Plastic extrusions are formed similarly to the way injection molded plastics are formed, although extrusions are formed through an open die. Plastic resins such as PVC, acrylic, polypropylene or ABS are fed through a hopper into the extruding barrel, which shears and melts the resin, pushing it through the open die to form a profile or shape.
Preferred Plastics, Inc. open_in_new
Location: Plainwell, MI
Preferred Plastics is an ISO 9001:2000-certified custom plastic extruder, specializing in rigid, flexible & co-extruded products, including extruded tubing. Preferred offers a wide range of secondary & in-line services, including cutting, drilling, punching, routing, stamping and more. By choosing preferred plastics as your custom extrusion manufacture you will be relying on someone you can trust!
FABEXCO open_in_new
Location: Modesto, CA
Our profile extrusion capabilities are vast and adaptable to meet your specific needs. Whether you require rigid, flexible, dual, or tri-profile extrusions, we have the expertise and technology to deliver. We are dedicated to pushing the boundaries of what's possible in plastic extrusion, and we welcome the opportunity to tackle even the most challenging projects.
Plastic Extrusion Technologies open_in_new
Location: Middlefield, OH
At Plastic Extrusion Technologies, we specialize in the production of extruded plastics, catering to both large-scale manufacturing needs and smaller custom projects, all tailored to your precise specifications. We understand the importance of high-quality products, prompt delivery, and responsive service in today's fast-paced business landscape, and we are committed to meeting these expectations.
Absolute Custom Extrusions open_in_new
Location: Milwaukee, WI
We have a long history of providing plastic extrusions. We will proudly serve you and we are committed to quality customer service. Our plastic extrusions are used in industries ranging from automotive to medical. These units are optimized for design, performance and quality. From pre-prototype to post production, we do it all. Please visit our website for more information!
Pexco open_in_new
Location: Johns Creek, GA
As our name suggests, we are a leading custom extruder of plastic shrink tubing, flexible and rigid tubing, and profiles in standard or custom colors in a multitude of material options. We use state-of-the-art machinery for our extrusions and perform secondary operations on site, such as drilling, slotting, notching, etc. Pexco is ISO 9001 certified.
Northland Plastics, Inc. open_in_new
Location: Sheboygan, WI
At Northland Plastics, we are the experts in unique custom plastic extrusions. We specialize in single and dual durometer profile extrusions, vacuum calibration, automated inline fabrication, custom fabrication, and more. Custom colors and various additives are also available. As an ISO 9001:2015 company, we value product quality, timely delivery, competitive pricing, and excellent customer service above all else. Contact Northland Plastics today for all your extrusion needs!
Petro Extrusion Technologies, Inc. open_in_new
Location: Middlesex, NJ
Petro specializes in plastic extrusions, offering our customers many capabilities, such as customized shapes & extruded tubing, along with tape application, coiling & angle cutting. We have a full staff of engineers who can assist you & ship out stock products within 24 hours of your order. At Petro, we take extreme pride in our service & quality. We will deliver a product on time – every time.
Polytec Plastics, Inc. open_in_new
Location: St. Charles, IL
We develop the most affordable and long lasting plastic extrusions. These extruded materials come in a variety of options and are Polytec Q-1 certified. We offer fast delivery and our customer service team is willing to design a perfect solution for your industry. If you are concerned about your budget then rest assured that our products are affordable. Please visit our website for more information!
Keller Products open_in_new
Location: Manchester, NH
Since our founding more than 55 years ago, we at Keller have been the most innovative thinkers in the plastic profile extrusion industry. Our continued investment in new technology continues to pay off for our company and our customers; we are able to offer programs that eliminate tooling costs, we offer stocking and inventory programs and we can provide concept to tooling in less than five days.
GSH Industries, Inc. open_in_new
Location: Strongsville, OH
At GSH we know plastic, rubber and aluminum extrusions. We do tubing, injection, plastic, aluminum and rubber fabrication. We serve a variety of industries with our products, including automotive, consumer, electrical and marine. We know plastic extrusions! Come to us for superior customer service, product knowledge, on-time delivery and competitive pricing!
This profile is immediately immersed in cold water to set the plastic; the profile is extruded continuously, passing through the die, through cold water tanks and onto a sawing table, where pre-specified lengths are cut.
Extruded plastics may be manufactured to meet the specifications for a broad range of niche applications, including but not limited to building trim, window and door sealants, vinyl siding, PVC pipe and surgical tubing. Plastic sheets and flexible plastic sheet rolls are also formed through extrusion, being pulled and stretched instead of cooled after the melted plastic exits the die; flexible plastic sheets are rolled through a series of large calenders before being rolled onto a tube.
