Get your Tailor-Made Solution for Platic Extrusion

Plastic extrusion is a method of creating continuous, uniform shapes from plastic beads, pellets or granules known for its efficiency and flexibility. It creates uniform profiles, whether simple shapes or more complex forms. By means of a shaping die, they are given different cross sections. The continuous shape can then be cut to create various forms for a wide variety of industries, such as pipes and small structural parts for construction, or plastic sheets or films for food packaging. The process of preparing the plastic for extrusion takes place under vacuum, ensuring both high product quality and the safe removal of all potentially hazardous gases and vapors.

In the first process step, raw material, usually in the form of plastic granules of varying sizes, is fed into an extruder via the feed hopper. A rotating screw then pushes the granules forward through the length of the extruder’s heated barrel.

The barrel is kept continuously under vacuum to degas the molten plastic in a process known as vacuum melt degassing. As the plastic melts, it releases various gases and vapors, causing bubbles to form. The vacuum pump gently draws these bubbles out of the plastic melt and removes all the air, vapor and gas released as it moves towards the shaping die. Without vacuum, these bubbles would create defects in the cooled plastic and therefore impact the quality of the product. Vacuum melt degassing solves this problem. It leaves behind a high-quality product without voids or other imperfections. Additionally, the gases that are released can be harmful to both human health and the environment. Extracting them at this stage with the vacuum pump allows them to be captured and disposed of appropriately, rather than being released into the ambient air.

When the homogenous molten mass reaches the end of the extruder, it is pushed evenly through a die. This is a thick metal disk that has an opening in a particular shape. By forcing the melt through the die, it takes on the cross-sectional shape of the opening in one continuous length. This can be complex, as in profile extrusion, or create simple shapes such as sheets, films, or strands.

A cooling system cools the extruded plastic, which sets, retaining its new form. It can then be cut, rolled or coiled as required.

There is a wide variety of materials that can be used for plastic extrusion processes. These materials can be grouped in three categories:

Yes, a wide range of other materials apart from plastic can also be extruded. Extrusion is commonly employed in the food industry to produce a variety of goods, such as pasta, sweets, and breakfast cereals, as well as pet and animal feed. Beyond food, extrusion is also utilized to manufacture goods made from rubber, metals, clay, and ceramics. This versatility makes extrusion a valuable process in various industries for creating complex shapes and uniform goods.

Thanks to its versatility and efficiency, plastic extrusion is used in a wide range of industries. The following are typical products:

Extrusion is a process that is perfectly suited to high-volume production. As it is by definition a continuous process, plastic profiles, tubes, sheets, or other shapes can be produced in high quantities without any impact on quality.

Plastic extrusion is often used in combination with other plastic production methods. For example, an extruded sheet may later be thermoformed. However, where different methods are possible, there are several advantages to the plastic extrusion process.

Plastic extrusion is ideal for high-volume manufacturing processes to create long continuous profiles, which can later be cut. As this method results in cross sections rather than three- dimensional shapes, these can nonetheless be quite complex. The extrusion process is faster than processes such as thermoforming or injection molding, where each shape must be formed individually. It creates less waste than thermoforming and injection molding, as the final profiles do not need to be trimmed. Any waste that is produced, such as misshapen parts at the very end of a run, can be immediately returned to the machine and reused.

Due to its nature, plastic extrusion can have serious environmental impacts if not carried out correctly. The gases released when the plastic is melted can be hazardous to the environment. However, vacuum pumps from Busch can ensure that these can be captured and processed appropriately.

In addition, the energy efficiency of our vacuum pumps makes your application more environmentally friendly. The integrated variable speed drive in our PLASTEX units can save you up to 50% in energy costs compared to vacuum pumps without – and therefore lower the carbon footprint of your whole manufacturing process. Plastic extrusion as a process also has the advantage that very little waste is produced. Furthermore, any unused plastic, or any trimmings from the end of a run, can be fed directly back into the machine and reused in the next process.

There are several vacuum pumps from Busch that are ideal for extrusion processes. The PLASTEX degassing unit from Busch is an all-in-one solution for plastic extrusion degassing. Consisting of a MINK dry claw vacuum pump, a separator and integrated control unit, these units are highly energy efficient.

For profile extrusion, DOLPHIN liquid ring vacuum pumps and MINK dry claw vacuum pumps are the best choice. Both are tailored to meet the demanding needs of the degassing application. With its dry technology, the MINK has the additional advantage that no operating fluid is required, saving on water costs and ensuring that there is nothing for the extracted gases to react with.

Whatever your process, we have the right vacuum solution. Contact us to discuss the specific needs of your application – our vacuum experts are happy to advise you.

Vacuum solutions from Busch are used in plastic extrusion processes throughout the world. Three such examples are in Germany, and all use MINK vacuum pumps.

Bada AG was one of the first companies to use the new MINK claw vacuum technology back in 2001. It produces technical thermoplastics for various industries, such as medical technology, electronics and household goods. It has five extrusion lines, and still uses MINK technology to this day.

At CompraXX GmbH, Busch technology degasses the plastic melt as the company develops and produces innovative plastic compounds for its customers.

PolyComp GmbH produces complex engineering plastics. Here too, MINK vacuum pumps degas the extruder lines.