

What is basic extrusion in plastic? ›

Plastics extrusion is a normally high volume manufacturing process where a polymer material, enriched with the desired additives, is melted and formed in a continuous process. The raw material (polymer) in the form of granulates, is gravity fed into the hopper and through the feed throat, drops on a rotating screw.

What are the disadvantages of plastic extrusion? ›

Disadvantages of extrusion
  • Variations in size of product.
  • Product limitations because of only one type of cross section can be obtained at a time.
  • High initial cost setup.
Aug 25, 2018

What is extrusion in simple words? ›

Meaning of extrusion in English

the process of forming something by forcing or pushing it out, especially through a small opening: Volcanic activity resulted in the extrusion of a lava sheet.

What is the disadvantage of extrusion? ›

Expansion – Once the extruded product is removed from the extruder, it will remain hot and expand (this is also called die swell). This is a disadvantage, as expansion rates are unpredictable, and the product may not come out as expected.

What is a good extrusion ratio? ›

Normally acceptable extrusion ratios for hard alloys are limited to 35:1 and for soft alloys, it is 100:1. The normal extrusion ratio range for hard alloys is from 10:1 to 35:1, and for soft alloys is 10:1 to 100:1.

What is the method of preparation of extruded products? ›

In extrusion process, hydration of starches and proteins (structure formers) takes place due to heat and shear. Starch and protein are turned into melt where droplets of water are entrapped and thereby hydrated. Coating: The flavouring of extruded products follows a similar pattern to colouring.

What is the difference between aluminum and extrusion? ›

You might find yourself asking, “What is the difference between extruding and casting of aluminum?” Extrusion is a process by which aluminum billets are forced through a die, resulting in a desired cross section. Whereas, casting is a process in which molten aluminum is poured into a mold and then allowed to solidify.


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