Applications
Manufacturers create plastic extrusions in order to fabricate an extremely wide variety of parts, products and shapes.
Plastic extrusion is a process that plays an important role in many industries, such as automotive, food and beverage, chemical processing, plumbing, HVAC, electronics, industrial water treatment and many commercial industries.
Products Produced
Manufacturers mold plastic pallets into an array of shapes, including: profiles, PVC channels, plastic strips, and plastic tubing. They use shapes like these to create a wide range of finished products, such as: engine components, auto exterior trim (decorative or functional), electronic housings, fencing, window frames, wire insulation, deck railings, plastic films, thermoplastic coatings and more.
History
Plastic extrusion has been in use since the early 19th century, when a few different inventors contributed to its rise. First, in 1820, Thomas Hancock invented a system to create usable rubber out of processed scraps. He called this a rubber masticator. Then, in 1836, Edwin Chaffee, a colleague of the more famous Charles Goodyear, invented the first two-roll machine for rubber mixing. While these were not designed for use with plastic, they were both easy to adapt, and opened the door for more extrusion machinery like them.
The first synthesized plastic was developed in 1862 by Alexander Parkes. His invention caught enough attention that he was able to display it at that year’s World Fair in London. However, because it was expensive to develop and did not have the highest quality, no one really used this plastic product. The first practical man-made plastic was celluloid. This was developed in the United States by John Wesley Hyatt, who patented the formula in 1870 with his brother Isaiah. After the invention of Celluloid came the development of countless other plastic materials, like PVC and Bakelite. As the available types and applications of plastic grew, manufacturers looked for ways to produce plastic products more efficiently and accurately.
Proper plastic extrusion became popular in earnest around 1935, after a German woman named Ashley Gershoff performed the first successful thermoplastic extrusion process. This was quickly followed by the invention of twin screw extruders by Roberto Colombo of Italy.
Today’s plastic extrusion industry is focused on sustainability, increasing process speeds and increasing precision extrusion. Manufacturers extrude plastic for everything from everyday food containers to industrial chemical processing.
Materials Process
Plastic extrusions are chosen for their various qualities, like how they react or do not react to certain chemicals or their level of transparency. Sometimes, an application requires qualities of more than one material, in which case, engineers may mix two plastics together using coextrusion.
The list of plastics available for plastic extrusion services is quite long. It includes, among others: low density polyethylene (LDPE), high density polyethylene (HDPE), vinyl, polypropylene, polystyrene, butyrate and PETG.
LDPE
LDPE, or low-density polyethylene, is durable and flexible. This plastic is also highly resistant to many substances, including a variety of esters, alcohols, bases and acids.
HDPE
Like LDPE, HDPE, or high-density polyethylene, is durable. It is also corrosion resistant, solvent resistant, with a high strength-to-weight ratio and a high tensile strength.
Vinyl
Vinyl, also known as PVC (polyvinyl chloride), is an extremely popular polymer. It is available as flexible PVC or rigid PVC. It offers the qualities of: insulation, salt resistance, acid resistance, corrosion resistance, base resistance, fat resistance and alcohol resistance. Unfortunately, unless it features a stabilizing additive, vinyl is not very thermally stable. Some of the most common PVC extrusions include: siding, pipes, floor coverings, angles and tubing.
Polypropylene
Polypropylene is another extremely popular polymer. It is thermally resistant, acid resistant, base resistant and chemical solvent resistant. It also has low density.
Polystyrene
Polystyrene is a polymer available in many different forms, including foam. Polystyrene is inexpensive, but because it so slowly degrades, it creates a lot of litter. Nevertheless, it is popular for use as packaging, containers and plastic cutlery.
Butyrate
Butyrate, derived from cellulose, is strong, tough and rigid. On top of that, it has high impact strength and superior dimensional stability. This plastic, which is transparent, is even easy to extrude.
PETG
PETG, or polyethylene terephthalate glycol-modified, is best known as polyester. Polyester is lightweight, strong and impact resistant. If treated, it can also serve as an alcohol barrier, a gas barrier and somewhat of a moisture barrier. it may be extruded into rigid or semi-rigid parts.
Process Details
While output speeds and operating temperatures may vary depending on properties of the material, the basic principles of plastic extrusion remain standardized.
Even though the plastic extrusion process is continuous, it can be divided into number of steps, for the sake of understanding.
1. Extruded plastics begin their journey as a collection of raw plastic materials (pre-processed plastic grains or resin specifically for extruding), suspended above a conveyance channel in a hopper. Sometimes, to equip specific properties like UV resistance and color to the product, these granules will have been mixed with chemical supplements before reaching the hopper.
2. Then, after the bottom of the hopper retracts or is removed, the granules fall directly into the channel via gravity, without any additional mechanisms.
3. As the raw material reaches the barrel, a long shearing screw, which rotates at certain RPM, pushes the beads forward in to the heated chamber.
There are two ways the plastic is melted:
a. by passing the raw material through the heating zones
b. by the friction and pressure that the raw material encounters
With the combination of the two heating actions, the material steadily reaches the melting point. For some applications, there is no need for heating zones when heat produced by friction is enough to melt the plastic.
4. When the molten plastic reaches the barrel end, the release is regulated by a break plate, which performs three functions, removing impurities by a screen, creating back pressure and straightening the plastic.
5. Next, the molten plastic encounters a die, which gives shape to the profile. Any imaginable plastic profile extrusion can be created with this process, as long as the profile is continuous.
6. The next step involves cooling the product under a controlled environment, so that stress points do not disorient the shape. The most common ways include bathing the product in water. In some more sophisticated methods, a vacuum is created during the bath, and for some requirements, cooling rolls are used.
7. After the extruded plastic is cooled it can be cut and prepared for shipment or sent on for additional processing like: painting, labeling, anti-static treatment or other surface treatment.
Design
During the design phase of plastic extrusion, manufacturers must think about a number of different factors. These include: material, process, die size and die shape. They make these decisions based on application specifications and requirements, such as production volume, tolerances, anticipated stresses, color requests, etc.
Because materials and dies are so easily modified, manufacturers offer almost unlimited custom plastic extrusion services. They can design and manufacturer extrusions with custom colors, thicknesses, textures, harnesses and more.
Machinery Used
Plastic extrusion tooling involves a plastic extruder and dies. In addition, extrusion equipment sometimes involves heat regulating equipment.
Extruder Machine
Typically, the extruding machine is made of a hopper, a conveyance channel and a shearing screw.
Die
A plastic extrusion die is a metal plate with a custom-shaped hole in it, through which plastic is forced and formed into a usable product. When the plastic comes out on the other side of the die, it can officially be called extruded plastic material.
Die shape depends on the application. For example, for sheet extrusion, manufacturers will use flat dies.
Heat Regulating Equipment
Regulating heat is the most important factor in the manufacturing process, overheating can degrade the polymer chemical structure. That’s why manufacturers often use heat regulating equipment. This ranges from fans to special heating regulating jackets.
Variations and Similar Processes
Cold Extrusion
Cold extrusion is an extrusion process during which the plastic material is processed below the recrystallization temperature, around room temperature. Aside from this, the cold extrusion line runs about the same the hot extrusion line.
Coextrusion
During coextrusion, manufacturers use multiple extruders on the extrusion line to make one piece. In doing so, they are able to mix two or more layers of different plastic resin types together and create a product with qualities from both. The different extruders melt their respective resins at the same time, then deliver them to a forked conveyance channel, where they all meet and mingle. They are extruded using a single die.
Blow Film Extrusion
Blow film extrusion, similar to blow molding, is the method used to make plastic films like shopping bags. This extrusion process makes use of a cylindrical die with an annular opening and an air outlet. Molten plastic exits the extruder barrel, where it encounters sets of rolls. The rolls pull the material, thereby changing its thickness. After this, the resin enters the die, where the air outlet blows air into it until the material spreads out and takes on the die’s cylindrical profile. After this, the plastic is cooled, usually by a cooling ring.
Plastic Injection Molding
Plastic injection molding is quite similar to plastic extrusion. In fact, plastic extrusion is considered a subtype of injection molding. During this process, manufacturers melt plastic pellets in a hopper, then inject them into two hollow cavities. These hollow cavities are then clamped together and held there under pressure. This helps join the molten plastic. Then, manufacturers allow the plastic shape to cool and harden. Once it’s solid, they separate the two halves of the mold and eject the new plastic part. Plastic injection molding is useful when you want to create tight tolerances. It is also great for high volume runs.
Benefits
Plastic extrusion is extremely popular, and for good reason. Its many benefits include: versatility, flexibility (both literally and figuratively), efficiency, affordability and formability. What’s more, the plastic extrusion process creates very little waste. This is because any leftover plastic can simply be gathered up, melted down and used again. Also, because plastic extrusions remain hot for a while after removal from the extrusion machine, manufacturers can make post-extrusion changes.
Things to Consider
If you’re considering a plastic extrusion, you need the assistance of a quality manufacturer. More than that, you need the assistance of the right quality manufacturer. The right manufacturer is one will meet all your needs, including your delivery preferences, delivery timeline, budget and custom requests. To help you on your way, we’ve provided you with the profiles of several industry leading plastic extrusion companies. Check them out to find the right one for you. Good luck!
